Early Motor Differences in Infants at Elevated Likelihood of Autism Spectrum Disorder and/or Attention Deficit Hyperactivity Disorder.

The infants were selected for family history, not for a confirmed ASD or ADHD diagnosis in the child, and the study did not make clinical determinations at 2 years. ADHD elevated likelihood was partly defined by parent-reported concerns and screening questionnaires, not only by clinical diagnosis. The key group difference appeared only at 10 months; it was not seen at 5 or 14 months, so it may be a narrow developmental observation. Several group comparisons did not survive correction for multiple testing, including the ASD-plus-ADHD group for total contralateral behaviours and object manipulations. The association with ADHD traits was based on parent report at 24 months and does not show that midline crossing predicts later diagnosed ADHD. Coding was done by one researcher, with 12% double coded, and task length varied slightly, so behaviours were converted to rates per minute. The Mullen scores may not match broader field norms because the team used stricter scoring than is common.

The supplied article lists funding from the Medical Research Council, MQ and the Innovative Medicines Initiative. It gives no author conflict-of-interest statement.

Do not treat reduced midline crossing at 10 months as a clinical sign of autism or ADHD. The children had no diagnosis at 2 years, the difference was not seen at 5 or 14 months, and the later association was with parent-reported ADHD traits rather than confirmed disorder.