Driving Performance in Obstructive Sleep Apnoea: Does Vulnerability Resolve with CPAP Treatment [Oral Presentation]

Introduction: Estimates suggest that OSA may be a contributing factor in up to 50,000 motor vehicle accidents per year in Australia alone. We have demonstrated that OSA patients are more vulnerable than healthy controls to sleep restriction and alcohol, resulting in impairment to simulated driving performance in the mid-afternoon. While CPAP is considered the gold standard treatment for OSA, many patients demonstrate incomplete recovery in some neurocognitive and subjective domains. The aim of this study is to determine if vulnerability to sleep restriction and alcohol is resolved following 3 months of CPAP treatment. Methods: To date, 8 OSA patients (7m, 1f; mean[sd]: age = 53.9[15.2]y; BMI = 35.5[11.1]kg/m2 ; RDI = 76.0[19.2]/hour), and 8 healthy controls (6m, 2f; age = 51.4[10.3]; BMI = 23.7[2.3]; RDI = 6.8[2.8]/hour) have completed a 90-minute mid-afternoon simulated driving task (AusEd) following normal (8h) and restricted (4h) sleep, and alcohol (BAC 0.05 g/dL) conditions both before and after a 3 month-period including CPAP treatment in the patient group only (CPAP used >4hrs on 86.0 [16]% of nights). Results: These preliminary data show significant pre-treatment effects of group, condition (p < 0.05), time on task and group ¥ condition interactions, indicative of greater vulnerability to sleep restriction and alcohol in patients vs. controls (p < 0.05). These effects appear to be reversed following treatment. Conclusions: Preliminary findings suggest that 3 months of CPAP treatment improves driving performance and removes the vulnerability effects to sleep restriction and alcohol. However, further data are required to more firmly establish these effects, and to investigate the potential influence of treatment compliance. Support: We acknowledge the support of NH&MRC project grant #390400. We also thank the AusEd driving simulator developers.