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Dorsolateral prefrontal hemodynamic responses during a verbal fluency task in hypomanic bipolar disorder
Author(s) -
Nishimura Yukika,
Takahashi Katsuyoshi,
Ohtani Toshiyuki,
IkedaSugita Reina,
Kasai Kiyoto,
Okazaki Yuji
Publication year - 2015
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1111/bdi.12252
Subject(s) - verbal fluency test , prefrontal cortex , bipolar disorder , psychology , dorsolateral prefrontal cortex , hypomania , audiology , cognition , cardiology , neuroscience , clinical psychology , neuropsychology , medicine , mania
Objectives Neuroimaging studies have suggested prefrontal dysfunction in response to cognitive activation in bipolar disorder ( BD ). However, its characteristics in manic states have not been well understood. Thus, we compared prefrontal hemodynamic responses during a cognitive task between hypomanic and depressive states in BD . We then longitudinally compared hypomanic and subsequent euthymic states. Methods The prefrontal function of 27 patients with BD (11 hypomanic and 16 depressed) and 12 age‐ and gender‐matched healthy controls ( HC s) was evaluated using near‐infrared spectroscopy ( NIRS ) during a verbal fluency task ( VFT ). Hypomanic symptoms were assessed using the Young Mania Rating Scale. Among the 11 hypomanic patients, eight participated in the second NIRS measurement after their hypomanic symptoms resolved. Results VFT performance did not differ among hypomanic, depressed, and HC groups. Both BD groups exhibited significantly lower activation during the VFT than HC s in the broader bilateral prefrontal cortex. Hemodynamic changes in the left dorsolateral prefrontal cortex ( DLPFC ) in the hypomanic patients with BD were significantly larger than those in the depressed patients. In addition, hypomanic symptom severity was positively correlated with activation in the left DLPFC and frontopolar cortex in patients with BD . Follow‐up measurement of the hypomanic patients revealed that prefrontal activation was decreased after hypomanic symptoms resolved. Conclusions Combining cross‐sectional and longitudinal assessments, the present results suggest that prefrontal hemodynamic responses associated with cognitive activation differ between hypomanic and depressive states in BD . NIRS measurement could be a useful tool for objectively evaluating state‐dependent characteristics of prefrontal hemodynamics in BD .