Validity of the Wearable Inertial Sensors for Walking Speed Assessment in Adults Post Stroke

Research Objectives Gait speed is an important indicator of walking and is used to track functional recovery after stroke. With the increasing popularity of advanced wearable technology, such as inertial sensors, there have been several studies examining validity of wearable sensors for gait assessments. However, their use in stroke walking assessments has been limited. The objective of this study was to examine the concurrent validity of walking speed measured with the APDM Mobility Lab system (APDM, Inc., Portland, OR, USA) with the clinically used 10-meter walk test (10MWT). Design Cross sectional study. Setting University research laboratory. Participants 20 adults with chronic stroke (age range: 18- 80 years). Interventions Individuals with stroke performed six trials of the 10MWT (3 at self-selected speeds and 3 at maximal walking speed) while wearing three inertial measurement units on both feet as well as the fifth lumbar vertebrae. Main Outcome Measures Comfortable and maximal walking speed measured using 10MWT and Mobility Lab software. Intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test absolute agreement and systemic bias. Results ICCs showed an excellent agreement between measures for comfortable walking speed [ICC: 0.988 (95% CI:0.967, 0.995; P < 0.001)] and for maximal walking speed [ICC: 0.981 (95% CI: 0.948, 0.993; P < 0.001)]. Bland Altman plots revealed a systematic bias with broad limit of agreement between the two measures for comfortable speed (0.269) and maximal speed (0.445). Conclusions These results support the use of three inertial sensors to provide a valid assessment of walking speed in adults post stroke. However, we revealed a systematic bias which may require the testing of wearable sensors with other gold standard instrumented walking assessments. Author(s) Disclosures None. Gait speed is an important indicator of walking and is used to track functional recovery after stroke. With the increasing popularity of advanced wearable technology, such as inertial sensors, there have been several studies examining validity of wearable sensors for gait assessments. However, their use in stroke walking assessments has been limited. The objective of this study was to examine the concurrent validity of walking speed measured with the APDM Mobility Lab system (APDM, Inc., Portland, OR, USA) with the clinically used 10-meter walk test (10MWT). Cross sectional study. University research laboratory. 20 adults with chronic stroke (age range: 18- 80 years). Individuals with stroke performed six trials of the 10MWT (3 at self-selected speeds and 3 at maximal walking speed) while wearing three inertial measurement units on both feet as well as the fifth lumbar vertebrae. Comfortable and maximal walking speed measured using 10MWT and Mobility Lab software. Intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test absolute agreement and systemic bias. ICCs showed an excellent agreement between measures for comfortable walking speed [ICC: 0.988 (95% CI:0.967, 0.995; P < 0.001)] and for maximal walking speed [ICC: 0.981 (95% CI: 0.948, 0.993; P < 0.001)]. Bland Altman plots revealed a systematic bias with broad limit of agreement between the two measures for comfortable speed (0.269) and maximal speed (0.445). These results support the use of three inertial sensors to provide a valid assessment of walking speed in adults post stroke. However, we revealed a systematic bias which may require the testing of wearable sensors with other gold standard instrumented walking assessments.