Smart speaker services like Amazon’s Alexa have shown that they can be adapted to monitor the breathing of babies, and recent development has enabled them to detect heartbeats without contacting the skin.
“Heart rhythm disorders are actually more common than some other well-known heart conditions. Cardiac arrhythmias can cause major morbidities such as strokes, but can be highly unpredictable in occurrence, and thus difficult to diagnose,” explained co-senior author Dr Arun Sridhar, assistant professor of cardiology at the UW School of Medicine. “Availability of a low-cost test that can be performed frequently and at the convenience of home can be a game-changer for certain patients in terms of early diagnosis and management.”
Instead of listening to the heartbeat, the smart speaker emits a continuous sound which bounces off the patient’s body. Changes in the received sound are associated with motions in the body from a heartbeat.
“The motion from someone’s breathing is orders of magnitude larger on the chest wall than the motion from heartbeats, so that poses a pretty big challenge,” said lead author Anran Wang, a doctoral student in the Allen School. “And the breathing signal is not regular so it’s hard to simply filter it out. Using the fact that smart speakers have multiple microphones, we designed a new beam-forming algorithm to help the speakers find heartbeats.”
Beam-forming is a technology where an array of emitters or receivers can change the direction in which a signal is emitted or received. Applications of such technology include directing sound only in one direction, such as a person watching TV while another wants quiet while they read,
Much in the way AI systems sort out sounds to identify human speech, the algorithm developed by the team can pick up heartbeats. As this does not produce the usual peaks seen in heartbeat monitors, this also requires processing the heartbeat further to extract the inter-beat interval.
“With this method, we are not getting the electric signal of the heart contracting. Instead we’re seeing the vibrations on the skin when the heart beats,” Mr Wang said.
The researchers tested their prototype smart speaker system on 26 healthy participants and 24 patients with hospitalised with a variety of cardiac conditions. The team compared the smart speaker’s inter-beat interval with one from a standard heartbeat monitor. Of the nearly 2,300 heartbeats measured for the healthy participants, the smart speaker’s median inter-beat interval was within 28 milliseconds of the standard monitor. With cardiac patients, the median inter-beat interval measured by the smart speaker was within 30 milliseconds of the standard.
The technology is currently set up for spot checks; a person concerned about their heart rhythm could sit in front of a smart speaker for a reading. In the future, the researchers hope that the system could be set up to monitor heartbeats for long periods, such as when they are sleeping, helping to diagnose conditions like sleep apnoea.
Source: Medical Xpress
