Abstract
Lower-limb strength is a marker of functional decline in elders. This work studies the feasibility of using the quasi-periodic nature of the distance between a subjects’ back and the chair backrest during a 30-s chair–stand test (CST) to carry out unsupervised measurements based on readings from a low-cost ultrasound sensor. The device comprises an ultrasound sensor, an Arduino UNO board, and a Bluetooth module. Sit-to-stand transitions are identified by filtering the signal with a moving minimum filter and comparing the output to an adaptive threshold. An inter-rater reliability (IRR) study was carried out to validate the device ability to count the same number of valid transitions as the gold-standard manual count. A group of elders (age: mean (m) = 80.79 years old, SD = 5.38; gender: 21 female and seven male) were asked to perform a 30-s CST using the device while a trained nurse manually counted valid transitions. Ultimately, a moving minimum filter was necessary to cancel the effect of outliers, likely produced because older people tend to produce more motion artefacts and, thus, noisier signals. While the intra-class correlation coefficient (ICC) for this study was good (ICC = 0.86, 95% confidence interval (CI) = 0.73, 0.93), it is not yet clear whether the results are sufficient to support clinical decision-making.
Highlights
The purpose of the present work is to develop a portable and autonomous device for older people to self-administer the 30-s chair–stand test (CST) at their homes
We studied the feasibility of using the quasi-periodic nature of the distance between a subject’s back and the chair backrest during a 30-s CST to carry out unsupervised measurements based on readings from a low-cost ultrasound sensor
The resulting peaks were considered eligible candidates for sit-to-stand transitions and were further processed to merge peaks closer to each other than a given threshold known as the minimum samples between peaks (MSBP) and to discard peaks smaller than another given threshold known as the minimum subject distance (MSD)
Summary
The purpose of the present work is to develop a portable and autonomous device for older people to self-administer the 30-s chair–stand test (CST) at their homes. CST a physical counting performance assessment tool; of older patients to repeatedly stand up from a 30-s chair, by is the number of times in particular, it measures lower-limb strength [1]. It does so by quantifying the ability of older patients they stand up over thirty seconds [1]. A successful aging path will delay the onset of disability as late in life as possible It is still not clear whether the results are good enough to make any clinical decisions based on the sensor outcomes
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