Do people with Parkinson’s disease look at task relevant stimuli when walking? An exploration of eye movements

Eye movements are impaired by Parkinson's disease (PD) although limited research has explored if PD affects the relevance of visual fixations when walking. Visual fixations may provide crucial contextual information for safe navigation and important insights into fall risk. This study aimed to: investigate visual fixations made while walking under a range of conditions in PD; identify their task relevance; and explore their relationship with clinical features. Thirty-eight people with mild-moderate PD and forty age-matched control participants completed a straight walk with (i) no additional stimuli and (ii) with additional stimuli (visual cues or a high contrast obstacle), whilst wearing a mobile eye-tracker. Fixations were extracted and classified by location and relevance. PD participants made proportionally fewer task-relevant fixations (floor, walls and additional stimuli ahead), caused by significantly more task-irrelevant fixations (floor, walls and ceiling away from waking path) during normal walking (p = 0.014). These group differences were not apparent with visual cues (p = 0.359). During obstacle crossing trials, PD made significantly more task-relevant fixations than controls (p = 0.007). Reduced bilateral visual acuity was associated with fewer fixations in PD. Our findings suggest that people with PD visually explore complex environments less efficiently likely owing to underlying PD pathology. Visual exploration improved with the addition of salient stimuli (for example visual cues or an obstacle) and thus developing and optimising visual interventions could prove critical to improving locomotor safety and reducing falls risk in home environments

Exploring the nature of visual fixations on other pedestrians

How we look at other people may affect conclusions drawn about the effect of changes in lighting when this task needs to be done after dark. This paper reports further analysis of the distance and duration of fixation on other pedestrians, updating a previous review by considering a greater number of fixations and by examining the influence on these of other characteristics such as the relative direction of travel. This analysis provides further support for a tendency to fixate others at a distance of 15 m and for a duration of 500 ms

Training & prompting pre-service teachers’ noticing in a standardized classroom simulation – a mobile eye-tracking study

Numerous events happening in classrooms require a teacher to select important and filter out irrelevant information. This crucial and challenging skill is referred to as noticing. For noticing classroom management events pre-service teachers have a smaller knowledge base and little teaching experience compared to expert teachers. Supporting pre-service teachers in developing their classroom management knowledge and noticing skill is, thus, of great importance for teacher education. Previous research finds positive effects of interventions on teachers’ noticing during video observation. To our knowledge, no studies depict noticing during teaching. We examined N = 46 pre-service teachers’ noticing with regard to classroom management during classroom teaching in a quasi-experimental between-subjects design. Pre-service teachers’ took part in a standardized classroom simulation after a classroom management training, with one group receiving prompting regarding evidence-based classroom management strategies before and during the classroom simulation and one group receiving only training. We also included a control group without classroom management training. To assess differences in pre-service teachers’ noticing, the classroom simulation elicited comparable conditions, including standardized classroom management events and student behavior. Mobile eye-tracking as well as retrospective video observations were used to explore teachers’ event-related and global noticing. Event-related noticing was assessed via count and accuracy of noticed classroom management events. Global noticing included objective parameters of teachers eye movements (visit/fixation counts and duration) onto the students in the standardized classroom simulation. The results show that training and prompting significantly affected pre-service teachers’ event-related noticing, with both experimental groups making fewer target and time errors compared to the control group. No significant differences were found with regard to global noticing. This includes fixation and visit count and duration on students. Correlational analysis showed a positive association between higher noticing accuracy and share of fixations on students. This study expands upon previous empirical research using mobile eye-tracking to obtain objective measures of teachers’ noticing. It sheds light on the relevance of knowledge for teachers’ noticing during teaching. It also takes a first step toward understanding how pre-service teachers’ noticing during classroom teaching can be promoted through fostering knowledge about classroom management through a training

Computational Methods for Measurement of Visual Attention from Videos towards Large-Scale Behavioral Analysis

