Editor – I read the article entitled “Leukoaraiosis, a common brain magnetic resonance imaging finding, as a predictor of traffic crashes” with great interests.1 The authors suggested that the persons with multiple and large multiple subcortical leukoaraiosis (LA) significantly involved in any traffic crashes and, in particular, crashes at crossroad. Because wide cognitive impairments including decline of attentive abilities have been reported to be associated with LA, the drivers with asymptomatic LA tend to make a collision.
Recently in Japan, following to the increase of aging, the numbers of collisions caused by elderly drivers is rapidly growing. The Revised Road Traffic Law restricted the drivers who are aged 70 and above have to attend a special course for safety driving at the time of license renewal. Furthermore, the Cognitive Impairment Screening Test for Senior Drivers for aged 75 and above was installed in June 2009. The test is consisted of main 5 questions as follows: write the year, month, date of the day; write the sown 5 alphabets in reverse order; after shown 16 drawings, remember the objects and write as much as recalling; after obtaining the hints for the objects shown in the previous question, further recall and write the objects; draw a clock suggesting specific time. Based on the test results, the most appropriate course will be given to each senior driver. If a driver highly suspected as cognitive impairment commits a specific violation (i.e., ignoring a stop signal) during a certain period before and after the time of license renewal, the person must take an additional medical examination. If necessary, the police revoke or suspend the driver’s license.
However, the manuscript suggests that nearly 90% of persons with multiple subcortical LA and 75 % of those with large multiple subcortical LA are less than 70 years-old. Although the Japanese government has tried to reduce the vehicle collisions by drivers with cognitive impairment, present measures are not applied for the most of drivers with asymptomatic LA. Therefore, the physicians have to conduct the drivers with multiple LA to receive the cognitive impairment test and driving skill test. The physicians have responsibility for preventing vehicle collision due to the driver’s brain lesions.