Researcher and emergency physician Brian Suffoletto studied 22 adults between the ages of 21 and 43, and gave volunteers a vodka drink with enough alcohol to produce a breath concentration of 0.2%. In the United States the legal drink drive limit, based on blood alcohol concentration per grams of alcohol in 100 ml of blood, is 0.08%.
Participants had an hour to finish the alcohol, and then had their breath alcohol concentration analyzed hourly over seven hours as they performed a walking task, walking in a straight line for 10 steps, before turning around and walking back 10 steps.
Researchers secured a smartphone to the participants’ lower back with an elastic belt. Using an app to record accelerometer data, the phones then measured acceleration, side-to-side, up-down and forward and backward motions while participants walked.
Some 90% of the time, researchers were able to use changes in gait detected by the phone sensors and the app to identify when a person’s blood alcohol limit exceeded 0.08%.
“This controlled lab study shows that our phones can be useful to identify ‘signatures’ of functional impairments related to alcohol,” Suffoletto, who was with the University of Pittsburgh School of Medicine when the research was conducted and is now with Stanford University School of Medicine’s Department of Emergency Medicine, said in a statement.
“We have powerful sensors we carry around with us wherever we go,” Suffoletto said. “We need to learn how to use them to best serve public health.
“I lost a close friend to a drinking and driving crash in college,” Suffoletto added. “And as an emergency physician, I have taken care of scores of adults with injuries related to acute alcohol intoxication. Because of this, I have dedicated the past 10 years to testing digital interventions to prevent deaths and injury related to excessive alcohol consumption.”
Alcohol, a central nervous system depressant, reduces brain function and impairs thinking, muscle coordination and reasoning, which can affect a person’s ability to drive a vehicle safely. According to the National Highway Traffic Safety Administration, drunk-driving crashes in the United States claim more than 10,000 lives a year.
Researchers say that the study, published Tuesday in the Journal of Studies on Alcohol and Drugs, is a “proof-of-concept study” that “provides a foundation for future research on using smartphones to remotely detect alcohol-related impairments.”
The team are planning further research with participants carrying phones in their hands and pockets.