Brief Neuropsychological Measures to Assess Crash Risk
Background: Practicing primary care physicians often encounter the difficult clinical situation of evaluating the older driver. We wanted to investigate the relation between self-reported driving behavior, neuropsychological measures, and crash risk to inform the development of a test battery that could predict unsafe driving behavior and was feasible for use by primary care physicians.
Methods: This study was a prospective follow-up of 107 drivers aged 65 years and older recruited from a primary care setting in 1995. Tests of attention, visual information processing, spatial orientation, and general mental status were administered at baseline. At baseline and after 2 years of follow-up, patients were asked about their driving history using the driving questionnaire. Risk for reported crashes in the follow-up period was assessed in relation to baseline driving history and measures of cognition.
Results: Baseline self-reports of driving habits and attitudes were associated with an increased risk of reporting a crash after 2 years of follow-up (relative risk ratio = 5.31; 95% confidence interval [CI], 0.63, 44.63). In addition, baseline tests of attention, visual information processing, and spatial orientation were associated with an increased risk of reporting motor vehicle crash at follow-up. For example, respondents with poor performance on the Trail Making Test - part A, were almost four times more likely to report a crash at follow-up (risk ratio = 3.15; 95% CI, 0.76, 13.07).
Conclusion: Although our conclusions are tempered by small sample size, this preliminary study suggests that brief cognitive tests and simple questions about driving habits warrant further investigation as indicators of crash risk with potential utility for assessing older drivers in primary care.
The evaluation of the older driver can be a difficult clinical challenge for the practicing primary care physician. Given the balance between maintaining independence and concern for public safety, at what point should physicians consider that the risk of driving is too great? Whereas clinical recommendations for office-based assessment of at-risk older drivers include static visual screening, auditory screening, Mini-Mental State Examination (MMSE), functional assessment, and review of alcohol use and medications, empirical evidence for these recommendations is limited. For example, total MMSE score and functional status appear to be poorly associated with crash risk. One problem is that standard tests, such as the MMSE, might not accurately assess the perceptual and attentional processes that could be more directly related to driving skill than memory or other tasks. In addition, it is possible that findings from studies conducted in specialty clinics might not generalize to the older drivers seen by the primary care physician.
According to the Global Burden of Disease project of the World Health Organization, motor vehicle accidents will rank third behind heart disease and major depression as a worldwide cause of disability by 2020. Older drivers make up approximately 13% of the current driving population and are the fastest growing segment of drivers. In the United States, 33 million drivers are expected to be aged 65 years and older in the year 2020. Compared with younger adults, the older driver is at a disadvantage because older adults often experience an increase in medical illness, psychopathology, and cognitive changes that influence driving ability and increase the risk of fatality. Despite a high frequency of voluntary adaptations, such as driving less at night and driving shorter distances over familiar roads, the older driver has a higher crash rate per mile driven than any other adult age-group. Older drivers with Alzheimer disease and other dementing illnesses, however, might be unable to assess their driving competency correctly and fail to self-regulate their driving behavior. At the same time, some older drivers, particularly women, might overrestrict their driving. What is desirable would be a history and physical examination protocol that could be administered by the physician or ancillary staff when the question of suitability for continued driving arises.
Several aspects of cognitive and neuropsychological function, such as visual and auditory attention, have been found to correlate with driving performance, but causal inference from cross-sectional studies is limited. When the information is obtained at the same interview, as is done in cross-sectional studies, one cannot be sure whether reports of driving behaviors and previous crashes are influenced by performance on the neuropsychological tests. For example, poor memory can influence both reports of past events and present performance on neuropsychological tests. Prospective studies have considerable advantages when compared with cross-sectional studies in assessing the temporal relation of neuropsychological tests and self-reported driving behavior and crash risk. In prospective studies, the temporal relation is clear. Despite potential problems with prospective studies, such as loss of follow-up as a result of death, refusals, or other reasons, only prospective follow-up studies can shed light on how performance at baseline predicts outcomes of interest.
Because we knew of no prospective studies of driving assessment of older adults from primary care settings, our goal was to investigate the relations between self-reported driving behavior, neuropsychological measures, and crash risk at follow-up so that we could develop a test battery that could predict unsafe driving behavior and that would be feasible for use by primary care physicians. This study was part of a larger project, the goal of which was to develop an assessment protocol that is valid and easy to administer for office-based assessment of driving. We capitalized on baseline assessments conducted in 1995 in one of the primary care practices that participated in the larger project and then obtained reports of crashes after 2 years of follow-up. Our goal was to examine whether performance on the brief neuropsychological assessment conducted in primary care or self-reported driving behavior was predictive of subsequent reports of crashes 2 years later.
