| Description |
Multiple Sclerosis (MS) is a chronic, neurological disorder characterized by imbalance and falls. Accurate perception and integration of three sensory inputs - the vestibular, vision, and somatosensory, is critical to produce human gaze and posture orientation. In MS, demyelination of pathways within the brainstem and cerebellum adversely affect gaze and postural stability. However, the deficits and the psychometric properties of these measures remain less examined. Moreover, the benefits of training on gaze and postural stability are unknown in MS. This study examined the deficits in gaze stability, dynamic balance, and self-report measures in persons with MS as compared to controls; assessed the test-retest reliability and response stability of gaze stability, postural sway, and dynamic balance tests; and investigated the effects of training on gaze stability, galvanic-induced postural sway, dynamic balance, and self-report measures in persons with MS. We hypothesized that persons with MS will demonstrate deficits in gaze and postural stability; that study measures will demonstrate moderate to good reliability and acceptable response stability; and that persons with MS will demonstrate significant improvements after training. Nineteen persons with MS at fall-risk and 14 controls were recruited and the assessments were carried out on 2 occasions. The participants then completed a 2-week training followed by re-assessments. Persons with MS demonstrated significant differences in the gaze stability, dynamic balance, and self-report measures versus controls. In addition, significant inter-relationships were found. The majority of gaze stabilization measures demonstrated moderate while the postural sway and dynamic balance measures showed good reliability. The aVOR gain, FGA, and FSST showed SEM % <20 and MDD95% <20, suggesting acceptable response stability. After training, gaze stability was achieved by recruiting substitutive oculomotor strategies whereas postural stability was achieved by sway response adaptations. Consistent improvements in dynamic balance and self-report measures suggest clinically meaningful changes. Taken together, these findings support the study hypothesis and suggest that significant deficits in gaze and posture may be present in persons with MS. This highlights the utility of these assessments in fall-risk evaluations in persons with MS. Moreover, the different strategical mechanisms for improvements after training suggest the clinical value of a focused training intervention. |
