Author: DanSmith

PPI funds secured for development work on the Prism glasses project

One project that has been simmering along is our idea for exploring of the clinical benefit of prism glasses. The project idea arose from discussions with colleagues about the use of prism glasses by people who have problems with vision and  attention following brain injury (e.g. hemispatial neglect). There is a well developed literature about how prism use in these groups, and we were really surprised that there was no similar literature for people with PSP.  We have some preliminary data from a survey about how and why people with PSP use prism glasses (see User Perspectives on the Efficacy of Prism Therapy for PSP), but these items may not necessarily reflect the activities that are important to people with PSP and we need more qualitative feedback on what is important to the users. Following some very helpful discussion with the NHS Research Design Service we were awarded for £250 to fund some patient-public involvement work to help guide the development of this project. The grant will help us get a feel for the kinds of questions we should be asking and what activites are important to people with PSP  (e.g. do they prefer to train to use prisms for reading or for mobility?), which will influence the design of future research projects. This latter question is also important because we already know from our work on rehabilitation of heminaopia that training needs to be task specific (e.g. Aimola et al., 2014; Lane et al., 2010), so it will be useful to understand which tasks shuold be prioritised for training. We’re planning to run the activities in May/June with Dr Uma Nath in Sunderland and the RDS, and in the longer term this PPI work will form the basis for a grant application to systematically evaluate study the efficacy of prism glasses as a treatment for PSP.

Aimola, Lina and Lane, Alison R. and Smith, Daniel T. and Kerkhoff, Georg and Ford, Gary A. and Schenk, Thomas (2014) ‘Efficacy and feasibility of home-based training for individuals with homonymous visual field defects.’, Neurorehabilitation and neural repair., 28 (3). pp. 207-218.

Lane, A.R. and Smith, D.T. and Ellison, A. and Schenk, T. (2010) ‘Visual exploration training is no better than attention training for treating hemianopia.’, Brain., 133 (6). pp. 1717-1728.

 

New paper: Does resource allocation in spatial working memory depend on what is recalled?

The latest paper from Siobhan’s PhD work, published in Journal of Vision, suggests so. In this study, we examined the serial position effect in spatial working memory using a continuous report task to explore how sources of recall error change across different positions in a sequence. We compared the sources of recall error in full and partial report tasks. The key take-home for this paper is that the serial position effect in precision in spatial working memory depends on whether a full sequence or only one item from that sequence is recalled. We found that when a full sequence is recalled, items presented early in this sequence are recalled more precisely than subsequent items (primacy effect). In contrast, when only a single item is to be recalled, this serial position effect is reduced and reversed. This finding reconciles previously contradictory findings in visuospatial working memory, where differences in the nature of the recall task appeared to determine whether a recency or primacy effect was observed. The key data are captured in the figure below:

Mean imprecision for whole report (sequential presentation mode only) and single probe tasks as a function of serial position at each set size. Error bars represent the standard error of the mean.

This finding is important because it suggests that the primacy effect in the whole report task results from accumulation of noise/error due to performing multiple goal-directed actions during recall, whereas only a single action was required in the partial report task. Additionally, this finding has important implications for models of capacity, and suggests that spatial STM is flexible and dynamic, with resource allocation being determined by the nature of the recall task.

You can read the paper open access here: https://jov.arvojournals.org/article.aspx?articleid=2785388 and the research was funded by an ESRC NINEDTP studentship awarded to Siobhan McAteer.

Motor Bias Project Review of the Year

Alexis Cheviet with one of the visual search tasks he created for the PSP project

The new year has begun for the Motor Bias project and we wanted to take some time to reflect on the ups and downs of 2022. Like most people we were delighted to emerge from the Covid 19 restrictions which had been so disruptive to our research. The most important consequence for us was the restart of the Dunhill Medical Trust funded PSP project, and the appointment of Dr Alexis Cheviet as a postdoc. Alexis made a great start to the project and we hit two major milestones, firstly when the project opened for recruitment at Sunderland Royal Infirmary, then when we collected data from our first group of patients. Achieving these goals would not have been possible without the fantastic support we recieved from Susan Wilson and Dr Uma Nath in Sunderland, Bryony Storey and Dr Claire McDonald in Gateshead and Dr Louise Wiblin and Kelly Hylton at James Cook in Middlesbrough, and we’re excited about getting recruitment up and running across all the sites in the new year.

Siobhan explaining her PhD work at ECVP 2022 in Nijmegen

In addition to testing our first patients in the PSP project this was a year of many other ‘firsts’: There were major milestones for Siobhan, who published her first paper (also the 1st registered report for the motor bias project), which used mixture modelling to establish the source of oculomotor interference in spatial short-term memory representations (McAteer et al., 2022), then promptly went and got her first job in industry. Fortunately Siobhan won’t be leaving until the summer so there’s lots of time to squeeze a few more papers out!  Dan published his first paper using Pavlovia/Psychopy, demonstrating the existence of a horizontal-vertical anisotropy in spatial short-term memory (Smith 2022) and Soazig gave her first keynote talk to the North West Vision Group. Other notable highlights were new papers from Alexis on attention in dyslexia (Cheviet et al., 2022) and the neural substrates of saccadic adaptation, (Metais et al., 2022), Soazig’s new collaboration on concussion with Dr Ali Lane, and we also delighted to see Dr Kasey Philyaw and Dr Rebekah Brockbank receive their PhDs. It was also a treat to return to in-person conferences and work from the Motor Bias project was presented at a very jolly EPS meeting in Stirling, ECVP in Nijmegen, ECEM in Leicester and NWVG in Liverpool. There were, of course, le

Dan with Dr Rebekah Brockbank(centre) and Prof Emily Oliver at Rebekah’s graduation

ss positive moments including some unsuccessful grant applications and some harshly rejected papers (curse you reviewer 2!!). However,

with a fair wind we’re confident the grants and papers can be revised and improved in the coming year.

