Hypotheses and Specific Aims
Specific Aims Impaired balance (upright postural control), visual instability and fatigue are common complaints in persons with multiple sclerosis (MS), often leading to advanced disability and lower quality of life. MS affects structures throughout the central nervous system (CNS), with frequent involvement of infratentorial structures including the brainstem and cerebellum.1-4 These structures play integral roles in the process of maintaining balance.5-8 Indeed, for the person with MS, involvement of these structures is strongly linked to impaired balance, often leading to falls.9,10 To our knowledge, no studies have established effective treatment to improve balance specifically for persons with MS who have involvement of brainstem/cerebellar structures.
Our previous study11 provides evidence that vestibular rehabilitation, an exercise program involving balance and eye movement training, greatly improves balance and fatigue in patients with MS who have primary complaints in these areas. Brainstem and cerebellar dysfunctions are strongly associated with impaired balance.9,10 Analysis from our previous study indicates that greater improvements in balance from vestibular rehabilitation are likely for persons with MS who have brainstem and/or cerebellar involvement. Neural plasticity has been reported in persons with MS following task-specific training.12-15 We conceptualize that vestibular rehabilitation targets the CNS, specifically the brainstem and cerebellum, by providing the necessary task-specific stimuli for effective neural reorganization, improving central sensory integration resulting in improved balance and visual stability. Functioning with impaired balance and visual stability can be highly fatiguing. As such, we anticipate that this intervention approach also improves fatigue.
We propose a 16-wk, two-group, stratified-blocked randomized controlled trial. Our primary aim is to determine if vestibular rehabilitation for persons with MS is more effective in improving balance for those who have brainstem and/or cerebellar involvement compared to persons with MS who do not. In addition, because eye movement exercises are an important part of the proposed vestibular rehabilitation program, we will determine if significant changes in visual stability for persons with MS who present with abnormal eye movements are possible following participation in this program. Lastly, we will expand our knowledge of the benefits of vestibular rehabilitation on fatigue
Primary Aim: To compare changes in balance based on two strata: participants with brainstem and/or cerebellar involvement and those without, and to compare changes between the two study groups: Experimental group (vestibular rehabilitation program) and Wait-listed Control group (wait-listed for vestibular rehabilitation instruction).
Hypothesis (H1): 1) Participants in the Experimental group having brainstem and/or cerebellar involvement will have greater improvements in balance compared to those without brainstem and/or cerebellar involvement; 2) The Experimental group will have greater improvements in balance compared to the Wait-listed Control group.
Secondary Aim 1: To identify changes in eye movement dysfunction for participants in the Experimental group having eye movement dysfunction at baseline, and to compare changes between the two study groups.
Hypothesis (H2): 1) Participants in the Experimental group who present with impaired eye movements at baseline will improve significantly in visual stability following performance in the vestibular rehabilitation program compared to baseline values; 2) Participants in the Experimental group who present with impaired eye movements will improve significantly in visual stability compared to participants in the Wait-listed Control group who also present with impaired eye movements.
Secondary Aim 2: To compare changes in self-reported fatigue based on brainstem and/or cerebellar involvement stratum and between the two study groups.
Hypothesis (H3): 1) Participants in the Experimental group having brainstem and/or cerebellar involvement will have greater improvements in fatigue compared to those without brainstem and/or cerebellar involvement; 2) The Experimental group will have greater improvements in fatigue compared to the Wait-listed Control group.
An overarching objective of our research is to set the stage for future investigations of the underlying mechanisms responsible for the benefits found from vestibular rehabilitation. CNS involvement and neural plasticity will serve as primary targets of future investigations.
