• Evolution of the volume of the Hippocampi, measured by MRI, between D0 and final visit (12 months ).
  

• Evolution of the neuropsychological scores between Day 0 and final visit.
  

Inclusion Criteria (Baseline Visit ("V0")):

1. Men or Women >= 60 years old
2. Patients with mild cognitive impairment (MCI) with progressive hippocampal amnestic syndrome, isolated or associated to other cognitive disorders
3. Grober and Buschke Test with free recall <17 and/or total recall <40
4. Clinical Dementia Rating (CDR - sum of the boxes) = 0.5
5. MMSE >= 24 and <= 28
6. General cognition and functional performance sufficiently preserved such that a diagnosis of Possible or Probable Alzheimer's Disease based on clinical (DSM-IV criteria) cannot be made by the site physician at the time of the screening visit. This evidence must be fully documented in the subject's study file before the Baseline visit.
7. Outpatient with an informant person: person from his/her close circle having a regular weekly contact with the patient and accepting to answer to assessment questionnaires.
8. Visual, hearing capacities (authorized equipment) and oral or written expression, sufficient for the correct performance of the tests (according to the physician's opinion).
9. Patient and informant person having signed the written informed consent form.

Exclusion Criteria (Baseline Visit ("V0")):

1. Patients with a contraindication to MRI:

   • Pacemaker, cardiac defibrillator or neurostimulator wearers
   • Wearers of implanted material activated by an electric, magnetic or mechanical system
   • Wearers of haemostatic clips of intracerebral aneurysms or carotid arteries
   • Wearers of cochlear implants
   • Patients with an intra ocular metallic foreign body
   • Claustrophobic patients
   • Any other contra-indication to MRI

2. Patients with an evolutive psychiatric pathology and/or unstable according to DSM-IV, particularly:

   • Major depressive episode during the previous 2 years or recurrent depression or bipolar disorders according to the DSM-IV and/or score >= 12 according to the 17-items depressive Hamilton's Scale
   • Patients presenting early hallucinations or cognitive fluctuations

3. Patients with neurological disorders:

   • Partial complex epilepsy
   • Dementia of any origin
   • Patients with Parkinson's disease
4. Patient presenting a major repercussion on the autonomy, assessed by IADL Lawton score higher or equal to 2 in at least 2 items or higher than 2 in at least 1 item, confirmed by an informant person.
5. Known vitamin B12 or folates deficiency (except if replacement treatment of stable posology since at least 6 months before selection) or known syphilis.
6. Abnormal Thyroid function (T3, T4, free thyroxine index, TSH). Euthyroid patients treated with stable doses for at least 3 months could be included.
7. Insulin dependent diabetes or diabetes not controlled by a regimen and/or oral antidiabetics, obstructive pulmonary disease, unstable asthma, recent hematological and/or oncological disorders ( 2 years).
8. Gastrointestinal, renal, hepatic, endocrine or cardiovascular clinically significant disease. Atrio ventricular block of 2nd or 3rd degree on ECG.
9. Patients with bradycardia <= 50.
10. Patients with unstable hypertension (systolic blood pressure > 160mmHg and/or diastolic blood pressure > 95mmHg) assessed by the investigator, the patient being treated or not by anti hypertensive drugs.
11. Patient previously treated with central cholinesterase inhibitors or memantine whatever the duration of the treatment and the date of prescription
12. Known or suspected history (<= 5 years) of alcoholism, or abusive drug use.
13. Patients with known hypersensitivity to donepezil chlorhydrate, to piperidine derivatives or to one of the excipients of the drug.
14. Patients having participated in a clinical trial during the previous 3 months.
15. Patient treated by a non-authorized drug during the study.

Inclusion criteria (Visit 1):

1. Patients with mild cognitive impairment (MCI) with progressive hippocampal amnestic syndrome, isolated or associated to other cognitive disorders
2. Clinical Dementia Rating (CDR - sum of the boxes) = 0.5
3. MMSE >= 24 and <= 28
4. General cognition and functional performance sufficiently preserved such that a diagnosis of Possible or Probable Alzheimer's Disease based on clinical and neuro-imaging findings (NINCDS-ADRDA or DSM-IV criteria) cannot be made by the site physician at the time of the screening visit. This evidence must be fully documented in the subject's study file.
5. Outpatient with an informant person: person from his/her close circle having a regular weekly contact with the patient and accepting to answer to assessment questionnaires.
6. Patients having performed an ECG within the previous 6 months
7. Visual, hearing capacities (authorized equipment) and oral or written expression, sufficient for the correct performance of the tests (according to the physician's opinion).
8. Clinical laboratory values must be within normal limits, or if abnormal, judged clinically insignificant by the investigator (not likely to cause cognitive impairment or medical instability).

Exclusion criteria (Visit 1):

1. Patients with an evolutive psychiatric pathology and/or unstable according to DSM-IV, particularly:

   • Major depressive episode during the previous 2 years or recurrent depression or bipolar disorders according to the DSM-IV and/or score 12 according to the 17-items depressive Hamilton's Scale
   • Patients presenting early hallucinations or cognitive fluctuations

2. Patients with neurological disorders :

   • Partial complex epilepsy
   • Dementia of any origin
   • Patients with Parkinson's disease
   • Patients with evidence of relevant CVD by brain imaging (CT or MRI) including multiple large vessel infarcts or a single strategically placed infarct (angular gyrus, thalamus, basal forebrain, or PCA or ACA territories), as well as multiple basal ganglia and white matter lacunes, or extensive periventricular white matter lesions, or combinations thereof.
3. Patient presenting a major repercussion on the autonomy, assessed by IADL Lawton score higher or equal to 2 in at least 2 items or higher than 2 in at least 1 item, confirmed by an informant person.
4. Known vitamin B12 or folates deficiency (except if replacement treatment of stable posology since at least 6 months before selection) or known syphilis.
5. Abnormal Thyroid function (T3, T4, free thyroxine index, TSH). Euthyroid patients treated with stable doses for at least 3 months could be included.
6. Insulin dependent diabetes or diabetes not controlled by a regimen and/or oral antidiabetics, obstructive pulmonary disease, unstable asthma, recent hematological and/or oncological disorders (<= 2 years).
7. Gastrointestinal, renal, hepatic, endocrine or cardiovascular clinically significant disease. Atrio ventricular block of 2nd or 3rd degree on ECG.
8. Patients with bradycardia <= 50.
9. Patients with unstable hypertension (systolic blood pressure > 160mmHg and/or diastolic blood pressure > 95mmHg) assessed by the investigator, the patient being treated or not by anti hypertensive drugs.
10. Patient previously treated with central cholinesterase inhibitors or memantine whatever the duration of the treatment and the date of prescription
11. Known or suspected history (<= 5 years) of alcoholism, or abusive drug use.
12. Patients with known hypersensitivity to donepezil chlorhydrate, to piperidine derivatives or to one of the excipients of the drug.
13. Patients having participated in a clinical trial during the previous 3 months.
14. Patient treated by a non-authorized drug during the study.