A TYPOLOGY OF SUBCLINICAL SENESCENT COGNITIVE DISORDER

Background. Cognitive impairment without dementia is commonly observed in ageing populations. The present study aims to describe types of im pairment and evolution over a one-year period. Method, Three hundred a nd ninety-seven normal French elderly persons demonstrating recent, ob servable change in cognitive performance were examined annually using a computerised cognitive examination. Results. Five subtypes were diff erentiated by cluster analysis. Two of the groups were predicted by lo gistic regression to be at high risk of senile dementia. Of 16 inciden t cases of senile dementia diagnosed in the following year, 13 were fo und to have derived from these two groups. The typology was also found to be useful in the description of age-associated memory impairment. Conclusions. Subclinical cognitive impairment was found to not constit ute a unitary phenomenon and heterogeneous subgroups could be differen tiated. The concept of 'normality' in elderly cohorts is reconsidered in the light of these findings.