Testing therapies to reduce severity of visual hallucinations

Prof Robin Walker, Royal Holloway University - £37,178

Many people with vision loss experience Charles Bonnet Syndrome (CBS), which leads to visual hallucinations. These hallucinations can range from simple shapes and patterns to vivid and realistic faces and scenes. They can severely affect a person’s life and can be distressing. This trial aims to test current suggested techniques for reducing the severity of hallucinations.

What is the problem?

Many people with vision loss experience Charles Bonnet Syndrome (CBS), which leads to visual hallucinations. It is currently believed CBS is due to the brain creating new visual signals to make up for the lack of signals being received from the eyes. These hallucinations can range from simple shapes and patterns to vivid and realistic faces and scenes. They can severely affect a person’s life and can be quite distressing. 

Several techniques are currently promoted which claim to reduce the severity and impact of these hallucinations, but no studies have been done to prove if they work. This trial tested two of the latest suggested techniques for reducing the severity of hallucinations.

What did the researchers do?

This study evaluated the efficacy of two techniques: eye movement therapy and distraction/interruption therapy.

Eye movement therapy involves making voluntary eye movements (e.g. quickly moving your eyes side to side or up and down) to try and disrupt the signals from the brain causing the hallucination.

Distraction/interruption therapy involves changing the environment to interrupt the hallucination. This can be done by changing lighting (turning lights off or on), moving into a different room, or changing your posture or task.  

Additionally, the team assessed the use of on-line survey tools to administer the study materials.

What did the researchers find?

This study found that hallucination characteristics, such as how often they occurred, how long they lasted, and how distressing they felt were closely linked to participants’ mental health.

Positive preliminary findings showed that by using these techniques, participants reported having an increased sense of control over their hallucinations despite not reducing their severity. Of the two techniques tested, the distraction strategy was associated with greater perceived control over hallucinations. It also received higher treatment satisfaction ratings, even though it did not significantly reduce symptoms.

Participants reported the strategies easy to use, and many continued using at least one of them after the study ended. The use of on-line survey tools was found to be efficient, but having a researcher engaging with participants directly (via telephone) improved study completion rates. 

How can this help and what’s next?

This feasibility study found that while behavioural strategies did not reduce the severity of visual hallucinations in Charles Bonnet Syndrome, they enhanced participants' sense of control and coping, with high levels of user satisfaction reported. Further research is needed to explore the nature of control strategies in more detail. This could help improve wellbeing and reduce the psychological burden of CBS.