June 10 (UPI) -- Scientists in Japan have tweaked a pair of commercial earmuffs to non-invasively measure a person's blood alcohol level.
The technology -- described in a proof-of-concept study published Thursday in the journal Scientific Reports -- works by measuring ethanol vapors released through the skin of the wearer's ears.
"For stable monitoring of transcutaneous gas, finding a body part with little interference on the measurement is essential," researchers wrote in their paper. "In this study, we have investigated the possibility of external ears for stable and real-time measurement of ethanol vapor."
To test the concept, the researchers integrated an ethanol vapor sensor into commercial earmuffs.
When the sensor detects the presence of ethanol, a light is triggered and the sensors measure the concentration of ethanol in the vapors.
To test the technology, researchers had three male volunteer don the earmuffs while slowly consuming alcoholic beverages for a little over two hours.
During the two-hour period, the researchers regularly captured breathalyzer readings from the three study participants.
The tests results showed both the sensors in the earmuffs and breathalyzer measured similar changes in ethanol concentration over the course of the two-hour experiment.
Studies have previously confirmed a stable relationship between blood alcohol content and the concentration of ethanol released in exhaled vapors.
"These findings suggest the suitability of the external ear for blood ethanol monitoring," researchers concluded.
The researchers plan to adapt the new technology to measure the concentrations of other volatile organic compounds in human blood.
In the future, the earmuffs may also be used to screen for diseases or assess a person's metabolism, they said.