“Walking speed measurement with an Ambient Measurement System (AMS) in patients with multiple sclerosis and walking impairment”. Francois Bethoux (Cleveland Clinic), Jonathan S. Varsanik (Atlas5D), Timothy W. Chevalier (Atlas5D), Elkan F. Halpern (MGH Institute for Technology Assessment), Darlene Stough (Cleveland Clinic), and Zebadiah M. Kimmel (Atlas5D). (2018). Gait & Posture, DOI: 10.1016/j.gaitpost.2018.01.033.
Walking speed is an important measure of gait impairment in multiple sclerosis (MS). The clinical assessment of walking speed requires dedicated time, space, and personnel, and may not accurately gauge real-world performance. The term “Ambient Measurement System” (AMS) refers to a new class of device that passively measures walking speed at home, without the need for dedicated space or specialized setup. This study compared an AMS, Echo5D, versus in-clinic standard measures of walking speed on a straight path. Twenty participants with MS and walking impairment were recruited from the Cleveland Clinic Mellen Center for MS. Each participant traversed an electronic GAITRite CIRFace (GC) sensor mat four times (two at comfortable pace, two at fast pace). Each participant then performed the Timed 25-Foot Walk (T25FW) twice, measured by a manual stopwatch (SW). All traversals were simultaneously measured by an array of Echo5D devices. Echo5D speeds were correlated with the Patient-Determined Disease Steps and the MS Walking Scale-12 patient-reported outcomes. Pearson correlations between Echo5D and clinical tests ranged from 0.89 to 0.98 (p < 0.0001). No statistically significant bias was found between Echo5D and GC. A small statistically significant bias was found between Echo5D and SW, with Echo5D reporting approximately 5% faster walking speeds in aggregate. Among MS patients with walking impairments, the Echo5D AMS acquired walking speeds which were closely correlated with the standard measures of GC and SW. The strong agreement supports the use of Echo5D to assess in-home, real-world walking performance in MS.