Gaze and Postural Stability in Multiple Sclerosis

A variety of sources of evidence suggest altered vestibular function in people diagnosed with
MS (PwMS). These sources of evidence include [a] subjective complaints of dizziness /
vertigo, [b] altered subjective visual vertical, [c] altered vestibular evoked myogenic
potentials, [d] altered performance on the vestibular dominant components of the sensory
organization test, and [e] pilot reports of gaze stabilization deficits during vestibular
ocular reflex (VOR) testing from the investigator's research group. These findings suggest
vestibular deficits are present in PwMS. Epidemiological studies document cerebellar and
brainstem involvement in 23% of PwMS at disease onset, increasing to 82% after longstanding
illness. These vestibular deficits contribute to motion sensitivity, dizziness, imbalance,
and falls. Regardless, dizziness and falls have a significant negative impact on quality of
life. Multiple studies show that falls are a major disabling symptom in MS affecting
approximately 75% of PwMS. The high incidence of falls in MS, is an important health concern
due to its associations with injury-related morbidities, mortality and financial costs.

The vestibular pathways responsible for gaze and postural stability, as well as sensory
integration reside in the brainstem, cerebellum and spinal cord. Demyelination of the
pathways involving the vestibular nuclei complex within the brainstem and cerebellum
adversely affect angular vestibulo-ocular reflex,vestibulo-spinal reflex function and sensory
integration in PwMS. While evidence reports impairments in posturography and otolith mediated
responses (vestibular evoked myogenic potentials), the responses mediated by the semicircular
canal end organs and vestibular pathways have not been examined. Specifically, the learning
and retention of gaze and postural stability as a result of task specific training program
has not been studied in a well controlled clinical trial.

This proposal seeks to examine gaze and postural stability outcomes utilizing outcome
measures that span the World Health Organization's International Classification of Function,
Disability, and Health. Following completion of the baseline examination, PwMS will be
randomized to one of two interventions: An Experimental Gaze and Postural Stability Training
Group (GPS) or a Standard Care Aerobic Exercise Control Group (SCA). The two groups differ
only by the presence of the GPS program in the experimental group. Both groups will
participate in supervised exercise 3 times per week for 6 weeks followed by a post
intervention testing period . After one month of no training, both groups will be brought
back for a final follow-up examination to determine the retention of any training induced
changes.

Inclusion Criteria:

- Neurologist-diagnosed, clinically definite MS

- Expanded Disability Severity Scale (EDSS) score of less than 6.0

- Current complaints of dizziness (DHI > 0)

- At risk of falls (determined by > 2 falls in past year or Dynamic Gait Index <19 or
Activity Specific Balance Confidence Scale <80

- Ability to tolerate repetitive 5 min bouts of angular head motions.

Exclusion Criteria:

- Central or Peripheral Nervous System disorders (other than MS)

- Otologic, Cervical spine, or lower extremity injury in last 12 months

- Exercise or alcohol use in last 48 hours

- Currently taking vestibular suppressant medications

- Peripheral Vestibular Pathology (BPPV, hypofunction, Meniere's disease

- Internuclear Opthalmoplegia

- MS exacerbation within last 8 weeks

- Orthopedic, neurologic, or cognitive comorbidities that would limit participation in
the study procedures