We would like to thank Dr. Tamara Bushnik and the NYULMC Rusk Research Team for their thoughts, suggestions, and contributions. This research was supported by 5K12 HD001097 (to J-RR, MSL, and PR).

1. Participant
<ol>
	<li>Recruit control participants older than 18 years, without a history of neurological dysfunction, significant eye injury, significant depression, major disability and/or electrical implants.</li>
	<li>Recruit Stroke participants older than 18 years, with a history of brain injury in the middle cerebral artery (MCA) distribution, have the ability to complete the Fugl-Meyer Scale, maintain a full range of eye movements35,36, have the ability to perform pointing tasks, and without the history of additional neurological dysfunction, significant eye health comorbidity, significant depression, major disability and/or electrical implants.</li>
	<li>Ask participants to sign a consent form approved by the Institutional Review Board of New York University&#8217;s School of Medicine.</li>
	<li>Participant Screening (for detailed exclusion criteria please see Rizzo et al37)
	<ol>
		<li>Take history and perform clinical examinations as discussed below.
		<ol>
			<li>Assess the cognitive state of participants with Mini Mental State Examination (MMSE)38.</li>
			<li>Perform neurological examination.</li>
			<li>Examine extraocular muscles and eye movements.
			<ol>
				<li>Ask the participants to follow the researcher&#8217;s finger with their eyes while keeping their head in one position. Draw an imaginary H letter in front of them and make sure that your finger moves far enough out and up/down, assessing center, up, down, left, right, down/left, down/right, up/left, and up/right.</li>
				<li>Ask the participants to follow and maintain the gaze on an object moved slowly through their visual field to assess smooth pursuit. Cover a distance of approximately 24 inches and using a pencil as a target, sweep back and forth slowly in horizontal and vertical directions, repeating each three times.</li>
				<li>Ask participants to look as fast as possible between 2 targets that are placed 24 inches apart to assess saccades. Use a pencil and a pen as targets and direct gaze to the targets in a back and forth manner three times horizontally and vertically.</li>
				<li>Ask the participants to fixate on an object as it moves slowly towards to their eyes to assess convergence, centering the target, a pencil, on the bridge of their nose. Following this procedure, repeat the test by bringing the same target from the nose back out to the starting position (divergence).</li>
				<li>Ask the patient to cover one eye and look at the researcher&#8217;s nose. Move the hand out of the patient&#8217;s visual field and then bring it in, wag the finger slowly and ask the patient to let the researcher know when the hand comes back into view, repeat this for upper left, upper right, lower left, and lower right quadrants. 
				NOTE: When the patient covers their right eye, cover the left eye, and vice versa.</li>
			</ol>
			</li>
			<li>Assess the visual impairment by a visual-motor Integration test.</li>
			<li>Assess the visual acuity by Snellen chart39,40.</li>
			<li>Assess the visual field with confrontation and if in question, perform Goldman or Humphrey visual field testing41,42.</li>
			<li>Assess hemi-spatial neglect via line bisection test and the single letter cancellation test43.</li>
			<li>Quantify the extent of disability via 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and a 10-item supplement survey44.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
2. Preparation for the experiment and the physical configuration of equipment
<ol>
	<li>Equipment:
	<ol>
		<li>Choose an eye tracker
		<ol>
			<li>Choose an eye tracker that is capable of head-mounted use (to avoid interference with desk-based reach movements) high spatial resolution (&#8804;0.1o) and high temporal resolution (&#8805;250 Hz).</li>
			<li>Record the binocular eye movement with the eye tracker at a sampling rate of 250 Hz (sampling eye position every 4 ms) tracking both pupil and corneal reflection.</li>
		</ol>
		</li>
		<li>Choose of a limb tracker
		<ol>
			<li>Choose a limb tracker that can map the movement in the x, y, z position, &#179; 0.08 cm accuracy, Latency &#179; of 3.5 ms.</li>
		</ol>
		</li>
		<li>Choose a laptop capable of running a customized script that controls real-time integration of data acquired from two systems and co-registering the signals in real-time (Table of Materials).</li>
		<li>Choose a display monitor capable of integrating with the chosen laptop and that is large enough to support one-to-one correspondence between monitor and tabletop reach space</li>
		<li>Define a rectangle identical in size to the display monitor on a table surface between the participant and the display monitor, to use as a functional reaching space for experimental work.</li>
	</ol>
	</li>
	<li>Set up preparation:
	<ol>
		<li>Set up a table with the height adjustable chair.</li>
		<li>Place a display monitor 40 cm from the far edge of the table (Table of Materials).</li>
		<li>Place a tabletop board (reaching surface) with the 1-1 ratio dimension with the display monitor.</li>
		<li>Set up the limb tracker by mounting the electromagnetic source under the table (Table of Materials).</li>
		<li>Set up the eye tracker, host PC (Table of Materials).
		<ol>
			<li>Attach four infrared (IR) illuminators to four corners of the monitor using straps.</li>
			<li>Set the eye tracker configurations from eye tracker setup options screen.
			<ol>
				<li>Select 13-point calibration from the pre-set configuration of the eye tracker.</li>
				<li>Select the high saccade sensitivity to detect small saccade.</li>
				<li>Select Pupil-CR mode to record both pupils and cornea.</li>
				<li>Select a sampling rate at 250 Hz.</li>
			</ol>
			</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Participant physical preparation
	<ol>
		<li>Seat participants on a height-adjustable chair at the table with the computer display.</li>
