(Science: disease) a progressive, neurodegenerative disease characterized by loss of function and death of nerve cells in several areas of the brain leading to loss of cognitive function such as memory and language. The cause of nerve cell death is unknown but the cells are recognized by the appearance of unusual helical protein filaments in the nerve cells (neurofibrillary tangles) and by degeneration in cortical regions of the brain, especially frontal and temporal lobes.
Alzheimers disease is the most common cause of dementia. A progressive form of presenile dementia that is similar to senile dementia except that it usually starts in the 40s or 50s. The first symptoms are impaired memory which is followed by impaired thought and speech and finally complete helplessness. A disease of the central nervous system, with symptoms including memory loss which increases over time until the body is no longer able to function due to the body’s inability to process the electrical signals via the degrading nervous system.