Effect of Auditory Psychometric Tasks and Low Alcohol Concentrations on the Useful Field of View

Abstract

 

Purpose:

 

Useful Field of View (UFOV) assessment is a valid and reliable index of driving performance and safety. Our goal was to investigate the effects on the UFOV of 1) auditory psychometric tasks that simulate the distraction effect of a hands–free cell phone, and 2) low alcohol concentrations.

 

Methods:

 

Thirty–seven healthy vehicle drivers aged 22±3 were subjected to a computer version of the UFOV test in two separate sessions undertaken according to a counterbalanced within–subject design. The two sessions: an "alcohol session" (breath alcohol concentrations 0.15 – 0.25 mg litre^–1) and "sober session", were conducted both while undertaking or not undertaking a psychometric test, the Paced Auditory Serial Addition Test (PASAT). In each session, the subjects performed three UFOV subtests: stimulus identification, divided attention, and selective attention. Scores were based on processing speed as the time taken to identify a central target and the location of a peripheral target. Each subject was instructed to concentrate on the PASAT while taking the UFOV test.

 

Results:

 

UFOV scores for the three subtests were affected when the PASAT was simultaneously performed (P < 0.01) in both the sober and alcohol sessions (Table 1) in that longer times were required to complete each task. UFOV test results were, however, not significantly affected by a low alcohol concentration. Percentages of correct responses and lapses in the PASAT were significantly (p<0.01) lower and higher, respectively, while taking the UFOV test. Table 1. Means and standard deviations obtained in the Useful Field of View (UFOV) test expressed as time in ms.  

 

Conclusions:

 

A moderate auditory task significantly affects a subject’s performance in the UFOV. According to UFOV risk categories our results suggest that using a hands–free cell phone while driving may lead to a "low–to–moderate" crash risk. UFOV scores were nevertheless unaffected by alcohol concentrations.

 

Keywords: visual search • clinical (human) or epidemiologic studies: risk factor assessment • space and scene perception