PSP: Progressive supranuclear palsy, a neurologic disorder of unknown origin that gradually destroys cells in many areas of the brain, leading to serious and permanent problems with the control of gait and balance. The most obvious sign of the disease is an inability to aim the eyes properly, which occurs because of damage in the area of the brain that coordinates eye movements. Some patients describe this effect as a blurring. Another common visual problem is an inability to maintain eye contact during a conversation. This can give the mistaken impression that the patient is hostile or uninterested. Patients also often show alterations of mood and behavior, including depression and apathy as well as progressive mild dementia.
The disease is "progressive" because it worsens over time; "supranuclear" because the main problem is not in the nuclei (clusters of cells in the brainstem) that directly control eye movements, but in higher centers that control the nuclei; and "palsy," which means weakness, in this case of eye movement.
PSP characteristically begins with loss of balance. Nearly all patients eventually develop the characteristic difficulty in moving the eyes up and down, the sign that often arouses a doctor's suspicion of the correct diagnosis. Although PSP gets progressively worse, no one dies from PSP itself. Difficulty swallowing can eventually permit aspiration of food into the trachea (windpipe). PSP may also be complicated by the effects of immobility, especially pneumonia, and by injuries from falls.
PSP is the disease that led to the death of the British comedian Dudley Moore in 2002. He developed pneumonia as a terminal event. PSP affects about 20,000 Americans, one in every 100,000 people over the age of 60. Patients are usually in middle or advanced age. Men are affected more often than women.
There is currently no effective treatment for PSP. In some patients the slowness, stiffness, and balance problems of PSP may respond to antiparkinsonian agents such as levodopa, or levodopa combined with anticholinergic agents or amantadine, but the effect is usually temporary. The speech, vision, and swallowing difficulties usually do not respond to any drug treatment. Antidepressant medications have been used with some modest success in PSP. The most commonly used of these drugs are fluoxetine (Prozac), amitriptyline (Elavil), and imipramine (Tofranil). The anti-PSP benefit of these drugs seems not to be related to their ability to relieve depression.
Non-drug treatment for PSP can take many forms. Patients frequently use weighted walking aids because of their tendency to fall backward. Bifocals or special glasses called prisms are sometimes prescribed for PSP patients to remedy the difficulty of looking down. Formal physical therapy is of no proven benefit in PSP, but certain exercises can be done to keep the joints limber. A surgical procedure that may be useful when there are swallowing disturbances is a gastrostomy to permit feeding directly into the stomach.
PSP was first described as a distinct disorder in 1964, when three scientists published a paper that distinguished the condition from Parkinson's disease (which is far more common). PSP is sometimes referred to as Steele-Richardson-Olszewksi syndrome after the scientists who defined the disorder. It is also sometimes called dementia-nuchal dystonia.