Publications

Walking speed measurement with an Ambient Measurement System (AMS) in patients with multiple sclerosis and walking impairment (manuscript publication)

Gait & Posture – March 2018

“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.

 

Movement measurements at home for multiple sclerosis: walking speed measured by a novel ambient measurement system (manuscript publication)

Multiple Sclerosis Journal – Experimental, Translational and Clinical – January 2018

“Movement measurements at home for multiple sclerosis: walking speed measured by a novel ambient measurement system”. Victoria M. J. Smith (MGH / Harvard), Jonathan S. Varsanik (Atlas5D), Rachel A. Walker (Atlas5D), Andrew W. Russo (MGH / Harvard), Kevin R. Patel (MGH / Harvard),  Wendy Gabel (Biogen), Glenn A. Phillips (Biogen), Zebadiah M. Kimmel (Atlas5D), and Eric C. Klawiter (MGH / Harvard) (2018). Multiple Sclerosis Journal – Experimental, Translational and Clinical, DOI: 10.1177/2055217317753465.

Background: Gait disturbance is a major contributor to clinical disability in multiple sclerosis (MS). A sensor was developed to assess walking speed at home for people with MS using infrared technology in real-time without the use of wearables. Objective: To develop continuous in-home outcome measures to assess gait in adults with MS. Methods: Movement measurements were collected continuously for 8 months from six people with MS. Average walking speed and peak walking speed were calculated from movement data, then analyzed for variability over time, by room (location), and over the course of the day. In-home continuous gait outcomes and variability were correlated with standard in-clinic gait outcomes. Results: Measured in-home average walking speed of participants ranged from 0.33 m/s to 0.96 m/s and peak walking speed ranged from 0.89 m/s to 1.51 m/s. Mean total within-participant coefficient of variation for daily average walking speed and peak walking speed were 10.75% and 10.93%, respectively. Average walking speed demonstrated a moderately strong correlation with baseline Timed 25-Foot Walk (rs = 0.714, P = 0.111). Conclusion: New non-wearable technology provides reliable and continuous in-home assessment of walking speed.

 

Validation of an ambient measurement system (AMS) for walking speed (manuscript publication)

Journal of Medical Engineering & Technology – April 2017

“Validation of an ambient measurement system (AMS) for walking speed”. Jonathan S. Varsanik (Atlas5D), Zebadiah M. Kimmel (Atlas5D), Carl de Moor (Biogen), Wendy Gabel (Biogen), and Glenn A. Phillips (Biogen) (2017). Journal Of Medical Engineering & Technology, DOI: 10.1080/03091902.2017.1308025

The purpose of this study was to validate the measurement of walking speed by a shelf-top ambient measurement system (AMS) that can be placed in a patient’s home. Twenty-eight healthy adults (16 male, 12 female) were asked to walk three pre-defined routes two times each (total of 168 traversals). For each traversal, walking speed was measured simultaneously by five sources: two independent AMSs and three human timers with stopwatches. Measurements across the five sources were compared by generalized estimating equations (GEE). Correlation coefficients compared pairwise for walking speeds across the two AMSs, three human timers, and three routes all exceeded 0.86 (p < .0001), and for AMS-to-AMS exceeded 0.92 (p < .0001). Aggregated across all routes, there was no significant difference in measured walking speeds between the two AMSs (p = .596). There was a statistically significant difference between the AMSs and human timers of 8.5 cm/s (p < .0001), which is comparable to differences reported for other non-worn sensors. The tested AMS demonstrated the ability to automatically measure walking speeds comparable to manual observation and recording, which is the current standard for assessing walking speed in a clinical setting.

 

Movement measurements at home for multiple sclerosis: walking speed and cane usage measured by an ambient measurement system (conference poster)

American Academy of Neurology (AAN) – April 2016

“Movement Measurements at Home for Multiple Sclerosis: Walking Speed and Cane Usage Measured by an Ambient Measurement System”. Scientific electronic poster (e-poster) presented at the American Academy of Neurology (AAN) annual conference on April 18, 2016. Authors: Victoria M. J. Smith (MGH / Harvard), Jonathan S. Varsanik (Atlas5D), Kevin R. Patel (MGH / Harvard), Wendy Gabel (Biogen), Glenn Phillips (Biogen), Zebadiah Kimmel (Atlas5D), Eric Klawiter (MGH / Harvard). Video contents copyright 2016 by Atlas5D; all rights reserved.

This study’s objective was to develop continuous in-home outcome measurements to assess gait in adults with multiple sclerosis (MS). Movement measurements were collected continuously for 4 months from the homes of six female people with MS (mean age 56.2, median EDSS 3.5, EDSS range 2-6.5). After two months, sensors were moved to a new location in the home. Spearman correlation was used to correlate in-home continuous gait outcomes with standard clinic gait outcomes. Wilcoxon signed-rank test was used to compare gait outcome for location and time of day. Measured in-home average walking speeds of users demonstrated a moderately strong correlation with Timed 25-Foot Walk (ρ=-0.60, p=0.21). Home cane usage was detected with cane users twice as frequently as non-cane users in a cane-detection measurement. New non-wearable technology provides reliable and continuous in-home assessment of walking speed and cane usage. This study demonstrates feasibility for development of new continuous outcome measures to assess gait in MS and other neurological diseases.