Progressive supranuclear palsy (PSP) is a rare brain disorder that causes serious and progressive problems with control of gait and balance, along with complex eye movement and thinking problems. The disorder's long name indicates that the disease begins slowly and continues to get worse (progressive), and causes weakness (palsy) by damaging certain parts of the brain above pea-sized structures called nuclei that control eye movements (supranuclear).
One of the classic signs of the disease is an inability to aim the eyes properly, which occurs because of lesions in the area of the brain that coordinates eye movements. Some individuals describe this effect as a blurring. Other eye problems iclude:
- Slow eye movements.
- Trouble voluntarily shifting gaze vertically (i.e., downward and/or upward).
- Trouble controlling eyelids.
- Tendency to move the head to look in different directions.
- Involuntary closing of the eyes.
- Prolonged or infrequent blinking.
- Difficulty in opening the eyes.
- Inability to maintain eye contact during a conversation.
Affected individuals often show alterations of thinking, memory, mood, and behavior, including:
- depression and apathy.
- changes in judgment, insight, and problem solving
- increased irritability and forgetfulness
- sudden laughing or crying or having angry outburst with no apparent reason.
- slowness of thought.
Although PSP gets progressively worse, no one dies from PSP itself.
PSP is often misdiagnosed as Parkinson’s disease, especially early in the disorder, as they share many symptoms, including stiffness, movement difficulties, clumsiness, bradykinesia (slow movement), and rigidity of muscles. The onset of both diseases is in late middle age. However, PSP progresses more rapidly than Parkinson’s disease.
There is currently no effective treatment for PSP, although scientists are searching for better ways to manage the disease. 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, but the effect is usually temporary. The speech, vision, and swallowing difficulties usually do not respond to any drug treatment. Botulinum toxin, which can be injected into muscles around the eyes, can treat excessive eye closing. Some antidepressant drugs may offer some benefits beyond treating depression, such as pain relief and decreased drooling. Weighted walking aids can help people from falling backward. Bifocals or special glasses called prisms are sometimes prescribed for PSP patients to remedy the difficulty of looking down. Certain exercises can be done to keep the joints limber. A surgical procedure, a gastrostomy, may be necessary when there are swallowing disturbances. This surgery involves the placement of a tube through the skin of the abdomen into the stomach (intestine) for feeding purposes.
PSP gets progressively worse but is not itself directly life-threatening. It does, however, predispose patients to serious complications such as pneumonia secondary to difficulty in swallowing (dysphagia). The most common complications are choking and pneumonia, head injury, and fractures caused by falls. The most common cause of death is pneumonia. With good attention to medical and nutritional needs, it is possible for indiviuals with PSP to live a decade or more after the disease appears.
PSP is one of the diseases being studied as part of the NINDS Parkinsons Disease Biomarkers Program, which aims to discover ways to identify individuals at risk for developing Parkinson's and related disorders, and to track disease progression. Genetis studies may identify underlying genetic causes and identify specific disease-causing mutations, which could point to additional targets for therapy development. Investigators are also developing animal models of PSP and other protein tau-related disorders, for research on disease mechanisms and preclinical testing of potential drugs. Other research focuses on therapies that aim to treat teh symptoms of PSP. Information from the National Library of Medicine’s MedlinePlus Progressive Supranuclear Palsy