		<li>Position the participant 60 cm away from the display monitor (Table of Materials).</li>
		<li>Fix the motion sensor (Table of Material) to the distal aspect of the index finger of the hand of the to be tested arm (dominant arms for controls, and both arms in participants with stroke)</li>
		<li>Place the eye tracker on the participants&#8217; headband and adjust the headband and cameras (Table of Materials).
		<ol>
			<li>Fitting the headband
			<ol>
				<li>Adjust the tightness and position of the headband (using headband knobs) so that the front pad is in the center of the forehead and the side pads above the participant&#8217;s ears.</li>
				<li>Make sure that the headband camera is in the center of the forehead and over the bridge of the nose.</li>
				<li>Ask participants to raise their eyebrows, and if the headband moves, refit it higher or lower on the forehead.</li>
			</ol>
			</li>
			<li>Adjust the camera and corneal illuminator position. Ask the participants to look at the display monitor.
			<ol>
				<li>From the camera screen, select the head camera image, verify that it shows four large spots from the IR markers that are positioned in the center of the head camera image. If they are not in the center, adjust accordingly.</li>
				<li>From the camera setup screen, select one eye at the time. Adjust the two eye cameras by lowering and raising the eye camera handle till the pupil of the eye is in the center of the camera image</li>
				<li>Focus the eye camera by rotating the lens holder.</li>
				<li>Set the pupil threshold by pressing the Auto Threshold button on the camera setup screen.</li>
				<li>Perform the same adjustment for the other eye.</li>
			</ol>
			</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Calibration
	<ol>
		<li>Calibrate the limb tracker output to reaching surface using a 9-point calibration, ask the participant to place their sensor attached finger on reaching surface (tabletop) locations as displayed on the monitor screen.</li>
		<li>Calibrate the eye tracker, ask participants to look at the calibration target that appears as a blue dot and maintain fixation until the next dot appears on the screen 
		NOTE: Calibration targets appear in 13 randomly selected positions on the screen</li>
		<li>Calibrate the eye tracker at least twice per session, first one at the start of the experiment and at its halfway point.</li>
	</ol>
	</li>
</ol>
3. Experiment
<ol>
	<li>Ask participants to move their finger onto the start position, covering the start circle on the screen with the finger-indicator dot (red dot), while fixating (eye) the start position on the screen. 
	NOTE: The start position is a correspondent location of the fixation point (blue dot) displays on the center of the screen (Figure 1a). The position of the finger is represented as 4 mm radius red dot on the screen.</li>
	<li>Require participants to maintain finger position on the start circle for 150 ms until the target appears.</li>
	<li>Ensure that participants fixate the start position until they hear a beep sound (&#8220;go beep&#8221;). (Figure 1) 
	NOTE: The duration between target appearance and the go signal is randomized between 250 to 750 ms to prevent anticipation of the go signal.</li>
	<li>Instruct participants to move both their eyes and fingertip quickly and accurately to the designated target as they hear the beep sound (Figure 1)
	<ol>
		<li>Designated target appears 1 cm radius white circle</li>
	</ol>
	</li>
	<li>Instruct participants to touch the tabletop location at the position of the virtual target as displayed on the screen by lifting the hand and finger and re-connecting the fingertip and tabletop
	<ol>
		<li>Make sure participants make a pointing movement by lifting the hand and finger rather than dragging the hand and finger on the tabletop.</li>
		<li>Display the end location of the reach as a red dot, following reach completion.</li>
		<li>Determine reach completion by a combination of low-velocity (&#60;5% peak) and 3 mm z-plane threshold.</li>
	</ol>
	</li>
	<li>Ask participants to perform a series of familiarization trials before starting data acquisition.</li>
	<li>Start data acquisition after participants touched 5 of the last 10 targets successfully.</li>
	<li>Ask participants to perform a series of look and reach trials as they were instructed during familiarization trials.
	<ol>
		<li>Have participants perform a total of 76 trials.</li>
	</ol>
	</li>
	<li>Have control participants perform the experiment with their dominant hand.</li>
	<li>Whenever it is possible, have participants with stroke perform the experiment with both the hands, more-affected and less-affected.</li>
	<li>Participants complete the entire experiment with at least one hand.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58885/58885fig1.jpg" /> 
Figure 1. Schematic view of setup and experiment. (a) Schematic representation of display monitor and reaching surface during a trial. (b) Sequencing of actions within visually-guided reach. First Fixation (F) appears. The target (T) appears after a randomized length of time. The &#8216;go&#8217; signal occurs as auditory beep sound (signified by the light-grey vertical bar) after an unpredictable time interval (concurrent offset of F) following by target appearance. Hand (H) and Eye (E) movements follow the go-signal. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58885/58885fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The advent of eye and hand tracking systems as available tools for objectively exploring the characteristics of ocular-manual motor systems has accelerated research studies, enabling a nuanced recording approach for an essential task in daily activities &#8211; eye-hand coordination. Many natural action-dependent tasks are visually guided and depend on vision as a primary sensory input. Gaze is programmed through ocular motor commands which point central vision at key spatial targets; this information is pivotal and assi...

