Objective: To identify factors in a medical examination that distinguish convicted older drivers with traffic violations from other drivers.
Design: Matched case-control study.
Setting: Two countries in Sweden.
Subjects: Thirty-seven drivers older than age 65, whose driving licenses have been temporarily suspended, each matched to one control subject based on age, sex, type of driving license, year of first license, living area, educational level, and annual distance driven.
Measurements: Case and control subjects were compared with respect to medical history, medication use, blood tests, drawing and memory tests, Mini-Mental State Examination, medical status findings, visual acuity, and brain imaging procedures.
Main results: The group of drivers with suspended driving licenses did not differ from matched controls with respect to visual acuity or presence of cardiovascular diseases. However, persons with suspended driving licenses were more likely than control subjects to have suspected or mild dementia (P < .010) and to perform less well on two easily administrated screening tests: copying a cube (P < .010) and 5-item recall (P < .010). Case subjects with crashes had significantly more cardiovascular diseases than case subjects with other moving violations (P < .050). These case subjects with crashes also had significantly more cognitive impairments than control subjects without crashes as shown by a higher clinical dementia rating score (CDR) (P < .001), lower score on the Mini-Mental State Examination (MMSE) (P < .050), and lower level of performance in the copying task (cube) (P < .050) and 5-item recall test (P < .010). They also had evidence of greater cognitive impairment than those case subjects with other moving violations.
Conclusions: Visual acuity and common medical examination did not distinguish convicted older drivers with crashes or other moving violations from controls. There was evidence that even mild cognitive impairment contributed to the risk of losing a driving license because of crashes.