Biomechanical Analysis of Alleged Abusive HeadTrauma Involving an Infant
I. ASSIGNMENT AND SCOPE
II. QUALIFICATIONS
III. MATERIALS REVIEWED
IV. SUMMARY OF BIOMECHANICAL OPINIONS
V. RELEVANT CLINICAL AND INVESTIGATIVE CHRONOLOGY
A. PRECEDING RESPIRATORY ILLNESS
B. DECEMBER 23 ACUTE PRESENTATION
C. DECEMBER 23 CT
D. DECEMBER 25 BRAIN MRI
E. DECEMBER 27 CERVICAL MRI
F. SKELETAL IMAGING AND EVOLUTION OF THE FINDINGS
G. BIOMECHANICAL SIGNIFICANCE OF THE CLINICAL AND INVESTIGATIVE CHRONOLOGY
VI. MEDICAL AND EXPERT PREDICATES
VII. BIOMECHANICAL PRINCIPLES AND METHODOLOGY
VIII. PUBLISHED BIOMECHANICAL LITERATURE
IX. APPLICATION TO THE ALLEGED EVENT
A. DESCRIPTION OF THE ALLEGED SHAKING EVENT
B. CASE-SPECIFIC RECONSTRUCTION
X. CERVICAL-SPINE CONSIDERATIONS
XI. SUBDURAL HEMORRHAGE AND TIMING
XII. RETINAL HEMORRHAGES
XIII. OTHER INTRACRANIAL AND NEUROLOGICAL FINDINGS
XIV. RSV, HYPOXIA, AND SEIZURE ACTIVITY
XV. BESS AND SUBDURAL COLLECTIONS
XVI. CHRONIC SUBDURAL HEMORRHAGE AND REBLEEDING
XVII. SKELETAL FINDINGS
XVIII. EVIDENCE AND SCIENTIFIC LITERATURE CONSIDERED IN FORMING MY BIOMECHANICAL OPINIONS
XIX. EVOLUTION AND CHARACTERIZATION OF THE EVIDENTIARY RECORD
XX. DISTINGUISHING OCCURRENCE FROM MECHANICAL SEVERITY
XXI. MEDICAL FINDINGS AND BIOMECHANICAL RECONSTRUCTION.
XXII. LIMITATIONS OF THIS ANALYSIS
XXIII. FINAL OPINIONS AND CONCLUSIONS
CASE-SPECIFIC BIOMECHANICAL OPINION
QUANTITATIVE RECONSTRUCTION
MEANING OF MR. GILMORE'S STATEMENTS
CAPACITY OF VIGOROUS SHAKING TO PRODUCE MECHANICAL LOADING AND INJURY
APPLICATION OF PUBLISHED EXPERIMENTAL AND COMPUTATIONAL STUDIES
INJURY-THRESHOLD OPINION
CERVICAL-SPINE OPINION
SKELETAL-IMAGING OPINION
MEDICAL FINDINGS AND MECHANICAL QUANTIFICATION
TEMPORAL RELATIONSHIP
ALTERNATIVE MEDICAL CAUSATION
ULTIMATE BIOMECHANICAL OPINION
XXIV. REFERENCES
I. ASSIGNMENT AND SCOPE
The New Mexico Law Offices of the Public Defender retained me to provide a biomechanical
analysis regarding the allegations involving the infant Jahseen S. Torres.
My assignment is to evaluate, within the limits of my education, training, experience, and the
available evidence.
the mechanical characteristics associated with vigorous or violent shaking
the extent to which the alleged event can be biomechanically reconstructed
the relevance and limitations of published literature on physical surrogates, computational models, finite elements, animal studies, and injury thresholds;
whether the available evidence permits a reliable quantitative comparison of the alleged event with the proposed injury thresholds;
the biomechanical significance, if any, of the cervical spine findings
what the medical and imaging findings can and cannot establish about the mechanical characteristics of the alleged event; and
whether the case-specific biomechanical evidence establishes that Mr. Gilmore subjected Jahseen to an injury-producing episode of violent shaking.
My role is not to independently diagnose the cause, age, or pathological significance of the reported subdural hemorrhages, retinal hemorrhages, diffusion abnormalities, microhemorrhagic findings,seizures, encephalopathy, possible benign enlargement of the subarachnoid spaces (BESS), skeletal abnormalities, or other medical findings.
Those questions involve pediatric medicine, pediatric radiology, neuroradiology, neurology,
ophthalmology, neuropathology, and related specialties. When such findings are relevant, I consider them medical or imaging predicates documented in the records or expressed by appropriately
qualified experts.
I do not offer an independent medical diagnosis of whether Jahseen sustained abusive head trauma (AHT), nor do I offer an opinion on Mr. Gilmore's guilt, innocence, intent, or credibility. My opinions address the mechanical evidence, the biomechanical literature, and what that evidence does and does not establish regarding the alleged violent-shaking mechanism.
A behavioral description such as 'shaking' is not a quantitative biomechanical measurement. To quantitatively reconstruct a shaking event, information is typically needed on amplitude, frequency, duration, number of cycles, direction, linear and angular acceleration, angular velocity, head excursion, cervical posture and loading, torso restraint, grip characteristics, and whether impact occurred. I did not measure those variables in this case.
II. QUALIFICATIONS
I am a Licensed Doctor of Chiropractic with more than forty years of clinical and professional experience in the spine, musculoskeletal system, soft-tissue injuries, injury mechanisms, and biomechanical analysis.
I am a Fellow of the American Academy of Spinal Biomechanical Engineering and a Diplomate of the American Academy of Pain Management. My professional education and continuing study have focused on spinal biomechanics, soft-tissue injuries, cervical injury mechanisms, acceleration deceleration trauma, and the evaluation of mechanical loading.
My curriculum vitae, previously provided, more fully describes my education, training, professional experience, publications, and qualifications and is incorporated herein by reference.
My opinions in this report are limited to matters within my professional scope. I am not a pediatrician, pediatric neurologist, pediatric neurosurgeon, neuroradiologist, pediatric radiologist, ophthalmologist, or neuropathologist, and I do not offer independent opinions reserved for those specialties.
III. MATERIALS REVIEWED
In preparing my opinions, I reviewed materials, including but not limited to:
Presbyterian Hospital medical records;
University of New Mexico Hospital and related medical records;
Early Intervention records;
Bernalillo County Sheriff's Office and Special Victims Unit investigative materials, including Detective Isaac Medina's incident report and interview documentation;
Children, Youth and Families Department records;
available radiology reports and imaging interpretations;
State exhibits and investigative materials;
pretrial interviews and/or expert materials involving Dr. Roland Auer, Dr. James Botros, Dr. Leslie Strickler, Dr. Kris Sperry, Dr. Shana Nisenbaum, Dr. Isaac Medina, Dr. Allison Richards, and other individuals identified in the case materials;
The reported statements and history concerning the events surrounding Jahseen's presentation; my May 8, 2026 report; and the peer-reviewed scientific literature cited in this revised report
The fact that I reviewed an opinion, record, interview, or publication does not mean I adopt every conclusion expressed therein. I reserve the right to supplement or amend my opinions if materially new information becomes available.
IV. SUMMARY OF BIOMECHANICAL OPINIONS
1. Within the limits of biomechanical analysis and to a reasonable degree of professional probability within my field, the available case-specific evidence does not permit a reliable quantitative reconstruction of the shaking described in the investigative record. Consequently, it does not permit a reliable biomechanical determination that the described exposure was quantitatively sufficient to constitute an injury-producing episode of violent shaking.
2. The principal event-specific mechanical variables necessary for reconstruction—including amplitude, frequency, duration, number of cycles, head excursion, angular velocity, angular acceleration, cervical loading, torso restraint, and other relevant characteristics—were not measured and cannot reliably be derived from qualitative descriptions alone.
3. The term “shaking,” even when used in a witness description or admission, does not establish mechanical severity. Mr. Gilmore's reported words—including “kind of shaking him”—are qualitative descriptions of shaking or movement; they do not quantitatively define the mechanical severity of the alleged exposure.
4. Published biomechanical research demonstrates that vigorous shaking of instrumented infant surrogates can generate substantial mechanical loading, and clinical observations provide evidence that serious injury can occur following shaking under some circumstances.¹˒²˒²¹ I therefore do not offer the opinion that vigorous shaking is mechanically incapable of producing substantial loading or serious injury.
5. Numerical kinematics measured in physical-surrogate experiments, tissue responses predicted by computational models, and observations from separate clinical events cannot be assumed to represent Jahseen's unmeasured mechanical exposure.¹–⁹˒²¹
6. Published systematic reviews identify important limitations in the derivation, scaling, validation, and application of injury criteria used in infant-shaking research.³–⁵ Independently of those limitations, the case-specific exposure was not quantitatively measured; therefore, the evidence does not permit a reliable determination that the alleged exposure either exceeded or remained below a proposed injury threshold.
