Hemispheric asymmetry in depression and mania - A longitudinal QEEG study in bipolar disorder

Background: previous research has been inconclusive about the nature of hem ispheric asymmetry in emotional processing. Method: 13 patients with DSM-IV bipolar disorder received repeated QEEGs over 2 years in different mood st ates. Z-score measures of asymmetry were assessed. Results: asymmetry in fr ontotemporal slow-wave activity appeared to be in opposite directions in de pression compared to mania/hypomania, Conclusions: mood change in bipolar d isorder is associated with change in QEEG asymmetry. Limitations: study of larger numbers of more homogenous patients under similar conditions is need ed. Clinical relevance: study of mood state-dependent asymmetry changes in bipolar disorder may lead to better understanding of hemispheric processing of emotion. (C) 1999 Elsevier Science B.V. All rights reserved.