The bells test
Progressive Supranuclear Palsy (PSP) is a rare and incurable neurodegenerative disease that affects ~7 in 100,000 people. People with PSP can have many of the same symptoms as people with Parkinson’s disease and their first diagnosis is often Parkinson’s disease. On average, it takes about 3 years for a patient to get their correct PSP diagnosis. This delay creates uncertainty for patients and restricts their ability to access appropriate support. Patients also require many additional hospital visits which is costly and burdensome for them and the NHS. Delayed diagnosis is also challenging for developing new treatments, because researchers cannot be certain which patients have PSP. Patient groups and doctors agree that research into new tools that address the challenge of early and accurate differential diagnosis of PSP and PD should be a high priority.
Our previous research shows that people with PSP also have severe problems with attention, and particularly with the ability to find a target object hidden among distractors (e.g. a ‘Where’s Wally’ type of puzzle), whereas people with Parkinson’s disease do not have this problem. The ability to search for a target can be measured scientifically using a test called the Bells Test (see image) which measures how quickly and accurately a person can find and circle bell-shaped objects hidden among other objects. In a recent study funded by the Vivensa Foundation we found that people with PSP had very disorganised search compare to people with Parkinson’s disease (see Figure A). In fact, the Bells test can discriminate between people with PSP and PD with 92% accuracy. The aim of this project, which is generously funded by the MRC, is to validate this finding in a new group of people with PSP and Parkinson’s disease.
Faster and more accurate diagnosis of PSP will reduce the costs of multiple hospital visits for carers and the NHS, give certainty to patients and carers, help ensure patients have access to appropriate care pathways and is a key enabler of trials of new drugs to treat PSP. The Bells test is non-invasive, quick, free and easy to score, so is very economical in terms of cost and clinician time. It already widely used in stroke medicine so barriers to adoption are low, and our team includes clinicians who specialise in Parkinson’s disease education for healthcare professionals who are ideally placed to ensure doctors hear about and use the findings of this research.
Search paths from from 3 representative participants. Notice the highly organised search in the neurotypical participant and the person with Parkinson’s disease, compared with the very disorganised search of the person with PSP.
This research has been approved by the North East – Tyne & Wear South Research Ethics Committee: 26/NE/0055
