New Jersey Bars 'Shaken Baby Syndrome' Expert Testimony When No Other Trauma Is Present — Landmark 6–1 Ruling

The New Jersey Supreme Court, in a 109-page opinion and a 6–1 decision, has become the first state high court in the United States to exclude expert testimony diagnosing "shaken baby syndrome" (now commonly called abusive head trauma, or AHT) when there is no independent evidence of impact or other external trauma.

The court concluded that the State failed to show "general acceptance in the relevant scientific communities" that shaking alone can reliably produce the classic triad of findings historically attributed to AHT. The majority emphasized that where criminal liability is at stake, experts must base conclusions on a sufficiently established scientific consensus rather than assumptions drawn from limited or contested research.

Decades of medical debate and growing research informed the decision. The hypothesis that violent shaking could cause fatal or severe brain injury in infants emerged in the 1970s and was later used in many prosecutions. Beginning in the 2000s, however, scientists, forensic-reform advocates and innocence organizations raised concerns that other medical conditions and injuries can mimic the combination of bleeding, swelling and neurological injury once treated as conclusive proof of abusive head trauma.

Those concerns led to numerous post-conviction reviews and exonerations: according to the National Registry of Exonerations, at least 41 parents and caregivers convicted on AHT-related evidence in 18 states have since been exonerated. Even physicians who helped popularize the shaking hypothesis have since expressed reservations about its forensic application.

The ruling grew from the criminal case against Darryl Nieves, charged in 2017 with aggravated assault and endangering the welfare of a child after his 11-month-old son—born prematurely with severe medical problems—showed signs of neurological injury. A trial judge in 2022 barred AHT testimony at Nieves' trial, calling it "an assumption packaged as a medical diagnosis, unsupported by any medical or scientific testing." A New Jersey appellate court affirmed that ruling, and the state Supreme Court has now upheld both lower-court decisions.

Dissent: Justice Rachel Wainer Apter disagreed, arguing that AHT is widely accepted by clinical disciplines that diagnose and treat it and cautioning that courts should be humble about scientific questions: "Judicial humility requires us to accept that we are judges, not scientists."

The majority acknowledged ethical and practical limits on research involving infant head trauma but warned those limits cannot be a substitute for rigorous evidence when criminal penalties follow. The decision does not declare AHT invalid in every context, but it draws a clear line for courtroom admissibility: where there is no evidence of impact or external trauma, expert testimony attributing injuries solely to shaking is inadmissible under New Jersey law.

Legal observers expect the ruling to reverberate nationwide. Prosecutors, defense attorneys, pediatric specialists and innocence advocates will closely study the opinion as other states consider post-conviction appeals and trial standards for expert proof in AHT cases. Notably, in Texas a death-row inmate, Robert Roberson, recently secured new proceedings to revisit a conviction that relied on AHT testimony.

This decision marks a major moment in the intersection of medical science and criminal law, highlighting the courts' evolving role in scrutinizing expert evidence where scientific consensus is contested and the stakes for defendants are high.