Animal and human studies have shown that a decrease in acetylcholine may be responsible for some of the cognition deficits in Alzheimer’s disease. This study will examine whether enhancing the chemical acetylcholine in the brain can improve memory and attention by identifying changes in brain function that occur during these cognitive tasks. Patients taking medications that slow the breakdown of this neurotransmitter have experienced improvements in memory.
Positron emission tomography (PET) and magnetic resonance imaging (MRI) will be used to measure brain activity and identify brain regions involved in memory and attention. Candidates for this study will be screened with a medical and psychiatric history and a physical examination including blood tests, urinalysis, chest X-ray, and electrocardiogram (ECG).
Those enrolled will perform memory and attention tasks during PET and MRI studies. The cognition tasks will be repeated twice-once during infusion of saline (a fluid with no drug effect) through a catheter inserted into a blood vessel and again during infusion of physostigmine, a drug that delays the breakdown of acetylcholine.
The PET procedure will be completed in one day; the MRI procedure will be done on two different days. During imaging, attention and memory tasks will be presented in short blocks of about 4-minutes duration. They will be repeated in sequence up to 10 times with a few minutes separation. Subjects will be shown pictures of faces or other visual stimuli and asked to decide whether the pictures are the same or different.
Information gained from this study may increase knowledge about how acetylcholine affects the brain’s response to memory and attention tasks and perhaps lead to better treatments for the cognitive deficits in Alzheimer’s disease.
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Genders Eligible for Study: Both Criteria
Three groups of subjects will be enrolled:
1. Subjects with Alzheimer’s Disease (AD) 45-100 years of age;
2. Healthy controls 20-50 years of age
3. Healthy controls 50-90 years of age
Only subjects with good health and without evidence of significant chronic disease will be accepted into the healthy control groups.
Only patients without evidence of significant chronic disease who meet standard clinical criteria for the diagnosis of dementia of Alzheimer’s disease type will be accepted into the study in the AD group.
Location and Contact Information
National Institute of Mental Health (NIMH), 9000 Rockville Pike Bethesda, Maryland, 20892, United States. PRPL Warren G. Magnuson Clinical Center National Institutes of Health Bethesda, Maryland, 20892-4754, United States