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V.N.Pradeep Ambati, Marlina Ponce De Leon, Fabricio Saucedo, Douglas Powell, Rebecca Reed-Jones; CONSTRAINING EYE MOVEMENTS WHEN REDIRECTING WALKING TRAJECTORIES IN PEOPLE WITH PARKINSON’S DISEASE. Journal of Vision 2013;13(9):788. doi: 10.1167/13.9.788.
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© ARVO (1962-2015); The Authors (2016-present)
Healthy young adults (YA) use different turning strategies when required to fixate their gaze. When free to make eye movements, a clear top-down turning sequence, where the eyes move first followed by the head, and body occurs. However, when YAs are required to fixate their gaze on a fixed target a clear bottom-up (pelvis to eyes) sequence occurs. These behaviors suggest anticipatory eye movement is critical for coordinating the body when turning. The Basal Ganglia have a central role in the control of eye movement. Therefore, examining individuals with Parkinson’s Disease can provide further insight into the role of eye movements in turning control. The current study addressed the hypothesis that PD patients would not exhibit anticipatory eye movements when turning. As a result, PD patients would not exhibit top-down control strategies when turning in a Fixed Gaze or Free Gaze condition. Data analysis focused on segment kinematics (Vicon motion capture system) and horizontal eye position (Applied Science Laboratories H6 eye tracker) of seven PD patients during 90-degree walking turns in two visual conditions: Fixed Gaze and Free Gaze. Segment kinematic analysis revealed no significant difference (p > 0.05) in the onset of the eyes, head and trunk between the Fixed Gaze and Free Gaze conditions. In addition, intersegment timing analysis within each gaze condition revealed no significant difference (p > 0.05) between segments. These results indicate PD patients do not make anticipatory eye movements when turning and as a result do not use top-down turning strategies. In fact, there is no significant difference in turning strategies between Fixed and Free gaze conditions. These observations support the important role of anticipatory eye redirection for turning control. Deficits in oculomotor control could result in increased use of alternative sensory modalities for navigation when executing a turn while walking.
Meeting abstract presented at VSS 2013
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