Primary depression with cognitive impairment, referred to as depressive pseudodementia, may be mistaken for a progressive degenerative dementia. Recognition of primary depression is clinically important because of its treatability.

To differentiate depression from degenerative dementia, author rsed brain Tc 99m-HMPAO SPECT. By the result the regionar cerebral blood flew(rCBF) in elderly depressed patient was decreased in the left temporoparietal cortex. The pattern of rCBF was different from that of dementia which shows decreased rCBF in bilateral cortex.

By using brain SPECT in depressed elderly patient with cognitive impairment, the discrimination from dementia will be more effective and accurate.