The most frequent first symptom of PSP is a loss of balance while walking. Individuals may have unexplained falls or a stiffness and awkwardness in gait. Sometimes the falls are described by the person experiencing them as attacks of dizziness.
Other common early symptoms are changes in personality such as a loss of interest in ordinary pleasurable activities or increased irritability, cantankerousness, and forgetfulness. Individuals may suddenly laugh or cry for no apparent reason, they may be apathetic, or they may have occasional angry outbursts, also for no apparent reason. It must be emphasized that the pattern of signs and symptoms can be quite different from person to person.
As the disease progresses, most people will begin to develop a blurring of vision and problems controlling eye movement. In fact, eye problems usually offer the first definitive clue that PSP is the proper diagnosis. Individuals affected by PSP have trouble voluntarily shifting their gaze downward, and also can have trouble controlling their eyelids. This can lead to involuntary closing of the eyes, prolonged or infrequent blinking, or difficulty in opening the eyes.
Another common visual problem is an inability to maintain eye contact during a conversation. This can give the mistaken impression that the person is hostile or uninterested.
Speech usually becomes slurred and swallowing solid foods or liquids can be difficult.
In rare cases, the symptoms will be more similar to those of Parkinson disease, and some individuals may even have tremors. This version is often referred to as “Parkinsonian PSP” or PSP-P.