Background: Practicing primary care physicians often encounter the difficult clinical situation of evaluating the older driver. We wanted to investigate the relation between self-reported driving behavior, neuropsychological measures, and crash risk to inform the development of a test battery that could predict unsafe driving behavior and was feasible for use by primary care physicians.
Methods: This study was a prospective follow-up of 107 drivers aged 65 years and older recruited from a primary care setting in 1995. Tests of attention, visual information processing, spatial orientation, and general mental status were administered at baseline. At baseline and after 2 years of follow-up, patients were asked about their driving history using the driving questionnaire. Risk for reported crashes in the follow-up period was assessed in relation to baseline driving history and measures of cognition.
Results: Baseline self-reports of driving habits and attitudes were associated with an increased risk of reporting a crash after 2 years of follow-up (relative risk ratio = 5.31; 95% confidence interval [CI], 0.63, 44.63). In addition, baseline tests of attention, visual information processing, and spatial orientation were associated with an increased risk of reporting motor vehicle crash at follow-up. For example, respondents with poor performance on the Trail Making Test - part A, were almost four times more likely to report a crash at follow-up (risk ratio = 3.15; 95% CI, 0.76, 13.07).
Conclusion: Although our conclusions are tempered by small sample size, this preliminary study suggests that brief cognitive tests and simple questions about driving habits warrant further investigation as indicators of crash risk with potential utility for assessing older drivers in primary care.
The evaluation of the older driver can be a difficult clinical challenge for the practicing primary care physician. Given the balance between maintaining independence and concern for public safety, at what point should physicians consider that the risk of driving is too great? Whereas clinical recommendations for office-based assessment of at-risk older drivers include static visual screening, auditory screening, Mini-Mental State Examination (MMSE), functional assessment, and review of alcohol use and medications, empirical evidence for these recommendations is limited. For example, total MMSE score and functional status appear to be poorly associated with crash risk. One problem is that standard tests, such as the MMSE, might not accurately assess the perceptual and attentional processes that could be more directly related to driving skill than memory or other tasks. In addition, it is possible that findings from studies conducted in specialty clinics might not generalize to the older drivers seen by the primary care physician.
According to the Global Burden of Disease project of the World Health Organization, motor vehicle accidents will rank third behind heart disease and major depression as a worldwide cause of disability by 2020. Older drivers make up approximately 13% of the current driving population and are the fastest growing segment of drivers. In the United States, 33 million drivers are expected to be aged 65 years and older in the year 2020. Compared with younger adults, the older driver is at a disadvantage because older adults often experience an increase in medical illness, psychopathology, and cognitive changes that influence driving ability and increase the risk of fatality. Despite a high frequency of voluntary adaptations, such as driving less at night and driving shorter distances over familiar roads, the older driver has a higher crash rate per mile driven than any other adult age-group. Older drivers with Alzheimer disease and other dementing illnesses, however, might be unable to assess their driving competency correctly and fail to self-regulate their driving behavior. At the same time, some older drivers, particularly women, might overrestrict their driving. What is desirable would be a history and physical examination protocol that could be administered by the physician or ancillary staff when the question of suitability for continued driving arises.
Several aspects of cognitive and neuropsychological function, such as visual and auditory attention, have been found to correlate with driving performance, but causal inference from cross-sectional studies is limited. When the information is obtained at the same interview, as is done in cross-sectional studies, one cannot be sure whether reports of driving behaviors and previous crashes are influenced by performance on the neuropsychological tests. For example, poor memory can influence both reports of past events and present performance on neuropsychological tests. Prospective studies have considerable advantages when compared with cross-sectional studies in assessing the temporal relation of neuropsychological tests and self-reported driving behavior and crash risk. In prospective studies, the temporal relation is clear. Despite potential problems with prospective studies, such as loss of follow-up as a result of death, refusals, or other reasons, only prospective follow-up studies can shed light on how performance at baseline predicts outcomes of interest.
Because we knew of no prospective studies of driving assessment of older adults from primary care settings, our goal was to investigate the relations between self-reported driving behavior, neuropsychological measures, and crash risk at follow-up so that we could develop a test battery that could predict unsafe driving behavior and that would be feasible for use by primary care physicians. This study was part of a larger project, the goal of which was to develop an assessment protocol that is valid and easy to administer for office-based assessment of driving. We capitalized on baseline assessments conducted in 1995 in one of the primary care practices that participated in the larger project and then obtained reports of crashes after 2 years of follow-up. Our goal was to examine whether performance on the brief neuropsychological assessment conducted in primary care or self-reported driving behavior was predictive of subsequent reports of crashes 2 years later.
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