Hot flashes are associated with altered brain function during a memory task

Objective:Vasomotor symptoms (VMS) are associated with decreased memory performance and alterations in brain function. We conducted a preliminary examination of VMS and patterns of brain activity during a verbal memory task to provide insights into the VMS-related brain mechanisms that can contribute to memory problems in midlife women.Methods:Fourteen postmenopausal women (mean age 53.5, 64% African-American) with moderate-to-severe VMS (>35/wk) and not taking hormone therapy completed functional magnetic resonance imaging (fMRI) assessments during word encoding and recognition, 24-hour physiologic VMS monitoring, symptom questionnaires, and two verbal memory tests.Results:In regression analyses, a higher number of physiologic VMS, but not reported VMS, was associated with worse verbal memory on immediate and delayed logical memory (r = 0.53 and r = 0.72, P < 0.05). On fMRI assessments, a higher number of physiologic VMS, but not subjective VMS, was associated with greater activation in the left orbitofrontal cortex, left medial and superior frontal gyrus, right superior frontal gyrus, and right parahippocampal gyrus during the encoding task (P < 0.005). During the recognition task, physiologic VMS were associated with greater activation in the left medial and superior frontal gyrus, left parahippocampal gyrus and hippocampus, right medial and superior frontal gyrus, right parahippocampal gyrus and hippocampus (P < 0.005), and with decreased activation in the ventral medial prefrontal cortex (P < 0.005). Those associations were independent of symptoms and hormone levels.Conclusions:Preliminary data suggest that VMS may contribute to memory performance through effects on the hippocampus and prefrontal cortex. Larger studies are warranted to determine the robustness of these initial observations.