Stroke is a leading cause of disability in the aged and the mechanisms underlying motor recovery are not well understood. A neglected component in rehabilitative therapies is a clear understanding of eye-hand coordination even though eye and hand movement is necessary for most functional activities. Of more concern is the fact that vision impairment in the aged is highly prevalent and largely undetected and the current methods used to screen the elderly lack sensitivity and specificity;unfortunately when one adds vision loss after stroke there is a significant impact on ADLs and an independent risk factor for dependency. The purpose of this project is to understand how eye training can be generalized to arm training in the elderly to improve eye-hand coordination and functional performance. The specific hypothesis behind this research proposal is that eye control precedes arm control;we propose that patients with hemiparesis have under-recognized deficits in the planning and control of eye movement that affects the planning and control of arm movement, a grave fact when amplified by the aging visual system, losing spatial and temporal performance. During simple object retrieval tasks, eye movements or saccades are completed prior to arm movements or reaches. During reaching, stroke patients demonstrate substantially more deviation from straight-line paths than do healthy subjects, despite using more conservative strategies and extensive feedback control. Inefficient saccades could increase extraocularneuromotor noise, limiting the planning and execution of arm movements. It has been shown that healthy individuals use various strategies to plan reaching movements, but not all of them are equally efficient. What is not known is whether the same is true for eye movements, and whether training the more efficient strategy can generalize to limb movements for reaching, yielding functional improvement post-stroke. A clear understanding of efficient oculomotor planning may translate into functional vision rehabilitation interventions to improve ADLs. One such approach may be in the design of videogames to promote more efficient oculomotor strategies and eye-hand coordination. The overarching goal of the present study is to better elucidate the visuomotor planning strategies in the elderly that may be implemented both in the elderly and in the elderly post-stroke to foster long-term functional recovery
Eye-hand coordination will prove critical for our aging population, as our normal visual system loses aspects temporally and spatially;vision loss problems and stroke, an additional co-morbidity and a potential additional cause of vision impairment, both have major impacts on disability within an elderly population. Stroke related visual deficits are associated with limitations in performing daily tasks, increased risk of falls, and impeded rehabilitative progress;falls are frequent among non-institutionalized long-term stroke survivors when compared to their community control subjects. Vision functions other than visual acuity may be affecting the daily function of older adults;these higher-level eye motor planning features are what we propose to characterize in this study on young adults and elderly with and without stroke.