7. The December 27 cervical MRI was reported to show no cervical cord or ligamentous injury. The absence of identified structural cervical injury is relevant to the overall biomechanical assessment but does not establish that shaking did not occur, that an injury-producing shaking event necessarily would have produced identifiable cervical injury, or that the alleged exposure was mechanically insufficient to cause intracranial injury.
8. The skeletal record evolved materially. Several initially questioned abnormalities were not subsequently confirmed, while the distal left femoral metaphyseal finding remained a documented finding in the medical record. Preliminary concern for multiple possible fractures should not be conflated with the narrower findings ultimately documented after additional imaging and pediatric-radiology review.
9. The reported intracranial, retinal, neurological, and skeletal findings are medically significant but do not themselves provide the event-specific mechanical measurements necessary to quantitatively reconstruct the alleged shaking exposure. I do not work backward from those findings to assign mechanical values that were not independently measured or otherwise established by the case-specific evidence.
10. My biomechanical opinions do not depend upon establishing RSV, hypoxia, seizure activity, BESS, chronic subdural collections, rebleeding, or another medical process as the cause of Jahseen's findings. My ultimate opinion is one of limitation in case-specific biomechanical quantification, not proof of either mechanical sufficiency or insufficiency.
V. RELEVANT CLINICAL AND INVESTIGATIVE CHRONOLOGY
A. Preceding Respiratory Illness
The records document a respiratory illness preceding Jahseen's acute presentation on December 23, 2022. On December 13, Jahseen tested positive for respiratory syncytial virus (RSV), and on December 21, he was re-evaluated for a viral illness. These records establish that a documented illness was present immediately before the acute presentation.
I consider this history part of the case's overall clinical chronology and factual context. I do not independently determine whether RSV caused or contributed to any neurological, radiological, or ophthalmological findings, as those are medical determinations outside the scope of my biomechanical expertise.
From a biomechanical standpoint, the preceding illness neither establishes nor excludes a traumatic mechanism. It is relevant because my analysis must distinguish the documented clinical history from what, on biomechanical grounds, can be attributed to the alleged shaking event. A preceding illness does not provide the event-specific mechanical information—such as magnitude, frequency, duration, number of cycles, head motion, or acceleration—needed to reconstruct or quantify the alleged shaking exposure.
Accordingly, I consider the preceding respiratory illness part of the complete chronology, but I do not rely on RSV as an alternative explanation for Jahseen's findings.
B. December 23 Acute Presentation
On December 23, emergency personnel responded to an acute episode marked by reported seizurelike activity, severe hypoxia, vomiting, and decreased responsiveness. Oxygen saturation was reportedly around 50%, and midazolam (Versed) was administered.
I consider these findings important for establishing the clinical chronology and the circumstances surrounding Jahseen's acute deterioration. I do not independently determine the medical cause of the seizure-like activity, hypoxia, vomiting, or decreased responsiveness, nor do I attribute those findings to a specific traumatic or nontraumatic mechanism.
From a biomechanical standpoint, the acute presentation indicates when Jahseen became clinically symptomatic and required emergency medical attention; it does not, by itself, establish the nature, magnitude, or timing of a preceding mechanical exposure. I therefore refer to December 23 as the date of the acute clinical presentation and do not assume that it necessarily represents the date on which every subsequently identified finding originated.
C. December 23 CT
The head CT obtained on December 23 was reported to show no acute intracranial hemorrhage or skull fracture. I accept the reported interpretation and do not independently reinterpret the CT.
From a biomechanical standpoint, this imaging result does not establish whether a specific mechanical event occurred, nor does it provide information about the magnitude or characteristics of any alleged shaking exposure. Similarly, the absence of acute intracranial hemorrhage reported on the December 23 CT, standing alone, does not permit me to determine when the subdural collections subsequently identified on MRI originated.
I therefore consider the December 23 CT part of the imaging chronology, without using it to establish or exclude the alleged shaking mechanism
D. December 25 Brain MRI
The December 25 brain MRI was reported to show bilateral subdural hemorrhagic collections, micro hemorrhagic findings, and areas of diffusion restriction. I accept these findings as reported and do not independently interpret the MRI or determine their pathological cause, precise age, or relationship to a specific event.
These findings are relevant to my analysis because they represent the intracranial abnormalities for which a mechanical explanation has been proposed. However, their presence alone does not provide the event-specific mechanical information needed to reconstruct the alleged shaking exposure. The MRI does not tell me the amplitude, frequency, duration, number of cycles, angular velocity, angular acceleration, head excursion, torso restraint, or other mechanical characteristics of the alleged event.
Accordingly, I consider the MRI findings as part of the medical evidence against which the proposed mechanism must be compared; I do not treat the findings themselves as a measure of the mechanical exposure that produced them.
E. December 27 Cervical MRI
The December 27 cervical MRI was reported to show no cervical cord or ligamentous injury. I accept that interpretation and do not independently reinterpret the MRI.
This finding is relevant to my biomechanical analysis because the cervical spine serves as the mechanical link between the torso and the head and necessarily transmits forces and motion during rapid flexion-extension of the head and neck. Experimental infant-surrogate shaking has demonstrated substantial cervical flexion and extension during vigorous shaking.¹
Davison et al. (2022) also examined the potential significance of cervical loading, analyzing pediatric-surrogate automotive crash and sled-test data and finding that cervical tensile injury criteria were exceeded more often than the selected closed-head injury criterion under the inertial loading conditions studied.¹⁰ The authors concluded that their findings supported the greater vulnerability of the pediatric cervical spine to inertial loading under those experimental conditions.
The absence of reported cervical cord or ligamentous injury in Jahseen is part of the biomechanical evidence I considered. It provides no affirmative evidence of structural cervical injury. Its absence does not, however, establish that shaking did not occur, does not establish that an injury-producing shaking event necessarily would have produced identifiable cervical structural injury, and does not permit the magnitude of the alleged exposure to be quantified.
Because the actual forces, accelerations, duration, number of cycles, and other characteristics of the alleged shaking are unknown, I do not use the cervical MRI to classify the alleged exposure as mechanically sufficient or insufficient to produce the intracranial findings.
F. Skeletal Imaging and Evolution of the Findings
The initial skeletal evaluation raised concern for several possible metaphyseal injuries. A pediatric radiologist did not interpret the initial images; a pediatric radiologist later reviewed them.
That subsequent evaluation materially narrowed the initial skeletal findings. Abnormalities initially noted at the distal left radius and the proximal and distal left humerus were not subsequently confirmed as fractures. The distal left femoral finding was handled differently, with additional dedicated knee views supporting a metaphyseal corner finding at that location. On the later repeat skeletal survey, no acute or healing fractures were identified, and the previously noted distal left femoral finding was no longer visible and was interpreted as likely reflecting interval healing.
Accordingly, the preliminary concern for multiple possible skeletal injuries should be distinguished from the findings ultimately documented after additional imaging and pediatric-radiology review. I reply on the radiologic interpretations in the medical record and do not independently interpret the radiographs, determine the medical cause of the distal femoral finding, or provide a pediatric radiology diagnosis.
From a biomechanical standpoint, neither the initially suspected skeletal abnormalities nor the subsequently documented distal femoral finding provides the event-specific mechanical information required to reconstruct the alleged shaking event. Therefore, I do not rely on the skeletal findings to establish or exclude an injury-producing shaking mechanism.
G. Biomechanical Significance of the Clinical and Investigative Chronology
The foregoing chronology outlines the clinical, imaging, and investigative findings that provide the factual context for my biomechanical analysis. I consider these findings because a biomechanical assessment must account for the available evidence relevant to the proposed mechanism while remaining within the limits of what that evidence can establish mechanically.
A medical finding that may be consistent with a proposed mechanism is not, by itself, a measurement of the mechanical exposure that produced it. Findings such as subdural hemorrhage, retinal hemorrhage, neurological abnormalities, skeletal findings, or the absence of cervical structural injury must therefore be distinguished from measurements of the forces and motions associated with the alleged event.
In this case, the available evidence does not establish the amplitude, frequency, duration, number of cycles, angular velocity, angular acceleration, head excursion, cervical loading, torso restraint, grip characteristics, or other event-specific mechanical variables necessary to reconstruct the alleged shaking exposure. The medical findings and clinical chronology are relevant to my analysis, but they do not provide those missing mechanical variables.
Accordingly, I do not use the medical findings themselves to infer or reconstruct an otherwise unmeasured mechanical exposure. My role is to evaluate whether the available case-specific evidence supports a reliable biomechanical determination of the alleged mechanism and the magnitude of the associated mechanical exposure.
VI. MEDICAL AND EXPERT PREDICATES
The medical experts whose opinions I reviewed have not reached identical conclusions regarding the significance, timing, and potential etiology of Jahseen's clinical, radiologic, ophthalmologic, neurological, and skeletal findings. Those differences are important to the present analysis because biomechanical reconstruction should not begin by assuming that a disputed medical interpretation independently establishes the magnitude or characteristics of an alleged mechanical event.
