Hippocampal atrophy correlates with clinical features of Alzheimer disease in African Americans

Context: Imaging measurements may aid in the characterization and diagnosis of patients with Alzheimer disease (AD). Most research studies, however, have been performed on predominantly white study groups despite the fact that there may be biological differences in AD between African American and white patients. Objective: To measure hippocampal volume in African American patients with AD and to correlate these measurements with the presence of AD and neuropsychological test performance. Design: Survey study. Setting: Academic center. Participants: Fifty-four healthy African American subjects and 32 African American patients with AD were studied. Hippocampal volumes were measured in all subjects from magnetic resonance images using established methods. Main Outcome Measure: Correlations were assessed between hippocampal volume and demographic variables, clinical group membership, and neuropsychological performance. Results: The hippocampi of patients were atrophic with respect to those of healthy subjects (P<.01). Significant direct correlations were present between hippocampal volumes and performance on several different neuropsychological tests (r>0.5 and P<.01 for every test evaluated) when patients and healthy subjects were combined. Conclusions: Hippocampal atrophy is a feature of AD in African Americans as it is in white subjects. The neuropsychological-hippocampal volume correlations indicate that hippocampal volume measurements do represent a measure of the structural substrate of functional impairment in AD.