Utilizing the ISway to Identify and Compare Balance Domain Deficits in People with Multiple Sclerosis

Abstract

Background and Purpose Balance impairments are a common symptom in people with Multiple Sclerosis (PwMS). The instrumented sway (ISway) is a reliable clinical balance assessment; however, this approach yields a vast range of outcomes that may hinder interpretation and delivery of evidence-based care. Identifying balance domains that are both altered in PwMS and clinically relevant would help isolate treatment targets. Therefore, we sought to develop a multiple sclerosis (MS)-specific model of balance and examine differences between 1) PwMS and neurotypical controls and 2) PwMS with (MS-F) and without a fall history (MS-NF). Methods 118 people with relapsing-remitting MS (MS-F = 39; MS-NF = 79) and 46 age-matched neurotypical controls completed the ISway balance assessment. 22 sway measures obtained from the ISway were entered into an exploratory factor analysis (EFA) to identify underlying balance domains. The model-derived balance domains were compared between 1) PwMS and age-matched, neurotypical controls and 2) MS-F and MS-NF. Results 3 distinct balance domains were identified: 1) sway amplitude and velocity, 2) sway frequency and jerk mediolateral (ML), and 3) sway frequency and jerk anteroposterior (AP), explaining 81.66% of balance variance. PwMS exhibited worse performance (i.e., greater amplitude and velocity of sway) in the sway velocity and amplitude domain compared to age-matched neurotypical controls (p = .003). MS-F exhibited worse performance in the sway velocity and amplitude domain compared to MS-NF (p = 0.046). The AP and ML sway frequency and jerk domains were not different between PwMS and neurotypical controls nor between MS-F and MS-NF. Discussion PwMS exhibited deficits within the sway amplitude and velocity domain compared to neurotypical controls, with a similar effect observed between MS-F and MS-NF. Recognizing balance domains altered in PwMS and related to falls may be useful for efficient and strategic balance assessment and rehabilitation. Balance impairments are a common symptom in people with Multiple Sclerosis (PwMS). The instrumented sway (ISway) is a reliable clinical balance assessment; however, this approach yields a vast range of outcomes that may hinder interpretation and delivery of evidence-based care. Identifying balance domains that are both altered in PwMS and clinically relevant would help isolate treatment targets. Therefore, we sought to develop a multiple sclerosis (MS)-specific model of balance and examine differences between 1) PwMS and neurotypical controls and 2) PwMS with (MS-F) and without a fall history (MS-NF). 118 people with relapsing-remitting MS (MS-F = 39; MS-NF = 79) and 46 age-matched neurotypical controls completed the ISway balance assessment. 22 sway measures obtained from the ISway were entered into an exploratory factor analysis (EFA) to identify underlying balance domains. The model-derived balance domains were compared between 1) PwMS and age-matched, neurotypical controls and 2) MS-F and MS-NF. 3 distinct balance domains were identified: 1) sway amplitude and velocity, 2) sway frequency and jerk mediolateral (ML), and 3) sway frequency and jerk anteroposterior (AP), explaining 81.66% of balance variance. PwMS exhibited worse performance (i.e., greater amplitude and velocity of sway) in the sway velocity and amplitude domain compared to age-matched neurotypical controls (p = .003). MS-F exhibited worse performance in the sway velocity and amplitude domain compared to MS-NF (p = 0.046). The AP and ML sway frequency and jerk domains were not different between PwMS and neurotypical controls nor between MS-F and MS-NF. PwMS exhibited deficits within the sway amplitude and velocity domain compared to neurotypical controls, with a similar effect observed between MS-F and MS-NF. Recognizing balance domains altered in PwMS and related to falls may be useful for efficient and strategic balance assessment and rehabilitation.