Alcohol and Cognitive Function: Assessment in Everyday Life and Laboratory Settings Using Mobile Phones

Background: Mobile phone (cellphone) technology makes it practicable to assess cognitive function in a natural setting. We assessed this method and compared impairment of performance due to alcohol in everyday life with measurements made in the laboratory. Methods: Thirty-eight volunteers (20 male, aged 18-54 years) took part in the everyday study, completing assessments twice a day for 14 days following requests sent by text messages to the mobile phone. Twenty-six of them (12 male, aged 19-54) took part in a subsequent two-period crossover lab study comparing alcohol with no alcohol (placebo). Results: Everyday entries with 5 or more units of alcohol consumed in the past 6 hours (inferred mean blood alcohol concentration 95 ml/100 ml) showed higher scores for errors in tests of attention and working memory compared with entries with no alcohol consumed that day. Response times were impaired for only 1 test, sustained attention to response. The laboratory comparison of alcohol (mean blood alcohol concentration 124 mg/100 ml) with placebo showed impairment to both reaction time and error scores for all tests. A similar degree of subjective drunkenness was reported in both settings. Conclusions: We found that mobile phones allowed practical research on cognitive performance in an everyday life setting. Alcohol impaired function in both laboratory and everyday life settings at relevant doses of alcohol.