Chair-Stand Device for the Assessment of Elderly Patients in Risk of Frailty

Frailty is an intermediate state in the ageing trajectory, preceding the onset of disability. It can be assessed via clinical, cognitive, nutritional, and physical performance components, whereas one component of physical assessment is measurement of lower limb strength. We propose a device for measuring lower limb strength based on the 30s sit-to-stand test (30s-STS) in an autonomous environment. The device is based on an ultrasound sensor that is mounted on the backrest of a chair and measures the distance to the back of the patient. A signal processing algorithm was developed with a dataset of healthy subjects and evaluated prospectively with geriatric patients. Results of evaluation show that measurement for geriatric patients is poorer than expected. Thus, we plan to retrain the algorithm with additional geriatric patients, and to study further the complexities of the 30s-STS analysing aspects such as the inter-observer-variability of reference annotations. The new algorithm will be evaluated as part of a clinical trial with 40 elderly patients at their dwelling. The clinical trial will also assess the acceptability of such a device in a home setting.