Measures of executive functions predicting Attention-Deficit/Hyperactivity Disorder core symptoms

Tshikani T Boshomane,Basil Pillay,Anneke Meyer

doi:10.4102/ajopa.v3i0.48

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood disorder, and in many children, ADHD is thought to be aggravated by a deficit in executive functions (EFs). This study tried to establish whether commonly used neuropsychological tests of EF also predicted the core symptoms of ADHD, namely hyperactivity/impulsiveness (H/I) and inattention, as well as total ADHD symptomatology, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR). The participants were children from the Limpopo province, South Africa, aged from 6 to 15 years (M = 11.7 years; SD = 1.7). One hundred and fifty-six children (51.3% girls) were assessed by neuropsychological tests of EFs: the Tower of London (ToL), Digits Forward and Digits Backward, Trails-A and Trails-B and Wisconsin Card Sorting Test (WCST). Forward stepwise regression analysis was employed to predict H/I and inattention, as well as total ADHD symptomatology, based on DSM-IV-TR criteria. All the tests, except Trails-A, were found to predict ADHD symptomatology. The WCST (total errors) was the best predictor of all the ADHD symptoms and also for H/I and inattention separately, followed by Trails-B and Digits Backwards, which were found to predict more symptoms of inattention than H/I. Perseverative errors on the WCST predicted more H/I symptomatology, whilst non-perseverating errors were more associated with inattention. The ToL and Digits Forward predicted fewer ADHD symptoms. The ToL seemed more sensitive to inattention, whilst Digits Forward showed a stronger association with H/I. The WCST, Digits Backwards and Trails-B may be used to measure EF to support the diagnosis of ADHD in a clinical setting and to indicate cognitive impairment.

Highlights

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed psychiatric disorder, affecting 5% – 7% of children and adolescents worldwide (Polanczyk, De Lima, Horta, Biederman, & Rohde, 2007) and 5.5% in the Limpopo province, South Africa (Meyer, Eilertsen, Sundet, Tshifularo, & Sagvolden, 2004)
The purpose of the study was to examine whether commonly used neuropsychological executive functions (EFs) tests, the Tower of London (ToL), Memory for Digits (MFD) (DF and Digits Backwards (DB)), Trails-A and Trails-B and Wisconsin Card Sorting Test (WCST) could predict the core symptoms of ADHD, namely H/I and inattention, as well as total ADHD symptomatology, as measured by a questionnaire (Appendix 1) based on the DSM-IV-TR criteria (American Psychiatric Association, 2000) in a South African population of primary school children
The responses on the WCST indicated that perseverative errors (PE) predicted more H/I symptomatology, whilst non-perseverative errors (NPE) were largely associated with inattention

Summary

Introduction

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed psychiatric disorder, affecting 5% – 7% of children and adolescents worldwide (Polanczyk, De Lima, Horta, Biederman, & Rohde, 2007) and 5.5% in the Limpopo province, South Africa (Meyer, Eilertsen, Sundet, Tshifularo, & Sagvolden, 2004). In about two-thirds of cases, ADHD continues into adulthood (Faraone, Biederman, & Mick, 2006). It is a neurodevelopmental disorder, characterised by the core symptoms of hyperactivity/impulsiveness (H/I), inattention or both (American Psychiatric Association, 2013). Hyperactivity manifests as greater than usual levels of movement and activity and an inability to remain still for a long time (Danielson et al, 2016), whilst impulsiveness is the tendency to act prematurely without anticipation or consideration of the consequences (Dalley, Everitt, & Robbins, 2011). The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) (American Psychiatric Association, 2000) requires a child to meet six or more of H/I or six or more of inattention behaviours, for at least 6 months, before the age of 7 years. The DSM-IV criteria are mainly similar to those of DSM-5, except for the age of onset that changed from 7 to 12 years of age

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