CPT Continuous Performance Task FASD Fetal alcohol spectrum disorder AIM The attention and inhibition problems found in children with attention-deficit-hyperactivity disorder (ADHD) are also common in children with fetal alcohol spectrum disorders (FASDs). Attempts to distinguish ADHD from FASDs in terms of these deficits are rare and were pursued in this study.METHOD A total of 116 children (47 with ADHD, 31 males, 16 females; 30 with FASDs, 17 males, 13 females; and 39 comparison children, 20 males, 19 females) participated. The mean age was 9 years 4 months (SD 1y 8mo) in the ADHD groups, 8 years 10 months (SD 1y 2mo) in the FASD group, and 9 years 1 month (SD 1y 1mo) in the comparison group. Sustained attention was tested with a slow event rate continuous performance task (CPT). Inhibitory control was tested with both a slow and fast event rate Go ⁄ No-Go task.
RESULTSOn the CPT task, children with ADHD, combined type (ADHD-C), ADHD, primarily inattentive type (ADHD-PI), and FASDs showed greater declines in task performance as a function of time than comparison children, suggesting sustained attention problems in all clinical groups. Children's Go ⁄ No-Go performance was event-rate dependent, with the ADHD-C group being affected in the slow condition and the ADHD-PI and FASD groups having problems with the fast condition.INTERPRETATION Children with ADHD-C are typically impaired in handling understimulation, while children with FASDs may have problems with overstimulation. The dissociation in responsivity to event rate between groups may have significant differential diagnostic value.The modern fetal alcohol spectrum disorders (FASDs) concept dates back to 1973, when it was first described as fetal alcohol syndrome (FAS).1 Since then, numerous papers have reported on the neurobehavioural symptoms associated with the disorders, including attention problems, restlessness, and impulsivity.2 Such problems are typically also seen in children with attention-deficit-hyperactivity disorder (ADHD).The fact that attention and impulsivity problems characterize both FASDs and ADHD has fuelled speculation regarding their overlap, but this possibility has rarely been tested by directly comparing both groups in the same design using neurocognitive tests of attention. Nanson and Hiscock 3 compared children with FAS with children with ADHD and a comparison group on a series of attention tasks. While the children with FAS were slower than those in the other two groups, their impulsivity and attention problems were similar to those of the children with ADHD. In addition, Coles et al. 4 directly compared the attention profiles of children with FAS and children with ADHD. Children with FAS had difficulties with encoding and shifting attention, while the children with ADHD had problems with focusing and sustaining attention. Interestingly, children with ADHD were found to be impulsive, unlike the children with FAS.The clinical relevance of the attention and impulsivity problems in ADHD is undisputed. In the search for the etiolog...