With humans living longer than ever before, diseases associated with aging are becoming a major focus of medical research. Neurodegenerative diseases, such as Alzheimer’s disease, are a major source of concern to aging adults. This is because such diseases not only lead to death, they do so through a particularly frightening route that includes loss of independence, memory, function, and personality. All adults experience a decline in certain aspects of brain function as they age. Memory, speed of cognition, and reasoning are among the functions most affected . The effects of aging on cognition appear to be due to atrophy of brain tissue in particular regions, especially the prefrontal cortex and parietal cortex , as well as decreased neurotransmitter levels.