Progressive supranuclear palsy

Overview

Progressive supranuclear palsy (often shortened to PSP) is a rare progressive neurodegenerative disease that causes vision difficulties and loss of balance while walking.

PSP is due to an abnormal build-up of a protein in the brain, called tau, which causes parts of the brain to deteriorate over time. As a result, people with PSP may experience increased difficulty with their thinking, speech, swallowing and movement.

Symptoms

Symptoms of PSP are most commonly seen in people in their early 60s, but may begin in some people who are in their 40s.

PSP can be confused with Parkinson’s disease and corticobasal syndrome because some symptoms – like the stiffness and slow movements – can resemble some of the common characteristics of these other neurodegenerative diseases. However, unlike Parkinson’s disease, people with PSP usually do not experience tremors.

Difficulties with movement

Early symptoms of this disease may relate to a person’s increased difficulty with walking and balance, often resulting in frequent falls. It is common for a person in the early stages of PSP to develop other motor-related symptoms like slowed or awkward movements while walking.

Difficulties with vision

The symptoms that help to differentiate PSP from other neurodegenerative diseases – like Parkinson’s – are often related to a person’s vision and eye movements.

People with PSP often experience blurred vision and an inability to control eye movements. Some cannot look downward or cannot open their eyelids. This increased difficulty with eye movements can make it appear that a person is disinterested in conversation because of the limited eye contact.

Changes in cognitive abilities

Changes in thinking and cognition may be experienced by some people with PSP. People with the cognitive symptoms of PSP typically experience difficulties with:

• Carrying out a plan,
• Problem-solving,
• Adapting to change,
• Making financial decisions,
• Memory, and
• Slurred speech.

Changes in mood and personality

People with PSP may experience changes in their behaviour and emotions that are similar to those exhibited by people with behavioural variant frontotemporal dementia (bvFTD).

The behavioural symptom that is commonly shared among people with bvFTD and PSP is their inability to control their behaviour in social situations; this may result in embarrassing social situations.

People with the emotional symptoms of PSP may appear to be indifferent towards other people, seem depressed, or have an inability to control their emotions (e.g. prolonged crying).

Diagnosis

It can be challenging to diagnose PSP early in the progression of the disease as there are a number of symptoms that are shared with similar neurodegenerative diseases, including:

• Parkinson’s disease,
• Alzheimer’s disease,
• Frontotemporal dementia, and
• Creutzfeldt-Jakob disease.

People who develop movement difficulties prior to vision challenges are most often misdiagnosed with Parkinson’s disease. PSP is often not considered until people experience challenges with their vision.

It's also common for changes in a person’s mood to be initially attributed to depression, or for changes in behaviour to be related to symptoms of another dementia like bvFTD and not PSP.

There is no single test to diagnose PSP. Physicians assess types of symptoms to help rule out other conditions that could be causing the symptoms, such as Parkinson’s disease or strokes.

Brain imaging

Brain imaging through medical resonance imaging (MRI) tests may be used to rule out other conditions, and helps to detect any abnormal changes, like shrinkage, in the parts of the brain that are associated with PSP.

Testing and exams

A thorough assessment may also include neuropsychological testing to evaluate cognitive functioning, or physical and neurological exams to assess a person’s movement and any changes in the person’s vision.

Risk factors

At present, there is no known cause of PSP. The disease appears to be sporadic, meaning that in most cases there is no family history of the disease, and that common risk factors have yet to be identified.

However, similar to other types of dementia, PSP is characterized by abnormal accumulation of tau protein in the parts of the brain that are most affected by PSP. It's still unknown what causes this surplus of the tau protein, and why it results in the deterioration of brain cells.

Treatment

Currently, there is no known cure for PSP. Medications that are used to manage symptoms of Parkinson’s disease may be of some benefit to people with similar symptoms.

Therapeutic approaches

Therapeutic approaches also support people living with PSP to manage symptoms of their disease:

• Physical therapy is often focused on fall prevention and exercises to improve balance. People with PSP are also frequently encouraged to use weighted walking aids to prevent them from falling backwards, such as a walker.
• Speech therapy may also be effective in addressing speech difficulties, or eating and swallowing challenges that are associated with the progression of PSP.

More information and resources

Progressive Supranuclear Palsy Society of Canada. The PSP Society of Canada provides information and support to people living with PSP and their families.