Dr. James Botros (Pediatric Neurosurgeon) reportedly characterized the subdural collections as chronic and approximately three to four weeks old. I consider that an attributed medical opinion and do not independently adopt or reject that dating. Published neuroradiologic literature recognizes the limitations of assigning a precise age to subdural collections based solely on imaging appearance and cautions against treating imaging characteristics as a precise temporal marker.¹¹ I cite that literature not to independently date Jahseen's collections, but to explain why uncertainty about their timing is relevant to biomechanical reconstruction. If the medical evidence does not reliably establish when a finding originated, biomechanics cannot supply that missing temporal relationship by retrospectively assuming that the finding resulted from a particular mechanical event on December 23.
Dr. Roland Auer (Neuropathologist) attributed significance to Jahseen's preceding respiratory illness, severe hypoxia, and seizure activity, and advanced alternative pathophysiological explanations for aspects of the presentation. I have considered those opinions but do not independently adopt his conclusions regarding medical causation. Published literature recognizes that RSV can, although uncommonly, be associated with neurological complications, including seizures and encephalopathic presentations.¹⁶ Conversely, published studies examining retinal hemorrhage following seizures generally indicate that retinal hemorrhage is uncommon following convulsions alone.¹²⁻¹⁵ I therefore do not cite these subjects as establishing an alternative medical cause for Jahseen's findings. Rather, they show that clinicians must evaluate the clinical circumstances medically and should not convert a biomechanical analysis into assumptions about the magnitude or characteristics of an alleged shaking event.
Dr. Leslie Strickler (Child-abuse pediatrician, a UNM professor of pediatrics, and Medical Director of CART) expressed a more qualified view regarding the significance of RSV and the seizure presentation. Her discussion of the skeletal imaging also distinguished upper-extremity abnormalities that were considered nontraumatic or not confirmed from the distal left femoral metaphyseal finding. I have incorporated that distinction because the biomechanical analysis should be based on the findings ultimately documented in the record rather than on preliminary abnormalities that were subsequently narrowed or not confirmed. I do not independently diagnose, exclude, or determine the cause of a fracture.
Dr. Kris Sperry (Forensic Pathologist) raised benign enlargement of the subarachnoid spaces (BESS) as a potential differential consideration. According to the materials I reviewed, Dr. Sperry had not personally reviewed the relevant imaging when expressing that consideration. I have reviewed the imaging materials made available to me in this matter, together with the corresponding radiology reports and opinions of the medical and radiologic experts. Nevertheless, I do not independently diagnose BESS, as that determination falls outside the scope of my biomechanical opinions.
BESS is, however, a recognized medical condition discussed in the pediatric literature in relation to subdural collections.¹⁷˒¹⁸ That literature does not establish BESS as the explanation for Jahseen's findings, nor does the presence of BESS exclude abuse or eliminate the need for an appropriate medical evaluation.¹⁷˒¹⁸ I cite this literature only to establish that BESS is a recognized medical consideration rather than a biomechanical theory I have created or independently diagnosed. My biomechanical opinions do not depend upon BESS being present.
Dr. Shana Nisenbaum (Treating physician at Presbyterian Hospital) and Issac Medina (Lead Investigator at Bernalillo County Sheriff’s Office) expressed concerns about the precision with which intracranial findings could be temporally assigned. Those concerns are relevant to my analysis and are consistent with published literature cautioning against overly precise age determination of subdural collections based solely on imaging characteristics.¹¹ I do not independently date the intracranial findings. From a biomechanical standpoint, however, if the medical evidence does not reliably establish a precise temporal relationship between a finding and the alleged event, biomechanics cannot legitimately supply that missing relationship by working backward from the finding and assuming a particular magnitude, duration, or mechanism of loading.
The scientific literature discussed above is not offered to resolve competing medical opinions or establish an alternative medical diagnosis. Its purpose is narrower. It demonstrates that several of the issues raised by the medical experts, including the temporal interpretation of subdural collections, neurological complications associated with respiratory illness, the relationship between seizures and retinal hemorrhage, and BESS in the setting of subdural collections, are recognized topics of medical investigation and scientific literature. Where that literature contains limitations, disagreement, or evidence contrary to a proposed explanation, I have considered those limitations as well.
For my purposes, the significance of these medical predicates is not which medical explanation ultimately proves correct. Rather, their significance is that biomechanical reconstruction cannot resolve a disputed medical diagnosis by assuming that a particular medical finding establishes the mechanical event that produced it. A medical finding may be consistent with a proposed mechanism without measuring the forces, motions, duration, or other mechanical characteristics of that event.
I consider these medical opinions and the related literature as premises for, rather than conclusions of, my biomechanical analysis. I do not independently resolve disagreements in pediatrics, neuroradiology, ophthalmology, neurology, neuropathology, or medical pathophysiology, nor do I offer an independent medical diagnosis of abusive head trauma or an alternative medical condition. Importantly, my biomechanical opinions do not depend on any one of these medical explanations being correct.
My analysis addresses a narrower question: whether the available case-specific evidence provides a scientifically reliable basis for reconstructing the mechanical severity of the shaking described in the investigative record and for determining that it constituted a quantitatively sufficient injury-producing episode of violent shaking. The medical findings, expert opinions, and scientific literature are relevant to that analysis, but they do not, on their own, provide measurements of the alleged event's acceleration, angular velocity, frequency, amplitude, duration, number of cycles, head excursion, cervical loading, or other event-specific mechanical parameters.
Accordingly, medically significant findings should not be treated as a quantitative reconstruction of the alleged event that produced them. Conversely, the inability to reconstruct the event biomechanically does not establish that shaking did not occur or that vigorous shaking cannot injure an infant. It defines the limits of what can reliably be concluded biomechanically from the evidence available in this case.
VII. BIOMECHANICAL PRINCIPLES AND METHODOLOGY
Biomechanical reconstruction requires characterizing the exposure under analysis. In a shaking
allegation, relevant variables may include:
amplitude of movement;
frequency;
duration;
number of cycles;
direction and plane of motion;
head excursion;
linear acceleration;
angular acceleration;
angular velocity;
location and movement of the center of rotation;
cervical flexion and extension;
torso movement or restraint;
grip and support conditions;
contact between the head and torso;
external impact, if any; and
the mechanical and anatomical properties of the subject.
The present record contains no instrumented measurements of the alleged event and does not provide sufficient information to reliably reconstruct the variables.
A qualitative description cannot be converted into a unique set of quantitative kinematics without assumptions. Making such assumptions and then comparing the resulting values with published
injury criteria would create an appearance of numerical precision that the evidence does not support. My methodology is therefore not to invent missing mechanical values. It is to identify what the available evidence permits and what it does not.
VIII. PUBLISHED BIOMECHANICAL LITERATURE
The scientific literature on infant shaking includes physical surrogate experiments, computational and finite-element models, animal models, and systematic reviews. These approaches provide important information on head kinematics, tissue response, and potential injury mechanisms, but they differ substantially in experimental design, model construction, input conditions, assumptions, scaling methods, validation, and injury criteria.³⁻⁵ The most recent systematic review identified ongoing limitations in translating results from animal, physical, and mathematical models to human infants, including reliance on scaled adult or animal injury thresholds and material properties, and the use of simplified shaking inputs.⁵
Jenny et al. used an instrumented infant surrogate with improved biofidelity and measured substantial angular acceleration and angular velocity during vigorous surrogate shaking.¹ The authors reported higher angular acceleration and angular velocity than in earlier infant-surrogate shaking experiments.¹ A subsequently published correction removed three references due to concerns about their immediate relevance to the accompanying text and renumbered the remaining references. The correction did not report any change to the experimentally measured kinematic results.¹
Stray-Pedersen et al. likewise used an instrumented infant surrogate during violent shaking and measured substantial centripetal forces and changes in tangential acceleration. The authors proposed that these loading characteristics may help explain mechanisms relevant to subdural hemorrhage.² That study provides useful information on the surrogate's mechanical behavior under the tested shaking conditions; it does not establish that the same mechanical exposure occurred in Jahseen.
Couper and Albermani used finite-element modeling to evaluate the infant brain's mechanical response to shaking-induced loading.⁶ Roth et al. similarly used finite-element analysis to examine simulated impact and shaking conditions.⁷ These studies provide information on predicted tissue responses given specified model inputs, material properties, assumptions, and boundary conditions. They do not measure the mechanical exposure Jahseen experienced.
