A number of changes normally occur in the aging individual. These changes affect neurocognitive function, organ function, senses, metabolism, sexual function, and sleep patterns. Of particular importance in aging adults, physicians need to understand the difference between normal cognitive decline associated with aging and pathologic decline. History, physical examination, imaging, laboratory studies, and neuropsychological testing may help determine possible causes of pathologic decline. Many conditions that cause pathologic cognitive decline have no cure, but symptoms may be managed with medications and a strong support system.