Self-Rated Distress Related to Medical Conditions is Associated with Future Crashes or Traffic Offences in Older Drivers

Ageing is associated with the development of medical conditions, both acute and chronic. The aim of this study was to determine whether medical factors were associated with subsequent self- and officially-reported crashes and traffic offences in a group of cognitively healthy older drivers. We surveyed medical conditions, medications taken for these conditions, and the amount of subjective distress associated with medical conditions in a group of 56 drivers aged 72-85 years for a period of 24 months. We also compared exposure to driving at baseline to the number of crashes or offences at 24 months. We found no relationship between the number of medical conditions or medications taken and whether a participant had a crash or offence. However, those who reported more subjective distress associated with their condition/s were more likely to have a crash or offence during the study period. Drivers who had a crash or offence also had a higher mean driving exposure. However, there was no relationship between reported distress and driving exposure which indicates that these may be independent risk factors for experiencing a crash or traffic offence

Driving Assessment and Subsequent Driving Outcome: A Prospective Study of Safe and Unsafe Healthy Driver Groups

Older drivers are an increasingly numerous section of the population who are often targeted for driving assessment. Little is known as to whether onroad driving assessments result in an older driver population who have fewer negative driving events. Fifty-eight healthy older drivers (mean age 77, range 71- 84, no diagnosis of neurological disorder), completed a non-enforced on-road driving assessment and detailed sensory-motor and cognitive testing. Selfreported and official data regarding crashes and traffic offences were collected for both the five years prior to the on-road assessment, and the 12 months following in order to determine whether those who received a Fail score on the on-road assessment had higher rates of negative driving events than those who passed (43 passed, 15 failed). No increase in adverse outcomes was found either retrospectively or prospectively for those who failed the on-road assessment. Similarly there were no significant differences in cognitive, sensory-motor, and demographic variables between those who passed and failed. Healthy older drivers who failed the on-road assessment did not show evidence of poorer driving behaviour even at the level of descriptive statistics

Prediction of Driving Ability in Healthy Older Adults and Adults with Alzheimer’s Dementia or Mild Cognitive Impairment

Normal ageing is associated with decline in visual, cognitive, and physical functioning, with concurrent increases in the incidence of chronic medical conditions, including cognitive disorders. Determining when age-related changes have adversely affected a person’s ability to drive safely is a complex task, particularly when cognitive disorders such as mild cognitive impairment and dementia are present. The aim of this research was to assess the utility of a number of off-road measures in predicting Pass and Fail outcomes for older drivers on a blinded on-road driving assessment with a driving specialist occupational therapist and a driving instructor, which is considered the ‘gold standard’ measure of driving ability. The off-road measures included standardized cognitive tests, computerized sensory-motor & cognitive tests, medical conditions, and personality measures. The research project comprised three studies. In Study 1 (Healthy Older Drivers study), 60 drivers with no diagnosed cognitive disorder (‘cognitively-unimpaired’), aged 70-84 years (mean age 76.7, 50% male), completed standard cognitive tests, computerized sensory-motor and cognitive tests (SMCTests™), and measures of personality. Results were used to form classification models for on-road assessment Pass and Fail outcome. Sixteen participants failed the on-road assessment. A backwards stepwise binary logistic regression model selected a measure of executive function and a computerized measure of visuomotor planning and coordination as the best predictors. Following leave-one-out cross-validation, this model was estimated to correctly predict 60% of an independent group of cognitively-unimpaired older drivers into on-road Pass and Fail groups. In Study 2 (Healthy Driver Follow-up study), 56 participants from the Healthy Older Drivers study were followed for 24 months using annual telephone interviews to assess driving behaviour, driving attitudes, medical conditions, and the occurrence of crashes and receipt of traffic offences. Official data regarding crashes and traffic offences were also obtained. The aim was to determine whether either the on-road Pass/Fail classification or the off-road measures could predict subsequent crashes and offences. Failing the on-road assessment was not associated with higher crash or offence rates and there were only two baseline measures that predicted crashes or offences (i.e., distance driven at baseline testing and, paradoxically, a lower error score on a measure of visuomotor planning and coordination). However, drivers who reported more distress associated with their medical condition(s) were more likely to have had a crash or offence at 24 months. The outcomes of the Healthy Older Drivers and Healthy Driver Follow-up studies suggest that there is little value in off-road or on-road assessment of cognitively-unimpaired older drivers due to the weak relationship with future negative driving outcomes. However, distress associated with medical conditions may be a useful measure. Study 3 (Dementia and Driving study) recruited a sample of 60 driving assessment centre referrals with mild cognitive impairment or Alzheimer’s dementia. These participants, aged 58-92 years (mean age 77.9, 60% male), performed a computerized battery of sensory-motor and cognitive tests and a formal blinded on-road driving assessment. A backwards stepwise binary logistic regression model selected measures of reaction time and movement speed of the upper limbs, visuomotor planning and coordination, and sustained attention. Following leave-one-out cross-validation, this model was estimated to correctly predict 68% of an independent group of drivers with mild cognitive impairment and Alzheimer’s dementia into on-road Pass and Fail groups. A subsample of 32 participants completed additional standard cognitive tests and provided information on medical conditions. A binary logistic regression model in this subsample was formed which selected measures of verbal fluency, the presence of heart disease, and a comprehensive cognitive screen. Following leave-one-out crossvalidation, this model would be expected to correctly classify 75% of an independent group of drivers with mild cognitive impairment and Alzheimer’s dementia into on-road Pass and Fail groups. The three measures in this model could be performed in around 35-50 min in a primary health setting. It is concluded that off-road and on-road assessment of older drivers with no diagnosis of cognitive or neurological disorder is an inaccurate and inefficient use of driving assessment resources, both for the prediction of on-road driving performance and for predicting future crashes and traffic offences. The Dementia and Driving study found a model comprising three measures that could be performed in a primary health setting with reasonable accuracy for correctly classifying people with mild cognitive impairment and Alzheimer’s dementia who go on to Pass and Fail an on-road driving assessment

On-road driving assessment errors associated with pass and fail outcomes for older drivers with cognitive impairment

Summary: Most on-road assessments do not make use of standardized scoring to determine driver safety. The current study sought to find a subset of driving errors that were related to on-road Pass and Fail outcomes in a group of 60 older drivers with cognitive impairment, and that were also considered important contributors to a Fail outcome by the driving specialist occupational therapist who administered the assessment. A number of useful errors were found that suggest that even a non-standardized driving assessment could incorporate a short list of driving errors that may assist in the determination of driving ability