Technology-based assessment of Short Physical Performance Battery in elderly population

Abstract

The Short Physical Performance Battery (SPPB) is an objective evaluation of the lower extremity strength [1]. It has been proposed as a reliable method to assess the physical performance of elderly people (65+) through three simple tasks of daily life (gait, standing, chair stand) [2]. In clinical research, the SPPB is administered by research staff who are experienced in the standardized protocol of the examination, with each component measured manually by a stopwatch [3,4]. Therefore, these investigations may be subject to possible interrater and intrarater variabilities [5]. This work aims to validate an automatic method for the objective assessment of SPPB through the combination of wearable inertial and sEMG sensors. The present study included a sub-cohort of Salus in the Apulia Study of 137 old subjects, recruited consecutively from 2019 on a recall-based from an ongoing population-based prospective cohort comprising 2472 individuals aged 65+ and residents in Castellana Grotte, Puglia (Italy). Eligible participants were equipped with an inertial sensor (positioned around the subjets' waist, BTS G- SENSOR2, BTS SpA) and four surface electromyographic probes (BTS FREEEMG, BTS SpA) on Tibialis Anterior (TA) and Gastrocnemius Medialis (GAM) of both legs. The medical doctor instructed subjects to perform three different tasks: balance (stance phase, semi-tandem phase, and tandem phase), five repetition STS and 4-m walk. A stopwatch was used to measure the time required by the subject to complete each task and then assign the SPPB score according to the specific range (SPPB). Kinematics and EMG data of subjects were collected via BTS EMGAnalyzer and exported in MATLAB R2020a to calculate the technology-based SPPB (tSPPB). Descriptive statistics were used to describe the demographic characteristics and outcomes of the sample. The Spearman correlations were used to explore the relationship between the SPPB and tSPPB total score and the three-component scores. We compared the internal consistency of the SPPB and tSPPB using Cronbach’s alpha. Ninety-seven subjects (mean age [±SD] = 75.1 ± 5.53, female = 50.5%) were finally included in the analysis. The total SPPB (9.49 ± 2.55) and tSPPB (8.88 ± 2.51) scores were significantly different, yet highly correlated (r = 0.87, p < 0.01). The alpha coefficient for the SPPB score was high (0.93, 95% CI: 0.90 - 0.96), suggesting that the two methods have relatively high internal consistency. Technology-based assessment of SPPB represents a step forward in adapting the administration of objective measures of physical function to significantly expand the reach of research and clinical practice to assess populations at risk of functional decline.