Subclinical dementia: relevance of cognitive symptoms and signs

In 1971 and 1972, a representative sample of 70-year-old people (n = 392) from a population study was rated with regard to psychiatric symptoms and signs. Subjects showing evidence of dementia of any degree, including slight and questionable, were excluded (n = 18). The remaining 374 subjects were followed longitudinally for 9 years. Thirty-eight subjects developed severe dementia during this period. They were compared to those who did not with regard to 19 reported and 17 observed items concerning general psychopathology, seven reported items concerning sleep, and a global rating of mental health. Five items correlated with the development of severe dementia: number of remembered dreams per week, latency of speech, speed of speech, difficulties in finding words, and memory for recent events. A stepwise logistic regression procedure demonstrated that a low frequency of remembered dreams, a reduced memory for recent events, and difficulties in finding words made independent contributions to the prediction of dementia. There were no differences with regard to affective items. There were no differences between the subjects who developed senile dementia of the Alzheimer type and those with multi-infarct dementia. The results thus support the hypothesis that symptoms pertaining to cognitive functions are the first to appear in the development of dementia.