Progressive supranuclear palsy (PSP)
Progressive supranuclear palsy (PSP) is a less well-known illness of the nervous system which is sometimes misdiagnosed as Parkinson’s, stroke, Alzheimer’s or Motor Neurone Disease. It can also go undiagnosed, especially in older people. Because of the similarity to some Parkinson’s symptoms, PSP is included in a group of diseases called Parkinson’s Plus Syndrome.
The term PSP stands for Progressive meaning ‘gradually getting worse’; Supranuclear meaning ‘above the nuclei of the brain’ (in particular the basal ganglia); and palsy meaning ‘paralysis’. PSP is also known as Steele-Richardson-Olszewski syndrome, from the family names of the 3 Canadian physicians who first described the condition in 1963.
PSP is linked to over-production of a protein called tau in certain areas of the brain. In PSP, tau forms into clumps that are thought to damage nerve cells or nerve endings in the brain stem, basal ganglia and cerebral cortex areas. These areas control balance, thought processes, eye movements, speech and the ability to swallow.
What causes PSP?
PSP affects people over the age of 40. It becomes increasingly common with age, and is found in all races and in both men and women alike.
Until recently PSP was thought to be rare, mainly because it went undiagnosed in many people. Doctors now think it could affect up to six in every 100,000 people. As diagnosis becomes more accurate, the number of people diagnosed with PSP is likely to rise.
There is no hard evidence to suggest that PSP is genetic, but research does suggest that some people may be more genetically disposed to it. No one knows why some people develop the condition, but there are several theories. Some scientists believe that it may be triggered by the delayed action of a virus, others think it could be caused by a blow to the head, or alternatively, have genetic causes. Research is ongoing.
Some of the most common symptoms of PSP are:
- poor balance and unsteady gait or walking
- frequent falls, generally backwards
- slowed movements
- rigidity or stiffness
- cramped writing
- visual difficulties, particularly when looking up or down; also slow blinking, difficulty in maintaining eye contact, tunnel vision and sensitivity to light
- quiet, slow and slurred speech
- difficulty in swallowing
- anxiety and/or depression, and loss of motivation.
As the illness progresses symptoms will increase. The course of the illness varies from one person to another, and some symptoms may only appear in the later stages. The order in which symptoms appear varies in each person, depending on the area of the brain affected.
PSP can be difficult to diagnose and is quite easy to confuse with other conditions with similar symptoms. There is no simple test to confirm it. Scanning techniques such as brain magnetic resonance imaging may help to rule out other conditions with similar symptoms.
A specialist doctor, usually a neurologist, will make careful observations over time to reach a diagnosis. This process may take two or three years. This lengthy diagnosis period can be frustrating for all concerned, but research into faster, more accurate diagnosis is under way.
A doctor may reach a diagnosis of PSP if the following features are present:
- a progressive illness with unexplained falls
- difficulty with looking up and down, as well as neck stiffness
- slowness of thought
- cramped handwriting
- poor response to Parkinson’s medications.
PSP and Parkinson’s
PSP is often confused with Parkinson’s due to the similarity of symptoms, particularly stiffness, bradykinesia and movement difficulties. One notable difference is that people with PSP find it hard to look up or down, whereas people with Parkinson’s may experience other eye-related problems, including double vision, uncontrolled blinking or excessive watering. However, this may not be obvious in the early stages of the illness.
Another difference concerns posture. People with PSP tend to stand straight or tilt their heads backwards (resulting in backwards falls), while people with Parkinson’s usually bend forwards.
Problems with speech and swallowing tend to be more common and severe in PSP than in Parkinson’s and are often more apparent earlier. The sense of smell may remain intact in PSP whereas it is often lost in Parkinson’s. Lastly and perhaps most obviously, tremor – almost universal in people with Parkinson’s – is rare in PSP.
Treatment and management
There is no specific treatment for PSP. Because it is a complex illness, a combination of approaches will probably be suggested.
Unfortunately, few medications are currently available to treat PSP effectively. Parkinson’s medicines are generally not very effective, although 20-30% of PSP patients respond quite well to levodopa at least initially. An experienced doctor or neurologist should always be involved in managing medication.
On the other hand, palliative medicine can be a great help. For example, muscle relaxants or gentle massage can help with cramps; bathing eyes with cotton wool dipped in cooled boiled water can ease the extreme dryness of the eyes due lack of eyelid blinking.
Health professionals such as physiotherapists, speech and language therapists, occupational therapists, specialist nurses, dieticians and social workers can all offer help, advice and support for those with PSP. Tell your doctor about any symptoms and difficulties so that he or she can put you in touch with the right member of the team. For example, in many countries an occupational therapist or physiotherapist will be able to provide gait assessment and suggest equipment and practical strategies. A speech and language therapist can advise on overcoming difficulties with speech, eating and swallowing.
As the illness progresses there is an increased risk of complications such as pneumonia due to an inability to swallow. If swallowing becomes too difficult, it may be necessary to introduce a feeding or PEG tube – for more information see Speech and language therapy.
Some countries have PSP organisations that can offer help, advice and support both for people with PSP and their carers. Your doctor or specialist nurse may be able to provide contact details, or you can ask at your local library or search using the Internet.
See also, PSP Europe.