Posted December 6, 2019

Richard Van Emmerik, Ph.D., University of Massachusetts Amherst

Multiple Sclerosis (MS) is a chronic neurological disorder characterized by steadily worsening function of the nervous system that often leads to significant disability affecting more than a million people in the United States. To date, existing treatments have been ineffective in slowing the decline of mobility and body functions. There is a critical need to quantify disability progression in a targeted and reliable way that would aid our ability to treat MS effectively and slow its progression. Most mobility assessment scales are limited by poor psychometric properties. Objective measures, including the Timed 25 Foot Walk (T25FW), used to assess progression of mobility impairment in MS may not be sensitive enough to detect subtle changes in sensorimotor function; further, these tests require that people be ambulatory.

Dr. Richard Van Emmerik’s lab focuses on sensorimotor changes in older individuals and in people with Multiple Sclerosis and how these changes can affect the control of posture and gait, leading to a loss of stability and falls. The team of researchers include Carolina Ionete and Farnaz Khalighinejad from the University of Massachusetts Memorial Medical Center in Worcester, Jane Kent, John Buoanaccorsi, Jules Miehm, Sumire Sato and Caitlin Rajala from the University of Massachusetts Amherst, Stephanie Jones from Smith College, and Jongil Lim from Texas A&M University in San Antonio. With support from a Fiscal Year 2015 Multiple Sclerosis Research Program Investigator-Initiated Research Award (IIRA), Dr. Van Emmerik and his team have been studying coordination and control of human movement and how different sensorimotor measurements can identify patients who have progressive MS. Specifically, investigators studied rapid hand or foot tapping ability measured by inertial sensors worn on the hand or foot in relapsing remitting MS (RRMS) and progressive MS (PMS) compared to non-MS controls (see Figure 1). They observed that both hand and foot tapping ability is reduced in both MS groups compared to controls. Interestingly, foot tapping ability was also reduced in the progressive compared to the non-progressive group with MS.

Dr. Van Emmerik’s team also performed an analysis of the separate movement phases which make up the tapping motion, namely the up-movement (‘gravity-resisting’) and down-movement (‘gravity-assisted’). This analysis showed increased variability in both MS groups compared to controls for up-movement in the foot but not the hand. There were no differences between MS subtypes, while foot velocity was decreased in the PMS group compared to controls in both movement phases. Up- and down-movement durations in this study showed consistent group differences compared to the overall tapping interval, suggesting that both gravity-assisted and gravity-resisting movements are affected. In addition, up-movement variability was increased in both MS groups compared to controls. Investigators hypothesized that the differences observed in the different movement phases may be due to spasticity or slowed maximal motor unit recruitment, and the nature of the mechanisms underlying the movements during the up-direction phase of tapping in MS patients should be explored further. Overall, these results show that foot-tapping, but not hand-tapping, may be more sensitive in differentiating MS patients from controls but also the different MS subtypes.

Currently, the team is performing follow-up visits to assess long-term patterns in sensorimotor functions and assess longitudinal changes across both MS subtypes, controls, and changes within individuals. If successful, the researchers will advance the current knowledge of the sensorimotor function changes in people with progressive forms of MS and how these relate to those diagnosed with relapsing-remitting (non-progressive) MS. Furthermore, these assessments are a cost-effective tool that can be developed further to be used routinely in MS patient exams to potentially identify and track disease progression.

Link:

Public and Technical Abstracts:  The MS Neuromotor Test: A Nonambulatory Measure of Sensorimotor Function to Identify and Track Progressive MS

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