Incremental Vestibulo-ocular Reflex Adaptation as a Novel Treatment for Dizziness in People With Multiple Sclerosis

The team will conduct the video head impulse test (vHIT), a physiologic assay of vestibular semicircular canal pathway function. Angular vestibulo-ocular reflex gain will be calculated as eye velocity / head velocity during self-generated and/or passive high frequency head rotations which will be conducted in the yaw, pitch, roll, and/or semicircular canal planes.

The ability of participants to see clearly while their head is in motion (e.g., during self-generated head movements while seated, while walking at their preferred walking speed) will be assessed using commercially available hardware and custom software while the participant's head is moving.

The BEST will be instrumented using inertial measurement units (IMU) placed at the head, upper torso, pelvis, and both ankles. The BEST is a 36-item assessment of the body systems that contribute to balance and walking. Total scores range from 0 to 108 points

The GDT is a 2-item assessment of aspects of spatial navigation. Task 1 is to walk 20 feet with eyes open. Task 2 is to walk 20 feet with eyes closed. Both tasks are timed, and the GDT result is the time needed to walk with eyes closed minus the time needed to walk with eyes open.

The DHI be used to assess participants' perceived level of handicap due dizziness. This measure consists of 25 questions that are answered as "yes" = 4 points (dizziness is always a factor), "sometimes" = 2 points (dizziness is sometimes a factor), or "no" = 0 points (dizziness is never a factor) for a given situation or issue. The maximum total score on this measure is 100 points with higher scores indicating higher levels of perceived handicap.

The ABCS consists of 16 questions for which the respondent answers how confident they feel in not becoming unsteady or falling in specific situations. Confidence is rated on a scale of 0% to 100% with 0% indicating "no confidence" and 100% indicating "complete confidence' in the ability to maintain balance. Average scores of ≥ 80% are associated with high levels of physical functioning in adults.

Visual analog scales are commonly used in clinical practice and research. The investigator will measure the severity of oscillopsia (unstable vision during head movement) and sense of disequilibrium while the participant walks 20' on separate visual analog scales. The distance from the zero anchor to the respondent's marking will be measured without units but to the nearest tenth. The response for each scale will be transformed to a 100-point scale

The investigator will measure the sense of disequilibrium while the participant walks 20' on separate visual analog scales. The distance from the zero anchor to the respondent's marking will be measured without units but to the nearest tenth.

The response for the scale will be transformed to a 100-point scale.

The MSQOL-54 is a multidimensional measure that consists of questions related to general and MS-specific health-related quality of life. The MSQOL-54 was created by adding 18 items related to MS-specific issues, e.g., fatigue and cognitive function.

The investigator will assess perception of change retrospectively across the entire study period with ratings using an 11-point Likert scale with anchors of "very much better" and "very much worse" with a middle point labeled "no change" to assess the magnitude of change in symptoms.