4.2Criminal Cases Involving Abuse Charges

Medical expert testimony invades the province of the jury by citing accepted medical terminology that may be misconstrued by laypersons as imparting emotionally-charged or legally conclusory connotations. People v McFarlane, 325 Mich App 507, 517-527 (2018). In McFarlane, the Court of Appeals “determined that the trial court plainly erred when it permitted the prosecution’s expert witness, a child abuse pediatrician, to use the diagnostic terms “’abusive head trauma’ and ‘definite pediatric child abuse,’ in her trial testimony, considering the defendant was charged with first-degree child abuse.” People v Alexander, ___ Mich App ___, ___ (2024). See McFarlane, 325 Mich App at 523-527. “Ultimately, the contested diagnoses implicated a level of willfulness and culpability that was solely within the purview of the jury to determine, as the prosecution’s expert witness expressly connected said diagnoses to the defendant’s state of mind.” Alexander, ___ Mich App at ___ (noting that the McFarlane Court clarified that “a physician may properly offer an opinion that, when the medical evidence is considered along with the child’s history, the child’s injuries were inflicted rather than caused by accident or disease because a jury is unlikely to be able to assess the medical evidence”) (quotation marks and citation omitted). “However, the McFarlane expert witness exceeded those bounds by providing an opinion that essentially implicated the defendant’s intent in perpetrating the alleged acts of abuse.” Alexander, ___ Mich App at ___, citing McFarlane, 325 Mich App at 523.

“[A]ny use of the word ‘abuse’ in the context of a medical diagnosis, irrespective of whether that is in fact an accepted medical diagnosis, constitutes plain error in a criminal proceeding involving charges of abuse.” People v Ackley (On Remand), 336 Mich App 586, 591-592, 594 (2021). (“medical expert testimony invade[s] the province of the jury by referencing accepted medical terminology that might be misunderstood by laypersons as conveying emotional or legally conclusory connotations”). The Ackley Court cautioned that “the bench and bar must be mindful of any impermissible words used by experts, and experts should be cautioned that some words may be accepted medical terminology but are unacceptable in a Michigan courtroom.” Id. at 593-594. “[E]xperts are permitted to draw and testify regarding conclusions that encompass a question to be decided by the jury, so long as the expert does not purport–or, importantly for this matter, even appear to purport–to draw a legal conclusion.” Id. at 595. “Thus, where it is possible to draw a medical diagnosis based on a physical examination, as opposed to a complainant’s self-reporting, an expert is fully permitted to testify that, in their opinion, a particular injury was not accidentally self-inflicted,” but “[t]he expert may not call that manner of injury ‘abuse,’ because, even if that is a term used in the medical community, it is also a legal conclusion and would be understood by laypersons to connote something different from what another doctor might understand.” Id.

“Where it is possible to draw a medical diagnosis based on a physical examination, as opposed to a complainant’s self-reporting, an expert is fully permitted to testify that, in their opinion, a particular injury was not accidentally self-inflicted.”Alexander, ___ Mich App at ___ (cleaned up). In Alexander, the prosecution’s expert witness “testified that her education, training, and experience provided her with knowledge concerning how to evaluate children, how to perform medical exams, how to identify injuries, how to diagnose, how to teach, how to conduct research all related to child abuse and neglect.” Id. at ___ (quotation marks omitted). The expert “further testified that prior to performing her evaluations of [the minor child], she examined the minor child’s medical records, which included a number of photographs of [the minor child’s] injuries and the results of [the minor child’s] x-ray report, in addition to information provided by the forensic interviewer.” Id. at ___. Unlike McFarlane, “[t]he contested terminology did not have the potential to conflate the expert’s medical diagnosis with any legal conclusion concerning defendant’s legal responsibility.” Id. at ___.The prosecution’s expert witness “did not suggest that defendant acted knowingly or intentionally when she testified that the children were diagnosed with medical torture or addressed any element of the crime charged.” Id. at ___. “[T]he term ‘medical torture’ is a medical diagnosis reserved for only severe cases in which the victim is subjected to at least two instances of physical harm and two instances of psychological harm, but does not suggest any amount of intentionality.” Id. at ____. “While [the expert witness] opined that [the minor child’s] injuries indicated that the minor child was exposed to at least two distinct physical assaults and at least two psychological maltreatments, warranting a diagnosis of ‘medical torture,’ she [explained that] her diagnosis was a consequence of her review of the medical records admitted in evidence, which included photographs of the ligature marks on [the minor child’s] extremities and an x-ray of the minor child’s ankles.” Id. at ___ (holding that “the contested terminology did not have the potential to conflate the expert’s medical diagnosis with any legal conclusion concerning defendant’s legal responsibility”).“Thus, even without the employment of terminology ‘medical torture,’ [the expert witness] could have properly testified about the extent of [the minor child’s] injuries, the nonaccidental nature of the minor child’s injuries, his repeated exposure to physical assault and psychological harm, and the nature of [the minor child’s] statements during his examination.” Id. at ___. Accordingly, “even if the trial court plainly erred by allowing [the expert witness] to use the label ‘medical torture,’ it [was] unlikely that the error affected the outcome of the trial considering the evidence presented.” Id. at ___  (noting that the trial court properly instructed the jury that it could consider the expert’s testimony as to why she reached her conclusions but not as evidence that the events actually happened).

