[Executive function characteristic in boys with attention deficit hyperactivity disorder comorbid learning disabilities].

OBJECTIVE

To study the executive function (EF) characteristics in boys with attention deficit hyperactivity disorder (ADHD) comorbid learning disabilities (LD).

METHODS

A total of 22 pure ADHD boys, 22 ADHD+LD boys and 22 normal controls (by criteria of DSM-IV) were collected as our samples. The groups were matched by ages (less than 6 months) and ADHD subtypes. The research instruments included the Stroop color-word task, Rey complex figure test, digit span test, trail making test, tower of Hanoi and verbal fluency test.

RESULTS

The differences of VIQ weren't significant among the three groups; pure ADHD and ADHD+LD groups had lower PIQ than the control group; ADHD+LD boys had lower IQ than the controls. The performance in the EF tests: (1) Both pure ADHD and ADHD+LD groups performed worse in the aspects of time of number-letter part and shifting time, the repeat response of verbal fluency, and the differences were significant. But the differences between ADHD and ADHD+LD weren't significant. (2) ADHD+LD group also showed deficits in the aspects of time and errors of Stroops 2 and 4, time of Stroop 4, word interference time, the immediate memory and delayed recalling detail score of Rey complex figure test, time of number trail making, error steps (rule violation) of Tow of Hanoi, and the differences were significant. (3) Both ADHD+LD and pure ADHD groups made more errors in the naming color of the color-word card (Stroop part 4), and ADHD+LD boys performed worse than pure ADHD boys.

CONCLUSION

The findings support the hypothesis that ADHD is related to EF deficit, whether or not comorbid LD. ADHD+LD showed significant difference in the aspects of inhibition, working memory, set shifting and fluency as compared with normal group, ADHD+LD boys perform more poorly than the pure ADHD boys. It's plausible that both ADHD and LD are associated with deficits of executive function.