Overlap with progressive supranuclear palsy (PSP)

Progressive supranuclear palsy (PSP) is a progressive brain disorder closely related to frontotemporal dementia (FTD). PSP primarily causes changes in the brain similar to Parkinson’s disease, but also causes shrinkage (atrophy) of the frontal lobes similar to FTD. For this reason, patients with PSP show features similar to Parkinson’s disease and, in addition, have features in common with FTD.

PSP affects approximately 6 in 100,000 people, most commonly between the ages of 60 and 70 years and lasts 6 to 7 years on average.

The common signs in PSP are usually changes in mobility and posture, with slowness of movements. Falls (most often backwards) are also common and may be the first sign. On examination, a reduction of vertical eye movements, or “vertical gaze palsy” is observed—and is the sign which gives this disorder its name. Stiffness (rigidity) of the muscles, particularly in the neck and spine, is also commonly present.

Later, behavioural and cognitive symptoms such as apathy, problems with reasoning, problem solving and motivation commonly appear and can be very disabling. A reduction in conversation and huskiness or slurring of speech can also occur.

In the brain, PSP causes a loss of nerve cells (neurons) predominantly in the brain stem and the frontal lobes. When examined under the microscope, neurons show an increase in the protein “tau”. Tau is also one of the proteins implicated in the causation of FTD. In other words, tau represents a strong common link between PSP and FTD although the distribution differs between the two diseases.

No simple diagnostic test is currently available for PSP. PSP diagnosis is based on clinical assessment, neuropsychological testing, brain imaging and the exclusion of other neurological or neurodegenerative disorders.

No cure or treatment is currently available for PSP. Unfortunately, the response to drugs used to treat Parkinson’s disease is rather poor. The management of PSP requires the expertise of health practitioners, neuropsychologists, speech and occupational therapists. Unlike some forms of dementia, PSP is very rarely inherited.

Several PSP support groups exist.  These groups improve awareness about PSP and to raise funding for new research. Their websites also provide information about PSP and forums for discussion. Links to these sites are listed below: