title: Decrease of event-related delta oscillations in euthymic patients with bipolar disorder.
abstract: Decreased delta oscillation upon cognitive load is common in patients with Alzheimer׳s disease, mild cognitive impairment, and schizophrenia. However, there is no previous study analyzing the delta responses in euthymic medication-free patients with bipolar disorder. Participants comprised of 22 euthymic medication-free patients with DSM-IV diagnoses of bipolar disorder and 21 healthy controls who were matched to the patients for sex, age, and education. Electroencephalographic activity was recorded at 30 electrode sites using an application of an auditory oddball paradigm. The maximum peak-to-peak amplitudes for each subject׳s averaged delta response (0.5-3.5Hz) were measured. There was a significant inter-group difference in evoked and event-related delta (0.5-3.5Hz) responses. Post-hoc comparisons revealed that the event-related delta oscillatory responses of the bipolar patient group were significantly lower than those of the healthy control group over the temporo-parietal and occipital electrode sites. Euthymic bipolar patients showed reduced event-related delta oscillatory responses in comparison to healthy subjects under cognitive load. The decrease of delta oscillations may be a common phenomenon that can be observed in different neuropsychiatric disorders with cognitive dysfunction.
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Yıldırım Beyazıt University, Ankara, Turkey; Ankara Ataturk Training and Education Hospital, Ankara, Turkey; Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey.
authors.forename: Murat İlhan
authors.initials: Mİ
authors.lastname: Atagün
authors.affiliation: Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey.
authors.forename: Bahar
authors.initials: B
authors.lastname: Güntekin
authors.affiliation: Yedikule Armenian Hospital, Istanbul, Turkey.
authors.forename: Belinda
authors.initials: B
authors.lastname: Maşalı
authors.affiliation: Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey.
authors.forename: Elif
authors.initials: E
authors.lastname: Tülay
authors.affiliation: Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey. Electronic address: e.basar@iku.edu.tr.
authors.forename: Erol
authors.initials: E
authors.lastname: Başar
mesh_terms: D000328:Adult; D000544:Alzheimer Disease / Q000503:physiopathology; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D003700:Delta Rhythm / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male
keywords: Auditory; Bipolar disorder; Delta oscillations; Electroencephalography (EEG); Event-related potentials