Accuracy of the DriveABLE cognitive assessment to determine cognitive fitness to drive

Objective

To evaluate the accuracy of the DriveABLE In-Office cognitive assessment in predicting cognitively impaired drivers’ performance on the DriveABLE On-Road Evaluation (DORE).

Design

Retrospective study comparing data from DriveABLE In-Office cognitive assessment outcomes with DORE outcomes.

Setting

Nineteen of the locations in North America providing the DriveABLE assessment between the years 2007 and 2010.

Participants

Database records from 3662 patients (2639 men, mean age 74.1 years, range 18 to 99 years of age; 1023 women, mean age 73.5 years, range 18 to 94 years of age) with suspected or confirmed cognitive impairment. All patients were referred for DriveABLE evaluation and received both the In-Office cognitive assessment and, regardless of the In-Office test results, the DORE. This is a subset of the database because typically the DriveABLE In-Office cognitive assessment serves as the cognitive assessment and only those whose results are in the indeterminate range go on to complete the road test (ie, DORE).

Main outcome measures

Accuracy of the In-Office assessment for predicting the outcome of the DORE.

Results

For the total sample, the error rate for predicting actual performance on the road test was 1.7% for pass predictions and 5.6% for fail predictions. Notably, these low error rates were consistent across the 4 years. On the basis of performance on the In-Office cognitive assessment, pass or fail decisions could have been made for more than half of the referrals, reducing the need to take dangerous drivers on the road and reducing the cost of the assessment process for patients and the system.

Conclusion

The accuracy of the DriveABLE In-Office cognitive assessment was evaluated in the context of normal clinical referral processes, with a large sample of referrals during a 4-year period and from multiple sites. The high and stable accuracy rates provide the evidence physicians need to be confident in using the recommendations from the DriveABLE cognitive evaluation to assist them in making evidence-based decisions about their patients’ ability to continue driving.