Comorbidity of attention deficit hyperactivity disorder (ADHD) and reading disabilities is greater than what would occur by chance.Objective
The main aim of our study was to investigate the neuropsychological functions in ADHD only, specific learning disability only, and comorbid ADHD and specific learning disability. We searched for any neuropsychological dysfunctions that could be categorized into groups and the main effect of each group of neuropsychological functions.Participants and methods
Our study participants were divided into four groups: three patient groups [ADHD only (n=30), specific learning disability only (n=30), and comorbid ADHD and specific learning disability (n=30)] and one control group (n=30), aged 7–13 years, with IQ equal to or above 90. The executive functions of all groups were examined: working memory (verbal and visuospatial), cognitive flexibility and set shifting (Wisconsin card sorting test, trail making test, and Stroop color and word test), planning (Tower of London), and response inhibition (continuous performance test).Results
Our study revealed that all three groups (ADHD, specific learning disability, and comorbid ADHD and specific learning disability) had a significant impairment in all executive functions, with the least scores in the comorbid ADHD and specific learning disability group, followed by the ADHD group and then the specific learning disability group.Conclusion
ADHD and specific learning disability share the same underlying cognitive deficit.