Investigation of a Link Between Heart Rate Variability and Frailty in Geriatric Patients Before and After Rehabilitation With Simultaneous Evaluation of a New Camera-based Technology for Measurement of Vital Signs

Frailty is an important geriatric syndrome, which indicates a reduced maximum resilience of patients and their organ system against external stressors. According to Fried's classification, frailty comprises of unintentional weight loss, exhaustion, muscle weakness, slowness while walking and low levels of activity. In geriatric patients, frailty is associated with a higher mortality and morbidity. Moreover, frailty patients are more often dependent on assistance after hospitalisation than non-frailty patients.

During geriatric therapy, geriatric patients are treated with multimodal rehabilitation comprising of activating nursing, physiotherapy, occupational therapy, psychiatric and speech therapy in order to increase mobility and patients' ability to help themselves. Success of rehabilitation measures is measured using the geriatric assessment (e.g. Barthel Index, Timed up and go test, Mini-Mental State Examination, Geriatric Depression Scale, measurement of hand power) at the beginning and end of the therapy. This geriatric therapy including the named geriatric assessment is not study-specific and is not prescribed by a study protocol, but is a routine treatment for frail patients.

Apart from these routinely used tests, recent literature indicated that heart rate variability, which can be easily measured with an ECG, could be an indicator for frailty. Beyond the medical problem whether heart rate variability can be used as a surrogate parameter for frailty, this study also has a technical aspect. In biomedical engineering, non-contact monitoring of vital signs has been an important and promising development in the last decade. Therefore, this study will also investigate if camera-based technologies such as photoplethysmography imaging (PPGI) and infrared thermography (IRT) can be used in a clinical environment for non-contact measurement of vital signs (heart rate, heart rate variability, respiratory rate) in geriatric patients. In this study, monitoring (with conventional and contactless technologies) should not trigger any observable/examining effect, but is merely a means to the end of observing the already existing HRV (and other vital parameters).