A Single Photon Emission Computerised Tomography Study of Regional Brain Function in Elderly Patients with Major Depression and with Alzheimer-Type Dementia

Abstract

The uptake, at rest, of 99mTc-exametazime into different brain regions was compared using SPECT for 20 elderly subjects with major depressive disorder, 20 with Alzheimer-type dementia, and 30 age-matched normal volunteers. Uptake was referred to calcarine-occipital cortex as a reference sensory area. Cross-sectional differences between the three groups were highly statistically significant, but reflected primarily the reductions in cortical uptake in the Alzheimer group. A detailed comparison of depressed patients and controls identified decrements in anterior cingulate, temporal and frontal cortex and in caudate and thalamus in men only. These decrements were correlated with impairment of performance on a trail-making task, but were also associated with continuing treatment with antidepressants or benzodiazepines. However, most depressed patients had quantitatively normal scans for posterior parietal association cortex, and this suggests that SPECT may find a limited role in the differential diagnosis of depression and dementia. The reduced brain function in some depressed patients may parallel the findings from studies of brain structure in elderly depressives; there was between good outcome at 6-18 months and increased tracer uptake in subcortical areas.

Changes in regional cerebral blood flow following antidepressant treatment in late‐life depression

“…The results partially support the notion of hypofrontality in patients with late-life depression as shown by most previous functional neuroimaging research (Upadhyaya et al, 1990;Curran et al, 1993;Philpot et al, 1993;Ebmeier et al, 1998;Navarro et al, 2001). Specifically, our results are consistent with those of Navarro et al (2001) in that rCBF of patients with unmedicated late-onset unipolar major depression showed significant decreases in both the left and right anterior frontal regions.…”

“…On the other hand, studies report a decrease/increase in regional CBF (rCBF) and/or glucose metabolism in particular regions of the brain. Such regions include the prefrontal cortex (PFC), cingulate, amygdala/hippocampus, basal ganglia, or thalamus, suggesting involvement of the networks that regulate mood and emotion (Buchsbaum et al, 1986;Curran et al, 1993;Dolan et al, 1993;Bench et al, 1995;Lesser et al, 1994;Goodwin, 1997;Mayberg et al, 1999;Nobler et al, 2000;Anand and Shekhar, 2003;Navarro et al, 2004). Although results of studies are inconsistent, most research focuses on dysfunction of mood-related circuits involving the multiple prefrontal cortices and limbic structures.…”

Changes in regional cerebral blood flow abnormalities in late‐life depression following response to electroconvulsive therapy

“…Among these reports, the most consistent findings are hypoperfusion and hypometabolism in the anterior brain structures, especially in the prefrontal cortex [1][2][3][4][5][6][7][8][9][10][11] and the anterior paralimbic regions, [9][10][11][12][13] and similar findings have also been reported in late-life depression. [14][15][16][17] However, the clinical significance of these findings remains controversial. Several studies investigated the changes of rCBF or rCMR before and after treatment, and demonstrated state-related increases of rCBF 13,[18][19][20] or rCMR for glucose 3,21 following response to antidepressant medication, while a few studies reported no significant increase.…”

Neuropsychology of memory and SPECT in the diagnosis and staging of dementia of Alzheimer type

“…characterised primarily by bilateral reduction of rCBF in the posterior temporoparietal cortex [11,14,30,35,50]. Hanyu et al [231 found that temporoparietal hypoperfusion was 82% sensitive and 89% specific for the diagnosis of DAT; although this pattern of hypoperfusion was present even in patients with mild DAT, it should be noted that 18% of their patients did not show this.…”