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 coordination1. 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 control2,3,4,5,6. 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 identified7,8,9,10,11,12,13,14,15,16. 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 function3.
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 action17,18,19,20. In fact, recent experiments have demonstrated that control systems for both movements share planning resources21,22. 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) limb23,24,25,26,27,28,29. Furthermore, eye-hand coordination and related motor control programs are susceptible to insult following neurological injuries, decoupling the relationships, temporally and spatially, between effectors30. Objective recordings of eye and hand control are paramount to characterizing the incoordination or degree of coordination impairment and improves the scientific understanding of eye-hand motor control mechanism in a functional context.
Although there are many studies of eye-hand coordination in healthy controls17,31,32,33,34, our group has advanced the field by our setting of neurological injury, for instance during stroke circuitry assessment, have investigated the spatial and temporal organization of hand movements, often in response to visually displayed spatial targets. Studies that have expanded the objective characterization to eye and hand have almost exclusively focused on the performance capacity to record both effectors post-stroke or in pathologic settings; the described protocol enables robust characterization of ocular and manual motor control in unconstrained and natural movements. Here we describe the technique in an investigation of visually-guided saccade-to-reach movements in subjects with chronic middle cerebral artery (MCA) stroke relative to healthy controls. For the simultaneous recording of saccade and reach, we employ concurrent eye and hand motion tracking.

<table><tbody><tr><td>27.0&quot; Dell LED-Lit monitor&amp;nbsp;</td><td>Dell</td><td>S2716DG</td><td>QHD resolution (2560 x 1440)</td></tr><tr><td>ASUS ROG G750JM 17-Inch&amp;nbsp;</td><td>AsusTek Computer Inc</td><td></td><td></td></tr><tr><td>Eye Link II</td><td>SR-Research</td><td>500 Hz binocular eye monitoring&lt;br/&gt; 0.01 &amp;ordm; RMS resolutions</td><td></td></tr><tr><td>Matlab</td><td>MathWorks</td><td></td><td></td></tr><tr><td>Polhemus MicroSensor 1.8&amp;nbsp;</td><td>Polhemus</td><td></td><td>240&amp;nbsp;Hz, 0.08&amp;nbsp;cm accuracy</td></tr></tbody></table>

efficiently recording the eye-hand coordination to incoordination spectrum

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.&#160;

Thirty participants participated in the research study. There were 17 participants in the control cohort, and 13 participants in the stroke cohort. Two participants couldn&#8217;t finish the whole experiment, so their data were excluded from the analysis.
Demographics and Questionnaire Assessments
Table 1 shows the clinical and demogra...

