Symptoms of Alzheimer's disease include memory problems in its early stage and greater memory loss and behavior changes in its mild stage, states the National Institute on Aging. Confusion and impulsive behavior characterize its moderate stage, while seizures and the inability to communicate are symptoms of its severe stage.
Alzheimer's is a disease that causes people to lose their memories due to the breakdown of brain tissue over time, explains WebMD. The disease most often affects people over the age of 65. Although the cause of the disease is unknown, research indicates that nerve damage from either neurofibrillary tangles or the buildup of plaque in the brain causes most of the symptoms.