Delaying the Progression of Driving Impairment in Individuals With Mild Alzheimer's Disease

The purpose of the study is to determine whether memantine delays the progression of driving impairment in patients with mild Alzheimer's Disease (AD).

It is well known, and of great concern to both patients and families, that individuals with Alzheimer's disease (AD) eventually become driving impaired. Drivers with dementia are estimated to be 2-8 times more likely to be involved in an automobile crash as unimpaired peers. Approximately half of individuals with mild AD have the skills needed to drive safely. Formal driver evaluation may be necessary to make this distinction. Some reviews in the literature have suggested that individuals identified as high risk, such as those with AD, be advised by their physicians to cease driving altogether. Other studies suggest that these individuals may continue to drive for up to 4 years following diagnosis. Memantine may be effective in delaying the progression of driving impairment in individuals with mild AD. If the investigators can demonstrate a significant delay in the decline in the driving ability, this could extend their driving time and therefore be of immense benefit to patients and their caregivers.

Comparison(s): Subjects treated with memantine over a period of 12 months, compared to subjects on placebo.

Eligibility Criteria:
Inclusion Criteria:

* Men and women ages 60 years of age and older
* Subjects must either be previously diagnosed with mild Alzheimer's Disease (AD) by a neurologist, psychiatrist, geriatrician, or be evaluated at a Memory Disorders Center prior to entry into the study
* Subjects must have a score of ≥ 23 on the Mini-Mental State Examination (MMSE) at the Screening Visit
* Subjects must receive a passing score on the DriveABLE test
* Female subjects must be at least 2 years post-menopausal or surgically sterile
* Written informed consent must be obtained from the subject prior to the initiation of any study specific procedures

Exclusion Criteria:

* Subjects who have been treated with a depot neuroleptic within six (6) months of the Screening Visit
* Subjects who fail the OPTEC vision test at the screening visit
* Subjects who score \> 7 on the Hachinski Test at the screening visit
* Subjects with evidence of clinically significant and active pulmonary, gastrointestinal, renal, hepatic, endocrine or cardiovascular system disease (subjects with controlled hypertension, right bundle branch block \[complete or partial\] and pacemakers may be included in the study). Subjects with thyroid disease may also be included in the study, provided they are euthyroid on treatment. Subjects with controlled diabetes may also be included
* Recent (\< 2years) B12 or folate deficiency that was considered clinically significant
* Subjects with evidence of other psychiatric/neurologic disorders including, but not limited to, stroke, Vascular Dementia, Lewy-Body Disease, Parkinson's Disease, seizure disorder, head injury with loss of consciousness within the past 5 years, any psychotic disorder, or bipolar disorder
* Subjects who are taking, or have taken, amantadine, ketamine, dextromethorphan that cannot be discontinued or switched to an allowable alternative medication prior to the minimum allowable interval before Baseline
* Subjects who have been in an investigational drug study or who have received treatment with an investigational drug within 30 days (or 5 half-lives, whichever is longer) of the Screening Visit
* Any condition, which would make the subject, in the opinion of the investigator, unsuitable for the study
* If subjects are taking Acetylcholinesterase inhibitors (AChEls), they must be on a stable dose for \> 3 months prior to baseline. No initiation of AChEls is permitted; discontinuation and dose reduction are permitted