The Impact of Eye and Body Training on the Injury Rate of Concussions in Female Soccer Players

The examination of the cervical spine and the surrounding tissue is used to identify cervical causes of headaches. Assessments include range of motion (degrees) and isometric strength (N) for the cervical spine, and extent of movement and deviation of mouth opening (degrees) for the jaw.

Passive, fast and low-amplitude rotational movements (head impulses, 10-15° eccentricity) are performed in the planes of each pair of semicircular canals (horizontal, RALP (right front-left rear), LARP (left front-right rear)) and induce VOR responses. During the examination, the subject is asked to fixate a target straight ahead. The eye movements during the VOR are measured with a high-speed video camera.

Evaluation of gain (ratio between head and eye movement) and presence of saccades (rapid, corrective eye movements) are measured.

During the DVA, visual acuity is determined during head movements in order to measure the effectiveness of the visual stabilization function. Static visual acuity (visual acuity without head movement) is determined by reducing the size of a Landolt with C on a computer screen until the athlete is no longer able to read it correctly. The visual acuity is then obtained with head movements (120°/s, ±30°). If the difference between the static and dynamic visual acuity is more than 0.2 logMAR, there is a visual stabilization disorder.The difference between static and dynamic visual acuity is assessed in logMAR.

The VOMS tests eye movements and vestibulo-oculomotor coordination. The screening covers five areas: Smooth pursuit, horizontal and vertical saccades, near convergence distance, horizontal vestibular eye reflex and visual motion sensitivity. For each area, the symptoms are rated on a Visual analogue scale (VAS), typically from 0 to 10, where 0 means the symptom is not present and 8-10 indicates severe severity. The near point convergence distance is measured in centimeters (cm).

BESS is a reliable and inexpensive tool to measure static balance. BESS consists of 6 tests that include both leg stance, one leg stance and tandem stance conditions, respectively, on both hard and foam surfaces with eyes closed. A stopwatch is used to determine participants' time during 20-second stance tests. The grading method is based on the score of the error table in the six tests. Errors include lifting the hip, walking, opening the eyes, grasping something, falling, leaving the test position after 5 seconds, flexion or abduction of the upper leg more than 30 degrees, and lifting the heel or front of the leg on the surface. If more than one mistake is made at the same time, they are counted as one mistake. The maximum total number of errors for any test is taken to be 10 (a higher score indicates mor balance errors and greater balance impairment).

The COBALT assesses balance through 5 conditions: 1 single-task and 4 dual-task. Participants are timed for 20 seconds using a stopwatch. In the single-task, they count backwards by 7s from 100. Dual-task conditions combine balance exercises with the cognitive task, with and without foam:

1. Double leg stance with eyes closed, head rotating side to side to a metronome at 120 bpm.
2. Eyes open, arms outstretched, thumbs up, focusing on thumbs while rotating side to side to a metronome at 40 bpm.

Scoring uses an error table across conditions. Errors include cognitive mistakes, hip lifting, walking, eye opening, grasping, falling, leaving position early, leg movement beyond 30 degrees, and not syncing head or trunk rotation with the metronome. Each test's maximum errors are 10, with higher scores indicating more balance issues and impairment.

Sway path length measurement using an accelerometer involves tracking the movement of the center of pressure (COP) during the BESS and COBALT. This measure provides an objective assessment of postural control by quantifying the total distance the COP travels. An accelerometer is placed on the hip to capture the body's movements, and the data is analyzed using specialized balance software. The sway path length is measured in millimeters (mm).

Sway path velocity measurement involves quantifying the speed at which the center of pressure (COP) moves. This parameter provides an objective assessment of postural control by indicating how quickly the COP travels. An accelerometer is placed on the hip to capture the body's movements, and the data is analyzed using specialized balance software. The measure is performed during the BESS and COBALT. The sway path velocity is measured in millimeters per seconds (mm/s).

Saccade latency in milliseconds (ms) during horizontal paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

Saccade latency in milliseconds (ms) during vertical paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

Saccade velocity in degrees per seconds (˚/s) during horizontal paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

Saccade velocity in degrees per seconds (˚/s) during vertical paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

The gain refers to the accuracy with which the eyes match the velocity of a moving target. It is a measure of how well the eye movement system keeps up with the speed of the moving object in the horizontal plane. Specifically, gain is calculated as the ratio of eye movement velocity to target velocity. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

The gain refers to the accuracy with which the eyes match the velocity of a moving target. It is a measure of how well the eye movement system keeps up with the speed of the moving object in the vertical plane. Specifically, gain is calculated as the ratio of eye movement velocity to target velocity. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.

Pupillometry is the measurement and analysis of pupil size and its response to light stimuli. The amplitude i.e maximum constriction is the difference between the baseline pupil size and the smallest pupil size achieved after exposure to the light stimulus. The amplitude is measured in millimeters (mm).

Pupillometry is the measurement and analysis of pupil size and its response to light stimuli. The velocity is the speed at which the pupil constricts or dilates in response to changes in light intensity. Typically reported in millimeters per second (mm/s).