Childhood mental ability and dementia

Objective: To examine links between childhood mental ability and dementia u sing data from a 1932 survey of the mental ability of the 1921 Scottish bir th cohort. Method: Patients with dementia from the 1921 Scottish birth coho rt were located in 1) a national survey of early-onset dementia (1974-1988) , 2) local mental health services, and 3) a survey of 264 of 519 surviving Aberdeen residents who took the 1932 test. Control subjects were identified in the 1932 Scottish Mental Survey. Results: Mean 1932 ability score for t he Scottish 1921 cohort did not differ from early-onset dementia. Early-ons et dementia was not associated with lower childhood mental ability when com pared with matched control subjects. In Aberdeen, mental ability scores wer e significantly lower in children who eventually developed late-onset demen tia when compared with other Aberdeen children tested in 1932. This differe nce was also detected between cases and tested subjects (controls) alive in 1994. Conclusions: Late-onset dementia is associated with lower mental abi lity scores in childhood. Early-onset dementia mental ability scores did no t differ from locally matched control subjects or from late-onset dementia. Mechanisms that account for the link between lower mental ability and late -onset dementia are probably not relevant to early-onset dementia.