Parametric neurocognitive task design: a pilot study of sustained attention in adolescents with bipolar disorder

Background: Disruption in attention is one of the core features of bipolar disorder (BP). Therefore, neurocognitive paradigms assessing brain function in response to tasks of increasing attentional difficulty may be useful to clarify the neurophysiology of bipolar disorder. The aim of this study was to obtain pilot performance data using a parametric task of sustained attention that might be useful as an experimental paradigm for future functional neuroimaging studies. We hypothesized that task performance would worsen as task difficulty increased in manic and euthymic bipolar and healthy subjects. Additionally, we hypothesized that the groups would exhibit a similar decline in task performance as level of task difficulty increased and that within each level of task difficulty there would be similar performance among groups. Methods: A novel parametric Continuous Performance Task-Identical Pairs (CPT-IP) version was administered to manic (N=10) and euthymic (N=10) adolescents with bipolar disorder and healthy controls (N=10). Results: There were no statistically significant group differences in task performance as measured by discriminability, percent correct, false positive hits, and reaction time. However, within each group, performance on all measures worsened with increased attentional difficulty (p<0.0001). There were no statistically significant task difficulty by group interactions. Furthermore, medication exposure and comorbid attention-deficit hyperactivity disorder were not associated with most measures of task performance. However, BP subjects who were treated with medications had slower task performance compared with BP subjects who were unmedicated. Limitations: Larger studies examining the effects of specific medication classes on task performance are necessary. Conclusions: The results of this pilot study suggest that manic and euthymic BP patients do not exhibit attentional dysfunction as compared to healthy adolescents using a novel parametric version of the CPT-IP. Furthermore, our parametric CPT-IP version may be useful as a novel parametric neurocognitive paradigm for future functional neuroimaging studies of bipolar adolescents. (C) 2004 Elsevier B.V. All rights reserved.