“[D]epending on the particular facts at issue in a matter and the expert’s specific expertise, a biomechanical engineer may testify, if not making a medical diagnosis, regarding the impact of the forces at play and a resulting injury.” People v Hawkins, ___ Mich App ___, ___ (2023) (“declin[ing] to articulate any bright-line rule prohibiting or allowing biomechanical engineers from providing testimony related to medical causation”). In Hawkins, a defendant charged with murder and child abuse retained a biomechanical engineer “as an expert witness to counter the prosecution’s evidence that the [8-month-old] decedent’s injuries were caused by multiple blows or incidents of trauma.” Id. at ___. The parties agreed that the biomechanical engineer “could testify regarding the general forces at play” and “how a typical person might be injured therefrom.” Id. at ___. Defendant also made it clear that the expert would “not offer a medical opinion or diagnosis evaluating the decedent’s cause of death[.]” Id. at ___. The proposed testimony—that the decedent’s injuries “could have been caused from a single impact or blow”—was within the expert’s area of expertise because it was “based on the expert’s biomechanical expertise and the forces at play[.]” Id. at ___. Accordingly, the Court of Appeals determined that the trial court abused its discretion by precluding the biomechanical engineer’s testimony under MRE 702. Hawkins, ___ Mich App at ___ (noting “[t]he facts that [the expert was] not a medical doctor and lack[ed] specific medical training and education are weaknesses or gaps in his testimony to be explored on cross-examination”).

“A court considering whether to admit expert testimony under MRE 702 acts as a gatekeeper and has a fundamental duty to ensure that the proffered expert testimony is both relevant and reliable.” People v Lemons, ___ Mich ___, ___ (2024) (quotation marks and citation omitted). “The job of the courts is to . . . ensur[e] that expert testimony employs the same level of intellectual rigor that characterizes the practice of an expert in the relevant field.” Lemons, ___ Mich at ___ (quotation marks and citation omitted). In Lemons, the “trial court stepped beyond its role as gatekeeper of relevant and reliable information” when it excluded the defendant’s biochemical engineer’s testimony because “biomechanical studies are not presently able to replicate the exact number and degree of injury to the brain that would occur as a result of Shaken Baby Syndrome [SBS].” Lemons, ___ Mich at ___ (observing that defendant’s biomechanical engineer testified that ”there [were] ‘good reasons,’ grounded in biomechanical science, to conclude that shaking is insufficient to produce the accelerations necessary to produce injuries typically associated with SBS without also causing significant injuries to the neck”).

“Biomechanics is the study of forces acting on and generated within the body and of the effects of these forces on the tissues, fluids, or materials used for diagnosis, treatment, or research purposes,” and “SBS is a multidisciplinary diagnosis based on the theory that vigorously shaking an infant creates great rotational acceleration and deceleration forces that result in a constellation of symptoms that may not manifest externally.” Id. at __ (cleaned up). ”[T]he SBS hypothesis is inherently grounded in biomechanical principles.” Id. at ___ (quotation marks and citation omitted). However, “just as a biomechanical engineer may not testify about medical causation outside of their expertise, the medical community is not the judge of the validity of biomechanical research, nor is it the sole relevant expert community with respect to SBS.” Id. at ___ (“find[ing] the position that biomechanics—the study of forces acting on and generated within the human body—is divorceable from a diagnosis of shaken baby syndrome to be untenable”).