Schiks et al. demonstrated that head kinematics during surrogate shaking are materially influenced by changes in the location of the head's center of rotation over time.⁸ Animal models provide additional information on biological and tissue responses to imposed loading, but their translation to human infant shaking remains uncertain.⁹ The most recent systematic review specifically noted that the extent to which the animal models reviewed accurately represent inflicted shaking trauma in human infants remains unknown.⁵
Systematic reviews have identified important limitations in applying published injury thresholds and model results to infant shaking.³⁻⁵ Schiks et al. reported that many injury thresholds used in shaking assessments were derived from loading conditions that did not adequately replicate the duration and repetitive characteristics of shaking, and that commonly used scaling methods for translating adult injury thresholds to infants lacked validation.³ The more recent Hutchinson review likewise identified continued reliance on scaled adult or animal data and simplified shaking inputs, and emphasized the need for more accurate shaking inputs and validated injury thresholds applicable to shaking.⁵
These limitations do not support the conclusion that vigorous shaking cannot injure an infant. Rather, they limit how far numerical accelerations, tissue responses, or injury thresholds derived from a particular surrogate experiment, animal study, or computational model can be applied directly to an individual case without corresponding case-specific mechanical data. Accordingly, I use this literature to understand the mechanics and potential consequences of vigorous shaking, but I do not assume the loading conditions created experimentally or computationally were the same as those Jahseen experienced.
IX. APPLICATION TO THE ALLEGED EVENT
A. Description of the Alleged Shaking Event
The investigative record contains statements attributed to Mr. Gilmore regarding Jahseen's movement while Mr. Gilmore attempted to elicit a response during an episode of unresponsiveness. Detective Medina's report quotes Mr. Gilmore as saying he 'started tapping on him and stuff' and then 'kind of shaking him.' The report further describes Mr. Gilmore as shaking Jahseen 'a little more' until Jahseen cried and later characterizes Mr. Gilmore's account as describing a 'gentle shake' intended to elicit a response.
Mr. Gilmore also reportedly stated, after being questioned about the medical findings, 'I probably was a little too aggressive with him and caused injuries to him, and that's what happened.' I have considered that statement. From a biomechanical standpoint, neither 'a little too aggressive' nor an individual's attribution of injury to his own actions provides the mechanical measurements needed to determine the magnitude of the exposure or whether a particular injury threshold was reached. I recognize that an individual's qualitative description of shaking may constitute evidence that some shaking or movement occurred and may be relevant to the broader medical and investigative assessment. From a biomechanical standpoint, however, qualitative descriptions such as “kind of shaking,” “a little more,” “gentle shake,” or “a little too aggressive” do not quantify mechanical exposure.
Such descriptions do not establish the amplitude, frequency, duration, number of cycles, angular velocity, angular acceleration, head excursion, cervical loading, torso restraint, grip characteristics, or other event-specific variables necessary to characterize the shaking biomechanically. Nor does an individual's later belief that his actions may have caused injury to provide those measurements.
Accordingly, I do not interpret Mr. Gilmore's qualitative description of shaking as an assumption that the event had the magnitude or kinematic characteristics observed during vigorous laboratory surrogate shaking. “Violent shaking,” as applied to this alleged event, is therefore not a measured biomechanical description. Whether the event reached a mechanically significant level must be evaluated based on the available case-specific evidence rather than inferred from the terminology used to describe it.
B. Case-Specific Reconstruction
The available case-specific evidence does not establish the amplitude, frequency, duration, number of cycles, direction of motion, head excursion, angular velocity, angular acceleration, torso restraint, cervical position and loading, grip characteristics, or other mechanical variables necessary to quantitatively reconstruct the shaking described in the investigative record.
Published biomechanical studies nevertheless provide useful information regarding what can occur under particular experimental or modeled shaking conditions. Jenny et al.¹ and Stray-Pedersen et al.² measured head kinematics during vigorous shaking of instrumented infant surrogates. Couper and Albermani⁶ and Roth et al.⁷ used computational or finite-element models to estimate tissue responses under specified loading conditions. These studies inform the mechanics and potential consequences of vigorous shaking, but their experimental or modeled inputs and outputs are not measurements of the exposure Jahseen experienced.
An additional limitation concerns the injury criteria used to interpret biomechanical models. Systematic reviews have reported that many injury thresholds applied in infant-shaking analyses were derived from adult or animal data and then scaled or extrapolated to infants.³˒⁴ The 2020 systematic review by Schiks et al. found that the loading conditions underlying many of these thresholds did not adequately reproduce the duration and repetitive characteristics of shaking and that methods used to scale adult injury thresholds to infants generally had not been validated for that purpose.³ A more recent systematic review by Hutchinson et al. similarly reported that the injury thresholds and material properties used in the reviewed models were based on scaled adult or animal data, and that shaking motions used as model inputs were often substantially simplified. The authors identified a continuing need for more accurate shaking inputs and validated injury thresholds applicable to shaking.⁵
More recent experimental work also demonstrates that assumptions concerning the mechanics of shaking can materially affect the resulting analysis. Schiks et al. demonstrated that the location of the head's center of rotation changes considerably during surrogate shaking and reported that incorporating this time-varying behavior substantially improved replication of the measured shaking motion. The authors concluded that existing infant-shaking injury-risk assessments and the injury thresholds used in those assessments warrant reevaluation.⁸
These limitations do not establish that vigorous shaking cannot injure an infant, nor do they render biomechanical research on infant shaking without value. Rather, they limit the reliability of taking a numerical acceleration, tissue response, or injury threshold derived from a particular surrogate experiment, animal study, adult-derived criterion, or computational model and applying that value directly to an individual infant whose actual mechanical exposure was not measured.
In this case, no case-specific measurement exists to determine where the alleged exposure would fall relative to those experimental or modeled conditions. Assigning the kinematics measured by Jenny or Stray-Pedersen, or the modeled tissue responses reported by Couper or Roth, to Jahseen would require assumptions about the alleged event that the available evidence does not establish.
Accordingly, I cannot reliably determine from the available case-specific biomechanical evidence that the shaking described in the investigative record reached or failed to reach a particular injury threshold. The scientifically supportable conclusion is narrower: the available evidence does not permit a reliable quantitative reconstruction of the alleged shaking exposure sufficient to determine its mechanical severity or to classify it biomechanically as an injury-producing episode of violent shaking.
My opinion does not rely upon the proposition that established infant injury thresholds demonstrate that the alleged shaking was mechanically insufficient. Rather, it recognizes both the limitations of presently available injury criteria and models and, independently, the absence of the case-specific mechanical measurements necessary to apply those criteria reliably to this event.
X. CERVICAL-SPINE CONSIDERATIONS
The cervical MRI was reported to show no cervical cord or ligamentous injury. I accept that interpretation and do not independently reinterpret the MRI. Accordingly, the available cervical imaging shows no structural cord or ligamentous injury that independently corroborates structural cervical injury in this case.
The cervical spine is relevant to the biomechanical analysis because it connects the torso and head and transmits forces and motion during rapid head movement. Experimental infant-surrogate shaking has shown substantial head and neck flexion and extension during vigorous shaking. Jenny et al. reported mean peak neck flexion of approximately 113 degrees and mean peak extension of approximately 123 degrees under the vigorous surrogate-shaking conditions they studied.¹
Davison et al. provide additional, although not directly case-specific, information regarding the relationship between inertial head loading and cervical loading.¹⁰ The authors analyzed full-scale automotive crash and deceleration sled tests involving forward-facing 3-year-old pediatric surrogates equipped with head accelerometers and cervical force sensors. Cervical peak-tension injury criteria were exceeded substantially more often than the selected closed-head injury criterion, and in the tests in which the head criterion was exceeded, the cervical tension criterion was also exceeded.¹⁰
These findings support the biomechanical relevance of considering the cervical spine when substantial inertial head loading is proposed. They do not, however, establish that structural cervical injury must occur before intracranial injury during manual infant shaking. The Davison experiments involved 3-year-old automotive surrogates subjected to crash and sled-test loading, not an infant subjected to the particular shaking described in this case. The experimental loading conditions, restraint conditions, surrogate characteristics, and injury criteria therefore cannot be directly assigned to Jahseen.
The absence of reported cervical cord or ligamentous injury in Jahseen is nevertheless part of the biomechanical evidence I considered. It provides no affirmative evidence of structural cervical cord or ligamentous injury. At the same time, the absence of such injury cannot, by itself, establish that shaking did not occur or that the alleged shaking was mechanically insufficient to produce intracranial injury.
Accordingly, my opinion regarding the cervical spine is limited. The available imaging did not identify structural injury to the cervical cord or ligaments. Published biomechanical research demonstrates that substantial head motion can impose substantial loading and excursion on the pediatric cervical spine,¹˒¹⁰ making the cervical findings relevant to the overall mechanical assessment. However, because the actual head motion, cervical loading, duration, number of cycles, torso restraint, and other event-specific mechanical variables in this case were not measured, I do not use either the presence or absence of cervical structural injury as a stand-alone criterion for determining whether the alleged shaking reached an injury-producing level.
XI. SUBDURAL HEMORRHAGE AND TIMING
The December 25 brain MRI was reported to show bilateral subdural hemorrhagic collections. I accept those findings as reported and do not independently interpret the imaging or determine the age, composition, pathological mechanism, or etiology of the collections.
Dr. Botros reportedly characterized the collections as chronic and approximately three to four weeks old. I consider that an attributed medical opinion and do not independently adopt or reject that dating. Other evidence and expert opinions reviewed in this matter do not assign the same degree of temporal precision.
