Identification of novel clinical testing methods and sensor-based parameters for sensitive detection of gait and balance impairment in early multiple sclerosis

Gait and balance problems are considered to be rare in early multiple sclerosis (MS) as these problems can hardly be detected at this stage by using routine neurological examination. However, patients frequently complain of gait and balance problems in early MS, and these problems can be detected by digital analysis when challenging tasks are used. Moreover, quantitative sensor-based measurement methods have the potential for being used for following up of patients' annual progression. In this study, we aimed to define the sensor-based and clinical parameters and challenging task conditions that are sensitive for the detection of gait and balance problems in the early stages of MS. We designed a study protocol using APDM MobilityLab System in patients with MS. We grouped 56 patients into three subgroups, and 23 healthy people were gender and age-matched with the early stages of MS group. Patients and the healthy control group performed normal speed walk, The Timed 25-foot walking, tandem walk, and quiet stance for 30 seconds in several balance tests such as Clinical Test of Sensory Interaction and Balance, Modified Balance Error Scoring System, Tandem Stance with APDM OPAL sensors. Patients also completed several patient-reported outcome measures (PROMs), such as the 12-Item Multiple Sclerosis Walking Scale (MSWS-12), The Upper Extremity Functional Index (UEFI), and The Modified Fatigue Impact Scale 5-Item (MFIS-5), The EQ-5D-3L and The Beck Depression Inventory (BDI). We examined lower extremity muscle strength, spasticity, and upper extremity function with the 9 Hole Peg Test (9-HPT) as well as SARA and SPRS scales. There were significant differences in selected balance and gait parameters, MSWS-12, UEFI, and MFIS-5 between mild, moderate and severe affected MS groups. We found that tandem walk and normal stance are not sensitive tests for discriminate an impairment in the early stages of the disease. Standing on foam was a sensitive method for detection of balance impairment in early MS, especially when performed eyes closed. One limb stance eyes closed stance was the most sensitive challenging task to observe difference between groups. We found that even though patients could perform all the tasks above, there is a significant difference in many sensor-based gait and balance parameters during the normal speed walk, T25FW, tandem walk and quiet stance tests between the healthy controls and early MS patients, pointing out to their significant potential to be used as biomarkers for detecting disability since the earliest stage of MS.