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Efficiently Recording the Eye-Hand Coordination to Incoordination Spectrum

Cerebral injury can damage both ocular and somatic motor systems. Characterization of motor control post-injury affords biomarkers that assist in disease detection, monitoring, and prognosis. We review a method to measure eye-hand movement control in health and in pathologic incoordination, with look-and-reach paradigms to assess coordination between eye and hand.

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 ...

efficiently-recording-eye-hand-coordination-to-incoordination

Universidad de Cartagena UDEC

Research

JoVE Journal

Behavior

7.8K Views.  New York University Langone Health. Cerebral injury can damage both ocular and somatic motor systems. Characterization of motor control post-injury affords biomarkers that assist in disease detection, monitoring, and prognosis. We review a method to measure eye-hand movement control in health and in pathologic incoordination, with look-and-reach paradigms to assess coordination between eye and hand.

Video: Efficiently Recording the Eye-Hand Coordination to Incoordination Spectrum

Vision Training Methods for Sports Concussion Mitigation and Management

There is emerging evidence supporting the use vision training, including light board training tools, as a concussion baseline and neuro-diagnostic tool and potentially as a supportive component to concussion prevention strategies. This paper is focused on providing detailed methods for select vision training tools and reporting normative data for comparison when vision training is a part of a sports management program. The overall program includes standard vision training methods including tachistoscope, Brock&#8217;s string, and strobe glasses, as well as specialized light board training algorithms. Stereopsis is measured as a means to monitor vision training affects. In addition, quantitative results for vision training methods as well as baseline and post-testing *A and Reaction Test measures with progressive scores are reported. Collegiate athletes consistently improve after six weeks of training in their stereopsis, *A and Reaction Test scores. When vision training is initiated as a team wide exercise, the incidence of concussion decreases in players who participate in training compared to players who do not receive the vision training. Vision training produces functional and performance changes that, when monitored, can be used to assess the success of the vision training and can be initiated as part of a sports medical intervention for concussion prevention.

This paper describes a protocol to conduct, quantitatively monitor, and assess the success of vision training initiated as part of a sports medical management program including intervention for concussion prevention and performance enhancement.

There is emerging evidence supporting the use vision training, including light board training tools, as a concussion baseline and neuro-diagnostic tool ...

VisualEyes: A Modular Software System for Oculomotor Experimentation

Eye movement studies have provided a strong foundation forming an understanding of how the brain acquires visual information in both the normal and dysfunctional brain.1 However, development of a platform to stimulate and store eye movements can require substantial programming, time and costs. Many systems do not offer the flexibility to program numerous stimuli for a variety of experimental needs. However, the VisualEyes System has a flexible architecture, allowing the operator to choose any background and foreground stimulus, program one or two screens for tandem or opposing eye movements and stimulate the left and right eye independently. This system can significantly reduce the programming development time needed to conduct an oculomotor study. The VisualEyes System will be discussed in three parts: 1) the oculomotor recording device to acquire eye movement responses, 2) the VisualEyes software written in LabView, to generate an array of stimuli and store responses as text files and 3) offline data analysis. Eye movements can be recorded by several types of instrumentation such as: a limbus tracking system, a sclera search coil, or a video image system. Typical eye movement stimuli such as saccadic steps, vergent ramps and vergent steps with the corresponding responses will be shown. In this video report, we demonstrate the flexibility of a system to create numerous visual stimuli and record eye movements that can be utilized by basic scientists and clinicians to study healthy as well as clinical populations.

Neural control and cognitive processes can be studied through eye movements. The VisualEyes software allows an operator to program stimuli on two computer screens independently using a simple, custom scripting language. The system can stimulate tandem eye movements (saccades and smooth pursuit) or opposing eye movements (vergence) or any combination.

Eye movement studies have provided a strong foundation forming an understanding of how the brain acquires visual information in both the normal and ...

