Cognitive Assessment using Mobile Phones
Everyday Assessment of the Effects of Alcohol
Cognitive assessments, such as tests of memory, attention, and reaction time can be set up on mobile phones. This has important advantages:
We carried out a study to evaluate this method, looking at the effects of alcohol consumption. We know from lab studies that alcohol affects performance on a range of tests. We set up a selection of tests on the mobile phone that we expected to be affected by alcohol. Some tests are not well adapted to the small screen on a mobile, but there are plenty of tests that will easily fit. Here is an example:
We recruited 38 volunteers. In this study we gave them phones to use, though in more recent studies volunteers have used their own phones. They carried out assessments twice a day for two weeks. We sent them an SMS message each time we wanted them to complete the tests. The times were randomised so that we would get a good spread of completion times.
Each assessment started with questions about how much alcohol they had consumed in the past 6 h and that day. We used this to divide our assessments into 3 groups:
The main analysis compared SA to NA. For the Number-Pairs test, accuracy (proportion of correct responses) after SA was worse than after NA (comparisons were time-matched). On average the were 10.5% incorrect responses for SA and 4.4 for NA. Performance on the two other tests we used was also impaired
After the two weeks of everyday assessment, volunteers took part in a lab study, looking at the same tests, with alcohol given as a drink containing vodka, which was compared to a matching drink containing no vodka. Doses were calculated to give blood alcohol a bit over the UK legal driving limit. The study used the pharmacological model, where the amount given was pre-determined, the drink had to be consumed in a short time, and dosage was double-blind. In short the typical artificial laboratory situation. In these lab tests, alcohol impaired performance, in particular increasing errors in number pairs from 4.7% to 7.3%. So the effect was a bit smaller in the lab. This was true of the other tests as well.
We did not have a direct measurement of blood alcohol in the everyday part of the study. We estimated this from a previous pub study where we asked drinkers how many drinks they had taken, and also breathalysed them. Using this relationship, we calculated that blood alcohol in our everyday assessments with SA was a bit lower than in the lab sessions. If our estimates are correct, we had a larger effect in everyday assessment with a lower blood alcohol. So while the lab and everyday assessments agree about the type of impairment we see, if anything, the lab studies underestimate the size of the impairment.
The other conclusion from the study was that everyday assessment using mobile phones was a practicable and effective method of measuring cognitive function..
The full reference to the paper is
Tiplady, B., Oshinowo, B., Thomson, J., & Drummond, G. B. (2009) Alcohol and Cognitive Function: Assessment in Everyday Life and Laboratory Settings Using Mobile Phones, Alcoholism Clinical and Experimental Research 33(12) 412-418. Abstract