IQ and the fronto-temporal cortex in bipolar disorder

Abstract

Cognitive changes are documented in bipolar disorder (BP). Cortical volume loss, especially in prefrontal regions, has also been reported, but associations between cognition and cortical abnormalities have not been fully documented. This study explores associations between cognitive performance and cortical parameters (area, thickness and volume) of the fronto-temporal cortex in 36 BP patients (25 BPI and 11 BPII). T1-weighted volumetric MRI images were obtained using a 1.5 Tesla scanner. Cortical parameters were measured using surface-based morphometry and their associations with estimated premorbid, current IQ, visual memory, and executive function explored. Premorbid IQ was associated with frontal cortical area and volume, but no such associations were present for current cognitive performance. Cortical parameters were not different in BPI and BPII patients, but the association between current IQ and temporal cortical area was stronger in BPII patients. The pattern of cortico-cognitive associations in BPI and BPII patients merits further consideration.