A Cohort Study of Early Onset Neurodegenerative Dementias Prognostic Factors

Early-onset dementia (EOD), which begins before the age of 65, is less common than late-onset dementia but represents a significant burden for the patient, their family and the healthcare system. The descriptive epidemiology is poorly known, and the National Reference Center for young patients, using English data (Harvey et al., 2003) estimates the number of subjects concerned in France at 18,318. It is degenerative dementia that is the most common cause of EOD and among them, Alzheimer's disease and then frontotemporal degeneration (FTD) (Vieira et al., 2013). The natural history and prognostic factors of PDD are not well known, and only AD has some data. Alzheimer's disease (AD) in young people appears to have a worse prognosis than that in older people, but this is debated (Stanley and Walker, 2014) and also depends on the criteria studied: cognition, function or survival. Prognostic factors other EOD, and in particular frontotemporal dementias, which moreover are heterogeneous pathologies, are even less known. Investigators have chosen to study the functional prognosis of patients because it is both very relevant to care needs and easy to measure. Among the prognostic factors of functional status, investigators will study in particular psycho-behavioral disorders, and in particular depression, which is very common in patients with EOD, a factor of poor quality of life and accessible to treatment. Other potential prognostic factors such as cognitive reserve, gender, clinical variants of AD and DFT, family status (living alone or having a caregiver), genetic status, family history of dementia, CSF biomarkers and MRI imaging will be studied . The evolution of instrumental activities of daily living will be measured. The social and paramedical resources used by the patient and his family will be collected, as well as the use of psychotropic and non-drug treatments. Finally, the overall evolution of the severity of dementia will be measured. Eligible patients will be included for 3 years and evaluated every 6 months.