Increasing age is accompanied by increased incidence and comorbidity of various chronic diseases. Many of these conditions, such as cardiovascular and kidney disease, can lead to declines in cognitive functioning. A simple additive effect may be commonly assumed. We here evaluate the hypothesis that such effects may be multiplicative/interactive rather than simply additive, resulting in disproportionate decrements in performance on tests of different cognitive functions. Participants were the 1,782 Canadians aged 65 years and older who completed the clinical assessment of the national Canadian Study of Health and Aging and who were without dementia. Participants were categorized as having either kidney disease, cardiovascular disease, neither, or both. Scores on a measure of verbal fluency showed the predicted interaction effects, but not in the predicted pattern of worst performance in the group with both disorders. Reasons for the relative lack of observed main effects of disease and multiplicative interactions, such as the exclusion of people with dementia and nature of the sample from the community, are discussed.
Objectives: Data from the Canadian Study of Health and Aging (CSHA) evaluated cognition and depression in a sample of older adults with diabetes and compared them with those without diabetes. Design: Neuropsychological test scores from a comprehensive clinical assessment were contrasted for the two groups and test scores from CSHA-1 in 1991 used to predict test scores five years later from CSHA-2 with diabetes and depression as additional predictors. Results: There were no differences at CSHA-1 between those with diabetes and those without after adjusting for covariates of age, education, and gender. Older adults with diabetes at CSHA-2 scored lower on a measure of short-term memory, with age, education and CSHA-1 test scores as significant covariates in hierarchical regression analyses. Diabetes and depression were both associated with a measure of verbal short term memory. Conclusions: In this relatively healthy community sample, diabetes appears to have modest influences upon cognition, with verbal short-term memory being the most sensitive to the effects of diabetes.
Abstract The present study examined the test-retest reliability of a 32-item version of the Waterloo Handedness Questionnaire (Steenhuis&Bryden, 1987, 1988, 1989) on 500 subjects. The questionnaire was shown to be reliable in terms of basic factor structure. High test-retest reliability was also found within subjects' responses and across items for both right-handers and left-handers, although left-handers were less consistent than right-handers, particularly with regard to direction of hand preference on individual questionnaire items. Furthermore, the direction of hand preference was more reliable than was the degree of hand preference. These data support a multidimensional view of hand preference in which both direction and degree can be reliably assessed.
Background: Severe brain injuries may be a risk factor for the development of dementia in later life. Less severe incidents with relatively short or even no loss of consciousness may not carry the same prognosis.
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Abstract An overview of specific neuropsychological data from the Canadian Study of Health and Aging is presented. Variables of interest were diagnosis (no cognitive impairment, cognitive loss without dementia, and dementia), language of test administration (French or English), and residence (community or institution). Persons with dementia scored below persons without dementia on all neuropsychological measures except the naming of coloured tokens. Some test differences were small and not clinically meaningful while others were substantial. In particular, and as expected, memory function differed between the groups. Language of test administration and place of residence also influenced neuropsychological results independently of diagnosis. Scores differed on some tests (primarily, visuospatial) depending on whether participants lived in institutions or in the community. Persons tested in French scored below those tested in English on many language-based tests.
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