In this MEDICA-tradefair.com interview, Prof. Ulf Kulau talks about ballistocardiography and explains how it can deliver insights into the cardiovascular health of astronauts.
Prof. Kulau, why do you plan to monitor the vital signs of astronaut Matthias Maurer onboard the ISS?
Prof. Ulf Kulau: We are studying the ballistocardiography (BCG) technique, which means we measure the motions of the human body generated by the heartbeat. We built a system that enables us to measure the smallest vibrations at low noise. The microgravity environment found aboard the International Space Station (ISS) has no gravitational acceleration as an external factor. This enables us to measure the actual acceleration caused by the heartbeat as a reference.
Our findings will deliver insights into future uses considering that astronauts will spend prolonged time in space as they embark on future missions to the moon and Mars. This will make their returns to earth far more challenging, which is why we need a good and accurate health monitoring system in the future for early problem detection, since absence of gravity changes the physiology of the heart.
Does this also facilitate medical applications on Earth?
Kulau: BCG could complement an electrocardiogram (ECG), for example. An ECG is a common, robust, and efficient method, while the BCG technique could produce a representation of the physiology of the heart. For the latter, we need the space measurements for reference and the option of deducting the influence of gravitational acceleration. We can do this via signal processing.
What kinds of sensors do you use?
Kulau: We use simple acceleration sensors and measure in a low frequency range. Most available sensors – including those used in the medical realm - measure in higher frequency. We measure acceleration at the low milli-G level, so the signal-to-noise ratio is high. We solve this problem by conducting signal processing directly on the sensors. This enables us to register even small accelerations.