Assessing Novel Orthostatic Vital Signs with a Wearable Sensor

Orthostatic hypotension (OH) is a reduction in blood pressure and cerebral blood flow upon standing. Presenting in nearly 30% of older adults, OH is associated with increased fall risk and other co-morbidities. The clinical standard for monitoring OH, a blood pressure (BP) cuff, fails to capture initial orthostatic hypotension (IOH) and rapid hemodynamic changes during orthostasis. In contrast, cerebral blood flow velocity (CBFV) and continuous BP requires costly instrumentation unsuitable for home monitoring. As result OH is often underdiagnosed and poorly managed. This paper proposes a novel method for monitoring OH using TRACE, a wireless earlobe sensor that quantifies orthostatic hypovolemia (OHV), postural orthostatic tachycardia (POT), and motion during a standup test. To our knowledge, OHV is a novel biometric that may be correlated with dizziness upon standing. It is extracted using a Savitzky-Golay filter algorithm with a 99% success rate. A proof of concept study on 101 older adults show that OHV is significantly different between symptomatic and asymptomatic individuals (p-value=0.0002). TRACE provides a promising, non-invasive method to remotely monitor OH in elderly individuals, which can help reduce the risk of falls and ultimately improve patient outcomes.