TY - JOUR
T1 - Portable Ultrasound-Based Device for Detecting Older Adults´ Sit-to-Stand Transitions in Unsupervised 30-Second Chair-Stand Tests
AU - Cobo, Antonio
AU - Villalba-Mora, Elena
AU - Hayn, Dieter
AU - Pérez-Rodríguez, Rodrigo
AU - Sánchez-Sánchez, Alberto
AU - Bernabé-Espiga, Raquel
AU - López-Diez-Picazo, Andrea
AU - Sánchez-Sánchez, Juan-Luis
AU - Moral, Cristian
AU - Rodriguez-Mañas, Leocadio
PY - 2020
Y1 - 2020
N2 - 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 e ect of outliers, likely produced because older people tend to produce more
motion artefacts and, thus, noisier signals. While the intra-class correlation coe cient (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 su cient to support clinical decision-making.
AB - 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 e ect of outliers, likely produced because older people tend to produce more
motion artefacts and, thus, noisier signals. While the intra-class correlation coe cient (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 su cient to support clinical decision-making.
KW - frailty syndrome; sit-to-stand; 30-s chair stand test; ultrasound; signal processing
KW - frailty syndrome; sit-to-stand; 30-s chair stand test; ultrasound; signal processing
U2 - 10.3390/s20071975
DO - 10.3390/s20071975
M3 - Article
SN - 1424-3210
JO - Sensors
JF - Sensors
ER -