Visual attention is one of the most important aspects of human social behavior, visual navigation, and interaction with the world, revealing information about their social, cognitive, and affective states. Although monitor-based and wearable eye trackers are widely available, they are not sufficient to support the large-scale collection of naturalistic gaze data in face-to-face social interactions or during interactions with 3D environments. Wearable eye trackers are burdensome to participants and bring issues of calibration, compliance, cost, and battery life. The ability to automatically measure attention from ordinary videos would deliver scalable, dense, and objective measurements to use in practice. This thesis investigates several computational methods to measure visual attention from videos using computer vision and its use for quantifying visual social cues such as eye contact and joint attention. Specifically, three methods are investigated. First, I present methods for detection of looks to camera in first-person view and its use for eye contact detection. Experimental results show that the presented method can achieve the first human expert-level detection of eye contact. Second, I develop a method for tracking heads in a 3d space for measuring attentional shifts. Lastly, I propose spatiotemporal deep neural networks for detecting time-varying attention targets in video and present its application for the detection of shared attention and joint attention. The method achieves state-of-the-art results on different benchmark datasets on attention measurement as well as the first empirical result on clinically-relevant gaze shift classification. Presented approaches have the benefit of linking gaze estimation to the broader tasks of action recognition and dynamic visual scene understanding, and bears potential as a useful tool for understanding attention in various contexts such as human social interactions, skill assessments, and human-robot interactions.Ph.D

Novel digital biomarkers for frontotemporal dementia

Frontotemporal dementia (FTD) is a heterogenous neurodegenerative disease and is caused by an autosomal dominant mutation in around one third of cases. This pattern of inheritance enables FTD to be studied in the presymptomatic phase, where individuals carry the genetic mutation but have yet to develop symptoms. There are currently no approved treatments for FTD, although clinical trials aiming to target interventions at the earliest disease stage, are underway. There is an urgent need for biomarkers that can reliably detect and monitor the progression of disease in the presymptomatic period, though there are a distinct lack of sensitive cognitive measures. This thesis aims to establish the validity and sensitivity of a set of digital biomarkers that can be used to measure cognitive function in FTD. I begin this thesis by describing the Ignite computerised cognitive assessment, developing normative properties for the tests through a remote data collection study in over 2,000 healthy controls. I build upon this validation by establishing the concurrent validity of Ignite with gold-standard pen and paper tasks, the test-retest reliability upon repeated administration, and demonstrate the tests are sensitive to presymptomatic impairment across several cognitive domains. I also describe a novel portable eye tracking experiment that can be completed outside of the lab, first highlighting the validity of the tests as measures of cognitive function and demonstrating their sensitivity in detecting early changes in social cognition in the presymptomatic period. Finally, I investigate a smartphone app that passively monitors human-device interactions to generate digital biomarkers of cognitive function. I establish the acceptability of the app in the general population before demonstrating the measures produced can detect differences in keyboard interactions in presymptomatic FTD mutation carriers. This work provides evidence that biomarkers generated from different digital devices are valid and sensitive measures of cognitive impairment in FTD. Therefore, digital biomarkers could replace outdated pen and paper tasks and be used as outcome measures in clinical trials

User HRTF Selection for 3D Auditory Mixed Reality

We introduce a novel approach for personalisation of an efficient 3D binaural rendering system designed for mobile, auditory mixed reality use cases. A head-related transfer function (HRTF) ranking method is outlined for users of real-time, interactive sound and music applications. Twenty participants tested the approach and its impact on their capacity to locate a continuous musical sound rendered in varying 3D positions. Analysis of HRTF rankings across three separate sessions reveal encouraging levels of reliability amongst some participants. Patterns of interaction show a significant benefit to horizontal precision that results from the selection process. In contrast, length of system exposure (rather than HRTF preference) demonstrates a significant degree of improvement to aspects of vertical perception and overall speed of response, with no detriment to horizontal accuracy. These findings provide an initial basis from which to consider priorities in the design of audio-only immersive applications and accompanying methods for effective user controlled personalisation

Embodied viewing and Degas’s Little Dancer Aged Fourteen: a multi-disciplinary experiment in eye-tracking and motion capture

This paper presents a cross-disciplinary project based on an experiment in eye-tracking and motion capture (Sainsbury’s Centre for Visual Arts), which aimed to study viewers’ movements around an iconic sculpture: Edgar Degas’s Little Dancer Aged Fourteen. The experiment studies how viewers respond to this three-dimensional artwork not only by looking at it but also through their own bodily reactions to it, such as by unconsciously mimicking a represented attitude or gesture. We compared two groups of viewers: classically trained dancers and non-dancers. Our hypothesis was that the skills and embodied experiences of the dancers would alter the ways in which they engage bodily with the work compared to the non-dancers. Our underlying research question was: how are vision and the body interlinked in esthetic and kinesthetic experience? This paper does not give results, which are forthcoming. It focuses on methodology and provides a commentary on the design and development of the interdisciplinary collaboration behind the project. It explores an interdisciplinary collaboration that bridges the humanities and experimental sciences and asks how being confronted with unfamiliar methodologies forces researchers in a given field to critically self-examine the limits and presuppositions of their practices