Electrophysiological and cognitive function in young euthymic patients with bipolar affective disorder

Objectives: EEG abnormalities and neurocognitive deficits have been reporte d in patients with bipolar affective disorder. The aim of this study was to ascertain whether brain function remains impaired in young bipolar patient s who have become euthymic in response to treatment. Methods: Brain function was assessed by quantitative electroencephalographi c (EEG) power-spectral mapping and by a battery of neuropsychological tests . The subjects were 29 euthymic bipolar patients aged 18-40 years and 26 he althy volunteers of similar age, IQ and socioeconomic status. Results: Grand means of spectral power of the resting EEG showed significan tly (from p < 0.01 to p < 0.0001) greater power in all wave bands (delta, t heta, alpha and beta) in patients compared with controls. The most marked i ncreases were in right temporal theta and left occipital beta power (with e yes open) encompassing brain areas concerned in visuospatial processing. Ne urocognitive performance was significantly impaired in the patients compare d with controls in a range of visuospatial tasks. Conclusions: The findings show significant disturbance of EEG activity and deficits in visuospatial processing in young bipolar patients despite clini cal euthymia, The abnormalities were not related to age of onset or duratio n of illness and do not appear to be attributable to medication. The cognit ive impairments were associated with the number of previous affective episo des.