An Accelerometry-Based Methodology for Assessment of Real-World Bilateral Upper Extremity Activity

Abstract

BackgroundThe use of both upper extremities (UE) is necessary for the completion of many everyday tasks. Few clinical assessments measure the abilities of the UEs to work together; rather, they assess unilateral function and compare it between affected and unaffected UEs. Furthermore, clinical assessments are unable to measure function that occurs in the real-world, outside the clinic. This study examines the validity of an innovative approach to assess real-world bilateral UE activity using accelerometry.MethodsSeventy-four neurologically intact adults completed ten tasks (donning/doffing shoes, grooming, stacking boxes, cutting playdough, folding towels, writing, unilateral sorting, bilateral sorting, unilateral typing, and bilateral typing) while wearing accelerometers on both wrists. Two variables, the Bilateral Magnitude and Magnitude Ratio, were derived from accelerometry data to distinguish between high- and low-intensity tasks, and between bilateral and unilateral tasks. Estimated energy expenditure and time spent in simultaneous UE activity for each task were also calculated.ResultsThe Bilateral Magnitude distinguished between high- and low-intensity tasks, and the Magnitude Ratio distinguished between unilateral and bilateral UE tasks. The Bilateral Magnitude was strongly correlated with estimated energy expenditure (ρ = 0.74, p<0.02), and the Magnitude Ratio was strongly correlated with time spent in simultaneous UE activity (ρ = 0.93, p<0.01) across tasks.ConclusionsThese results demonstrate face validity and construct validity of this methodology to quantify bilateral UE activity during the performance of everyday tasks performed in a laboratory setting, and can now be used to assess bilateral UE activity in real-world environments.

Changes in Upper-Extremity Functional Capacity and Daily Performance During Outpatient Occupational Therapy for People With Stroke

“…The wear period was chosen as a practical compromise to obtain the data but not overburden the participants with measures and decrease wearing adherence (Bailey, Klaesner, & Lang, 2015;Barak, Wu, Dai, Duncan, & Behrman, 2014). Accelerometers are a well-established valid and reliable tool used to objectively measure UE use in daily life (Bailey et al, 2014;Lang et al, 2013;Uswatte, Foo, et al, 2005). They are the size of a wristwatch and measure UE activity in raw accelerations along three axes.…”

“…Bailey et al, 2014) and then summing the vector magnitude from each limb for each second of activity (Bailey et al, 2014). A bilateral magnitude value of 0 indicates that no activity occurred in either UE at that second.…”

“…An increase in the bilateral magnitude indicates that the UEs moved with increasing intensity. For example, lower bilateral magnitude values would be expected during tasks such as typing or writing, and higher values would be expected during a task such as placing an item on a shelf with both hands (Bailey et al, 2014).…”

“…The magnitude ratio quantifies the contribution of each UE to activity (Bailey et al, 2014) and is calculated for each second of data by dividing the vector magnitude of the paretic UE by the vector magnitude of the nonparetic UE. To prevent skewness, the natural log of this ratio is then used as the magnitude ratio (Bailey et al, 2014).…”

“…Accelerometry has been established as an objective, unbiased tool to measure realworld UE performance in daily life (Bailey, Klaesner, & Lang, 2014;Uswatte, Foo, et al, 2005;Uswatte et al, 2006). Accelerometers have been used to record UE performance of people in the inpatient rehabilitation setting very early after stroke (Lang, Wagner, Edwards, & Dromerick, 2007) and to determine hours of total UE activity in healthy control participants and people who have had a stroke (Bailey, Klaesner, & Lang, 2015;de Niet, Bussmann, Ribbers, & Stam, 2007;Uswatte, Foo, et al, 2005;Uswatte et al, 2006).…”