Rate of forgetting in dementia and depression.
ABSTRACT Patients with mild dementia of the Alzheimer's type (DAT), patients with major depression, and normal control subjects were examined for rate of forgetting line drawings of common objects after the groups had been equated for acquisition by the variation of stimulus exposure time. Depressed and DAT patients demonstrated learning impairments, but only the DAT group showed rapid forgetting in the first 10 min after learning to criterion. This finding suggests that some form of deficient consolidation contributes to memory loss in DAT but not in depression and implicates the disruption of different psychobiological mechanisms in these disorders. The rate of forgetting paradigm may be clinically useful for distinguishing patients with early DAT from elderly depressed patients with memory deficits. (53 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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- "Among studies that have used a matched control group, several (Kramer-Ginsberg et al 1999; Hart et al 1987; Boone et al 1995) suggested the presence of disturbances across a range of cognitive domains in LLD. However, in recent work, Butters et al (2004) found that group differences between controls and individuals with LLD in a range of cognitive domains (e.g., executive function, episodic memory, language processing, and visual spatial function) were fully mediated by deficits in processing speed. "
ABSTRACT: A number of studies have examined clinical factors linked to worse neuropsychological performance in late life depression (LLD). To understand the influence of LLD on cognition, it is important to determine if deficits in a number of cognitive domains are relatively independent, or mediated by depression- related deficits in a basic domain such as processing speed. Patients who met DSM-IV criteria for major depression (n = 155) were administered a comprehensive neuropsychological battery of tasks grouped into episodic memory, language, working memory, executive function, and processing speed domains. Multiple regression analyses were conducted to determine contributions of predictor variables to cognitive domains. Age, depression severity, education, race and vascular risk factors all made significant and independent contributions to one or more domains of cognitive function, with all five making independent contributions to processing speed. Age of onset made no independent contribution, after accounting for age and vascular risk factors. Of the five cognitive domains investigated, changes in processing speed were found to most fully mediate the influence of predictor variables on all other cognitive domains. While slowed processing speed appears to be the most core cognitive deficit in LLD, it was closely followed by executive function as a core cognitive deficit. Future research is needed to help clarify mechanisms leading to LLD- related changes in processing speed, including the potential role of white matter abnormalities.Biological Psychiatry 08/2006; 60(1):58-65. DOI:10.1016/j.biopsych.2005.09.019 · 10.25 Impact Factor
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- "The results showed early accelerated forgetting in AD patients after the first 10 min, while the forgetting profiles in the subsequent intervals (2 and 18 hours) was parallel in the two groups. On the basis of these data, Hart et al. (1987) argued that forgetting was accelerated in AD patients during the first minutes after acquisition of the information , but normal after longer delays. "
ABSTRACT: In this study we explored the rate of forgetting from long-term memory in Alzheimer's (AD) and multi-infarct (MID) dementia. For this purpose, we administered to 15 AD, 15 MID, and 22 control subjects two tasks exploring, respectively, long-term verbal and long-term visuo-spatial memory. The absolute rate of forgetting in both tasks was computed as the difference between immediate and delayed recall of memorandum. Since level of immediate recall was significantly different between groups, a proportional rate of forgetting (percentage of memorandum lost passing from immediate to delayed recall) was computed for each patient. In the verbal task (Rey's 15 words) AD patients displayed significantly larger absolute and proportional rates of forgetting than MID and control subjects. In the spatial task (Corsi block supraspan), the absolute rate of forgetting was only marginally different between groups. Nevertheless, AD patients demonstrated a larger proportional rate of forgetting than MID and normal subjects. These results point out an exalted decay of information from long-term memory store in AD patients. In the light of previous data (Corkin et al., 1984; Kopelman, 1985) we propose that long-term memory deficits in AD is due, at least in part, to an abnormal forgetting of information within the first few minutes following acquisition. Information still present in the subsequent period (10 min to several days) is retained normally. The normal rate of forgetting in MID patients, further, suggests different mechanisms underlying memory disorders in vascular and degenerative dementias.International Journal of Neuroscience 12/1993; 73(1-2):1-11. DOI:10.3109/00207459308987206 · 1.53 Impact Factor
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