Neuroscience

Eye Tracking Young Children with Autism

The rise of accessible commercial eye-tracking systems has fueled a rapid increase in their use in psychological and psychiatric research. By providing a direct, detailed and objective measure of gaze behavior, eye-tracking has become a valuable tool for examining abnormal perceptual strategies in clinical populations and has been used to identify disorder-specific characteristics1, promote early identification2, and inform treatment3. In particular, investigators of autism spectrum disorders (ASD) have benefited from integrating eye-tracking into their research paradigms4-7. Eye-tracking has largely been used in these studies to reveal mechanisms underlying impaired task performance8 and abnormal brain functioning9, particularly during the processing of social information1,10-11. While older children and adults with ASD comprise the preponderance of research in this area, eye-tracking may be especially useful for studying young children with the disorder as it offers a non-invasive tool for assessing and quantifying early-emerging developmental abnormalities2,12-13. Implementing eye-tracking with young children with ASD, however, is associated with a number of unique challenges, including issues with compliant behavior resulting from specific task demands and disorder-related psychosocial considerations. In this protocol, we detail methodological considerations for optimizing research design, data acquisition and psychometric analysis while eye-tracking young children with ASD. The provided recommendations are also designed to be more broadly applicable for eye-tracking children with other developmental disabilities. By offering guidelines for best practices in these areas based upon lessons derived from our own work, we hope to help other investigators make sound research design and analysis choices while avoiding common pitfalls that can compromise data acquisition while eye-tracking young children with ASD or other developmental difficulties.

Eye tracking has long been used to study gaze patterns in typically-developing individuals, but recent technological advancements have made its use with clinical populations, including autism, more feasible. While eye-tracking young children with autism can offer insight into early symptom manifestations, it involves methodological challenges. Suggestions for best practices are provided.

The rise of accessible commercial eye-tracking systems has fueled a rapid increase in their use in psychological and psychiatric research. By providing a ...

Medicine

Eye-Tracking Control to Assess Cognitive Functions in Patients with Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with pathological involvement of upper and lower motoneurons, subsequently leading to progressive loss of motor and speech abilities. In addition, cognitive functions are impaired in a subset of patients. To evaluate these potential deficits in severely physically impaired ALS patients, eye-tracking is a promising means to conduct cognitive tests. The present article focuses on how eye movements, an indirect means of communication for physically disabled patients, can be utilized to allow for detailed neuropsychological assessment. The requirements, in terms of oculomotor parameters that have to be met for sufficient eye-tracking in ALS patients are presented. The properties of stimuli, including type of neuropsychological tests and style of presentation, best suited to successfully assess cognitive functioning, are also described. Furthermore, recommendations regarding procedural requirements are provided. Overall, this methodology provides a reliable, easy to administer and fast approach for assessing cognitive deficits in patients who are unable to speak or write such as patients with severe ALS. The only confounding factor might be deficits in voluntary eye movement control in a subset of ALS patients.

Cognitive deficits are common in about one third of patients with amyotrophic lateral sclerosis, a neurological condition leading to progressive impairments in speech and movement abilities. To conduct cognitive tests in patients unable to speak or write a reliable and easy to administer eye-tracking paradigm was developed.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with pathological involvement of upper and lower motoneurons, subsequently leading to ...

Recording Horizontal Saccade Performances Accurately in Neurological Patients Using Electro-oculogram

Electro-oculogram (EOG) has been widely used for clinical eye movement recording, especially horizontal saccades, although the video-oculography (VOG) has largely taken the place of it nowadays due to its higher spatial accuracy. However, there are situations in which EOG has clear advantages over VOG, e.g., subjects with narrow eye clefts or having cataract lenses, and patients with movement disorders. The present article shows that if properly implemented, EOG can achieve an accuracy almost as good as VOG with substantial stability for recording, while circumventing problems associated with VOG recording. The present paper describes a practical method for recording horizontal saccades using oculomotor paradigms with high accuracy and stability by EOG in neurological patients. The necessary measures are to use an Ag-AgCl electrode with a wide plastic fringe capable of reducing noise, and to wait for sufficient light adaptation to occur. This waiting period also helps to lower the impedance between the electrodes and the skin, thereby ensuring stable signal recorded as time goes by. Furthermore, re-calibration is performed as needed during the task performance. Using this method, the experimenter can avoid drifts of signals, as well as contamination of artifacts or noise from the electromyogram and electroencephalogram, and can collect sufficient data for clinical evaluation of saccades. Thus when implemented, EOG can still be a method of high practicability that can be widely applied to neurological patients, but may be effective also for studies in normal subjects.

