Alzheimer's is the predominant form of senile dementia in older adults. Approximately 50% of persons over age 75 suffer from this disease. The disease potentially affects all domains of cognition though different individuals will manifest different symptoms.
The early stages of Alzheimer's are characterized by a loss of memory, reduced attention span, and loss of verbal communication skills. Individuals in early stages of Alzheimer's are often capable of driving, living on their own and even holding simple jobs. In many individuals the early symptoms are mistaken for old age and the disease is not properly diagnosed till later stages.
As the disease progresses, some individuals will begin to misperceive objects, hallucinate and often hear voices. Some patients will believe they are speaking to a relative who has been dead for some time. They often misidentify close relatives and tend to regress back into early adulthood and sometimes childhood. Some individuals who have immigrated as adults from foreign countries will forget the English they have since learned and remember only their childhood language.
The final stages of Alzheimer's are often painful to endure for close family members. Patients will begin to sleep the majority of the day and forget how to do basic activities of daily life like eating or defecating. Often the requirements of caregiving exceed the capacities of immediate family members and the patient is institutionalized in a nursing home.
While many Alzheimer's patients die from other causes such as cancer, heart attack, pneumonia, and other diseases typical of old age, the neurological degeneration caused by Alzheimer's can cause an individual to die from aspiration.