“As it relates to reliability, the focus of the MRE 702 inquiry must be solely on principles and methodology, not on the conclusions that they generate.” Lemons, ___ Mich at ___ (quotation marks and citation omitted). “That said, it is not enough that the expert’s opinion rests on data viewed as legitimate in the context of a particular area of expertise.” Id. at ___ (quotation marks and citation omitted). “Instead, the proponent must also show that any opinion based on those data expresses conclusions reached through reliable principles and methodology.” Id. at ___ (cleaned up). “The test of admissibility is not whether a particular scientific opinion has the best foundation, or even whether the opinion is supported by the best methodology or unassailable research.” Id. at ___ (quotation marks and citation omitted). “A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.” Id. at ___ (quotation marks and citation omitted).

“When evaluating the reliability of a scientific theory or technique, courts consider certain factors, including but not limited to whether the theory has been or can be tested, whether it has been published and peer-reviewed, its level of general acceptance, and its rate of error if known.” Id. at ___ (cleaned up). “In the context of expert evidence, relevance is sometimes referred to as ‘fit’: The trial court must ensure the expert’s testimony is sufficiently tied to the facts of the case, so that it ‘fits’ the dispute and will assist the trier of fact.” Id. at ___ (quotation marks and citation omitted). “‘Fit’ is not always obvious, and scientific validity for one purpose is not necessarily scientific validity for other, unrelated purposes.” Id. at ___ (quotation marks and citation omitted).

“In the realm of the biomechanical evidence underlying SBS, there can never be a perfectly replicated model of a shaken infant for obvious ethical reasons.” Id. at ___ (stating that “there will always be at least some gap between the data and the conclusions reached”). “This cannot and does not prohibit a qualified expert from testifying, on the basis of reliable principles and methodologies, about what can be extrapolated from various imperfect modeling about how an infant’s body reacts to shaking.” Id. at ___. “Any limitations in the conclusions that can be drawn from biomechanical studies as applied to the facts of this case go to its weight, not admissibility.” Id. at ___. “There is nothing inherently problematic about presenting to a jury expert testimony in biomechanics.” Id. at ___.

The Lemons Court held that the defendant’s expert witness’s “testimony satisfied the requirements of MRE 702” because “[h]e was a qualified expert in the field of biomechanical engineering,” “[h]is testimony regarding the biomechanical mechanism of SBS would assist the trier of fact in ascertaining a fact at issue—whether [defendant’s infant daughter] died from injuries caused by abusive shaking,” and “[b]iomechanical engineering is a legitimate field of scientific study and [defendant’s expert’s] testimony was based on sufficient facts or data and was the product of reliable principles and methods.” Lemons, ___ Mich at ___ (quotation marks and citation omitted) (noting that “conclusions and methodology are not entirely distinct from one another”).

Furthermore, the expert’s “testimony was not ‘far removed’ or missing a connecting link between data, methodology, and conclusion. Rather, it was based on studies specifically designed to test the effects of abusive shaking on infants, utilized various models to test the hypotheses, and specifically concluded that shaking without serious injury to the neck could not produce symptoms associated with SBS.” Id. at ___. “[I]t would be unreasonable to conclude that the subject of scientific testimony must be ‘known’ to a certainty because arguably, there are no certainties in science.” Id. at ___ (quotation marks and citation omitted) (Therefore, the Lemons Court held that “although clearly not universally accepted, [defendant’s expert’s] opinion [was] certainly objective, rational, and based on sound and trustworthy scientific literature.” Id. at ___ (cleaned up).”The opinion “‘fit’ the facts in dispute . . . and would assist the trier of fact in determining whether the prosecution could prove beyond a reasonable doubt that [defendant’s daughter’s] cause of death was SBS.” Id. at ___ (citation omitted) (holding that “the trial court abused its discretion by misapplying MRE 702 and ordering that biomechanical evidence was inadmissible”).