Published neuroradiologic literature recognizes limitations in using the imaging appearance of subdural collections to establish their precise age or chronology. Wittschieber et al. specifically cautioned that mixed-density subdural collections do not, by themselves, establish repeated trauma 23 and that hypodense collections are not synonymous with chronicity.¹¹ This literature does not establish the age of Jahseen's collections or determine their cause; rather, it demonstrates why imaging appearance alone should not be converted into a precise date or sequence of mechanical events.
From a biomechanical standpoint, the presence of a subdural collection is not itself a measure of the mechanical exposure that produced it. The finding does not establish the magnitude or mechanical characteristics of the alleged shaking exposure, or other event-specific mechanical variables necessary to reconstruct an alleged shaking event.
Accordingly, unless the medical evidence independently establishes a sufficiently reliable temporal relationship between the intracranial findings and a particular event, I cannot biomechanically create that relationship by working backward from the finding and assuming the magnitude, timing, or characteristics of an otherwise unmeasured mechanical exposure.
XII. RETINAL HEMORRHAGES
Retinal hemorrhages were reported in Jahseen. I accept that finding as documented but do not independently classify their distribution, severity, retinal layers involved, age, pattern, or etiology. Those determinations fall within the appropriate medical and ophthalmologic specialties.
Sandramouli et al. prospectively examined 33 children after convulsions and identified no retinal hemorrhages.¹² Tyagi et al. similarly examined 32 children younger than two years after convulsions and found no retinal hemorrhages.¹³ Curcoy et al., in a prospective study of 182 infants admitted after a first convulsion, identified retinal hemorrhages in two children; both were subsequently diagnosed as having been abused.¹⁴ Mei-Zahav et al. prospectively evaluated 153 children after convulsive episodes and identified one child with unilateral retinal hemorrhage for which the subsequent investigation did not identify another explanation.¹⁵
Taken together, these studies indicate that retinal hemorrhage after convulsions is uncommon and that **convulsions alone are not well supported in the published literature as a general explanation for retinal hemorrhage in infants and young children.¹²⁻¹⁵ I therefore do not rely on seizure activity, by itself, as an explanation for Jahseen's retinal hemorrhages.
Conversely, I do not independently infer the mechanical characteristics of an alleged shaking event from the presence of retinal hemorrhages. Published medical literature recognizes that the pattern, severity, distribution, and associated findings may be important to the medical and ophthalmologic assessment of retinal hemorrhage. I do not independently make those determinations in this case.
From a biomechanical standpoint, the retinal findings do not establish the magnitude or mechanical characteristics of the alleged shaking exposure, torso restraint, grip characteristics, or other mechanical variables associated with the alleged shaking event. The presence of retinal hemorrhage may be medically relevant to the assessment of a proposed mechanism, but it is not itself a quantitative measurement of that mechanism.
Accordingly, I consider the retinal findings as part of the overall medical evidence but do not use them to calculate or retrospectively assign the mechanical severity of the alleged shaking exposure.
XIII. OTHER INTRACRANIAL AND NEUROLOGICAL FINDINGS
The records include reported microhemorrhagic findings, diffusion restriction, seizure activity, severe hypoxia, and altered responsiveness. I accept these findings as reported but do not independently determine their neurological, neuroradiological, or neuropathological significance or cause.
I do not independently diagnose diffuse axonal injury, traumatic axonal injury, hypoxic-ischemic encephalopathy, or any other neuropathological process. Nor do I use the presence or absence of any particular neurological diagnosis as proof that shaking did or did not occur.
From a biomechanical standpoint, these findings do not identify a unique mechanical exposure or independently establish the magnitude or characteristics of the alleged shaking event. Their medical interpretation may inform diagnosis and causation, but that determination is separate from quantitatively reconstructing an otherwise unmeasured mechanical exposure.
I therefore consider these findings as part of the overall medical evidence without using them to infer mechanical parameters that were not independently measured or otherwise established in the casespecific record.
XIV. RSV, HYPOXIA, AND SEIZURE ACTIVITY
Jahseen had a documented RSV infection preceding the December 23 presentation. The records also document severe hypoxia and seizure-like activity during the acute presentation.
Published medical literature recognizes that RSV, although uncommon, can be associated with neurological complications, including seizures and encephalopathic presentations. Saravanos et al. addressed these complications in a systematic review and aggregated case series.¹⁶
That literature establishes RSV-associated neurological complications as a recognized medical phenomenon; it does not establish that RSV caused or contributed to Jahseen's seizures, intracranial
findings, retinal hemorrhages, diffusion abnormalities, or acute presentation. I do not independently make that medical causation determination.
Dr. Auer attributed substantial significance to the preceding respiratory illness, severe hypoxia, and seizure activity, while Dr. Strickler expressed a more qualified view. I consider those differing medical opinions but do not resolve them independently.
For purposes of my biomechanical analysis, I do not rely on RSV, hypoxia, or seizure activity as an alternative cause of Jahseen's findings. Their relevance is narrower: recognized physiological and medical considerations reinforce the distinction between determining medical causation and reconstructing the magnitude and characteristics of an alleged mechanical event. My biomechanical opinions do not depend on RSV or any of these physiological processes being established as the cause of Jahseen's findings.
XV. BESS AND SUBDURAL COLLECTIONS
Another expert raised BESS as a potential differential consideration. I do not independently diagnose Jahseen with benign enlargement of the subarachnoid spaces (BESS).
Published pediatric literature recognizes an association between BESS and subdural collections. Raissaki et al. emphasized that subdural collections can occur in children with BESS and cautioned that the coexistence of BESS and a subdural collection neither establishes nor safely excludes abuse without appropriate evaluation for concomitant injuries.¹⁷ Hansen et al. similarly reported that BESS can coexist with other findings concerning for injury and supported comprehensive evaluation for abuse.¹⁸
I cite this literature to establish that BESS is a recognized medical consideration in the evaluation of subdural collections, not to establish that Jahseen had BESS or that BESS caused his findings.
I do not rely on BESS as an alternative explanation for Jahseen's findings. From a biomechanical standpoint, whether BESS is present or absent does not establish the magnitude or characteristics of the alleged shaking exposure. My biomechanical opinions therefore do not depend on BESS being present
XVI. CHRONIC SUBDURAL HEMORRHAGE AND REBLEEDING
Rebleeding within a preexisting chronic subdural collection is a recognized radiologic phenomenon.
Wright et al. evaluated radiographically identified rebleeding in children with abusive-head-traumaassociated subdural hemorrhage. Rebleeding occurred within preexisting chronic collections. In the reported rebleeding events, the authors did not identify any new trauma or parenchymal injury, and the events were not typically associated with acute neurological deterioration.¹⁹
These observations establish that radiographic rebleeding can occur within a preexisting chronic subdural collection. They do not establish that such rebleeding occurred in Jahseen or that it caused his December 23 acute presentation. I do not make that medical determination independently.
Feldman et al., studying children classified as having abusive head trauma with acute hemorrhage superimposed on chronic subdural hemorrhage, favored repeated abuse over spontaneous rebleeding as the explanation for most of those findings in the population studied.²⁰ I have considered that literature as well. I do not attribute Jahseen's findings to spontaneous rebleeding.
This literature is less relevant to my biomechanical analysis. The existence of recognized mechanisms by which the appearance and timing of subdural collections may evolve does not establish what occurred in Jahseen. It does, however, reinforce the need to determine the age, evolution, and medical cause of a subdural collection from appropriate medical evidence rather than inferring them biomechanically from an otherwise unmeasured alleged event.
Accordingly, my biomechanical opinions do not depend upon spontaneous rebleeding having occurred.
XVII. SKELETAL FINDINGS
The initial skeletal survey raised concern for several possible metaphyseal injuries. A pediatric radiologist did not interpret those initial images. When a pediatric radiologist subsequently reviewed the imaging, several of the initially suspected abnormalities—including those involving the distal left radius and the proximal and distal left humerus—were not confirmed as fractures.
The distal left femoral finding was managed differently. Additional dedicated knee views supported a metaphyseal corner finding at that location. On the later repeat skeletal survey, no acute or healing fractures were identified, and the previously noted distal left femoral finding was no longer visible and was interpreted as likely having healed during the interval.
Accordingly, the final imaging record differs from the preliminary impression of multiple possible skeletal injuries. Several initially suspected abnormalities were not subsequently confirmed, while the distal left femoral metaphyseal finding remained documented in the medical record.
I do not independently interpret these radiographs, determine the medical cause of the distal femoral finding, or provide a pediatric radiology diagnosis. I rely on the radiologic interpretations in the records. The presence or absence of these skeletal findings, by itself, does not allow me to determine the forces, movements, duration, or other mechanical characteristics of the alleged shaking event.
I therefore do not rely on the absence of skeletal injury to exclude an injury-producing shaking event. Conversely, the distal femoral finding does not establish the mechanical characteristics of the alleged shaking event and does not provide the event-specific information necessary for me to determine, biomechanically, whether that event was sufficient to produce the reported head injuries.
