Frontal cerebral perfusion dysfunction in elderly late-onset major depression assessed by 99MTC-HMPAO SPECT

Baseline regional cerebral blood flow of thirty unmedicated late-onset unipolar major depressed patients over the age of 60 years and 20 sex-, age-, and vascular risk factor-matched healthy controls was imaged with single photon emission computed tomography, using technetium-99m hexamethylpropylene amine oxime as a tracer. To avoid errors of diagnosis--in particular, confusion between major depression and organic cognitive impairment--only treatment responders were included in the final sample. Statistically significant differences were observed in both left and right anterior frontal regions, with reduced uptake in depressed patients; these differences were more pronounced in the left hemisphere. Among patients, there was no correlation between regional cerebral blood flow and the severity of baseline symptoms. Our results support the hypothesis that certain neuroanatomic regions of the central nervous system may be functionally involved in elderly unipolar major depression, particularly in the late-onset subgroup.