Self-Reported ADHD Symptoms and Interhemispheric Interaction in Adults: A Dimensional Approach

Saleh M H Mohamed,Jaap J Van Der Meere,Norbert A Börger,Reint H Geuze

doi:10.1155/2015/254868

Abstract

The present study applied the dimensional approach to test whether self-reported symptoms of Attention Deficit/Hyperactivity Disorder (ADHD) in adults are associated with the speed of interhemispheric interaction. A sample of first grade students (N = 112) completed Conners' Adult ADHD Rating Scales and letter matching reaction time tasks. In the tasks, participants had to match a single target letter displayed below the fixation cross, either on left or right visual field, with one of two letters displayed above the fixation cross, one letter on each visual field. For each task, identical letters were presented either within the same visual field (within hemisphere condition) or across visual fields (across hemisphere condition). Interhemispheric interaction was indexed as the difference in mean reaction time between within and across hemisphere conditions. Comorbid problems such as depression, anxiety, and stress may affect task performance and are controlled for in this study. Findings indicated that self-reported ADHD symptomology, especially hyperactivity, in the presence of stress was weakly but significantly associated with fast interhemispheric interaction.

Highlights

A recent meta-analytic review indicates that childhood and adulthood Attention Deficit/Hyperactivity disorder (ADHD: DSM-IV) are characterized by compromised information processing skills including executive function demonstrated in reaction time studies [1]
Recent meta-analytic reviews on the structure of the corpus callosum in patients with ADHD concluded that there is some evidence that its size is reduced; some potential confounders have to be taken into consideration such as a small sample size; some patients were on medication during the assessment
Answers on the questionnaire might be considered reliable because only 15 subjects had a score above seven on the inconsistency index of the Conners’ Adult ADHD Rating Scales (CAARS) purported to identify random or careless responding

Summary

Introduction

A recent meta-analytic review indicates that childhood and adulthood Attention Deficit/Hyperactivity disorder (ADHD: DSM-IV) are characterized by compromised information processing skills including executive function demonstrated in reaction time studies [1]. These cognitive skills are traditionally associated with prefrontal lobe functioning, and brain mapping studies reported reduced activation in fronto-parietal-cerebral areas (see, e.g., the meta-analysis of Hart and colleagues [2]). Evidence is growing that cognitive skills including executive function rely on the cooperation between the two cerebral hemispheres subserved by the corpus callosum [3,4,5] This suggests that compromised information processing skills in ADHD may be associated with inefficient interhemispheric communication. Two dichotic listening studies provided some indication that interhemispheric interaction is compromised in patients with ADHD with deficits located in one hemisphere and/or poor interhemispheric interaction [13, 14]

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