Colour perception among the very elderly related to visual and cognitive function.

Colour perception was studied among a representative sample of 95-year olds and compared with previously examined 80-year olds and a group with Alzheimer's disease (AD), mean age of 80 years. The 95-year olds' results were on a significantly lower level than the other two groups but showed a similar pattern as to colour -discrimination, -naming, -preferences and colour/form recognition. Visual function among 95-year olds had only minor influence on their result in contrast to cognitive function which had a more profound impact. Most interestingly though, the subjects with Alzheimer's diagnosis, younger than the 95-year olds but with a conclusive diagnosis of dementia, performed on an overall higher level than the 95-year olds. This advantage for the Alzheimer group remained even when compared with a sub sample of the 95-year olds with possible dementia diagnosis excluded. On the other hand, only including 95-year olds with a Mini Mental Examination score of >26 in comparison with the Alzheimer group made the differences between the two groups disappear. It is suggested that colour perception as measured in this study is well preserved throughout life. The overall lower colour perception ability in 95-year olds compared with both 80-year olds and subjects with AD may be an expression of the complexity of very high age rather than any isolated concomitant factor.