Transcranial direct current stimulation in the treatment of visual hallucinations in Charles Bonnet syndrome: A randomized placebo-controlled crossover trial.

da Silva Morgan, Katrina, Schumacher, Julia, Collerton, Daniel, Colloby, Sean J., Elder, Greg, Olsen, Kirsty, Ffytche, Dominic H. and Taylor, John-Paul (2022) Transcranial direct current stimulation in the treatment of visual hallucinations in Charles Bonnet syndrome: A randomized placebo-controlled crossover trial. Ophthalmology, 129 (12). pp. 1368-1379. ISSN 0161-6420

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To investigate the potential therapeutic benefits and tolerability of inhibitory transcranial direct current stimulation (tDCS) on the remediation of visual hallucinations in Charles Bonnet Syndrome (CBS).

Randomized, double-masked(blind), placebo-controlled crossover trial.

Sixteen individuals diagnosed with CBS secondary to visual impairment caused by eye disease experiencing recurrent visual hallucinations.

All participants received four consecutive days of active and placebo cathodal stimulation (current density: 0.29mA/cm2) to the visual cortex (Oz) over two defined treatment weeks, separated by a four-week wash-out period.

Main Outcome Measures
Ratings of visual hallucination frequency and duration following active and placebo stimulation, accounting for treatment order, using a 2x2 repeated measures model. Secondary outcomes included impact ratings of visual hallucinations and electrophysiological measures.

When compared to placebo treatment, active inhibitory stimulation of visual cortex resulted in a significant reduction in the frequency of visual hallucinations measured by the North East Visual Hallucinations Interview, with a moderate-to-large effect size. Impact measures of visual hallucinations improved in both placebo and active conditions suggesting support and education for CBS may have therapeutic benefits. Participants who demonstrated greater occipital excitability on electroencephalography assessment at the start of treatment were more likely to report a positive treatment response. Stimulation was found to be tolerable in all participants with no significant adverse effects reported, including no deterioration in pre-existing visual impairment.

Findings indicate that inhibitory tDCS of visual cortex may reduce the frequency of visual hallucinations in people with CBS, particularly individuals who demonstrate greater occipital excitability prior to stimulation. tDCS may offer a feasible, novel intervention option for CBS with no significant side effects, warranting larger scale clinical trials to further characterize its efficacy.

Item Type: Article
Additional Information: Funding information: This work was supported by a grant from the Macular Society (BH152932). Additional support came from the NIHR Newcastle Biomedical Research Centre (BRC) based at Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University and the South London and Maudsley NHS Foundation Trust Mental Health BRC. D.H.ff., D.C., K.O., and J.-P.T.: Supported by NIHR Programme Grants for Applied Research (RP-PG-0610-10100 - SHAPED). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funding organization had no role in the design or conduct of the study. HUMAN SUBJECTS: Human subjects are included in this study. All participants provided written informed consent, and ethical approval was granted by the local Research Ethics and NHS Research and Development Committees (ref: 17/NE/0131). This study was conducted in concordance with the tenets of the Declaration of Helsinki and is registered at under the identifier ISRCTN16758036.
Uncontrolled Keywords: Charles Bonnet syndrome, Visual Hallucinations, Non-invasive stimulation, Macular Degeneration
Subjects: A300 Clinical Medicine
C800 Psychology
Department: Faculties > Health and Life Sciences > Psychology
Depositing User: Elena Carlaw
Date Deposited: 05 Jul 2022 12:09
Last Modified: 09 Jul 2023 03:30

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