Progressive supranuclear palsy
Progressive supranuclear palsy is a brain disorder that affects movement, vision, speech, and thinking ability (cognition). The signs and symptoms of this disorder usually become apparent in mid- to late adulthood, most often in a person's 60s. Most people with progressive supranuclear palsy survive 5 to 9 years after the disease first appears, although a few affected individuals have lived for more than a decade.
Loss of balance and frequent falls are the most common early signs of progressive supranuclear palsy. Affected individuals have problems with walking, including poor coordination and an unsteady, lurching gait. Other movement abnormalities develop as the disease progresses, including unusually slow movements (bradykinesia), clumsiness, and stiffness of the trunk muscles. These problems worsen with time, and most affected people ultimately require wheelchair assistance.
Progressive supranuclear palsy is also characterized by abnormal eye movements, which typically develop several years after the other movement problems first appear. Restricted up-and-down eye movement (vertical gaze palsy) is a hallmark of this disease. Other eye movement problems include difficulty opening and closing the eyelids, infrequent blinking, and pulling back (retraction) of the eyelids. These abnormalities can lead to blurred vision, an increased sensitivity to light (photophobia), and a staring gaze.
Additional features of progressive supranuclear palsy include slow and slurred speech (dysarthria) and trouble swallowing (dysphagia). Most affected individuals also experience changes in personality and behavior, such as a general loss of interest and enthusiasm (apathy). They develop problems with cognition, including difficulties with attention, planning, and problem solving. As the cognitive and behavioral problems worsen, affected individuals increasingly require help with personal care and other activities of daily living.
The only proven risk factor for progressive supranuclear palsy is age. The condition typically affects people around the age of 60, and is virtually unknown in people under the age of 40.
The characteristic signs and symptoms of progressive supranuclear palsy include:
- A loss of balance while walking. A tendency to fall backward can occur very early in the disease.
- An inability to aim your eyes properly. You may have particular difficulty looking downward, or experience blurring and doubled vision. This difficulty with focusing the eyes can make some people spill food or appear disinterested in conversation because of poor eye contact.
- Other issues develop as the disease advances, including slow movement (bradykinesia), clumsiness, and stiffness. These problems worsen with time, with most affected people ultimately needing a wheelchair. Weakening of the muscles in the mouth, tongue and throat lead to slurred speech and difficulty swallowing. This often causes aspiration pneumonia, the most common cause of death in people with PSP
Additional signs and symptoms of progressive supranuclear palsy vary and may mimic those of Parkinson's disease and dementia. These signs and symptoms worsen as the disease advances, and may include:
- Stiffness and awkward movements
- Problems with speech and swallowing
- Sensitivity to light
- Sleep disturbances
- Loss of interest in pleasurable activities
- Impulsive behavior, possibly including laughing or crying for no reason
- Difficulties with memory, reasoning, problem-solving and decision-making
- Depression and anxiety
- A surprised or frightened facial expression, resulting from rigid facial muscles
- Changes in personality, mood and behavior; irritability; and forgetfulness
While progressive supranuclear palsy is usually sporadic, some cases run in families. In most cases, the genetic cause is unknown, but some are due to mutations or "variations" in the MAPT gene. The signs and symptoms of the disorder result from deterioration of cells in areas of your brain, especially those that help you control body movements (midbrain) and thinking (frontal lobe).
The MAPT gene gives the body instructions to make a protein called tau. This protein is found in nerve cells (neurons) in the brain and in other parts of the nervous system. It plays a part in putting together and stabilizing components of the structure of cells, helping cells to keep their shape, and aiding in cell division and the transport of materials. Clumps of tau are characteristic of other neurodegenerative disorders, such as Alzheimer's disease.It appears that gene mutations or variations that affect the function of the tau protein cause PSP, or cause an increased risk for a person to develop PSP.
Abnormal tau is also found in people with PSP who don't have MAPT mutations. Therefore, researchers think that additional genetic and environmental factors contribute to the development of PSP. However, other specific genes that may be involved have not yet been identified.
Rarely, progressive supranuclear palsy occurs within a family. But a genetic link isn't clear, and most people with progressive supranuclear palsy haven't inherited the disorder.
There is no known way to prevent PSP.
Progressive supranuclear palsy is usually sporadic (not inherited), but in rare cases it can be inherited. While the genetic cause of PSP not usually known, it can be caused by a mutation in a gene called MAPT. To our knowledge, MAPT is currently the only gene for which clinical genetic testing for PSP is available. This means that if a person with PSP is found to have a disease-causing mutation in the MAPT gene, genetic testing of other family members for the same mutation in this gene may be available. Each child of a person with PSP caused by a MAPT mutation has a 50% chance to inherit the mutated gene. However, if a person with PSP does not have a mutation in the MAPT gene (which is most often the case), clinical genetic testing for other family members is not available.
This disease can be difficult to diagnose because signs and symptoms are similar to those of Parkinson's disease. Indications that you have progressive supranuclear palsy rather than Parkinson's disease include:
- A lack of shaking (tremors)
- A poor response to Parkinson's medications
- Difficulty moving your eyes, particularly downward
MRI to determine if you have shrinkage in specific regions of the brain associated with progressive supranuclear palsy. MRI can also help to exclude disorders that may mimic progressive supranuclear palsy, such as stroke.
A positron emission tomography (PET) scan also may be recommended to check for early signs of brain abnormalities that may not appear on MRI. Researchers are working to develop medical tests that can diagnose progressive supranuclear palsy.
Some people with progressive supranuclear palsy develop speech problems (apraxia of speech) years before experiencing other symptoms. This speech problem may be the first sign of progressive supranuclear palsy.
Progressive supranuclear palsy gets progressively worse. Most people become dependent for care within three or four years from onset, and quality of life is significantly reduced. However, with good attention to medical and nutritional needs, it is possible for many people with PSP to live a decade or more after the first symptoms appear. The condition predisposes people to serious complications such as pneumonia (the most common cause of death) secondary to difficulty in swallowing (dysphagia). Other complications that people may experience include choking, head injury, and fractures caused by falls.
There are currently no treatments that alter the course of disease for people with progressive supranuclear palsy (PSP), and no drugs that provide significant relief of symptoms. However, supportive treatment may be helpful and may include:
- Management of dysphagia and dysarthria with the help of dietitians as well as speech and language therapists
- Early occupational therapy to promote longer independence in performing activities of daily living
- The use of mirror-prism lenses for those with severe limitation of extraocular movements to read and feed themselves
- The use of eyelid crutches, alone or in combination with botox therapy, for inability to open the eyes andblepharospasm
- Physical therapy for symptomatic treatment of postural instability and falls, including gait and balance training
- Parkinson's disease medications, which increase levels of a brain chemical involved in smooth, controlled muscle movements (dopamine). The effectiveness of these medications is limited and usually temporary, lasting about two to three years
- Botulinum toxin type A (Botox), which may be injected in small doses into the muscles around your eyes. Botox blocks the chemical signals that cause muscles to contract, which can improve eyelid spasms
- Eyeglasses with bifocal or prism lenses, which may help ease problems with looking downward
- Speech and swallowing evaluations, to help you learn safer swallowing techniques
A surgical procedure called a gastrostomy may be necessary when there are swallowing disturbances or a high risk of severe choking.
Researchers are working to develop medication to treat progressive supranuclear palsy, including therapies that may block the formation of tau.
- Mayo Clinic
- Genetics Home Reference