An atypical parkinsonian syndrome
Progressive supranuclear palsy (PSP) is a progressive brain condition that mainly affects balance, walking, eye movements, speech and swallowing, while other thinking skills may become affected later in the illness.
PSP is associated with a build-up of abnormal tau protein in the brain, leading to gradual damage in areas that control movement, balance and thinking.
What is progressive supranuclear palsy?
PSP is a neurodegenerative condition, meaning it gradually worsens over time. It is sometimes grouped with the ‘atypical parkinsonian syndromes’ because it can resemble Parkinson’s disease, particularly in its early stages. However, PSP tends to progress differently and usually responds poorly, or only briefly, to standard Parkinson’s medications.
There are several recognised clinical patterns (subtypes), each with a different balance of features:
- PSP-Richardson syndrome – the ‘classic’ pattern, with early falls, postural instability and prominent eye movement problems
- PSP-parkinsonism – more Parkinson-like early on, with slowness and stiffness predominating, sometimes with a brief response to Parkinson’s medication
- other, less common presentations – predominantly affecting speech and language or causing gait freezing, without the full classic pattern.
Over time, PSP typically affects:
- balance and walking, with increasing fall risk
- eye movements, especially voluntary vertical gaze
- speech and swallowing
- thinking and behaviour, particularly planning, flexibility and motivation
- later in the condition, independence in daily activities may also become affected.
What happens in the brain?
PSP is associated with progressive shrinkage and dysfunction in the brainstem and parts of the brain, including the basal ganglia and frontal brain regions. This is caused by a build-up of abnormal tau protein inside brain cells, a process known as a tauopathy. Because these affected regions control balance, eye movement and planning, PSP typically produces a combination of:
- cognitive/behavioural symptoms (slowed thinking, reduced flexibility, apathy)
- motor symptoms (falls, stiffness, slowed movement, speech and swallowing difficulty).
What increases the risk of progressive supranuclear palsy?
PSP is rare and its exact cause isn’t fully understood, but several factors are associated with increased likelihood of developing it.
Factors that can’t be changed include:
- age – the strongest known risk factor. PSP typically develops in people over 60, and risk increases with age.
- genetics – most cases occur sporadically, without a family history. A genetic variation in the MAPT gene, which provides instructions for making tau protein, has been linked to a modestly increased risk, though carrying this variation doesn’t mean a person will develop PSP.
- sex – PSP appears to be slightly more common in men than women.
Factors that may play a role, with less well-established evidence than for conditions like vascular dementia or Alzheimer’s disease, include:
- environmental exposures – some research has explored potential links to certain environmental toxins, though no specific exposure has been confirmed as a clear cause
- general brain health – cardiovascular health and lifestyle factors have drawn some research interest as possible influences on risk or symptom severity, though this hasn’t been clearly established for PSP specifically.
Common patient questions
No. PSP can look similar to Parkinson’s disease, but it usually causes earlier balance problems and falls, distinctive eye movement changes, and a limited or short-lived response to Parkinson’s medications. Both conditions are grouped as movement disorders because they share overlapping features, but their underlying disease courses differ.
Often, yes. Many people develop slowed thinking, difficulty planning or multitasking, reduced initiative (apathy) and problems with emotional regulation. Mood changes can also occur. These are part of the underlying brain changes, not simply a reaction to physical symptoms.
Most cases occur sporadically, without a family history. Rare genetic factors may slightly increase risk, but PSP is not typically considered an inherited condition.
There is currently no treatment that stops or reverses PSP. Care focuses on maximising safety, function and quality of life through a multidisciplinary approach, which may include:
- physiotherapy (balance and falls prevention)
- speech pathology (speech and swallowing support)
- occupational therapy (home safety and equipment)
- in some cases, trials of medication for stiffness or mood symptoms.