Wearable-Sensor-Instrumented Assessment of Prolonged Walking Identifies Performance Deficits in Older Adults With Normal Clinical Presentation

Background and Purpose: Wearable sensors provide robust, objective information about movement quality. The Kinesis Gait uses shin-mounted accelerometers to augment clinical assessment by capturing gait spatiotemporal characteristics and quantifying fall risk. When used during a Six-Minute Walk Test (6MWT), the Kinesis Gait may capture gait quality deterioration over longer distances akin to those navigated during community ambulation. This analysis investigated the value of an instrumented 6MWT compared to clinical measures of function and muscle quality to identify older adults at risk of difficulty with community mobility. Methods: Forty-two older adults completed functional assessments (Four Square Step Test [FSST], stair climb power [SCP], Five Times Sit-to-Stand [5xSTS]), a Kinesis-instrumented 6MWT, and received CT imaging of hip and thigh muscles. Gait performance was characterized during the first and last minute of the 6MWT with Kinesis risk scores and gait spatiotemporal characteristics. Muscle attenuation was calculated from CT images to quantify muscle quality with lower scores indicating more fatty infiltration. Results and Discussion: No statistically significant differences in Kinesis-measured gait performance were found between the first to last minute of the 6MWT. However, clinically abnormal gait compared to age- and sex-matched normative data was identified in 7 participants (16.7%) only in the last minute of the 6MWT (“gait deterioration”) and in 20 participants (47.6%) at both timepoints. Participants with gait deterioration were statistically similar to those with clinically normal gait (n = 15 [35.7%]) in terms of age, physical functioning, and muscle quality but were younger ( P = .042), had better physical functioning (SCP- P = .030, FSST- P = .049, 6MWT distance- P = .003), and had better hip abductor muscle quality (left- P = .002; right- P = .008) compared to those with clinically abnormal gait at both timepoints. Conclusions: The instrumented 6MWT identified a subgroup with clinically significant gait deterioration during a longer walking task likely to experience functional decline and difficulty when navigating community distances. Future studies should evaluate if training cardiovascular fitness improves prolonged gait performance in this group and can thereby help decrease fall risk.