Looking forward to 2023 the big aims will be to collect a nice big sample of patients for the PSP project and present the initial findings at FESN in Thessalonika, hopefully as part of a symposium, to publish more data from Siobhan’s PhD, to start some PPI work to develop Dan’s idea for a project looking at how prism glasses are used by people with PSP and ultimately get a grant to support the work, and to finally finish Soazigs EPS grant on presaccadic attention and working memory. It’s going to be a busy year!

User Perspectives on the Efficacy of Prism Therapy for Progressive Supranuclear Palsy (PSP)

A person reading using prism glasses

People with PSP often experience problems with their vision. A very common issue is a paralysis of the eyes which prevents the person from looking downwards. This vertical gaze paralysis makes it hard to do everyday tasks that usually require looking down; such as reading, using an electronic device (e.g., phone, tablet, or computer keyboard), and cutting up food. One solution that is often recommended is to use light-bending prism glasses, shown in the top figure. These glasses bend light from the lower portion of the visual field so the person can see things they cannot look at directly. In principle this seems like an effective solution that should allow people with PSP to retain some of their independence. However, somewhat surprisingly, there is very little scientific evidence that people with PSP benefit from using prisms. Furthermore, very little is known about how and why people use prism glasses, what kind of instruction or training they are given, and what challenges or issues people with PSP experience when trying to use prisms. To try and start answering these question, Dr Ali Lane and I supervised a research project by two masters students (Dan Ford and James Ireland) in which 35 people with PSP were recruited with the help of the PSP Association to tell us about their experiences of using prism glasses.

The majority of participants (74%) had heard of prism glasses, and of these participants 76% had actually tried them. The most common source of information about prisms was a neuro-ophthalmologist (40%), followed by the PSP association (20%), and the most common source of the prisms themselves was an NHS prescription. When we asked about the kinds of things prisms helped people with the most common response was reading (37% of people), followed by eating (24%), using electronic devices (19%), and watching TV (19%). However, when we asked whether people still used the prisms only 20% of people reported persisting with them. This relatively low adherence may be related to the frequency with which people reported experiencing unpleasant side effects such as disorientation (37.5%) and double vision (19%), and practical problems with the weight and fit with existing eyewear. Overall, 43% of people agreed or strongly agreed that the found the prisms useful, but only 18.5% agreed that they liked the prisms.

The results of our survey indicate that while many people with PSP are aware of prism glasses, there is scope to improve patient knowledge of this rehabilitation aid. Furthermore, while some people find them useful for reading, eating, and using electronic devices, most people with PSP do not appear to benefit from prisms or they find them hard to use. Even those who do find them beneficial do not reliably persist with their use. It is likely that better fitting and more systematic training and practice would improve the usefulness of the prisms and reduce the negative impact of side-effects such disorientation. Indeed, there is evidence from stroke survivors with inattention that training improves adherence and outcomes of prism glasses therapy. However, no such training exists for people with PSP.

It is important to be cautious when drawing conclusions from a relatively small sample, but the findings seem to suggest that current approaches to prism therapy for PSP are, unfortunately, relatively ineffective. We believe this is likely due to a lack of reliable training advice for patients, which results from a dearth of scientific evidence about the optimal way to train people in the fitting and use of prisms for different tasks. The only way to resolve this issue is to conduct more evidence-based research that can establish the optimal way to use prism glasses for the rehabilitation of PSP. We are currently looking for ways to fund more research in the important area and would be interested in hearing from people who are considering studying for a PhD on this topic.

You can learn more about our other research into attention and memory in PSP here

Siobhan’s 1st paper on “Oculomotor rehearsal in visuospatial working memory” published!

We were delighted that the first paper from Siobhan’s ESRC NINE DTP  grant finally came out in Attention, Perception and Psychophysics. The paper was a bit of a landmark for us both, as it was Siobhan first experiment and the first time either of us had tried to publish using the Registered Report format. This ended up being a very long processess, and towards the end we had a bit of scare becasue RRs were omitted from the JISC open access deal with Springer, but we got there in the end! The key take-home is that saccadic interference (making irrelvant eye-movements while trying to hold something in memory) causes a highly selective impairment spatial short term memory and does not affect visual short term memory. The novelty of our task was to (a) directly compare spatial and visual STM in the experiment using the same participants and the same task at encoding, but varying the task at recall (in one condition people recalled location, in the other they recalled colour) and (b) to show that, once you control for covert attention, the interference effect in spatial STM is explained by increased guessing. This is important, firstly because it suggests that saccadic interference increases the signal-to-noise of internal spatial maps that represent the memorised locations, rather than reducing the precision of memory representations per se. Secondly, the fact that visual STM was unaffected by saccadic interference is very hard to reconcile with slot models of VSWM. You can read the paper here, which is available gold open access, and

McAteer, S.M., McGregor, A. & Smith, D.T. Oculomotor rehearsal in visuospatial working memory. Atten Percept Psychophys (2022). https://doi.org/10.3758/s13414-022-02601-4