HIPPOCAMPAL VOLUMES IN ALZHEIMERS-DISEASE, PARKINSONS-DISEASE WITH AND WITHOUT DEMENTIA, AND IN VASCULAR DEMENTIA - AN MRI STUDY

Hippocampal atrophy detected by volumetric MRI is a sensitive feature of early Alzheimer's disease (AD), but there are no studies evaluating hippocampal atrophy by MR volumetry in other dementing diseases. We t herefore compared hippocampal volumes in a total of 113 subjects: 50 p atients with mild to moderate AD, 9 patients with vascular dementia (V aD), 12 patients with idiopathic Parkinson's disease (PD) without deme ntia, 8 patients with PD and dementia (PDD), and 34 elderly control su bjects. Thin, coronal, contiguous images were obtained by a 1.5-T MR i mager. All patient groups had significantly smaller volumes of the hip pocampus compared with the control group. In the PDD group, the absolu te volumes were even smaller than in the AD group. In the PD group, th e volumes were diminished to a lesser but significant extent. The volu mes in the VaD group varied: of nine patients, two had no atrophy, thr ee had unilateral, and four had bilateral atrophy. We postulate that h ippocampal atrophy does not seem to be a specific phenomenon of dement ia in AD but also occurs in VaD and PDD, and even in PD when no dement ia is present. However, coexistence of AD pathology in our PD and VaD patients cannot be ruled out. Further studies with access to neuropath ologic data are needed.