Amygdalar volume and psychiatric symptoms in Alzheimer's disease: an MRI analysis.

OBJECTIVES: We measured the volumes of the amygdala to test the hypothesis that the reduction of amygdalar volume may be associated with psychiatric symptoms in Alzheimer's disease.

MATERIALS AND METHODS: Twenty-seven patients underwent neuropsychological investigation including the assessment of general clinical severity by the Mini-Mental State Examination (MMSE) and Neuropsychiatric Inventory (NPI). All patients underwent magnetic resonance imaging (MRI) of the head, from which the volumes of the amygdalae were measured. The obtained values were compared with those of controls (n = 15).

RESULTS: Patients with Alzheimer's dementia showed significant reduction in MRI volumetric measurements compared with controls. We found a significant correlation of MMSE score and absolute amygdala volume (r = 0.62, P < 0.01). Neither the absolute nor relative volume of the amygdala showed any correlation with NPI scores.

CONCLUSIONS: The atrophy of the amygdala does not have a direct association with the existence of neuropsychiatric symptoms. MRI volumetry of the amygdala may be relevant as a marker of dementia severity in Alzheimer's disease.