XVIII. EVIDENCE AND SCIENTIFIC LITERATURE CONSIDERED IN FORMING MY BIOMECHANICAL OPINIONS
In forming my biomechanical opinions, I considered the medical findings, investigative information, expert opinions, and scientific literature relevant to the proposed mechanism, including evidence cited by treating physicians and other professionals when evaluating the possibility of abusive head trauma. My consideration of this information should not be interpreted as an independent medical determination that these findings establish or exclude an abusive mechanism of injury.
The information I considered includes:
the reported bilateral subdural hemorrhagic collections;
the reported retinal hemorrhages;
the reported neurological and diffusion abnormalities;
the circumstances surrounding the acute December 23 presentation;
Mr. Gilmore's descriptions of shaking or movement;
concern for nonaccidental trauma documented during the medical evaluation;
the distal left femoral metaphyseal finding;
Mr. Gilmore's statement that he may have been “a little too aggressive” and caused injury; and the differing medical opinions concerning the potential significance of RSV, hypoxia, seizure activity, BESS, chronic subdural collections, and rebleeding in the overall medical presentation.
I have also considered scientific literature demonstrating that vigorous shaking of instrumented infant surrogates can produce substantial head motion, angular velocity, angular acceleration, and other
mechanical loading under the experimental conditions examined.¹˒² I have likewise considered computational and finite-element studies that predict tissue responses given specified model inputs, assumptions, material properties, and boundary conditions.⁶˒⁷ These studies provide useful information on the mechanics and potential consequences of vigorous shaking under the conditions examined; they do not establish the mechanical conditions that occurred in this case.
Systematic reviews further demonstrate important limitations in translating experimental and modeled results into a case-specific determination of injury-producing exposure.³⁻⁵ These limitations include differences in experimental and model design, simplified shaking inputs, model assumptions, validation, scaling methods, and reliance in some analyses on injury criteria or material properties derived from or scaled to adult or animal data.³⁻⁵ Accordingly, numerical accelerations, predicted tissue responses, or injury thresholds derived from a particular experiment or model cannot be assumed to represent the exposure experienced by Jahseen without corresponding case-specific mechanical information.
I have also considered Feldman et al. (2022), who reported a series of infants described as having experienced independently witnessed shaking without identified head impact. Some developed neurological symptoms, including subdural and retinal hemorrhages. The authors concluded that their observations support the proposition that isolated shaking can cause findings associated with abusive head trauma.²¹ I consider this study relevant to the general proposition that shaking without identified impact can be associated with serious injury. It does not provide measurements of the mechanical exposure alleged in this case or establish that the circumstances reported by Feldman et al. were mechanically equivalent to those involving Jahseen.
I therefore do not dispute that vigorous shaking can generate substantial mechanical loading or that injury can occur under certain shaking conditions.¹˒²˒²¹ The biomechanical question in this case is different: whether the available evidence permits the mechanical exposure described in the investigative record to be quantitatively reconstructed and reliably compared with experimental conditions, modeled tissue responses, or proposed injury criteria.
The available case-specific evidence does not establish the amplitude, frequency, duration, number of cycles, angular velocity, angular acceleration, head excursion, cervical loading, torso restraint, grip characteristics, or other mechanical variables required to perform such a quantitative reconstruction. The medical findings themselves do not provide those missing mechanical measurements, and numerical conditions produced in experimental or computational studies cannot substitute for them.
Accordingly, I do not offer an opinion on whether the medical findings establish or exclude abusive head trauma. That determination is outside the scope of my biomechanical analysis. Nor do I offer the converse opinion that the described shaking was biomechanically shown to be insufficient to cause injury. My opinion is narrower: the available case-specific evidence does not permit a reliable biomechanical determination that the described shaking exposure was quantitatively sufficient to constitute an injury-producing episode of violent shaking.
XIX. EVOLUTION AND CHARACTERIZATION OF THE EVIDENTIARY RECORD
The evidentiary record developed as additional medical evaluations, imaging reviews, investigative information, and expert opinions became available. Early skeletal imaging raised concern for multiple possible metaphyseal abnormalities. Subsequent pediatric radiologic evaluation did not confirm several of the initially questioned upper-extremity abnormalities as fractures. The distal left femoral metaphyseal finding was treated differently and remained a documented finding in the medical record, with later imaging interpreted as showing interval resolution or healing.
I rely on the radiologic interpretations contained in the medical record and do not independently interpret the pediatric radiographs or determine the medical cause of the distal femoral finding. This report addresses the significance of the skeletal findings to my biomechanical analysis elsewhere.
The investigative record likewise contains qualitative descriptions attributed to Mr. Gilmore regarding his actions while attempting to elicit a response from Jahseen, including “kind of shaking him,” descriptions of a gentler shake, and his later statement that he may have been “a little too aggressive” and caused injury. I have considered all of these statements. They may be relevant to determining whether some shaking or movement occurred, but they do not quantify the mechanical characteristics of that movement.
I do not determine guilt, innocence, intent, credibility, or the appropriateness of investigative or medical decisions. My consideration of the evolving evidentiary record is limited to the biomechanical question presented: whether the available case-specific evidence permits a reliable quantitative reconstruction of the described shaking exposure and a determination of its mechanical severity.
In my opinion, the available evidence does not permit such a quantitative reconstruction. This does not establish that shaking did not occur or that the event was mechanically mild; it establishes that the available case-specific evidence cannot reliably determine its mechanical magnitude.
XX. DISTINGUISHING OCCURRENCE FROM MECHANICAL SEVERITY
A statement that an infant was “shaken” may indicate that some shaking or movement occurred. Without additional information, it does not quantify the mechanical severity of that movement.
Shaking is not a single, mechanically uniform exposure. Its biomechanical characteristics can vary with the amplitude and frequency of movement, duration and number of cycles, direction of motion, head excursion, angular velocity and acceleration, grip and torso restraint, cervical motion and loading, and whether impact occurred.
Published physical-surrogate experiments demonstrate that vigorous shaking under specified experimental conditions can generate substantial head motion and acceleration.¹˒² Other research shows that the resulting kinematics are sensitive to experimental and modeling conditions, including changes in the location of the head's center of rotation.⁸ Computational studies predict tissue responses based on specified inputs, assumptions, material properties, and boundary conditions.⁶˒⁷ Systematic reviews identify ongoing limitations in model design, simplified shaking inputs, validation, scaling, and the injury criteria used to translate these results into predictions of injury.³⁻⁵
Clinical observations, including Feldman et al. (2022), provide evidence that serious injury can occur after reported or independently witnessed shaking without identified impact in some circumstances.²¹ Such observations are relevant to whether shaking can cause injury; they do not provide a quantitative reconstruction of a separate alleged event for which the relevant mechanical variables were not measured.
Accordingly, Mr. Gilmore's qualitative description of “kind of shaking” cannot scientifically justify assigning to this event the numerical kinematics measured during a particular surrogate experiment, the tissue responses predicted by a computational model, or an injury criterion derived from a different experimental population or loading environment.
Conversely, the inability to quantify the alleged event does not establish that it was mechanically mild or insufficient to cause injury. The scientifically supportable conclusion is narrower: the magnitude of the alleged exposure cannot be reliably reconstructed from the available case-specific evidence, and therefore it cannot reliably be classified biomechanically as an injury-producing episode of violent shaking.
XXI. MEDICAL FINDINGS AND BIOMECHANICAL RECONSTRUCTION
It is important to distinguish between identifying and medically interpreting an injury or clinical finding and quantitatively reconstructing the mechanical exposure associated with it.
Medical findings may provide important information regarding diagnosis, causation, timing, and mechanism when evaluated by appropriately qualified physicians and other specialists. My biomechanical analysis does not challenge the medical significance of those findings.
From a biomechanical standpoint, however, even if a particular finding is medically determined to be traumatic, the finding itself does not provide a unique numerical value for angular acceleration, angular velocity, linear acceleration, duration, frequency, number of cycles, direction of loading, head excursion, cervical loading, or other mechanical characteristics of the event that produced it.
Biological tissues respond to mechanical loading in complex ways, and experimental and computational research seeks to relate specific loading conditions to resulting tissue responses and injury risk. However, current systematic reviews identify substantial limitations in translating those relationships to infant shaking, including differences in experimental conditions, model assumptions, material properties, scaling methods, validation, simplified shaking inputs, and injury criteria derived from adult or animal data.³⁻⁵
Accordingly, I do not work backward from the reported subdural hemorrhagic collections, retinal hemorrhages, diffusion abnormalities, skeletal findings, or other medical findings to assign Jahseen a specific set of mechanical values that the case-specific evidence did not independently measure or establish.
This does not mean those findings lack diagnostic or medical significance. Appropriately qualified physicians may consider the combination of clinical, ophthalmologic, radiologic, skeletal, historical, and other evidence when determining diagnosis and medical causation. Those multidisciplinary medical determinations are distinct from the biomechanical question of whether the magnitude and characteristics of a particular alleged mechanical exposure can be quantitatively reconstructed.
