Neuropsychological deficits and CT scan changes in elderly depressives

Abstract

SynopsisA number of computerized tests were used to study visual attention, memory and learning in elderly depressed patients. Impairment was found in approximately 70% of depressed patients and was seen particularly in memory and in measures of latency. Depressed patients showed equivalent impairment in short-term memory but less impairment in conditional associative learning compared to a group of patients with early dementia of the Alzheimer-type (DAT), matched for age and pre-morbid IQ. With respect to qualitative differences between depression and DAT, depressed patients showed a different pattern of errors and a consistently prolonged latency of response which was independent of delay in a delayed matching-to-sample test. On recovery from depression, although improvement was seen in most test scores, performance in measures of latency and in a number of tests of memory and learning failed to reach the level seen in a group of matched control subjects and approximately 35% of patients continued to show impairment. For the depressed patients, ventricular brain ratio (VBR) correlated with measures of slowing. In addition, in the ‘recovered-depressives’, VBR correlated with poor performance at high levels of task difficulty. These findings are discussed with respect to previous literature on the pattern of cognitive impairment and CT scan findings in depression.

Evidence of an early information processing speed deficit in unipolar major depression

“…Our laboratory has preliminary findings that the anticholinergic antidepressant amitriptyline impairs IT in healthy subjects. However, there have been mixed findings of the effects of medication on neuropsychological function in depressed patients (Glass et al 1981 ;Abas et al 1990). A study by Spring et al (1992) indicated that the adverse cognitive effects of amitriptyline were observed only after depressive symptoms had improved.…”

Antidepressant mechanisms: functional and molecular correlates of excitatory amino acid neurotransmission

“…These impairments include deficits in tasks sensitive to hippocampal dysfunction: visual delayed match-to-sample 46 and verbal learning. 3 Interestingly, the verbal learning impairment found in patients with chronic depression was correlated with the degree of reduction of hippocampal grey matter found using magnetic resonance imaging.…”

A study of performance on tests from the CANTAB battery sensitive to frontal lobe dysfunction in a large sample of normal volunteers: Implications for theories of executive functioning and cognitive aging

“…The main guiding principles have been to use some tests that can be related to the extensive neuropsychological literature in animals and to employ tests that can be broken down into their cognitive components in order to define more readily which functions are impaired and which are spared. The battery has now been used quite extensively in the testing of patients with Alzheimer's disease and other forms of dementia (Sahakian et al, 1988Sahgal et al, 1991Sahgal et al, ,1992, patients with basal ganglia disorders such as Parkinson's disease (Downes et al, 1989;Owen et al, 1992, Korsakoff's syndrome (Joyce & Robbins, 1991), depression (Abas et al, 1990;Beats et al, 1996), schizophrenia , HIV-positive patients , and children with minimal learning disabilities or autism (Hughes et al, 1994). The tests have also been validated in neurosurgical patients with excisions of the temporal or frontal lobes and amygdalohippocampectomy (Owen et al, 1995).…”