Can cognitive tests differentiate PSP and Parkinson's Disease
Research type
Research Study
Full title
Can cognitive tests differentiate Progressive Supranuclear Palsy and Parkinson's Disease
IRAS ID
271735
Contact name
Daniel Smith
Contact email
Sponsor organisation
Durham University
Duration of Study in the UK
3 years, 0 months, 1 days
Research summary
Summary of Research
Progressive Supranuclear Palsy (PSP) is a rare brain disease that that causes problems with walking, swallowing, speech and eye-movements. It is a rare disease and sometimes mistaken for Parkinson’s disease (PD). Existing research, including a pilot study we ran from 2015-2019, suggests that people with PSP have some problems with visuospatial attention and short term memory that people PD do not experience. The current study will extend this research by comparing people with PSP and people with PD on a range of tests that measure these cognitive functions. Specifically people with PSP, people with Parkinson’s disease and healthy participants will complete computer based tests that measure their visual attention. For example, in one test participants must search a scene to find a target object. We will also measure short term memory, the ability to recognise emotions and eye-movements. These tests can be completed using a laptop, so we can test people in their own homes. We will compare the scores of the different groups using a statistical technique called Linear Discriminant Analysis to establish whether a person’s score on our tests of attention and memory can be used as way of accurately classifying them as having either PSP or PD.
Summary of Results
The Background: We were interested in how a disease called Progressive Supranuclear Palsy (PSP) affects mental processes like attention, short-term memory and the ability to recognise emotions. PSP is a very rare disease, affecting about 7 people in every 100,000. The two diseases have very similar symptoms, but correct diagnosis of PSP takes 3.5 years longer than a correct diagnosis of Parkinson’s disease. This delay is a problem because people with PSP have to have more visits to hospital and makes it very hard to run clinical trials for new treatments. We believed that people with PSP might have a particular pattern of cognitive problems that could make it easier to doctors to tell the difference between PSP and Parkinson’s disease. We worked with NHS trusts in South Tees, Gateshead, Northumbria and South Tyneside & Sunderland to test this idea. This research was generously funded by the Dunhill Medical Trust.
The Study: We asked for volunteers from three groups of people: people with PSP, people with Parkinson’s disease and healthy older people. There were 29 volunteers in each group. The volunteers did the tests in their own homes, usually in two or three home visits. They did tests of attention, the Bells test (shown at the end), where they had to find 35 bells hidden among 280 other objects, a memory test where they had to remember the colour or location of spots, a test of emotion recognition and a general cognitive assessment called the Montreal Cognitive Assessment (MoCA). We also measured eye movements, reading, visual disability and quality of life.
The Results: We found large differences between people with PSP, people with Parkinson’s disease and healthy older volunteers on most of the tests. The most important differences were:
1. People with PSP had problems with visual attention. Their ability to was slow and disorganised compared to people with Parkinson’s disease.
2. We can use the results of the Bells test to tell which patients had PSP and which had Parkinson’s disease with an accuracy of 92%. We think the search test is very sensitive to PSP because PSP affects parts of the brain responsible for eye-movements, planning and limb movements.
3. People with PSP and people with Parkinson’s disease had some problems with short term memory compared to the healthy participants. The problem was more severe for people with PSP, and they tended to make more guesses than the people with Parkinson’s disease, but the overall pattern was quite similar. These findings suggest that people with PSP have a reduced memory capacity.
4. People with PSP had very severe problems telling the difference between the negative emotions of anger, disgust and fear. People with Parkinson’s disease also sometimes got confused between these emotions, but not as often as the people with PSP. The healthy, older participants also occasionally confused these emotions.
5. People with PSP also had significantly worse score on the MoCA, which tested general cognitive function, experienced more severe problems their eye-movements and reading, reported more problems with their vision and had a lower quality of life that people with Parkinson’s and healthy older people.
Conclusions: People with PSP have problems with attention, short-term memory and recognising emotions. These problems are more severe than the problems experienced in Parkinson’s disease. The key finding was that we could reliably tell the difference between people with PSP and people with Parkinson’s disease using the visual search task. This means that the Bells test task has great potential as a new test for PSP. We are very grateful to everyone who took part in this study. These results take us a big step closer to our goal of developing a cheap and effective tool that will help doctors to make earlier and more accurate diagnoses of PSP.
Next steps: We are writing up the results for publication in a leading medical journal. We are also preparing a new research project in collaboration with NHS trusts in Teesside, Northumbria, Sunderland & South Tees, Gateshead, Newcastle University and Oxford University. This will be a large-scale trial to test whether the Bells test can be used to help doctors make earlier and more accurate diagnoses of PSP.REC name
North East - Newcastle & North Tyneside 1 Research Ethics Committee
REC reference
19/NE/0369
Date of REC Opinion
14 Feb 2020
REC opinion
Further Information Favourable Opinion