RecruitingACTRN12624001291572

Validating a measure of eye movements after concussion

Validating a measure of eye movements after concussion in healthy and mild Traumatic Brain Injury (mTBI) participants aged between 18 - 40 years old.

Sponsor

Auckland University of Technology

Enrollment

30 participants

Start Date

Apr 17, 2025

Study Type

Observational

Conditions

Concussion

Summary

This study's primary aim is validating a clinical measure of eye movements 'Hart Strings' for use in further research. Participants will complete the Hart Strings measure twice, while wearing Tobii Eye Tracker 3 eye-tracking glasses. This will allow exploration of validity, through the correlation between Hart Strings and eye-tracking outcomes such as fixations, latency and mean saccade error, and the within-session reliability of the Hart Strings test. Additional data on Hart Strings reliability (within- and between-session) will be collected during a separate clinical trial of cross-over design. The study hypothesis is that the Hart Strings will identify (characterised by a lower score) poorer oculomotor performance where the eye-tracking outcomes are also poor (characterised by increased latency, fixations and/or saccade error).

Eligibility

Sex: Both males and femalesMin Age: 18 YearssMax Age: 40 Yearss

Inclusion Criteria5

Healthy participants
i: 18-40 years old.
mTBI participants
i: 18-40 years old.
ii: have ongoing symptoms from a diagnosis of mTBI (mild traumatic brain injury) within the last six months.

Exclusion Criteria10

Healthy group:
i: a self-reported history of mTBI in the previous 12 months or complaining of residual symptoms from a previous mTBI at any point.
ii: diagnosed peripheral vestibular conditions such as BPPV, and/or oculomotor or visual problems that are not mitigated with wearing corrective lenses.
iii: self-reported acute illness; or a positive response to any of the COVID-19 screening questions indicating risk of potential infection.
iiii: musculoskeletal issues or medical conditions that would limit the ability to safely and consistently perform the outcome measure (e.g. neck injuries, an ankle sprain limited standing).
mTBI group:
i: a diagnosis of moderate/severe TBI
ii: diagnosed peripheral vestibular conditions such as BPPV, and/or oculomotor or visual problems prior to the mTBI that are not mitigated with wearing corrective lenses.
iii: self-reported acute illness; or a positive response to any of the COVID-19 screening questions indicating risk of potential infection.
iiii: musculoskeletal issues or medical conditions that would limit the ability to safely and consistently perform the outcome measure (e.g. neck injuries, an ankle sprain limiting standing).

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Interventions

- Participants will complete the Hart Strings test. This assesses vestibular and oculomotor function through three standardised, timed conditions and is currently used in clinical practice by physiotherapists. These are an adaptation of the Hart Chart Rock exercise, and Saccade grids exercise, commonly used as treatments for oculomotor dysfunction. The third condition challenges the Vestibulo-Ocular Reflex as per the Dynamic Visual Acuity Test. Participants stand with feet together, 90cm from a wall, with two Hart charts (10cm x 10cm grid of letters) on the wall at eye level, 30cm apart. Participants will complete each condition as fast as possible for 30 seconds in a set pattern. The position of the last completed letter on the grid provides the score. Participants will complete two repetitions of the Hart Strings test, separated by five minutes of rest. These tests will be administered by a member of the research team who will observe participants and monitor adherence. - During the Hart Strings testing, participants will wear Tobii Eye Tracker 3 eye-tracking glasses to enable concurrent data collection. The eye tracking glasses are portable and are worn like a regular pair of reading glasses. They employ infrared light to enhance the contrast between the pupil and the iris, facilitating detection by the camera on the principle of pupil centre corneal reflection. It’s scene camera offers resolution of 1920 x 1080 pixels at 25 frames per second (FPS). With a gaze position accuracy of 0.6° for all distances, the glasses provide a gaze-tracking range of 95° horizontally and 63° vertically. The software conducts a frame-by-frame analysis of gaze data. This involves identifying the nature and location of gaze behaviour, including duration of eye movements, saccades, fixations, and blinks. The glasses need to be calibrated prior to testing; this takes approximately 30 seconds.