The medical findings therefore cannot substitute for missing case-specific mechanical measurements. Nor, standing alone, do they permit me to calculate the magnitude of Mr. Gilmore's described actions or determine that those actions possessed the quantitative mechanical characteristics of the vigorous shaking conditions examined in particular laboratory experiments or computational models.
Conversely, my inability to make that quantitative determination does not establish that the described shaking was mechanically insufficient to cause injury. It defines the limit of the biomechanical conclusion that can reliably be reached from the available case-specific evidence.
XXII. LIMITATIONS OF THIS ANALYSIS
The opinions expressed in this report are subject to the following limitations:
1. No instrumented or other quantitative measurement of the alleged shaking event was obtained.
2. Available descriptions of the event are qualitative and do not establish the event-specific mechanical variables necessary for a reliable quantitative reconstruction, including amplitude, frequency, duration, number of cycles, head excursion, angular velocity, angular acceleration, cervical loading, torso restraint, and other relevant characteristics of the alleged exposure.
3. No validated method exists to convert the word “shaking,” or another qualitative description of shaking, standing alone, into a unique set of head and cervical kinematics or a quantified mechanical exposure.
4. Published biomechanical studies differ substantially in experimental and surrogate design, anatomical representation, material properties, input conditions, boundary conditions, model assumptions, validation methods, scaling procedures, and selected injury criteria.³⁻⁵ These differences limit direct numerical comparison between individual studies and the direct application of their results to an unmeasured, case-specific event.
5. Published systematic reviews identify important limitations in the injury criteria used in infantshaking research, including reliance in some models on thresholds or material properties derived or scaled from adult or animal data, limitations in validation and scaling methods, and shaking inputs that may simplify the duration, repetition, and kinematic characteristics of actual shaking.³⁻⁵ These limitations do not establish that vigorous shaking cannot cause injury; they limit the reliability with which particular numerical thresholds or modeled results can be transferred to an individual case.
6. Published experimental and clinical evidence demonstrates that vigorous shaking can generate substantial mechanical loading and that serious injury can occur following shaking under some circumstances.¹˒²˒²¹ Those studies establish important general propositions concerning the potential consequences of shaking, but they do not establish the quantitative kinematics of a separate alleged event for which the relevant mechanical variables were not measured.
7. The medical evidence and expert opinions do not provide a uniformly precise and undisputed temporal relationship between all reported findings and a single, quantitatively described mechanical event. I therefore do not biomechanically assign findings to a particular event date or mechanical exposure where that relationship has not otherwise been reliably established.
8. I do not independently resolve disagreements involving pediatrics, neuroradiology, ophthalmology, neurology, neuropathology, pediatric radiology, or other medical specialties, and I do not independently diagnose abusive head trauma or an alternative medical condition. I rely upon medical findings and opinions within their appropriate professional context.
9. The inability to quantitatively reconstruct the alleged shaking exposure does not establish that shaking did not occur, that the exposure was mechanically mild, or that vigorous shaking cannot cause injury. Conversely, the presence of medical findings associated with abusive head trauma does not, by itself, provide the missing event-specific mechanical measurements necessary to quantify the alleged exposure. My biomechanical conclusion is therefore limited to case-specific quantification, not proof of either mechanical sufficiency or insufficiency.
10. My biomechanical opinions do not depend upon establishing an alternative medical cause for Jahseen's findings. Determining whether RSV, hypoxia, seizure activity, BESS, chronic subdural collections, rebleeding, or another medical process caused or contributed to particular findings is a medical determination outside the scope of my biomechanical opinions.
11. I do not offer opinions concerning guilt, innocence, intent, credibility, racial bias, probable cause, or the propriety of investigative, prosecutorial, or medical decisions. Those matters are outside the scope of my biomechanical analysis.
XXIII. FINAL OPINIONS AND CONCLUSIONS
1. Case-Specific Biomechanical Opinion
Within the limits of biomechanical analysis and to a reasonable degree of professional probability within my field, the available case-specific evidence does not permit a reliable quantitative reconstruction of the shaking described in the investigative record. Consequently, the available biomechanical evidence does not permit a reliable determination that the described exposure was quantitatively sufficient to constitute an injury-producing episode of violent shaking.
This is not an opinion that shaking did not occur, that the described event was mechanically mild, or that sufficiently vigorous shaking is incapable of producing serious injury. It is an opinion concerning the limits of what can reliably be determined biomechanically from the available case-specific evidence.
2. Quantitative Reconstruction
The available evidence is insufficient to conduct a reliable quantitative biomechanical reconstruction of the alleged shaking event. The principal event-specific mechanical variables—including amplitude, frequency, duration, number of cycles, head excursion, angular velocity, angular acceleration, cervical loading, torso restraint, and other relevant characteristics—were not measured and cannot be reliably derived from qualitative descriptions alone.
3. Meaning of Mr. Gilmore's Statements
The investigative record contains qualitative descriptions of shaking or movement, including “kind of shaking him” and a gentler shake, as well as Mr. Gilmore's later statement that he may have been “a little too aggressive” and caused injury. I have considered these statements as evidence.
Such statements may be relevant to determining whether any shaking or movement occurred, but they do not quantify the mechanical severity of that movement. By themselves, they do not establish the amplitude, frequency, duration, number of cycles, acceleration, velocity, head excursion, cervical loading, or other mechanical characteristics necessary to define the exposure quantitatively.
4. Capacity of Vigorous Shaking to Produce Mechanical Loading and Injury
Published biomechanical research shows that vigorous shaking of instrumented infant surrogates can produce substantial head motion, angular velocity, angular acceleration, and associated mechanical loading under the experimental conditions examined.¹˒² Clinical observations, including those by Feldman et al. (2022), also provide evidence that serious neurological and AHT-associated findings can occur after independently witnessed shaking without an identified head impact in some cases.²¹
I therefore do not offer the opinion that vigorous shaking is mechanically incapable of producing substantial loading or serious injury. These general scientific observations, however, do not establish the magnitude or mechanical characteristics of the exposure alleged in this particular case.
5. Application of Published Experimental and Computational Studies
Physical-surrogate experiments, computational and finite-element models, animal studies, and clinical observations provide useful information on the mechanics, tissue responses, and potential consequences of shaking under specific conditions.¹–⁹˒²¹ Their results depend on the experimental or model conditions, including surrogate or anatomical characteristics, loading inputs, material properties, boundary conditions, model assumptions, scaling procedures, validation methods, and selected injury criteria.³–⁵
Accordingly, numerical kinematics measured in a particular surrogate experiment, tissue responses predicted by a computational model, or observations from a separate clinical event cannot be assumed to represent the unmeasured mechanical exposure Jahseen experienced. Published systematic reviews specifically identify limitations in translating physical and mathematical models and their associated injury criteria to human infant shaking.³–⁵
6. Injury-Threshold Opinion
The available evidence does not permit a reliable case-specific determination of whether the alleged exposure exceeded or remained below a proposed injury threshold.
Published systematic reviews identify substantial limitations in the injury criteria used in infantshaking research. These include reliance on thresholds derived from or scaled to adult or animal data, loading conditions that do not adequately replicate the duration and repetitive characteristics of shaking, limitations in validation and scaling methods, and uncertainty about the applicability of specific criteria to infant biological tissues.³–⁵
Regardless of those threshold limitations, the mechanical exposure in this case was not quantitatively measured. Therefore, even a sufficiently validated injury criterion would require reliable, casespecific mechanical inputs before the alleged event could be placed quantitatively above or below that criterion.
My current opinion is therefore not that established biomechanical thresholds demonstrate that the alleged shaking was insufficient to cause injury. Rather, the available evidence does not permit a reliable case-specific determination of whether the alleged shaking was above or below the threshold.
7. Cervical-Spine Opinion
The December 27 cervical MRI was reported to show no cervical cord or ligamentous injury. I accept that interpretation as reported and do not independently reinterpret the MRI.
Published biomechanical research demonstrates that substantial inertial head motion can result in substantial cervical loading.¹˒¹⁰ Davison et al., using 3-year-old automotive surrogates in crash and sled-test conditions, found that cervical peak-tension injury criteria were exceeded more often than the selected closed-head criterion. Those experiments involved loading conditions and pediatric surrogates materially different from the alleged event in this case and cannot be directly applied to Jahseen.¹⁰
Accordingly, the available cervical imaging shows no structural cord or ligamentous injury that independently corroborates structural cervical injury. Its absence is relevant to the overall biomechanical assessment but does not establish that shaking did not occur, that an injury-producing shaking event necessarily would have produced identifiable cervical structural injury, or that the alleged exposure was mechanically insufficient to cause intracranial injury.
8. Skeletal-Imaging Opinion
The initial skeletal evaluation raised concern for multiple possible metaphyseal abnormalities. Subsequent pediatric radiology evaluation did not confirm several of the initially questioned upperextremity abnormalities as fractures. The distal left femoral metaphyseal finding was handled differently and remained a documented finding in the medical record, with subsequent imaging interpreted as showing interval resolution or healing.
