title: Interictal slow-wave focus in left medial temporal lobe during bilateral electroconvulsive therapy.
abstract: The interictal state between two electroconvulsive therapy (ECT) sessions is clinically characterised by possible cognitive adverse effects like mild amnestic syndrome. ECT-induced amnestic deficits can persist for several weeks after ECT. Electrophysiologically, slowing of brain electrical activity in the interictal state has often been reported. Especially, for bilateral ECT a correlation between enhanced left frontotemporal theta activity and retrograde amnesia has been demonstrated. This study focuses on the topographic distribution of cortical slow-wave oscillations during the interictal state of a bilateral ECT cycle. Twelve patients with major depression have been investigated with 32-channel resting EEG 24 h after the 6th ECT session. As controls, 8 major depressive patients were investigated prior to antidepressive treatment. The generating sources of slow-wave activity are estimated within the theta frequency band with low-resolution brain electromagnetic tomography. Source analysis revealed a distinct pattern of theta activity in the depth of the left temporal lobe (fusiform and parahippocampal gyri, Brodmann areas 37 and 36, respectively; p< 0.05) during the interictal state. This finding suggests a dysfunction of the left medial temporal lobe memory system during the interictal state of a bilateral ECT cycle. It will further be discussed whether it is possible to obtain information about activity of deep brain structures like the hippocampal formation from scalp-recorded signals.
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany. andres.neuhaus@charite.de
authors.forename: Andres H
authors.initials: AH
authors.lastname: Neuhaus
authors.forename: Juergen
authors.initials: J
authors.lastname: Gallinat
authors.forename: Malek
authors.initials: M
authors.lastname: Bajbouj
authors.forename: Friedel M
authors.initials: FM
authors.lastname: Reischies
mesh_terms: D000328:Adult; D000648:Amnesia, Retrograde / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D003865:Major Depressive Disorder / Q000628:therapy*; D004565:Electroconvulsive Therapy / Q000009:adverse effects*; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013702:Temporal Lobe; D013826:Theta Rhythm