Comparison of children with and without ADHD on measures of neurocognitive ability and androgen exposure
Boys with Attention-Deficit/Hyperactivity Disorder (ADHD) were recruited from a local neuropsychology office with controls recruited from the community to assess the relationship between prenatal androgen exposure and ADHD, as well as the possible cognitive correlates of this exposure. Putative physiological markers of prenatal androgen exposure that were measured for each child included several types of otoacoustic emissions (OAEs) as well as finger-length ratios (FLRs). Neurocognitive measures included tasks which assessed components of attention, general intelligence, reading ability, and visuospatial skills. Several other variables which may also be related to androgen exposure were included (e.g., sleep disturbance, handedness, number of older brothers) in the analyses. Children ranged in age from 7 to 12 years old with 13 controls, 19 children with ADHD/Combined Type (ADHD/C), 10 with ADHD/Inattentive Type (ADHD/IA), and an additional 11 children with ADHD/IA who were rated by their parents as having relatively high levels of an experimental construct (sluggish cognitive tempo; SCT). Because more boys than girls are diagnosed with ADHD, it was hypothesized that ADHD may be associated with prenatal masculinizing hormones (i.e., androgens), and that children with ADHD would appear more masculine on markers of androgen exposure (OAEs and FLRs) than controls. However, in our current study children with ADHD did not differ from controls on these measures. There was some evidence that children with SCT may represent a more homogenous group of children within the ADHD/IA diagnostic group, and that they may share a deficit in alerting attention. Consistent with theories suggesting subtype differences in attention, children with ADHD/C did not appear to have a deficit in alerting attention, but rather appeared more cognitively impulsive and to have a deficit in auditory attention. Children with SCT were more likely to be rated by their parents as having disrupted sleep.