Journal of Alzheimer's disease : JAD
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The evaluation and management of patients with cognitive decline pose many diagnostic and therapeutic challenges. While most cognitive disorders need a standard screening for common reversible causes, the diagnosis of `not so usual' causes are delayed and often missed. ⋯ Many more metabolic, nutritional, endocrinal, toxic, post operative, autoimmune, cerebrovascular, genetic, infectious, and hemorheological factors are now emerging as unusual causes. This review deals with the recognition and evaluation of these unusual causes of cognitive decline.
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Comparative Study
The outcome of elderly patients with cognitive complaints but normal neuropsychological tests.
Elderly patients may present with prominent cognitive complaints and have performances in neuropsychological tests within the normal range for the age and education, and thus do not fulfill the criteria for mild cognitive impairment (MCI). There is insufficient evidence to support the clinical decision in these cases ("pre-MCI"). Forty-three subjects, 11 controls, 15 "pre-MCI," and 17 MCI, were followed for about three and half years with neuropsychological testing and magnetic resonance imaging including volumetric measurements of the hippocampus and amygdala. ⋯ In contrast, all control subjects remained stable and had no volumetric decreases. As expected, MCI patients underwent significant deterioration in several neuropsychological tests, often progressed to Alzheimer's disease, and showed decreases both in total hippocampal and amygdalar volumes. Elderly people presenting with cognitive complaints may be in an initial phase of a degenerative disorder and should be followed clinically, even if they have normal neuropsychological tests.
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Comparative Study
Lost and found: bespoke memory testing for Alzheimer's disease and semantic dementia.
The neural network activated during Topographical Memory (TM) tasks in controls overlaps with the earliest affected regions in Alzheimer's disease (AD) but not with those of Semantic Dementia (SD). This suggests that clinical TM tests could be more bespoke to neural dysfunction in early AD and therefore more sensitive and specific. We hypothesized that TM impairment would be characteristic of AD but not of SD making it useful both for early diagnosis and differential diagnosis. ⋯ The VRLT achieved 95% sensitivity and 94% specificity in discriminating AD patients from controls; at the same cutoff, 70% of MCI patients were impaired. When combined with either naming performance or global dementia severity, there was complete separation of AD from SD. The VRLT is ecologically valid, highly sensitive to early AD, and useful in discriminating AD from the non-Alzheimer dementia, SD.
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Cognitive dysfunction in the elderly commonly observed following anesthesia has been attributed to age-related neuronal changes exacerbated by pharmacotoxic effects. However, the extent to which these changes may persist following recovery from surgery is still largely unknown. This study investigates the long-term effects of anesthesia on cognitive functioning after orthopedic surgery in 270 elderly patients over the age of 65 who completed a computerized cognitive battery before and 8 days, 4 and 13 months after surgery. ⋯ On the other hand, a clear dissociation effect was observed for several areas of visuospatial functioning which persisted up to the 13-month follow-up. This specific pattern of visuospatial deficit was found to be independent of apolipoprotein E genotype and closely resembles what has recently been termed vascular mild cognitive impairment, in turn associated with subtle sub-cortical vascular changes. The observation of only minor differences between persons operated by general and regional anesthesia makes it difficult to attribute these changes directly to the anesthetic agents themselves, suggesting that cognitive dysfunction may be attributable at least in part to peri-operative conditions, notably stress and glucocorticoid exposure.
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An inverted U-shape function between cortisol levels and memory performance has been reported in studies on both young animals and humans. Yet little is known about this relationship in normal aging or in older subjects with cognitive impairment. This issue is particularly significant since increased levels of cortisol have been reported in Alzheimer's disease (AD). ⋯ Higher cortisol levels were associated with better memory performance in healthy elderly (p=0.005), while higher cortisol levels were correlated with poorer memory performance in MCI subjects (p=0.011). No correlation between cortisol and memory was found in the AD group (p > 0.05). These results suggest that the relationship between cortisol levels and memory performance in the aging process could vary according to the presence or absence of cognitive impairment.