Functional magnetic resonance imaging of working memory reveals frontal hypoactivation in middle-aged adults with cognitive complaints

Abstract

Older adults with cardiovascular disease (CVD) often complain about cognitive difficulties including reduced processing speed and attention. On cross-sectional examination, such reports relate more closely to mood than to cognitive performance; yet, in longitudinal studies, these complaints have foreshadowed cognitive decline over time. To test the hypothesis that self-reported cognitive difficulties reflect early changes in brain function, we examined cognitive complaints and depression in relation to blood oxygen level dependent (BOLD) response to a cognitive task in middle-aged adults at risk for CVD. Forty-nine adults (ages 40 to 60 years) completed a measure of perceived cognitive dysfunction (Cognitive Difficulties Scale), medical history questionnaire, neuropsychological assessment and functional magnetic resonance imaging (fMRI) during a working memory task. Increased report of cognitive difficulties was significantly associated with weaker task-related activation in the right superior frontal/ middle frontal gyrus (F(4,44) = 3.26; p = .020, CDS ß = -0.39; p = .009) and the right inferior frontal gyrus (F(4,44) = 3.14; p = .024, CDS ß = -0.45; p = .003), independent of age, education, and self-reported depressive symptoms. Lower activation intensity in the right superior frontal gyrus was related to trends toward poorer task performance. Thus, self-reported cognitive difficulties among cognitively normal middle-aged adults may provide important clinical information about early brain vulnerability that should be carefully monitored.