Sustained attention and impulsivity in Tourette syndrome : relationship to attention deficit hyperactivity disorder and obsessive-compulsive behaviour
Date
1995
Authors
Sherman, Elisabeth Mary Suzanne
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Abstract
The purpose of this study was to determine whether children with Tourette Syndrome (TS) have impairments in sustained attention and impulsivity that are not accounted for by comorbid Attention Deficit Hyperactivity Disorder (ADHD). A secondary goal was to determine whether poor performance on a continuous performance task (CPT) was related to the severity of obsessive-compulsive behaviour (OCB) and tic severity. 58 children were compared on the CPT: 17 children with TS (TS-Only group), 9 children with TS and ADHD (TS-ADHD group), 16 children with ADHD (ADHD group), and 17 controls. Contrary to recent findings, only the TS-ADHD group made more errors of omission (misses) on the CPT than controls. However, although the difference between TS-Only children and controls was not statistically significant, 35% of TS-Only children had scores which fell below 2 standard deviations from the control mean in terms of sustained attention. Compared to controls, neither TS-ADHD children nor TS-Only children showed impulsivity as measured by errors of commission (false alarms), although a subgroup of TS-ADHD children had clinically significant impulsivity problems. Severity of OCB was related to errors of commission independently of ADHD and TS ratings. The results of this study suggest that only a subgroup of TS children have measurable deficits in sustained attention and that impulse-control problems in TS children may also be related to comorbid OCB. The TS-specificity of attention problems given the base rate of attention problems in clinical samples in general and the role of tic location as a confound in 1) the measurement of attention in TS and 2) the diagnosis of ADHD in TS are also discussed.