A Pilot Study to Test Multiple Medication Usage and Driver Functioning (Report)

This study explored the relationship between older drivers who take multiple medications, (polypharmacy) and their driving functioning. A patient-level administrative claims database containing prescription information and E-codes identifying the incidence of motor vehicle injuries was mined, yielding combinations of drugs that became inclusion criteria in a field study of driver performance among 44 older adults (ages 57 to 89; mean: 79). Driving performance evaluations by an occupational therapist/certified driving rehabilitation specialist, a brake response time measure, and functional screening measures were conducted for the study sample, whose drug profiles were documented through a brown bag review by a licensed pharmacist. The relationship between medication usage and each of these outcome measures was examined in descriptive data summaries and regression analyses. The driving evaluations were carried out in a dual-brake vehicle also equipped with speed sensor (OBD-2), GPS logger, and two miniature video cameras (drivers face and forward road views) plus digital recorder. A sub-sample allowed the same instrumentation package to be installed in their private cars for a week of independent driving; this supported an analysis of within-subject variability in driving behavior during a formal driving evaluation versus independent driving.