Journal of Visualized Experiments www.jove.com Copyright © 2019 Journal of Visualized Experiments March 2019 | 145 | e58885 | Page 1 of 10 Video Article Efficiently Recording The Eye-Hand Coordination To Incoordination Spectrum John-Ross Rizzo* 1,2 , Mahya Beheshti* 1 , James Fung 1 , Janet C. Rucker 2,3 , Todd E. Hudson 1,2 1 Dept. of Rehabilitation Med, New York University Langone Health 2 Dept. of Neurology, New York University Langone Health 3 Dept. of Ophthalmology, New York University Langone Health * These authors contributed equally Correspondence to: John-Ross Rizzo at JohnRoss.Rizzo@nyumc.org URL: https://www.jove.com/video/58885 DOI: doi:10.3791/58885 Keywords: Behavior, Issue 145, Brain injuries, eye movements, eye tracker, limb motion tracker, Stroke, Ocular motor coordination Date Published: 3/21/2019 Citation: Rizzo, J.R., Beheshti, M., Fung, J., Rucker, J.C., Hudson, T.E. Efficiently Recording The Eye-Hand Coordination To Incoordination Spectrum. J. Vis. Exp. (145), e58885, doi:10.3791/58885 (2019). Abstract The objective analysis of eye movements has a significant history and has been long proven to be an important research tool in the setting of brain injury. Quantitative recordings have a strong capacity to screen diagnostically. Concurrent examinations of the eye and upper limb movements directed toward shared functional goals (e.g., eye-hand coordination) serve as an additional robust biomarker-laden path to capture and interrogate neural injury, including acquired brain injury (ABI). While quantitative dual-effector recordings in 3-D afford ample opportunities within ocular-manual motor investigations in the setting of ABI, the feasibility of such dual recordings for both eye and hand is challenging in pathological settings, particularly when approached with research-grade rigor. Here we describe the integration of an eye tracking system with a motion tracking system intended primarily for limb control research to study a natural behavior. The protocol enables the investigation of unrestricted, three-dimensional (3D) eye-hand coordination tasks. More specifically, we review a method to assess eye-hand coordination in visually guided saccade-to-reach tasks in subjects with chronic middle cerebral artery (MCA) stroke and compare them to healthy controls. Special attention is paid to the specific eye- and limb-tracking system properties in order to obtain high fidelity data from participants post-injury. Sampling rate, accuracy, permissible head movement range given anticipated tolerance and the feasibility of use were several of the critical properties considered when selecting an eye tracker and an approach. The limb tracker was selected based on a similar rubric but included the need for 3-D recording, dynamic interaction and a miniaturized physical footprint. The quantitative data provided by this method and the overall approach when executed correctly has tremendous potential to further refine our mechanistic understanding of eye-hand control and help inform feasible diagnostic and pragmatic interventions within the neurological and rehabilitative practice. Video Link The video component of this article can be found at https://www.jove.com/video/58885/ Introduction A critical element of the neurological function is eye-hand coordination or the integration of ocular and manual motor systems for the planning and execution of combined function towards a shared goal, for example, a look, reach and grab of the television remote. Many purposeful tasks depend on visually guided actions, such as reaching, grasping, object manipulation and tool use, which hinge on the temporally and spatially coupled eye and hand movements. Acquired brain injuries (ABI) cause not only limb dysfunction but also ocular dysfunction; more recently, there is also evidence pointing to the dysfunction of eye-hand coordination 1 . Coordinated eye-hand motor control programs are susceptible to insult in neurological injuries from vascular, traumatic and degenerative etiologies. These insults may cause a breakdown between any of the indispensable relationships needed for the integrated and rapid motor control 2,3,4,5,6 . Many studies on the manual motor function have been completed and have leveraged visual guidance as a core pillar of the paradigm without a method or protocol in place to analyze eye movements concurrently. In ABI, conspicuous motor deficits are often detected during the bedside clinical examination. However, concurrent ocular motor impairments and complex impairments involving the integration of sensory and motor systems may be subclinical and necessitate objective recording to be identified 7,8,9,10,11,12,13,14,15,16 . Ocular-manual motor coordination depends on a large and interconnected cerebral network, highlighting the need for a detailed study. An eye-hand coordination evaluation with dual objective recordings provides an opportunity to assay both cognitive and motor function in multiple populations, including healthy controls and subjects with a history of brain injury, thus providing insight into cerebral circuitry and function 3 . While saccades are ballistic movements that can vary in amplitude depending on task need, studies have shown dependencies between saccade and hand movement during visually guided action 17,18,19,20 . In fact, recent experiments have demonstrated that control systems for both movements share planning resources 21,22 . The motor planning hub for eye-hand coordination lies in the posterior parietal cortex. In a stroke, there are well-known deficits in motor control; hemiparetic patients have been shown to generate inaccurate predictions given a set of neural commands, when asked to perform visually guided hand movements, using either the more affected (contralateral) or less affected (ipsilateral)