research

Guess what?! Eye gaze and conversation in Parkinsons research published

Timothy Hodgson Parkinsons, research, Uncategorized

This month we published a paper in the International Journal of Language and Communication Disorders entitled “Gaze-speech coordination during social interaction in Parkinson’s disease“. The research used mobile eye tracking to examine how people with and without Parkinsons use eye movements during spoken conversation. In order to get people talking we asked them to play a card guessing game, based on the children’s guessing game “HedBanz” in which one player has to describe an object written on a card and the other player has to guess. A link to the full open access publication is available here.

Previous research has shown that eye movements are important in signalling “turn taking” in conversation, whereby the speaker indicates to their conversation partner that the end of the speech turn is coming. Although you might not be aware that you are doing it, we often direct our eye gaze towards the other persons face to indicate it is their turn to speak next. Other work by myself and others has shown how the voluntary control of eye movements is affected in Parkinsons disease. Taking these findings together, we wondered if there were differences in how patients used their eyes during speech and conversation.

The results showed that people with Parkinsons tend to make longer duration periods of eye fixation on the other persons face and elsewhere. They did less well when describing cards to the other player, suggesting problems with speech, but guessed just as many objects when listening to someone else describing, suggesting that their condition didn’t affect their ability to understand others. We also found that the timing of speech turns was subtly different when a patient was playing the game, with a tendency towards shorter gaps and more interruptions in speech, indicating people with Parkinsons may be slightly more impulsive and sometimes “jump in” to interrupt others more.

The results confirm something I have personally noticed about people with Parkinsons over the years: That they sometimes have a subtly different pattern of gaze during conversation including extended periods of eye contact. This can be slightly disconcerting if you are not aware of it and together with phenomena like reduced facial expression might adversely affect social interaction and communication. We think that wider public knowledge and awareness of some of these more subtle features of the condition could itself improve the quality of life and social connectedness of people with Parkinsons.

The research was conducted in collaboration with Gemma Ezard (Lincolnshire NHS) and Frouke Hermans (formerly University of Lincoln now at the Open University in the Netherlands) and was funded by BA/Leverhulme small grant Ref: SG152231

Visual Attention and Paeleolithic Stone Tools

Timothy Hodgson General news, Publications, research

This month we published a study describing how people direct eye movements during viewing of ancient stone tools. The work was led by Maria Silva Gago, Emiliano Bruner and other researchers from CENIEH University of Burgos Spain together with myself and former Lincoln PhD student Flora Ioannidou (now at University of Aberdeen).

The research used eye tracking and the “mouse click” attention tracking technique to measure which areas of stone tools attracted peoples interest most. High resolution photographs of Paeleolithic hand axes (example right), along with much more ancient (approximate 2 million year old) roughly worked tools (example below) were shown to participants. We found that people’s attention was drawn to the “knapped” surfaces of  tools, as well as areas such as the base where the tool would normally be grasped. This was the case even though participants were just viewing pictures and not handling the objects and weren’t told the objects were tools.

We also ran the images through a computer model which calculated the”salience” of different regions of the images.  Some very influential models of vision suggest that attention is simply attracted to regions that stand out visually from the background (i.e. are more “salient”), but the computer model did not seem to explain our results very well. Instead, we think it was how the different parts of the tool might be grasped and used, rather than just how visually interesting it was, that was directing the viewers’ eyes.

The results support the theory of object-action affordances proposed by James J Gibson in the 1970s. He suggested that the brain very quickly detects features of objects that are relevant for action, priming a tendency for us to carry out the associated action. One possibility is that through evolution our ancestors’ brains became increasingly sophisticated at detecting action affordances in stone objects. This lead in turn to the manufacture of more sophisticated tools with enhanced features designed to activate action affordances. This in turn may have caused further development in the brain’s object-action affordance network in an ongoing process of coevolution between human cognitive capacities and tool complexity.

The full paper is published in the journal Perception and can be read online here.

Some example eye movement sequences recorded in the study are shown below.

Hemi-disconnection project at Great Ormond Street Hospital

Timothy Hodgson Eyelander, General news, research

This week I have been at Great Ormond Street Hospital London setting up some tasks on an Eyelink Duo eye tracker for a project led by Dr Luis Lacerda and Prof. Chris Clark with Vision Specialist Clinical Scientist Sian Hanley.

The project will examine children’s recovery of visual function following Hemisphere disconnection surgery (which can be used to treat severe epilepsy). Luis’ team will evaluate the effectiveness of our Eyelander game for training visual search ability in these children as well as UCL’s Read Right programme, developed by my old colleague and collaborator Prof. Alex Leff.

It’s been great to visit and a privilege to be involved in such an exciting project with such an outstanding team of researchers and clinicians. Feel free to get in touch with Luis if you would like to know more about the project.

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.