Dementia: new theories, new treatments.

Approximately 4 million people in the United States suffer from Alzheimer’s disease—an irreversible, progressive, neurodegenerative disorder. Ten percent of people over age 65 and half of people over age 85 are affected by the disease. The estimated annual cost of caring for a patient with advanced Alzheimer’s disease is more than $50,000. Given that Alzheimer’s is expected to become a much more prominent problem over the next 20 years, the Memory Assessment Clinic at Grady Memorial Hospital in Atlanta represents a cooperative effort to find answers to this puzzling disease. Morehouse School of Medicine, Emory University School of Medicine, and Grady Health Systems are partners in the clinic. ‘‘Alzheimer’s disease is diagnosed as ‘irreversible’ among the types of dementia,’’ said Dr. LaRoy Penix. Other diseases that are considered ‘‘irreversible’’ are Pick’s Disease, Huntington’s Chorea, Parkinson’s Disease, Diffuse Lewy-body Dementia, Multiple Sclerosis, and Creutzfeldt-Jakob Disease. Other types of dementia are diagnosed as ‘‘treatable—potentially reversible’’ and ‘‘treatable—not reversible.’’ ‘‘Alzheimer’s starts with short-term memory loss of about 2 to 3 points per year on the MMSE—the Mini-Mental State Examination—and eventually affects executive functions, visual spatial orientation and language,’’ Dr. Penix said. ‘‘Patients may survive 8 to 10 years after diagnosis or 20 years after onset.’’ The pathological features of Alzheimer’s disease are: neurofibrillary tangles—twisted nerve cell fibers; senile (neuritic) plaques—protein deposits or clumps; congophilic amyloid angiopathy; loss of cholinergic neurons in the nucleus basalis of Meynert; and de-afferentation of the hippocampus. Identifying risk factors is important in dealing with Alzheimer’s. ‘‘One possible risk factor is the presence of too much amyloid precursor protein,’’ Dr. Penix said. The A-beta protein cascade theory of Alzheimer’s disease (Mattson, 1999) is the leading theory of what causes Alzheimer’s, Dr. Penix said. It includes a sequence of conditions in the brain that results in dementia.