The article describes a practical method for recording horizontal eye movements with high accuracy by electro-oculogram in neurological patients, using a cup Ag-AgCl electrode with a wide plastic fringe. Stable measurement requires proper selection and fixation of electrodes, taking sufficient time for light adaptation to occur, and re-calibration as needed.

Electro-oculogram (EOG) has been widely used for clinical eye movement recording, especially horizontal saccades, although the video-oculography (VOG) has ...

Comparing Eye-tracking Data of Children with High-functioning ASD, Comorbid ADHD, and of a Control Watching Social Videos

Children with autism spectrum disorders (ASD) are known to have sensory-perceptual processing deficits that weaken their abilities to attend and perceive social stimuli in daily living contexts. Since daily social episodes consist of subtle dynamic changes in social information, any failure to attend to or process subtle human nonverbal cues, such as facial expression, postures, and gestures, might lead to inappropriate social interaction. Traditional behavioral rating scales or assessment tools based on static social scenes have limitations in capturing the moment-to-moment changes in social scenarios. An eye-tracking assessment, which can be administered in a video-based mode, is therefore preferred, to augment clinical observation. In this study, using the single-case comparison design, the eye-tracking data of three participants, a child with autism spectrum disorder (ASD), another with comorbid attention deficit-hyperactive disorder (ADHD), and a neurotypical control, are captured while they view a video of social scenarios. The eye-tracking experiment has helped answer the research question: How does social attention differ between the three participants? By predefining areas of interest (AOIs), their visual attention on relevant or irrelevant social stimuli, how fast each participant attends to the first social stimuli appearing in the videos, for how long each participant continues to attend to those stimuli within the AOIs, and the gaze shifts between multiple social stimuli appearing concurrently in the same social scene are captured, compared, and analyzed in a video-based eye-tracking experiment.

This is a qualitative comparative case study analysis of eye-tracking data on the first moments of social video scenes as viewed by three participants: one with autism spectrum disorder, one with comorbid attention deficit-hyperactive disorder, and one neurotypical control.

Children with autism spectrum disorders (ASD) are known to have sensory-perceptual processing deficits that weaken their abilities to attend and perceive ...

Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, like the microperimetry, can test only one eye at a time. Therefore, they cannot explain how the defects in each eye affect the binocular interaction and real-world function. Dichoptic stimulus presentation with a gaze-controlled system could provide a reliable measure of monocular/binocular visual fields. However, dichoptic stimulus presentation and simultaneous eye-tracking are challenging because optical devices of instruments that present stimulus dichoptically (e.g., haploscope) always interfere with eye-trackers (e.g., infrared video-based eye-trackers). Therefore, the goals were 1) to develop a method for dichoptic stimulus presentation with simultaneous eye-tracking, using 3D-shutter glasses and 3D-ready monitors, that is not affected by interference and 2) to use this method to develop a protocol for assessing central visual field in subjects with central vision loss. The results showed that this setup provides a practical solution for reliably measuring eye-movements in dichoptic viewing condition. In addition, it was also demonstrated that this method can assess gaze-controlled binocular central visual field in subjects with central vision loss.

Presented here is a protocol for assessing binocular eye movements and gaze-controlled central visual field screening in participants with central vision loss.

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, ...

Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements can be observed. VisualEyes2020 (VE2020) was developed based on the lack of customizable software-based visual stimulation available for researchers that does not rely on motors or actuators within a traditional haploscope. This new instrument and methodology have been developed for a novel haploscope configuration utilizing both eye tracking and autorefractor systems. Analysis software that enables the synchronized analysis of eye movement and accommodative responses provides vision researchers and clinicians with a reproducible environment and shareable tool. The Vision and Neural Engineering Laboratory&#39;s (VNEL) Eye Movement Analysis Program (VEMAP) was established to process recordings produced by VE2020&#39;s eye trackers, while the Accommodative Movement Analysis Program (AMAP) was created to process the recording outputs from the corresponding autorefractor system. The VNEL studies three primary stimuli: accommodation (blur-driven changes in the convexity of the intraocular lens), vergence (inward, convergent rotation and outward, divergent rotation of the eyes), and saccades (conjugate eye movements). The VEMAP and AMAP utilize similar data flow processes, manual operator interactions, and interventions where necessary; however, these analysis platforms advance the establishment of an objective software suite that minimizes operator reliance. The utility of a graphical interface and its corresponding algorithms allow for a broad range of visual experiments to be conducted with minimal required prior coding experience from its operator(s).

