Parkinsons

Posts relating to research into Parkinsons Disease

Orienting to social cues in Parkinsons

Timothy Hodgson General news, Impact, Parkinsons, Publications, social neuroscience

This month we published a paper in the journal Experimental Brain Research reporting how eye movements are influenced by social cues in people with Parkinsons disease.

Previous studies have suggested that Parkinsons patients have problems in directing visual attention due to loss of the chemical dopamine within the basal ganglia of the brain, but no one has specifically looked at whether they have particular problems with social cues. This question is important as problems with processing social information may lead to difficulties in everyday life for people with Parkinsons. It is also a question of scientific interest as it has been suggested that we have specialised brain pathways for processing social information (the so-called “Social Brain hypothesis”).

We used a task in which pictures of someone else’s eyes, arrows and pointing fingers are shown on a computer screen, whilst people track a spot jumping around the screen with their eyes (see picture; you can see a video of the task here). Often people make an eye movement by mistake in the direction indicted by the eyes, arrows or fingers, even when they are meant to respond directly at the target (the little black spot) and ignore the pictures. We found healthy adults made more of these errors with pointing finger cues compared to the other cue types (suggesting pointing fingers provide a particularly strong cues to eye movements) whereas people with Parkinsons made similarly high errors for all 3 cue types.

Although not specifically better or worse for socially relevant cues (eyes / fingers), Parkinsons patients clearly had difficulty in suppressing their distracting influence. This suggests the basal ganglia plays a role in controlling eye movements in response to social and non-social cues. But this doesn’t mean that people with Parkinsons don’t have particular problems with maintaining attention in social situations. On the contrary, social interaction might often take place in a busy environment, with lots of sensory information competing for attention. These deficits in the control of eye movements might therefore lead to difficulty in social interaction and might impact on patients’ quality of life.

A link to the paper can be found here

Eyelander game evaluation and Parkinsons and Spatial Memory studies published

Timothy Hodgson Eyelander, Parkinsons, Publications, research

Research in patients both young and old can be difficult, time consuming and stressful to carry out (e.g. due to the ethical approval process, patient recruitment and practical difficulties in testing patients with physical disabilities etc). Yet the importance and potential benefits to patients themselves of such research far out weighs the difficulty entailed in conducting it.

Two of my recently published papers reflect the outcome of patient based projects. Both studies use tasks which require viewers to search through items on a screen using saccadic eye movements. The first addressed the issue of working memory and oculomotor control in Parkinsons disease, a topic I have been researching since the late 1990s. Whilst the second reports the clinical trial evaluating the effectiveness of the Eyelander video game for children who have had neurological injury leading to partial visual field loss (hemianopia).

In the first study, published in the April 2019 edition of the Journal of Cognitive Neuroscience we recorded eye movements while participants performed a version of the CANTAB Spatial Working Memory task which requires patients to search through boxes on a computer screen to find hidden tokens. I first had the idea to do this study whilst watching patients performing this task on a touch screen when I was a post-doctoral research fellow at Charing Cross Hospital, London. I could see that patients were using eye movements a lot in this token “foraging” task, but at the time we didnt have the technology to track their eye movements properly. It was only later that suitable eye tracking equipment and software became available to carry out the research. Amongst other findings the paper shows that people with Parkinsons don’t use eye movements to plan ahead or look back at locations they’ve already searched as effectively as controls, most likely due to an imbalance of the neurotransmitter dopamine in the prefrontal cerebral cortex.

 

The second paper, published in the December 2018 edition of Journal of Visual Impairment and Blindness describes the evaluation of our visual search  game for children with partial visual loss following brain injury affecting the visual parts of the cerebral cortex. The results showed children were able to play the game at home unsupervised and that it had a positive effect on parallel measures of functional visual ability which was similar in magnitude to effects reported for visual search training in adult with partial visual loss following stroke. The Eyelander game is now available for anyone to play online, so please take a look. We are also starting a collaborative project with Great Ormond Street Hospital to evaluate its effectiveness for treating visual field loss following neurosurgical procedures in children.

Lincoln and District Parkinsons Group

Timothy Hodgson Parkinsons

I am very honoured to have been invited to be  Branch President for the Lincoln and District Branch of Parkinsons UK for 2017-18.

I have been working with members of the local group over the last 4 years investigating the control of eye movements in Parkinsons. This has been a long standing research interest off and on since my days as a post-doctoral research fellow at Charing Cross Hospital in London.

Parkinson's diseaseOur research has shown that there is a particular “marker” of Parkinsons in eye movements, namely “multi-stepping” or jerkiness of eye movements measurable under certain conditions with a computerised eye tracker. In other situations some people with Parkinsons appear to be slightly more distractable and not organise eye movements as efficiently as healthy people when carrying out problem solving and memory tasks.

parkinsons saccades
Multistepping saccades

The research has potential in the future to help in the early diagnosis of Parkinsons, the assessment of cognitive impairments in Parkinsons as well as helping people with Parkinsons understand the subtle ways in which the condition might affect them beyond the obvious symptoms seen in other sort of movement.

I’ve also observed that People with Parkinson are extra-ordinarily nice and generous people with an enthusiasm for research. I continue to do whatever I can in my own little way to go the extra mile (or 20!) to support them, so I was very pleased to accept the appointment as Branch President. I am looking forward to meeting established and new members at the Annual General Meeting next month in Bracebridge Heath and giving a short update on recent research.