Left-Handedness in Children with Neurodevelopmental Disorders

Abstract

Objective

This cross-sectional study investigated handedness in patients followed in a university-based child development clinic. The goal was to expand on previous research that identified mixed handedness in children and adolescents as being a risk factor for language problems, scholastic difficulties, and attention-deficit hyperactivity disorder (ADHD).

Methods

Young adult patients and parents of patients < 18 years completed a 13-item survey approved by the university’s institutional review board. The items documented primary and comorbid diagnoses; age, gender, race and ethnicity of patients; age at first diagnosis; type of health care provider who diagnosed child; birth month; and hand preference for common activities of daily living (i.e., writing, eating, throwing ball, bathing, brushing teeth).

Results

996 surveys were completed from February 2016 through August 2016. Males comprised 73.3% (n=731) of the study sample. The average age was 9.26 years ( males = 9.26,   females = 9.47, range 2 to 22 years). ADHD as a single diagnosis was the most common category (40.9%, n=408), followed by ADHD with comorbidities (not including autism) (36.0%, n=359). Autism with ADHD and comorbid conditions comprised 10.3% (n=359) of the sample. 82.1% (n=813) of the total study sample preferred the right hand for writing, less than the 90% reported for the general population. Left-handedness was reported by 15.6% (n=155) and mixed-handedness by 2.2% (n=22) of the sample.

Conclusions

Our findings support the possible interconnection among left handedness/mixed-handedness, right hemisphere neurotransmitter dysfunction, and ADHD, autism, and learning problems.