Progressive supranuclear palsy (PSP) is a rare brain disease. It affects brain cells that control the movement of your eyes. This leads to serious and permanent problems with balance and the way you walk. It usually occurs in middle-aged or elderly people. Symptoms are very different in each person, but may include personality changes, speech, vision and swallowing problems. Doctors sometimes confuse PSP with Parkinson's disease or Alzheimer's disease.
PSP has no cure and no effective treatments. Walking aids, special glasses and certain medicines might help somewhat. Although the disease gets worse over time, it isn't fatal on its own. However, PSP is dangerous because it increases your risk of pneumonia and choking from swallowing problems and injuries from falling.
NIH: National Institute of Neurological Disorders and Stroke