The Trail-making Test B and driver screening in the emergency department

Emergency departments (EDs) rarely screen for older driving safety. The Trail-Making Test B (TMT-B) is a neuropsychological test that may predict ability to drive. We sought to examine the driving patterns of older ED patients and the feasibility of screening patients in the ED using the TMT-B.

At a single ED at a tertiary care center, we administered the TMT-B and a survey of health status and driving habits to a convenience sample of adult (age 18 and older) ED patients. We excluded those with altered mentation, critical illness, or language barriers. The TMT-B, scored by the time of first attempt, requires connection of letters and numbers in sequence on paper, and a time > or = 180 s may suggest elevated driving risk. We compared time to complete the TMT-B among ED patients to published norms.

Of 144 patients ages 18 to 95, 95 (72.2%) were current drivers, and 91.4 percent of drivers were able to complete the TMT-B; 47.1 percent of drivers were older (65+), and 88.8 percent of older drivers rated their ability as good or excellent. In multivariate logistic regression, neither TMT-B performance nor being older predicted a recent collision. The mean TMT-B completion time was 66.1 (SD = 36.3, median = 56) s among drivers under age 65 and 117.5 (SD = 79.2, median = 95) s among those 65 or older. Approximately 1.9 percent (95% CI: 0.04-10.2) of drivers under 65 and 14.0 percent (95% CI: 5.3-27.9%) of drivers 65 or older required 180 s or more for the TMT-B. Using unpaired T-tests, study TMT-B times were not significantly different from previously published norms except among 25- to 34-year-olds (79.2 versus 50.7 s; p < 0.05) and 80- to 84-year-olds (223.9 versus 146.8 s; p < 0.01).

Many older ED patients drive, and relatively healthy ED patients are able to complete the TMT-B with results similar to standard nomograms. The TMT-B may prove useful as part of targeted driver screening programs in EDs.