Sex Effects on Mirror Overflow during Finger Tapping in Children with ADHD.

Area of Science:

• Neuroscience
• Developmental Psychology
• Child Psychiatry

Background:

• Excessive mirror overflow is a documented characteristic in children with Attention Deficit/Hyperactivity Disorder (ADHD).
• Previous research has often focused on a limited age range, potentially overlooking developmental variations.

Purpose of the Study:

• To investigate the impact of ADHD diagnosis and sex on mirror overflow.
• To examine the effects of diagnosis and sex on the standard deviation (SD) of tap time in children aged 5-12.
• To expand upon existing literature by including a broader age range.

Main Methods:

• A finger sequencing task was administered to 148 children with ADHD and 112 typically developing (TD) children.
• Mirror overflow, SD of tap time, and mean tap time were measured using finger twitch transducers.
• Participants were age- and sex-matched to ensure robust comparisons.

Main Results:

• Children with ADHD, both boys and girls, exhibited significantly higher levels of mirror overflow compared to their same-sex TD peers.
• Boys with ADHD demonstrated increased variability in tap times (higher SD) relative to TD boys.
• No significant diagnostic effect on tap time variability was found in girls.

Conclusions:

• Both boys and girls with ADHD display excessive mirror overflow, a finding consistent across sexes in this study.
• Motor variability differences were observed in boys with ADHD but not in girls, suggesting sex-specific patterns.
• The broader age range examined may explain the lack of observed sex differences in mirror overflow, contrasting with some prior reports.