In a new proof-of-principle study published in Scientific Reports, researchers from Japan have developed a non-invasive way to measure blood alcohol levels using a device that resembles earmuffs.
Some might wonder how you would test alcohol levels using a device placed over your ears – and to answer that question, we have to turn to something called Volatile organic compounds (VOCs). Our bodies release hundreds of different VOC vapors on a daily basis. Some of these vapors are related to our metabolism, while others are a result of a disease process taking place in the body which can increase the release of different VOCs from the skin. This is the reason why some people who become ill sometimes have a distinct smell, it comes down to changes in the secretions of these VOC vapors.
Now, you may also know if you have ever been on a night out binging on the drink that alcohol does something similar. Remember that time you woke up after a big night getting wrecked, smelling of alcohol? Yes, as levels of ethanol rise in the bloodstream, ethanol vapor is also released by the skin.
Knowing this, the authors of the new study wanted to develop a non-invasive way to detect ethanol concentration by measuring the amounts of ethanol vapor released by the ears. They chose the ears as a body part to limit interference from things such as sweat glands, and so Kohji Mitsubayashi and the team modified a version of commercial earmuffs and fitted them with a sensor capable of detecting ethanol vapor.
The sensor fitted in the earmuffs releases light every time it detects ethanol vapor, and provides a mechanism to calculate the level of ethanol in the blood. The more intense the light, the higher the ethanol concentration.
The researchers then set out to continuously monitor the ethanol vapor released by the ears of three male participants who had consumed alcohol with a concentration of 0.4 grams per kilogram (0.014 ounces per 2.2 pounds) of body weight for 140 minutes. At the same time, they also assessed ethanol concentrations in the participant's breath using a different ethanol sensor, as well as a reagent that changes color when in contact with ethanol to compare the proof of concept device with other ethanol detection methods.
Their findings showed that the device could detect ethanol concentration from the ears, and those measurements were similar to the breath tests they had done in all three participants, suggesting the device could be a new alternative way to detect ethanol by screening the ears.
Furthermore, the researchers showed that the highest level of ethanol they detected from the ears was double that previously detected by alternative methods that recorded ethanol levels from the skin of the hands, suggesting it might be a more accurate alternative to breathalyzer than hand skin measurements.
"These findings suggest the suitability of the external ear for blood ethanol monitoring. The monitoring system is potentially applicable to other VOCs [by] changing an enzyme. Using this versatility, we will further investigate external ear-derived VOCs for non-invasive and real-time assessment of metabolisms and disease screening." the researchers concluded in the write-up of their paper.