Dementia
Alzheimer's
A buildup of plaque on the neurons of the brain that eventually kill the brain cells. Cause is as yet unknown.
Multi-infarc dementia
Multiple small strokes that kill brain cells with each occurrence. Eventually reaching same conditions as experienced with Alzheimer's disease.
Huntington's chorea
Very rare, 100% hereditary, incurable condition that is usually not discovered until after the childbearing years thus passing on the fatal genes.