Alzheimer disease is a frequent disease in the late ages that results in global alteration of cognitive functions. In which memory complaint can be isolated in the early stages.

Physiopathology of neuronal degenerescence in Alzheimer disease is complex, two main histological lesions are known, amyloid plaques and neurofibrillar tangles. Beyond the histological knowledge, alterations of neuronal metabolism are described such as oxydative phosphorylation and glycolytic pathway. These metabolism alterations are involved in neuronal death.

Multi-nucleus magnetic resonance spectroscopy is a non-invasive non-irradiant imagery technique already used in routine. This technic allows the phosphoenergetic pool assessment, that inform about cellular metabolism.

The aim of the study is to explore the phosphorylated metabolism patterns as predictive biomarkers of cognitive decline in patients with a memory complaint diagnosed.

Inclusion Criteria:

1. Memory complaint, leading to a medical visit at the Centre Mémoire de Ressources et de Recherche (CMRR) of Poitiers, and for which an MRI is needed in routine exploration.
2. Age inferior at 90 years old
3. Mini Mental State Examination (MMSE) score between 20 and 30
4. Patient without guardianship measure, without restricted liberty.
5. Patient who benefits from social security

Exclusion Criteria:

1. Vascular, tumor, inflammatory pathology diagnosed by MRI
2. Other diagnosed neurodegenerative disease than Alzheimer disease
3. Other non neurodegenerative neurological disease
4. Vital risk at short term
5. Severe and uncontrolled psychiatric disease