Instead of defining cognitive impairment according to group norms, another way could be to measure an individual?s cognitive performance over time and use their own rate of decline as an indicator of whether they have a cognitive deficit. For example, the figure (Figure 9) shows cognitive performance over three time points for eight individuals. Persons A, D, and G have very rapid slopes of cognitive decline, whereas individuals B and F are relatively stable over the time period. Cognitive decline could be measured in different ways, for example a decline of X points on a test or using the mean level of cognitive change on a task etc.

Measuring cognitive decline is a good way of defining cognitive impairment because it takes into account each person?s premorbid level of cognitive functioning, and allows for individual variations in cognitive performance. For example, although Individual H seems to perform low at all points in comparison to other persons, his performance is stable. In the example in module 1.7. he would have been classified as cognitive impaired because his performance was lower than would be expected given his age, despite the fact that his cognitive functioning is constantly relatively low over many years. However, from a practical point of view, it is unrealistic to test people with neuropsychological tests repetitively over long periods of time to assess change (expensive / requires trained personnel, etc.).

Página en inglés. Es necesario registro en www.ttmed.com/dementia