Your smartphone may be able to tell if you’re drunk by analysing your walk

  • Researchers have found a novel way to gain real-time information about alcohol intoxication
  • The technology can tell, with 90% accuracy, whether someone has had too much to drink 
  • This can help prevent death and injury related to excessive alcohol consumption

It seems like there is no limit to what you can do with a smartphone these days. To add to that never-ending list is another (positive) aspect: your walk may offer your smartphone clues to whether you’ve had too much to drink.

According to a new preliminary study published in the Journal of Studies on Alcohol and Drugs, your device can detect changes in the way you walk.

Lead researcher Brian Suffoletto, MD, from Stanford University School of Medicine's Department of Emergency Medicine, explained that having real-time information about alcohol intoxication could help people reduce their alcohol consumption, and ultimately prevent drinking and driving, or alert a sponsor in the case of someone undergoing addiction treatment.

Suffoletto conducted the experiment with his former colleagues at the University of Pittsburgh in Pennsylvania.

The test: smartphones on backs

The research team recruited 22 adults between the ages of 21 and 43. The experiment was carried out in a lab where participants received a vodka gimlet (cocktail) which produced a breath alcohol concentration (BrAC) of 0.20%. All participants had to finish their drink within one hour.

They were then monitored hourly for seven hours by having their BrAC tested, and were asked to perform a walking task.

During this task, smartphones were placed on each participant's lower back, secured with an elastic belt. Each participant walked a straight line for 10 steps, turned around, and walked back 10 steps.

What the smartphones measured

The smartphones measured acceleration and mediolateral (side to side), vertical (up and down) and anteroposterior (forward and backward) movements while the participants walked.

The researchers wrote that about 90% of the time, they were able to use changes in gait (manner of walking) to identify when participants' BrAC exceeded 0.08% – the legal limit for driving in the US.

Previous studies found an association between changes in gait, such as swaying side to side, with the number of drinks a person consumed, but this study is the first to find a link between gait and blood alcohol concentration, and breath alcohol concentration levels. 

"This controlled lab study shows that our phones can be useful to identify 'signatures' of functional impairments related to alcohol," Suffoletto said.

Shortcomings that need to be worked on

Of course, no one carries their smartphone on their lower back in real life, so in order for the research results to be more credible, the team is now working on conducting additional research – only this time participants will be tested while carrying their phones in their hands and pockets.

The researchers also acknowledged that their work was a “proof-of-concept” study and a small investigation, but added that it "provides a foundation for future research on using smartphones to remotely detect alcohol-related impairments".

Suffoletto explained that their research is much more than academic to him. "I lost a close friend to a drinking and driving crash in college. 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 injuries related to excessive alcohol consumption."

The emergency physician added that since we carry these “powerful sensors” with us wherever we go, we need to learn how to use them to serve public health.

Alcohol abuse in SA one of the worst worldwide

According to the World Health Organization (WHO), globally, 3.3 million deaths occur every year as a result of the harmful use of alcohol.

Data published by the organisation in 2018 also shows that South Africa has some of the heaviest drinkers globally, with a road traffic death rate (39.7 per 100 000 per annum) double the global rate. 

Adapting interventions and tools such as smartphones will, therefore, be valuable in countries like SA in curbing the consumption of binge drinkers, and potentially deterring people who are above the legal alcohol limit from getting behind the wheel.

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