Alzheimer's disease is a progressive disorder that attacks the brain's nerve cells, causing intellectual decline. Alzheimer's is the most common cause of dementia for those over the age of 65.
Staging of the intellectual effects of Alzheimer's disease range from Stage 1, with no impairment, to Stage 7, with very severe cognitive decline. According to the Alzheimer's Association, Stage 3 is when early-stage Alzheimer's can be diagnosed. Memory and concentration deficits become apparent during clinical testing by this phase.
According to the Mayo Clinic, some of the early signs of the intellectual effects of Alzheimer's disease may include the repetition of things, putting items in illogical locations and forgetting the location, difficulty balancing the checkbook and difficulty expressing thoughts.
In Stage 4, people have decreased knowledge of recent events. By Stage 5, they may be unable to recall past events, such as the name of their high school. Times, dates and events become confused.
By the time Alzheimer's disease has reached Stage 6, it becomes difficult for a person to remember the names of family members. Stage 7 leaves the individual unable to respond or speak. Assistance is needed for all activities of daily living.
There is no cure for Alzheimer's disease. According to the Alzheimer's Foundation of America, the life expectancy ranges from eight to 10 years from diagnosis.