What is the cause of PSP?
The symptoms of PSP are caused by a gradual deterioration of brain cells in a few tiny but important places in the base of the brain. The most important such place, the “substantia nigra” (sub-STAN-cha NYE-gra), is also affected in Parkinson’s disease and damage to it accounts for the symptoms that PSP and Parkinson’s have in common. However, several important areas are affected in PSP that are normal in Parkinson’s (and vice-versa). Moreover, under the microscope, the appearance of the damaged brain cells in PSP is quite different from those in Parkinson’s and resembles, rather, the degeneration in Alzheimer’s disease. However, the location of the damaged cells is quite different in PSP and Alzheimer’s. Furthermore, in PSP there are no amyloid plaques, deposits of waxy protein that are a hallmark of brain cells in Alzheimer’s.
