The effect of shoulder immobilization on driving performance.

Background: The purpose of this study was to evaluate the effect of sling immobilization on driving performance with use of a driving simulator.

Methods: This is a prospective trial with a cohort of 21 healthy volunteers comparing their driving ability with and without sling immobilization on their dominant (driving) extremity. Multiple variables, including number of collisions, off-road excursions, and centerline crossings, were measured with a validated driving simulator. Trials were separated by 2 weeks to control for "adaptations" to the simulator. Statistical significance was found in collisions between sling and no-sling tests.

Results: The total number of collisions for trial 1 (no sling) was 36 (mean, 1.7 ± 1.2) compared with 73 (3.7 ± 1.6) (P < .01) for trial 2 (sling immobilization). Approximately 70% of participants with upper extremity immobilization were involved in ≥3 collisions; approximately 70% of no-sling participants were involved in ≤2 collisions. There was no statistically significant difference between groups with respect to overall vehicle road position and control.

Conclusion: Sling immobilization of the dominant driving arm results in a decrease in driving performance and safety with respect to the number of collisions in a simulated driving circuit (P < .01). There were no significant differences in driving parameters that are indicative of overall vehicle position and control. The decrease in driving performance with respect to the number of collisions is likely to be related to the effect the immobilized arm has on effectively performing evasive maneuvers during hazardous driving conditions.