Progressive supranuclear palsy: a condition causing movement issues and dementia

PSP is caused by a build-up of the protein tau, which you can read about in our blog post about proteins related to dementia. Tau also underpins frontotemporal dementia and corticobasal syndrome, depending on which part of the brain is most affected. Because of the overlap between other diseases, PSP can be difficult to diagnose, leading to frequent misdiagnoses.

In PSP, tau mainly accumulates in the part of the brain that controls eye movement, damaging the nerve cells here. This disrupts movement, which can cause difficulties with balance, vision, speech, and swallowing. As PSP is progressive, these symptoms get worse over time, but the symptoms each person with PSP experiences will be different.

People with PSP have less control over their movement; this often starts with moving more slowly and having stiffer muscles. Physiotherapists can help people with PSP maintain their mobility for longer using exercises that help loosen muscles and joints. With time, these movement difficulties will get worse and often affect balance causing frequent falls.

The muscles controlling the mouth can also be affected, resulting in slurred or slow speech and difficulty swallowing. Issues with swallowing can be very dangerous and lead to choking and a type of pneumonia called aspiration pneumonia. Speech and language therapists can help people with PSP combat these issues to keep them safe and able to communicate better.

In PSP, movement issues are prominent in the eyes causing problems with vision, such as a restricted field of vision, blurred vision, involuntary or slow eye movement, double vision, and difficulty looking down. People with PSP may find it harder to close their eyes and move them making it more challenging to maintain eye contact or read. Although standard glasses cannot correct these issues, specialist lenses containing prisms can help people look down without moving their eyes, and double vision can often be eased by covering one eye.

Posterior cortical atrophy (PCA) is another form of dementia that affects vision, however the difference is that PCA impairs the processing of visual information, whereas PSP affects the control of eye movement. You can read more about PCA in this blog post.

Impairment in thinking skills – known as cognitive symptoms – often come after the physical symptoms of PSP. People with PSP may experience memory problems, but more commonly encounter issues with their executive functions. These tasks are performed by the nerve cells in the front of the brain and include skills like planning, decision-making, impulse control, complex thoughts, and concentration.

There are around 4,000 people living in the UK who have PSP, most of whom are over the age of 60. Unfortunately, there is not currently a cure for PSP, but research is ongoing to find one, which you can follow on the PSP Association’s website.