RITA: Measuring impairment due to alcohol and other drugs at the roadside Brian Tiplady 26 th October 2006

RITA: Measuring impairment due to alcohol and other drugs at the roadside Brian Tiplady 26 th October 2006

Alcohol and Driving Large, effects on accident risk Moderate amounts of alcohol lead to substantial increase in risk Source: Compton et al., 2002

Alcohol Impairments Lab tests show impairment on a wide variety of abilities –Attention –Motor skills –Memory –Comprehension and Judgement Both speed and accuracy of performance are important

Other Drugs and Driving Performance effects easy to demonstrate in laboratory at relevant doses Much harder to demonstrate increased driving risk New methods such as responsibility analysis have increased reliability Now accepted that both prescription and illicit drugs impair driving –Benzodiazepines (when taken during the day, e.g. for anxiety) –Cannabis

The Enforcement Problem An offence to be in charge of a motorised vehicle while unfit to drive through drink or drugs Alcohol is easy to measure in the body, and de facto limits can be set up based on lab evidence Other drugs present different problems –Non-invasive assays generally not adequate –Many drugs and more metabolites –Illicit drugs are much harder to study Drugs other than alcohol, particularly illicit ones, are a growing problem

In practice, for drugs other than alcohol: Only presence or absence of drug can be determined with sufficient reliability Impairment must be demonstrated in the individual case, and cannot be inferred from drug concentrations Present method is Field Impairment Testing The Enforcement Problem

Field Impairment Testing (FIT) Administered by trained Police Officers –Pupil examination –Estimate 30 seconds –Walk heel to toe along a straight line and turn –One leg stand –Finger to nose with eyes shut Effective, but has considerable subjective element Could we do better with objective tests similar to those used in the lab?

Home Office Scientific Branch (HOSDB) Project Development of a portable roadside screening device for driver impairment Battery of tests assessing different aspects of driving ability Tests should be straightforward, consistent, and easy to use by all drivers Short duration (~10 minutes) Sensitive to effects of a wide range of legal and illicit drugs

Home Office Scientific Branch (HOSDB) Project Phase I : Development and evaluation of several prototype systems Phase II : Development of single portable tester at HOSDB, with range of candidate tests Phase III : Evaluation of tester: –Substantial numbers of subjects –Wide age-range –Variety of drugs (alcohol, prescribed, illicit) Main target is drugs other than alcohol. Alcohol is useful for evaluation because of its well-documented effects

Phase I: Layout of one tester

Tests in one Phase I System Arrow Flankers –Attention in the presence of distracting information Paired Associate Learning –Spatial working memory Length Estimation –Size judgements

Arrow Flanker Test

Evaluations of Prototype Tester 1.Volunteer Study with Alcohol –15 healthy volunteers (8 male, aged ) took part –Low (50 mg/100 ml) and high (80) alcohol showed significant impairment compared to placebo –Impairment to both speed and accuracy

Evaluations of Prototype Tester 2.Field Study at Music Festivals –55 volunteers recruited (30 male, aged 17-45) took part –Drug and alcohol consumption from questionnaire –Cozart® saliva test and breathalyser –Performance on impairment tester

Overall Impairment Index ANOVA EthanolF = 7.36 p<0.01 DrugF = 0.55n.s. InteractionF = 0.17n.s.

Overall Impairment Index Pairwise Comparisons High vs Zero t = 3.58 p<0.001 Low vs Zero t = 0.13n.s.

Arrows Speed Accuracy Red Circles: High Alcohol Open Circles: No and Low Alcohol

Conclusions Prototype devices effective both in lab and field settings Impairments to speed and accuracy of performance were detected Overlap between impaired and non- impaired persons may be an issue Concept warrants further development

Phase II: Roadside Impairment Testing Apparatus (RITA) Selection of tests from prototypes (30 mins) –Critical Tracking Task –Length Estimation –Paired Associate Learning –Sustained Attention to Response Test –Choice Reaction Time –Arrow Flanker Task Implementation on Handheld Device at HOSDB –14 cm diagonal screen size –Input via touch screen and push buttons

Phase III Large scale evaluations –N of subjects in the 00s –Wide range of ages Alcohol evaluation study –Recruitment complete Study/studies on other drug classes Test selection for final ten minute battery

Phase III Alcohol Evaluation Carried out at Royal Infirmary, Edinburgh 120 volunteers spread evenly across age-bands 18-24, 25-30, 31-40, 41-50, 51-60, Three sessions: one dose-finding and two main Dose of alcohol to take them to a maximum blood alcohol concentration of 90 mg/100ml –Sufficiently well-tolerated –Most people unfit to drive at this concentration RITA and FIT carried out over next 2 hours Taxi home at end of session

Phase III Key Dates 2005/6 22 nd November: Phase III presented to Government’s Science and Technology Committee 1 st December: Protocol submitted to ethics committee 4 th December: Article in New Scientist 25 th January: Recruitment started 4 th April: Article on study in local paper 7 th September: Sessions completed Ongoing: Data review and analysis

Recruitment Initially by newspaper advertisement Posters in waiting rooms, places of work Flyers distributed – carryouts were particularly effective Word of mouth became increasingly important as study went on

Recruitment

Summary and Conclusions Once sensitivity to alcohol is established, work with other drugs may be initiated Opportunity both to improve enforcement and to obtain more detailed knowledge of drug effects on driving skills Persuasion is as important as enforcement

T : M : E : W: Brian Tiplady: Contact Information Thanks to: University of Surrey: Andria Degia Julia Boyle HOSDB: Philip Dixon University of Edinburgh Gordon Drummond Stephanie Dodds Caroline Maciver Clinical Research Facility, Jean Antonelli Edinburgh Sharon Cameron Finny Paterson

Brian Tiplady: Contact Information