Smartphones might soon be able to tell if somebody is drunk, even if the phone user doesn't know the fact.
Brian Suffoletto, now from Stanford University in California and his colleagues from Pittsburgh University in Pennsylvania, wanted to detect changes in movement patterns when people are drunk from the accelero-meters that are embedded in most smartphones.
Suffoletto and his team recruited 22 volunteers and gave a mixed drink with enough vodka each hour for a 0.2 percent breath alcohol content well above the 0.08 legal US driving limit.
Then a smartphone fastened to the lower back of each participant. The volunteers were breathed every hour for the next 7 hours and then requested that they walk ten steps straight and turn around, and then walk 10 steps back.
More than 90 % of the time, the scientists could accurately predict when breath alcohol concentrations are higher than 0.08% using changes in the gait, measured by an accelero-meter on their smartphone.
Suffoletto says it is a next step to determine whether similar accuracy can be achieved when the telephone is positioned in various positions , for example, when held in the hand or pocket of a person.
"To people who want an alert when signs of impairment are being shown, it could be used," Suffoletto says. Previous research by his team has found that people do not understand that they're affected by drunkenness up to 50 % of the time.
"It may alert people who can not recognise the impairment, and prevent them when they are [drunk] from driving their car," he says.
As data relating to the use of smart phones and sensors, including accelero-meters, can be collected by third persons to see if the user of a smartphone has drunk, Suffoletto says.
"If anyone would like to do the work and analyse it, they could probably find out about change in walking patterns," he says.
But Suffoletto says "would be a leap" to find somebody poisoned on their way alone without any more evidence.