VisualEyes2020 (VE2020) is a custom scripting language that presents, records, and synchronizes visual eye movement stimuli. VE2020 provides stimuli for conjugate eye movements (saccades and smooth pursuit), disconjugate eye movements (vergence), accommodation, and combinations of each. Two analysis programs unify the data processing from the eye tracking and accommodation recording systems.

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements ...

Bioengineering

Characterizing the Relationship Between Eye Movement Parameters and Cognitive Functions in Non-demented Parkinson's Disease Patients with Eye Tracking

Cognitive impairment is a common phenomenon in Parkinson&#8217;s disease that has implications on the prognosis. A simple, noninvasive and objective proxy measurement of cognitive function in Parkinson&#8217;s disease will be helpful in detecting early cognitive decline. As a physiological metric, eye movement parameter is not confounded by the subject&#39;s attributes and intelligence and can function as a proxy marker if it correlates with cognitive functions. To this end, this study explored the relationship between the eye movement parameters and performance in cognitive tests in multiple domains. In the experiment, a visual search task with eye tracking was set up, where subjects were asked to look for a number embedded in an array of alphabets scattered randomly on a computer screen. The differentiation between the number and the alphabet is an overlearned task such that the confounding effect of cognitive ability on the eye movement parameters is minimized. The average saccadic amplitude and fixation duration were captured and calculated during the visual search task. The cognitive assessment battery covered domains of frontal-executive functions, attention, verbal and visual memory. It was found that prolonged fixation duration was associated with poorer performance in verbal fluency, visual and verbal memory, allowing further exploration on the use of eye movement parameters as proxy markers for cognitive function in Parkinson&#8217;s disease patients. The experimental paradigm has been found to be highly tolerable in our group of Parkinson&#39;s disease patients and could be applied transdiagnostically to other disease entities for similar research questions.

Here, we present a protocol to study the relationship between the eye movement parameters and cognitive functions in non-demented Parkinson&#39;s disease patients. The experiment used an eye tracker to measure the saccadic amplitude and fixation duration in a visual search task. The correlation with performance in multi-domain cognitive tasks was subsequently measured.

Cognitive impairment is a common phenomenon in Parkinson&#8217;s disease that has implications on the prognosis. A simple, noninvasive and objective proxy ...

Evaluating Optokinetic Reflex Responses in Mice: A New High-Precision Protocol

Quantification of Visual Feature Selectivity of the Optokinetic Reflex in Mice

The optokinetic reflex (OKR) is an essential innate eye movement that is triggered by the global motion of the visual environment and serves to stabilize retinal images. Due to its importance and robustness, the OKR has been used to study visual-motor learning and to evaluate the visual functions of mice with different genetic backgrounds, ages, and drug treatments. Here, we introduce a procedure for evaluating OKR responses of head-fixed mice with high accuracy. Head fixation can rule out the contribution of vestibular stimulation on eye movements, making it possible to measure eye movements triggered only by visual motion. The OKR is elicited by a virtual drum system, in which a vertical grating presented on three computer monitors drifts horizontally in an oscillatory manner or unidirectionally at a constant velocity. With this virtual reality system, we can systematically change visual parameters like spatial frequency, temporal/oscillation frequency, contrast, luminance, and the direction of gratings, and quantify tuning curves of visual feature selectivity. High-speed infrared video-oculography ensures accurate measurement of the trajectory of eye movements. The eyes of individual mice are calibrated to provide opportunities to compare the OKRs between animals of different ages, genders, and genetic backgrounds. The quantitative power of this technique allows it to detect changes in the OKR when this behavior plastically adapts due to aging, sensory experience, or motor learning; thus, it makes this technique a valuable addition to the repertoire of tools used to investigate the plasticity of ocular behaviors.

Author Spotlight: An Accurate and Quantitative Approach to Study Visual Feature Selectivity of the Optokinetic Reflex in Mice 

Here, we describe a standard protocol for quantifying the optokinetic reflex. It combines virtual drum stimulation and video-oculography, and thus allows precise evaluation of the feature selectivity of the behavior and its adaptive plasticity.

The optokinetic reflex (OKR) is an essential innate eye movement that is triggered by the global motion of the visual environment and serves to stabilize ...