Investigation into the suitability of a portable psychometric device to be used in the field: An illicit drugs field investigation

Rationale: Driving performance is easily disrupted as a direct consequence of the use of alcohol, licit and illicit drugs. The use of such drugs has a high degree of correlation with increased accident risk. Europe wide research projects into drugged driving have called for the development of a portable objective device capable of screening those impaired through drug use which can be used at the roadside. Objective: This study investigated the cognitive and psychomotor performance of a cohort of polydrug drug users in field conditions. Volunteers completed a psychometric test battery on a hand held device in music festival conditions. The test battery comprised a critical tracking task (CTT) and a sustained attention to response task (SART). Volunteers also took a breathanalyser and provided a saliva sample for a DOA screen. Results: On the CTT significance was observed for tracking error following response to a peripheral stimulus in the high alcohol (>80 mg/100 ml) illicit drug group (p = 0.0090) and approached significance for the low alcohol (<80 mg/100 ml) illicit drug group (p = 0.088). For the SART, incorrect presses to the target stimulus was impaired for volunteers in both the low (<80 mg/100 ml) alcohol illicit drug group (p = 0.0080) and the high alcohol (>80 mg/100 ml) illicit drug group (p = 0.0415). Discrimination analysis demonstrated that the impairment device was able to discriminate between those individuals who had consumed neither alcohol nor drugs (94.12%), those in the low alcohol drug group (46.67%) and those in the high alcohol drug group (60.00%). Conclusion: It is possible to derive an impairment ratio. Further research will demonstrate whether this device could significantly contribute to drug driving detection and road traffic safety.