S4‐02‐04: Prodromal Alzheimer's disease: Data from the PAQUID study

Background: Prodromal Alzheimer’s Disease (AD) is the phase of the disease occuring before the Dementia phase of AD defined with DSM IV criteria for Dementia. Prodromal AD has been extensively descripted in clinical setting. However, the recourse to clinical setting of subjects with prodromal AD is an arbitrary event in the evolution of the disease. This event is related to many factors, such as complaints, difficulties in complexe activities of daily living, presence of a more or less attentive or anxious familly circle, age, etc. Thus the only way to obtain a natural history description of prodromal AD is to conduct population based cohort with long term follow-up and repetition of cognitive assessment. Methods: The Paquid study is a prospective cohort constituted in 1988-1989 on 3,777 elderly subjects living in the community in the Bordeaux area (France). These subjects were followed-up about every two years for twenty years with repeated cognitive and functionnal assessments and active research of incident cases of Dementia. Results: The first decline in cognitive performances appeared as early as 12 years before dementia in measures of semantic memory and conceptual formation. Then more global deficits appeared that were concomitant with an increase in memory comlaints and depressive symptoms. About two years later, as a consequence of cognitive dysfunction, the subjects started to become slightly dependent in their activities of daily living. in the last trhree years, the impairment significantly worsened until the subjects reached the dementia phase. Conclusions: This approach describing the 14 years preceding dementia, provides a clear illustration of the particularly long and progressive phase of AD, and shows the successive emergence of cognitive deficits during this phase.