ABSTRACT
OBJECTS: Through comparison of the 99mTc-HMPAO SPECT image of depressive pseudo-dementia group with those of control group(depression group free from cognitive unpairment) and DAT(Dementia of Alzheimer's type), we tried to see part of pathophysiology of the depressive pseudodementia of the elderly. METHODS: The subjects consisted off patients with dementia of Alzheimer type(DAT group), 7 patients with depression free from cognitive impairment(depression group), 7 patients with depressive pseudodementia(depressive pseudodementia group), and 4 normal controls. Depression patients were diagnosed according to DSM III-R DAT patients were diagnosed by DSM III-R and NINCDS-ADRDA criteria of DAT. All were rated with Hamilton Rating Scale for Depression and Mini Mental State Exam. All underwent 99mTc-HMPAO SPECT scan. The images of each group were analysed using SPM of Friston, which compares the images on voxel-by-voxel basis. RESULTS: The results were as follows 1) DAT group showed significant decrease in cerebral blood flow (CBF) compared with controls in the right frontal region, the right temporal region, and both temporal regions(p<0.05). 2) Depression group showed significant decrease in CBF in the left frontal region(p<0.05). 3) Depressive pseudodementia group showed significant decrease in CBF compared with controls in the right temporal region and the left parietal region(p<0.05). 4) Depressive pseudodementia group showed significant decrease in CBF compared with depression group in the right temporal region and both parietal regions(p<0.05). CONCLUSION: Depressive pseudodementia group showed decreased CBF in temporo-parietal region, similar to that of the DAT group. This result supports the hypothesis that depressive psuedodementia includes a subgroup of patients with early-stage primary dementia.