She may be confused about whether it's an embarrassing court-ordered device intended to control her excessive alcohol consumption or a neat new fashion accessory ("Can Chanel help me out by getting me some stickers to put on it," she tweeted this weekend, "so I can at least wear a chic dress?"), but technology-wise, Lindsay Lohan's new Scram (Secure Continuous Remote Alcohol Monitor) is a nifty bit of kit.
Most drivers under the influence in the US are obliged to give up alcohol as a condition of their sentence or probation order (Lohan is on probation following a drink-driving conviction in 2007). Unfortunately, abstinence is a notoriously difficult condition to verify: blood, breath and urine tests are reliable, but only at the moment they are conducted, which for cost and manpower reasons is rarely. At any other moment, you can be wazzocked.
Hence the emergence of a continuous testing technique known as transdermal alcohol monitoring. This makes use of the fact that, besides being evacuated in breath and urine, a very small proportion of ingested alcohol is also excreted from our bodies through the skin, in sweat ("sensible perspiration") and vapour ("insensible perspiration"). Research has shown the concentration of alcohol in both forms of perspiration rises in line with the amount of alcohol the subject has consumed.
The tamper-proof Scram ankle bracelet our heroine is currently sporting was designed by a US company called Alcohol Monitoring Systems. It works by continuously collecting insensible perspiration from just above the skin's surface, analysing it at very frequent intervals with an in-built electrochemical fuel cell sensor, then sending the results according to a predetermined schedule via a 900MHz radio signal to a remote computer that monitors and interprets the data.
While they cannot measure alcohol consumption with the precision of a blood test, Scrams are now widely accepted – though not, of course, by determined or desperate defence lawyers – as reliable screening devices for detecting "drinking events" that random testing would almost certainly miss. Cheers, Lindsay.
