Gaze and Postural Stability in Multiple Sclerosis

In order to provide information that will improve therapy, the goals of this project are to determine if persons with MS with complaints of dizziness and at risk for falls can improve their balance and vision stability as a result of a bout of specific treatment. This project seeks to do this by conducting an experiment where people with MS are randomly assigned to a group that practices activities known to help improve inner ear function or a group that practices activities known to improve endurance and strength but that should not change inner ear function. Such a comparison will allow us to gain understanding of how the inner ear system is affected in MS and how it responds to treatment.

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.

Eligibility Criteria:
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