Normative observations on neuropsychological test performances in old age.

As part of a study of dementia, 162 normal volunteers in the age range of 65-84 years were given a battery of nine neuropsychological tests assessing temporal orientation, short-term memory, language functions, and visuoperceptive capacity. When compared to subjects less than 65 years of age, the groups showed little evidence of generalized decline in cognitive function before the age of 80 years. The 80-84 years subgroup showed a higher overall failure rate on the tests than the younger subgroups. Nevertheless, 70% of all subjects in the 80-84 years subgroup made no more than one failure on the nine tests. There were substantial differences among the tests in respect to their sensitivity to the effects of aging. The largest decline in performance was shown on tests of short-term visual memory, serial digit learning, and facial recognition. The other verbal, memory, and visuoperceptive tests were performed well up to the age of 80 years. The findings are interpreted as providing limited support for the hypothesis that normal aging does not necessarily involve a general decline in level of cognitive functioning. The clinical application of the tests that were sensitive or insensitive to the effects of aging is considered.