Basic and complex cognitive functions in Adult ADHD.

Saleh M. H. Mohamed,Matthias Weisbrod,Oliver Tucha,Trinidad Garcia,Steffen Aschenbrenner,Anselm B. M Fuermaier,Lara Tucha,Marah Butzbach

doi:10.1371/journal.pone.0256228

Abstract

BackgroundMany clinical studies reported deficits in basic and complex cognitive functions in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). However, the extent in which deficits in basic functions (i.e., processing speed and distractibility) contribute to complex cognitive impairments (i.e., working memory, planning, cognitive flexibility, memory functions) in adults with ADHD is not well-studied. So far, literature show only one study, revealing that basic functions explain 27–74% of executive dysfunctions. Yet, the authors reported that findings could be affected by the selection of neuropsychological tests. The goal of the present research is to replicate such a finding using a different sample and a different set of neuropsychological tests.MethodsForty-eight adult patients with ADHD were compared with 48 healthy controls in basic cognitive functions, namely processing speed and distractibility and more complex cognitive functions, namely selective attention, cognitive flexibility, planning, working memory, verbal fluency, and verbal memory. Basic and complex cognitive functions were assessed using the Vigilance and Sustained Attention, Selective Attention, N-Back, Tower of London, Trail Making Test, Word Fluency, and Verbal Learning and Memory.Results and conclusionLogistic regression analyses showed that impairments in complex cognitive functions explained 25% of the variance in ADHD diagnosis. The explained variance dropped from 25% to 9% after considering basic functions of processing speed and distractibility. This 64% reduction highlights the importance of basic functions for impairments in complex functions in patients with ADHD.

Highlights

Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder that negatively affects several life domains
Logistic regression analyses showed that impairments in complex cognitive functions explained 25% of the variance in ADHD diagnosis
Mann-Whitney tests revealed significant differences between patients with ADHD and controls in mean reaction times and omission errors on the WAFV test with medium effect sizes: patients were slower and showed more omission errors compared to controls

Summary

Introduction

Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder that negatively affects several life domains. Besides the behavioral symptoms of ADHD, studies have reported impairments in basic cognitive processes such as slow processing speed, distractibility, and increased reaction time variability [5,6,7,8,9]. In particular, is a consistently replicated deficit of neuropsychological performance in ADHD [5,14,15]. The studies even suggested that slow processing speed in ADHD may disappear after controlling for reaction time variability ADHD [5,14,15]. Many clinical studies reported deficits in basic and complex cognitive functions in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). The extent in which deficits in basic functions (i.e., processing speed and distractibility) contribute to complex cognitive impairments (i.e., working memory, planning, cognitive flexibility, memory functions) in adults with ADHD is not well-studied. The goal of the present research is to replicate such a finding using a different sample and a different set of neuropsychological tests

Objectives

Results

Discussion

Conclusion