Whole body vibration to address motor and sensory impairments in people with multiple sclerosis

Multiple Sclerosis (MS) is a progressive degenerative condition of the central nervous system which affects both motor and sensory components. Common symptoms include muscle weakness, balance and mobility problems, fatigue, and sensory problems. There is a strong body of evidence that exercise intervention can be beneficial for people with MS (PwMS). However there is very little evidence in the MS literature about treatments that may target the sensory system. Whole Body Vibration (WBV) is a technology that has potential to influence the motor and sensory systems due to its mechanism. Vibration stimulus is delivered through the mechanoreceptors of the feet and stimulates muscle spindle activity what enhances muscle contraction. WBV intervention has been suggested to have a beneficial effect on muscle strength, balance, flexibility and bone mineral density in healthy populations. Initially, a systematic review of the literature was undertaken to examine the effects of WBV intervention in neurological populations. The findings of this review suggested insufficient evidence of the effects of WBV intervention when compared to no intervention or to other treatments. It has also highlighted a number of limitations in the reviewed studies, such as lack of using “gold standard” tools, high variability of study protocols or lack of blind assessors. One of the main concerns in the systematic review was that only one study had looked at changes in sensation after WBV intervention. In order to assess changes in the sensory system post exercise intervention, reliable measurement tools are essential. However, only one study investigated reliability of sensory tools in PwMS. Therefore, test-retest and inter-rater reliability studies of four sensory measures in PwMS were carried out. The findings from these studies indicated that the ICC values for the Neurothesiometer (NT) and Verbal Analogue Scale (VAS) for sensation were high and these two scales should be considered for measuring changes in sensation in ambulatory PwMS. Sensory information plays an important role in motor control and in providing feedback required to perform motor tasks, such as walking or to control balance. The next study investigated the relationship between foot vibration threshold and walking and balance in PwMS. Findings revealed that foot vibration threshold measured with NT has good to moderate relationship with the Berg balance scale, the 6 minute walking test and the Timed Up and Go test. This study has also provided the preliminary evidence that vibration threshold can distinguish between those PwMS with and without walking limitations. Taking into account the findings from literature review, the RCT used a “gold standard” tool to measure strength, a reliable tool to measure changes in vibration threshold and a novel, more comprehensive tool to measure changes in balance. It investigated the feasibility and effectiveness of 12 weeks of WBV intervention on muscle strength, sensation and other clinical measures in PwMS. Findings suggest that WBV intervention is feasible and well tolerated by PwMS. Significant between group differences were only found for vibration threshold, unexpectedly in favour of the exercise group only. Although WBV and exercise interventions improved certain variables, no significant between group differences for muscle strength, gait and balance were found. This suggested that WBV intervention was not more effective than standard exercise but it may be as effective as the exercises. This thesis added to the literature the preliminary evidence of clinical sensory assessments in individual with MS and suggested that WBV may work to the same degree as the exercises in PwMS.