Pioneering clinical trial opens new sites

From Aberdeen to Cornwall and Dartford to Wrexham, the TOP HAT trial now has a total of 26 sites across England, Scotland and Wales. The 4 additional locations mean more people will now have an opportunity to take part.

How common are visual hallucinations?

Hallucinations affect many people with Parkinson's at some point and can be extremely distressing for patients and their families. Hallucinations and delusions can appear in both younger and older people in the earlier stages of the condition but are more common in people who've had Parkinson's for a long time. Read more information about hallucinations and delusions.

There are steps you can take to manage and reduce your hallucinations or delusions, which you can read about in our magazine. But the medications available to manage these symptoms in people with Parkinson's are severely limited.

What is the TOP HAT trial?

Parkinson's UK is funding a large-scale clinical trial to investigate the potential of a drug called ondansetron in people with Parkinson's or Lewy body dementia (LBD) who experience visual hallucinations.

Ondansetron is an anti-sickness drug that is already approved and in use in the UK, mainly to help reduce nausea in people undergoing cancer treatment. The drug first showed potential for treating visual hallucinations in Parkinson's in the early 1990s. 

The trial aims to recruit 306 people with Parkinson's or LBD across England, Scotland and Wales. Sites in Romford, Oxford, Sherwood Forest and Bury have recently opened.

Dr Beckie Port, Head of Research Communications and Engagement at Parkinson's UK, comments: 

''Research suggests that up to 75% of people with Parkinson's may experience hallucinations at some point. But with severely limited options when it comes to medications, managing hallucinations may worsen other Parkinson's symptoms.

''To understand if ondansetron has potential to relieve visual hallucinations, researchers are calling for people who experience troubling visual hallucinations on at least a weekly basis to come forward and take part in the TOP HAT trial. 

''However, if this particular study isn't for you then there are many other projects taking place across the UK. You can browse them all on our Take Part Hub.''