How is progressive supranuclear palsy diagnosed?
Progressive supranuclear palsy is sometimes mistaken for Parkinson's disease, which is also associated with stiffness, frequent falls, slurred speech, difficulty swallowing, and decreased spontaneous movement. The facial expression in Parkinson's, however, is blank or mask-like, whereas in PSP it is a grimace and wide-eyed stare. Progressive
supranuclear palsy does not cause the uncontrolled shaking (tremor) in muscles at rest that is associated with Parkinson's disease. Posture is stooped in Parkinson's disease, but erect in PSP. Speech is of low volume in both diseases, but is more slurred and irregular in rhythm in progressive supranuclear palsy.
Multiple strokes or abnormal accumulations of fluid within the skull (hydrocephalus) can also cause balance problems similar to progressive supranuclear palsy. A neurological examination may show Parkinsonian movements with typical stiffness and lack of coordination. Dementia is mild. Eye movements are limited, particularly vertical movements. However, vision, hearing, sensation, and voluntary control of movement remain intact. An MRI might show shrinking of the brainstem. Magnetic resonance imaging (MRI) scans of the brain may be needed to rule out these conditions. In advanced cases, MRI shows characteristic abnormalities in the brainstem described as "mouse ears."