Prodromal Alzheimer's disease: Successive emergence of the clinical symptoms

Whereas cognitive deficits are known to be detectable long before the typical symptoms of Alzheimer's disease (AD) are evident, previous studies have failed to determine when cognitive functioning actually begins to decline before dementia. Utilizing the long follow-up of the PAQUID study, we examined the emergence of the first clinical symptoms over a 14-year period of follow-up before the dementia phase of AD.

This study relies on a case-control sample selected from the PAQUID cohort. Of the 3,777 initial subjects of the cohort, 350 subjects experienced development of AD during the 14 years of follow-up. The cases were matched to 350 elderly control subjects. The evolution of scores on cognitive, functional, and depression scales was described throughout the 14-year follow-up using a semiparametric extension of the mixed-effects linear model.