Wendy Ming1, Dimitrios J Palidis1, Miriam Spering2, Martin J McKeown3. 1. Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada. 2. Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada 2International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada 3Djavad Movafaghian Center for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada 4Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, British Columbia, Canada. 3. Djavad Movafaghian Center for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada 4Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, British Columbia, Canada 5Division of Neurology and Pacific Parkinson's Research Centre, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Abstract
PURPOSE: Visual impairments are frequent in Parkinson's disease (PD) and impact normal functioning in daily activities. Visual contrast sensitivity is a powerful nonmotor sign for discriminating PD patients from controls. However, it is usually assessed with static visual stimuli. Here we examined the interaction between perception and eye movements in static and dynamic contrast sensitivity tasks in a cohort of mildly impaired, early-stage PD patients. METHODS: Patients (n = 13) and healthy age-matched controls (n = 12) viewed stimuli of various spatial frequencies (0-8 cyc/deg) and speeds (0°/s, 10°/s, 30°/s) on a computer monitor. Detection thresholds were determined by asking participants to adjust luminance contrast until they could just barely see the stimulus. Eye position was recorded with a video-based eye tracker. RESULTS: Patients' static contrast sensitivity was impaired in the intermediate spatial-frequency range and this impairment correlated with fixational instability. However, dynamic contrast sensitivity and patients' smooth pursuit were relatively normal. An independent component analysis revealed contrast sensitivity profiles differentiating patients and controls. CONCLUSIONS: Our study simultaneously assesses perceptual contrast sensitivity and eye movements in PD, revealing a possible link between fixational instability and perceptual deficits. Spatiotemporal contrast sensitivity profiles may represent an easily measurable metric as a component of a broader combined biometric for nonmotor features observed in PD.
PURPOSE: Visual impairments are frequent in Parkinson's disease (PD) and impact normal functioning in daily activities. Visual contrast sensitivity is a powerful nonmotor sign for discriminating PD patients from controls. However, it is usually assessed with static visual stimuli. Here we examined the interaction between perception and eye movements in static and dynamic contrast sensitivity tasks in a cohort of mildly impaired, early-stage PD patients. METHODS: Patients (n = 13) and healthy age-matched controls (n = 12) viewed stimuli of various spatial frequencies (0-8 cyc/deg) and speeds (0°/s, 10°/s, 30°/s) on a computer monitor. Detection thresholds were determined by asking participants to adjust luminance contrast until they could just barely see the stimulus. Eye position was recorded with a video-based eye tracker. RESULTS: Patients' static contrast sensitivity was impaired in the intermediate spatial-frequency range and this impairment correlated with fixational instability. However, dynamic contrast sensitivity and patients' smooth pursuit were relatively normal. An independent component analysis revealed contrast sensitivity profiles differentiating patients and controls. CONCLUSIONS: Our study simultaneously assesses perceptual contrast sensitivity and eye movements in PD, revealing a possible link between fixational instability and perceptual deficits. Spatiotemporal contrast sensitivity profiles may represent an easily measurable metric as a component of a broader combined biometric for nonmotor features observed in PD.
Authors: Ane Murueta-Goyena; Rocío Del Pino; Marta Galdós; Begoña Arana; Marian Acera; Mar Carmona-Abellán; Tamara Fernández-Valle; Beatriz Tijero; Olaia Lucas-Jiménez; Natalia Ojeda; Naroa Ibarretxe-Bilbao; Javier Peña; Jesus Cortes; Unai Ayala; Maitane Barrenechea; Juan Carlos Gómez-Esteban; Iñigo Gabilondo Journal: Ann Neurol Date: 2020-11-09 Impact factor: 10.422