Shaken Baby Syndrome: New Jersey Supreme Court State v Nieves

New Jersey Supreme Court Decision – Shaken Baby Syndrome/Abusive Head Trauma

On November 20, 2025, the New Jersey Supreme Court, in a six-to-one ruling, decided State v. Nieves, ___ N.J. ___ (2025), in which it held that expert testimony regarding Shaken Baby Syndrome/Abusive Head Trauma (SBS/AHT), without impact, was not sufficiently reliable to be presented to a jury in two separate cases — State v. Nieves and State v. Cifelli.

Facts and Procedural History

In both Nieves and Cifelli, the infants exhibited the “triad of symptoms” that have been associated with SBS/AHT, namely, subdural hematoma, retinal hemorrhages, and encephalopathy. Dr. Gladibel Medina, a child abuse pediatrician, determined that the infants were victims of child abuse, specifically SBS/AHT, and as a result, the fathers of both children were charged with aggravated assault and child endangerment.

The State sought to present Medina’s expert testimony that the only explanation for the infants’ triad of symptoms, was that they were both shaken by their fathers, the sole caregivers at the time of the injury. The defense in both cases challenged the scientific basis and reliability of the theory that shaking alone, without some other form of impact to the infant’s head, can cause the symptoms associated with SBS/AHT, and to preclude Medina’s testimony at trial.

The trial court conducted a hearing in Nieves in accord with the prior standard under Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), and in a lengthy written decision concluded that expert testimony of shaking-only SBS/AHT was not scientifically reliable, barred admission of the evidence at Nieves’s trial, and dismissed the indictment against Nieves. The trial court in Cifelli adopted the decision barring the testimony in that case.

The Appellate Division consolidated the appeals and affirmed. State v. Nieves, 476 N.J. Super. 609 (App. Div. 2023). The Appellate Division found that “there is a real dispute in the larger medical and scientific community about the validity of shaking only SBS/AHT theory, despite its seeming acceptance in the pediatric medical community.” The Appellate Court explained that where the underlying theory integrates multiple scientific disciplines, as in the SBS/AHT theory, the proponent must establish cross-disciplinary validation to establish reliability. The Supreme Court granted certification in Nieves and leave to appeal in Cifelli.

The Supreme Court affirmed, determining that the State had failed to carry its burden that Dr. Medina’s expert testimony regarding SBS/AHT, without impact, was reliable. In reaching that determination the Court traced the evolution of the history of SBS/AHT theory through the extensive scientific articles and studies over the past six decades. The Court determined that the studies had not shown a general acceptance that shaking alone can generate the forces necessary to cause subdural hematomas, retinal hemorrhages, and encephalopathy. The Court found that the relevant scientific communities for purposes of determining the reliability of SBS/AHT expert testimony were both the medical/pediatric community and the biomechanical engineering community. The Court found that although there was evidence of general acceptance of SBS/AHT in the medical community, the State failed to also establish general acceptance in the biomechanical community.

Nonetheless, the Court held that the State could present evidence to the jury in cases where there is physical evidence of trauma to a child or other evidence of abuse. Moreover, if new, reliable, scientific evidence is developed, the State can, in a future case, make a showing under the standard in Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), adopted by the Court, after the trial court’s decision in this case, in State v. Olenowski (Olenowski I), 253 N.J. 133, 139 (2023), that expert testimony regarding SBS/AHT without impact is reliable. “In such a case, scientific evidence and research, both old and new, could be presented and considered. Science is constantly evolving, so the door is not forever closed on making such a showing of reliability.”

Conclusion – Key Takeaways from the New Jersey Shaken Baby Case

Expert testimony regarding Shaken Baby Syndrome/Abusive Head Trauma (SBS/AHT), without impact, is not sufficiently reliable to be presented to a jury in New Jersey. Nonetheless, evidence of physical trauma to a child or other evidence of abuse remains admissible. Moreover, if new, reliable, scientific evidence is developed, the State can, in a future case, make a showing that SBS/AHT, without impact, is reliable under Olenowski.

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