Children With Alcohol-Related Neurodevelopmental Disorder or Attention Deficit/Hyperactivity Disorder Differ on Neuropsychological Tasks and Measures of Eye Movement Control

Abstract

Children with alcohol-related neurodevelopmental disorder or attention deficit/hyperactivity disorder differ on neuropsychological tasks and measures of eye movement control. M.Sc. Thesis, Queen’s University, Kingston, Ontario, Canada, January 2010.

Background: Alcohol-related neurodevelopmental disorder (ARND) accounts for the majority of diagnoses associated with prenatal alcohol exposure. Unfortunately, ARND frequently poses a significant clinical challenge as these patients lack the visible physical characteristics associated with alcohol teratogenicity. Moreover, the cognitive and behavioural disabilities are complex and overlap with those of attention deficit/hyperactivity disorder (ADHD). Furthermore, co-morbid ADHD is prevalent in children with prenatal alcohol exposure. While early and accurate diagnosis provides the best prognosis for those affected, there is a lack of tools for differential diagnosis between these two disorders. The goal of this study was to test the hypothesis that children with ARND exhibit different performance from children with ADHD on computer-based neuropsychological tests and eye movement tasks. Methods: Our study group was composed of 42 children with ARND and 31 children with ADHD aged 8-15 years, male and female. Children completed four tasks selected from the Cambridge Neuropsychological Test Automated Battery (CANTAB®) that provided measures of attention, planning, strategy and spatial working memory. Subjects also performed pro- and anti-saccade tasks, and eye movements were recorded using a mobile eye-tracking system. Results: Children with ARND demonstrated elevated decision times on a visual matching test of attention and longer response times on a task of spatial working memory, although the two groups had similar errors scores. Also, compared to children with ADHD, children with ARND had greater anticipatory errors in both the pro- and anti-saccade tasks. Conclusion: This study demonstrates that there are measurable differences in executive function and eye movement control between children with ARND or ADHD. Greater deficits in visuospatial processing in ARND may underlie these differences. These findings demonstrate that the neurobehavioural phenotypes of children with ARND or ADHD have distinct features, which may be accounted for by differences in the patterns of brain injury underlying these two disorders.