The Traffic Sign Recognition Test (TSRT) is used to study differences between 37 dementia patients (mean age 71.1 years) who continued to drive and 47 normal elderly volunteers (mean age 70 years). Each group was tested with the TSRT similar to that used for licensing in the state of Indiana. The differences in total number of signs correctly identified was determined using the Wilcoxon Rank Sum Test. The difference between groups of each individual sign recognition was determined using a Chi Square test. The affected group was also tested with a neuropsychological battery (NB) to measure skills though to be needed for driving. Drivers with dementia correctly identified 5.95 of the 10 traffic signs as compared to the normal elderly subjects who correctly identified 8.77 total signs. The "Slow Moving Vehicle" sign provided the largest difference between the 2 groups: demented drivers correctly identified the sign 39% of the time, compared with 89% in the normal subjects. Only 76% of the demented drivers correctly identified a stop sign compared with 98% of the normal subjects. The percentage of correctly identified signs on the TSRT also correlated with several tests in the NB. Drivers with dementia who continue to drive perform worse on traffic sign recognition than normal elderly drivers. (A)
Abstract