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VISUAL SEARCH ABILITIES OF POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE PATIENTS IN REAL-WORLD SETTINGS
P366 P1-297
Poster Presentations: Sunday, July 16, 2017 VISUAL SEARCH ABILITIES OF POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE PATIENTS IN REAL-WORLD SETTINGS
Ayako Suzuki1, Keir Yong2, Ian McCarthy1, Tatsuto Suzuki1, Dilek Ocal3, Nikolaos N. Papadosifos1, Derrick Boampong1, Nick Tyler1, Sebastian J. Crutch2, 1University College London, Engineering Sciences, London, United Kingdom; 2Dementia Research Centre, Institute of Neurology, University College London, London, United Kingdom; 3 University College London, Institute of Neurology, London, United Kingdom. Contact e-mail: [email protected] Background: Posterior cortical atrophy (PCA) is a neurodegenerative condition characterised by progressive corticovisual impairments and pathological involvement of posterior parietal and occipito-temporal regions. While Alzheimer’s Disease is the predominant cause of PCA, unlike typical Alzheimer’s Disease (tAD), episodic memory, executive functions, and linguistic skills in individuals with PCA are relatively well-preserved in early disease stages. Due to corticovisual
Figure 1. A room plan for the directed overhead lighting experiment (a) and participant view of the setting (b). The task was carried out under varying conditions of door position (left, right), obstacle (table) position (left, right) and overhead lighting position (A: ¼target, B: ¼middle, C: ¼closed).
Figure 2. A room plan for testing ground lighting uniformity (a) and participant view (b: inconsistent, c: consistent) of the setting. Two tables and a centre chair remain stationary throughout this experiment. High stool (1) and lounger (2) are situated right or left as clutter.
Figure 3. A captured scene and a fixation (red circle) from a video of a participant with PCA, recorded by the point-of-view camera.
impairment, PCA patients often experience difficulties in carrying out everyday tasks involving navigation and object finding, but the relationship between such difficulties and eye movement abnormalities is little understood. Eye tracking offers a means to assess how patients with PCA and tAD explore the visual environment. This study assessed differences in eye fixation (visual gaze on a single location) position relating to visual search characteristics as individuals with PCA, tAD and healthy controls engaged in daily life situations. Methods: Ten PCA patients, 9 tAD patients and 12 healthy controls completed two tasks, both involving being asked to locate and reach a target destination within a controlled environment set up in the UCL Pedestrian Accessibility Movement and Environment Laboratory (PAMELA). The first task (36 trials) was carried out under varying conditions of door position (left, right), obstacle (left, right) and overhead lighting position (¼target, ¼middle, ¼closed) (Figure 1). The second task (32 trials) was carried out under varying conditions of door position (left, right), clutter (left, right) and ground lighting uniformity (consistent, inconsistent) (Figure 2). Participants’ fixation position and fixation duration were monitored with mobile eye tracking glasses. Fixation position was related to videos recorded using a point-ofview camera. Head and shoulder positions were recorded (reported elsewhere). Results: The three participant groups exhibited different eye behaviours. Patient groups showed an increased tendency for more frequent and longer fixations on parts of the experimental setting other than the target destination (Figure 3) relative to the control group. Conclusions: These data illustrate inefficient visual search in patient groups, particularly in the PCA group. Future investigations will reveal which environmental features attract the fixation of participants with PCA and tAD. These results may assist in understanding dementiarelated corticovisual impairment and developing optimal environments for individuals experiencing such impairment.
Poster Presentations: Sunday, July 16, 2017 VISUAL SEARCH ABILITIES OF POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE PATIENTS IN REAL-WORLD SETTINGS
Ayako Suzuki1, Keir Yong2, Ian McCarthy1, Tatsuto Suzuki1, Dilek Ocal3, Nikolaos N. Papadosifos1, Derrick Boampong1, Nick Tyler1, Sebastian J. Crutch2, 1University College London, Engineering Sciences, London, United Kingdom; 2Dementia Research Centre, Institute of Neurology, University College London, London, United Kingdom; 3 University College London, Institute of Neurology, London, United Kingdom. Contact e-mail: [email protected] Background: Posterior cortical atrophy (PCA) is a neurodegenerative condition characterised by progressive corticovisual impairments and pathological involvement of posterior parietal and occipito-temporal regions. While Alzheimer’s Disease is the predominant cause of PCA, unlike typical Alzheimer’s Disease (tAD), episodic memory, executive functions, and linguistic skills in individuals with PCA are relatively well-preserved in early disease stages. Due to corticovisual
Figure 1. A room plan for the directed overhead lighting experiment (a) and participant view of the setting (b). The task was carried out under varying conditions of door position (left, right), obstacle (table) position (left, right) and overhead lighting position (A: ¼target, B: ¼middle, C: ¼closed).
Figure 2. A room plan for testing ground lighting uniformity (a) and participant view (b: inconsistent, c: consistent) of the setting. Two tables and a centre chair remain stationary throughout this experiment. High stool (1) and lounger (2) are situated right or left as clutter.
Figure 3. A captured scene and a fixation (red circle) from a video of a participant with PCA, recorded by the point-of-view camera.
impairment, PCA patients often experience difficulties in carrying out everyday tasks involving navigation and object finding, but the relationship between such difficulties and eye movement abnormalities is little understood. Eye tracking offers a means to assess how patients with PCA and tAD explore the visual environment. This study assessed differences in eye fixation (visual gaze on a single location) position relating to visual search characteristics as individuals with PCA, tAD and healthy controls engaged in daily life situations. Methods: Ten PCA patients, 9 tAD patients and 12 healthy controls completed two tasks, both involving being asked to locate and reach a target destination within a controlled environment set up in the UCL Pedestrian Accessibility Movement and Environment Laboratory (PAMELA). The first task (36 trials) was carried out under varying conditions of door position (left, right), obstacle (left, right) and overhead lighting position (¼target, ¼middle, ¼closed) (Figure 1). The second task (32 trials) was carried out under varying conditions of door position (left, right), clutter (left, right) and ground lighting uniformity (consistent, inconsistent) (Figure 2). Participants’ fixation position and fixation duration were monitored with mobile eye tracking glasses. Fixation position was related to videos recorded using a point-ofview camera. Head and shoulder positions were recorded (reported elsewhere). Results: The three participant groups exhibited different eye behaviours. Patient groups showed an increased tendency for more frequent and longer fixations on parts of the experimental setting other than the target destination (Figure 3) relative to the control group. Conclusions: These data illustrate inefficient visual search in patient groups, particularly in the PCA group. Future investigations will reveal which environmental features attract the fixation of participants with PCA and tAD. These results may assist in understanding dementiarelated corticovisual impairment and developing optimal environments for individuals experiencing such impairment.