VISMAC Version 1.0
Research type
Research Study
Full title
Treating VISual hallucinations in people with MACular Degeneration: a non-invasive stimulation study
IRAS ID
220721
Contact name
Simon Douglas
Contact email
Sponsor organisation
Northumberland, Tyne and Wear NHS Foundation Trust
ISRCTN Number
ISRCTN16758036
Duration of Study in the UK
1 years, 6 months, days
Research summary
Charles Bonnet Syndrome (CBS) occurs in patients with eye disease who experience visual hallucinations in the absence of psychiatric illness. Up to one-third of CBS patients judge these hallucinations to be unpleasant or distressing and interfere with daily life. Currently, no effective treatments exist for CBS.
Visual hallucinations in CBS are believed to be the result of over-activity in the visual part of the brain; studies have found that a well-tolerated, non-invasive treatment known as transcranial direct current stimulation (tDCS) can alter activity levels in the brain using a weak electrical current applied using electrodes on the scalp. As tDCS can be used to reduce activity in the brain, it may be possible to reduce the over-activity of the visual cortex seen in CBS, potentially causing a reduction in visual hallucinations. This study aims to investigate both what causes visual hallucinations in CBS (such as increased activity in the visual cortex) and determine whether tDCS can be used to help treat visual hallucinations in CBS patients.
The study will take part in two phases:
i) Phase I, at King's College London, will investigate which stimulation settings are best for reducing visual hallucinations in CBS. Patients experiencing frequent or continuous hallucinations will be asked to provide 'real-time' feedback as to how changing the location, length and strength of stimulation impacts their visual hallucinations.
ii) Phase II, at Newcastle University, will use the optimal settings determined from phase I to form a pilot treatment study. All participants will receive a course of active (real) tDCS treatment or placebo (pretend) treatment over four consecutive days, returning to receive the opposite treatment after a month so that the effects can be compared. Before and after stimulation treatment brain activity will be measured so that we can better understand visual hallucinations, and the effects of tDCS.REC name
North East - Tyne & Wear South Research Ethics Committee
REC reference
17/NE/0131
Date of REC Opinion
7 Jun 2017
REC opinion
Further Information Favourable Opinion