I rely on the radiologic interpretations in the medical record and do not independently interpret the pediatric radiographs or determine the medical cause of the distal femoral finding. The skeletal findings do not provide the event-specific mechanical information necessary to quantitatively reconstruct the alleged shaking exposure, and I do not rely on the presence or absence of skeletal injury to establish or exclude an injury-producing shaking event.
9. Medical Findings and Mechanical Quantification
The reported subdural hemorrhagic collections, retinal hemorrhages, neurological and diffusion abnormalities, microhemorrhagic findings, seizure activity, hypoxia, and skeletal findings constitute medically significant evidence that must be evaluated by the appropriate specialists.
From a biomechanical standpoint, however, those findings do not, in themselves, provide unique numerical values for the amplitude, frequency, duration, number of cycles, angular velocity, angular acceleration, head excursion, cervical loading, or other mechanical characteristics of the event that produced them.
I therefore do not work backward from the medical findings and assign mechanical values to Jahseen that were not independently measured or otherwise established by the case-specific evidence. This does not diminish the diagnostic significance those findings may have when evaluated by appropriately qualified medical specialists. opinions, or relevant literature, but I do not independently determine whether any of them caused or contributed to the reported findings.
Those medical-causation determinations are reserved for appropriately qualified medical specialists and are distinct from my biomechanical assessment of whether the alleged mechanical exposure can be reliably reconstructed and quantified.
12. Ultimate Biomechanical Opinion
I do not offer an opinion on Mr. Gilmore's guilt or innocence, intent, or credibility, nor on whether Jahseen did or did not sustain abusive head trauma. Those determinations are outside the scope of my biomechanical analysis.
Within the limits of biomechanical analysis and to a reasonable degree of professional probability within my field, the available case-specific evidence does not permit a reliable quantitative reconstruction of the shaking described in the investigative record. Consequently, it does not permit a reliable biomechanical determination that the described exposure was quantitatively sufficient to constitute an injury-producing episode of violent shaking.
The available evidence likewise does not permit a reliable determination of whether the alleged exposure exceeded or remained below a proposed injury threshold. This is not an opinion that the exposure was biomechanically proven insufficient to cause injury.
Published research demonstrates that vigorous shaking can generate substantial mechanical loading and that serious injury can occur under certain shaking conditions.¹˒²˒²¹ At the same time, the experimental, computational, and clinical literature does not provide the missing case-specific mechanical measurements needed to determine the magnitude of this alleged event. Systematic reviews further identify significant limitations in translating specific experimental conditions, computational predictions, and injury criteria to an individual unmeasured infant-shaking event.³–⁵
Accordingly, my ultimate opinion is one of limitation in case-specific biomechanical quantification, not proof of either mechanical sufficiency or insufficiency. It defines what the available mechanical evidence can—and cannot—reliably establish about the alleged shaking event in this case.
XXIV. REFERENCES
1. Jenny CA, Bertocci G, Fukuda T, Rangarajan N, Shams T. Biomechanical response of the infant head to shaking: an experimental investigation. J Neurotrauma. 2017;34(8):1579-1588. doi:10.1089/neu.2016.4687. Published correction: J Neurotrauma. 2017;34(12):2092. doi:10.1089/neu.2016.4687.correx.
2. Stray-Pedersen A, Strisland F, Rognum TO, Schiks LAH, Loeve AJ. Violent infant surrogate shaking: continuous high-magnitude centripetal force and abrupt shift in tangential acceleration may explain high risk of subdural hemorrhage. Neurotrauma Rep. 2021;2(1):224-231. doi:10.1089/neur.2021.0013.
3. Schiks LAH, Dankelman J, Loeve AJ. Thresholds for the assessment of inflicted head injury by shaking trauma in infants: a systematic review. Forensic Sci Int. 2020;306:110060. doi:10.1016/j.forsciint.2019.110060.
4. van Zandwijk JP, Vester MEM, Bilo RAC, van Rijn RR, Loeve AJ. Modeling of inflicted head injury by shaking trauma in children: what can we learn? Part II: a systematic review of mathematical and physical models. Forensic Sci Med Pathol. 2019;15(3):423-436. doi:10.1007/s12024-019-00093-7.
5. Hutchinson K, van Zandwijk JP, Vester MEM, et al. Modeling of inflicted head injury by shaking trauma in children: what can we learn? Update to Parts I & II: a systematic review of animal, mathematical and physical models. Forensic Sci Med Pathol. 2025;21(1):366-381. doi:10.1007/s12024-023-00765-5.
6. Couper Z, Albermani F. Mechanical response of infant brain to manually inflicted shaking. Proc Inst Mech Eng H. 2010;224(1):1-15. doi:10.1243/09544119JEIM587.
7. Roth S, Raul JS, Ludes B, Willinger R. Finite element analysis of impact and shaking inflicted to a child. Int J Legal Med. 2007;121(3):223-228. doi:10.1007/s00414-006-0129-3.
8. Schiks LAH, Dankelman J, Loeve AJ. Inflicted head-injury by shaking-trauma in infants: the importance of spatiotemporal variations of the head's rotation center. Sci Rep. 2023;13:15226. doi:10.1038/s41598-023- 42373-x.
9. Vester MEM, Bilo RAC, Loeve AJ, van Rijn RR, van Zandwijk JP. Modeling of inflicted head injury by shaking trauma in children: what can we learn? Part I: a systematic review of animal models. Forensic Sci Med Pathol. 2019;15(3):408-422. doi:10.1007/s12024-019-0082-3
10. Davison MA, Button KD, Benzel EC, Weaver BT, Rundell SA. A biomechanical assessment of shaken baby syndrome: what about the spine? World Neurosurg. 2022;163:e223-e229. doi:10.1016/j.wneu.2022.03.104.
11. Wittschieber D, Karger B, Pfeiffer H, Hahnemann ML. Understanding subdural collections in pediatric abusive head trauma. AJNR Am J Neuroradiol. 2019;40(3):388-395. doi:10.3174/ajnr.A5855.
12. Sandramouli S, Robinson R, Tsaloumas M, Willshaw HE. Retinal haemorrhages and convulsions. Arch Dis Child. 1997;76(5):449-451. doi:10.1136/adc.76.5.449.
13. Tyagi AK, Scotcher S, Kozeis N, Willshaw HE. Can convulsions alone cause retinal haemorrhages in infants? Br J Ophthalmol. 1998;82(6):659-660. doi:10.1136/bjo.82.6.659.
14. Curcoy AI, Trenchs V, Morales M, Serra A, Pineda M, Pou J. Do retinal haemorrhages occur in infants with convulsions? Arch Dis Child. 2009;94(11):873-875. doi:10.1136/adc.2007.132522.
15. Mei-Zahav M, Uziel Y, Raz J, Ginot N, Wolach B, Fainmesser P. Convulsions and retinal haemorrhage: should we look further? Arch Dis Child. 2002;86(5):334-335. doi:10.1136/adc.86.5.334.
16. Saravanos GL, King CL, Deng L, et al. Respiratory syncytial virus-associated neurologic complications in children: a systematic review and aggregated case series. J Pediatr. 2021;239:39-49.e9. doi:10.1016/j.jpeds.2021.06.045.
17. Raissaki M, Adamsbaum C, Argyropoulou MI, et al. Benign enlargement of the subarachnoid spaces and subdural collections-when to evaluate for abuse. Pediatr Radiol. 2023;53(4):752-767. doi:10.1007/s00247- 023-05611-y.
18. Hansen JB, Frazier T, Moffatt M, Zinkus T, Anderst JD. Evaluations for abuse in young children with subdural hemorrhages: findings based on symptom severity and benign enlargement of the subarachnoid spaces. J Neurosurg Pediatr. 2018;21(1):31-37. doi:10.3171/2017.7.PEDS17317.
19. Wright JN, Feyma TJ, Ishak GE, et al. Subdural hemorrhage rebleeding in abused children: frequency, associations and clinical presentation. Pediatr Radiol. 2019;49(13):1762-1772. doi:10.1007/s00247-019- 04483-5. Published correction: Pediatr Radiol. 2020;50(8):1161. doi:10.1007/s00247-020-04687-0.
20. Feldman KW, Sugar NF, Browd SR. Initial clinical presentation of children with acute and chronic versus acute subdural hemorrhage resulting from abusive head trauma. J Neurosurg Pediatr. 2015;16(2):177-185. doi:10.3171/2014.12.PEDS14607.
21. Feldman KW, Melville JD, Johnson KL, Valvano TJ, Piper AC, Lakin KL, Petrak CS. Abusive head trauma follows witnessed infant shaking. Child Abuse Rev. 2022;31(3):e2739. doi:10.1002/car.2739.
I reserve the right to supplement or modify my opinions if additional prior or subsequent medical records, imaging, incident photographs/video, deposition testimony, or other relevant evidence becomes available.
Steven B. Ross, D.C., F.A.S.B.E., D.A.A.P.M.
Date: September 16, 2026
Comments