Dementia and Driving: An Annotated Bibliography [*].

The American Academy of Neurology. Report of the Quality Standards Subcommittee. Practice parameter: risk of driving and Alzheimer's disease (an evidence-based review). Dubinsky RM, Stein AC, Lyons K. Neurology 2000 Jun 27;54(12):2205-11

The Quality Standards Subcommittee used evidence-based review of the medical literature to design practice parameters to help physicians make recommendations about driving in patients with Alzheimer's disease (AD). The authors compared the relative rates of crashes and other performance measurements of driving ability. Studies were divided into the following groups: crash statistics, evaluation of driving performance, and analysis of driving task components.

Driving was found to be mildly impaired in those drivers with probable AD at a severity of Clinical Dementia Rating (CDR) 0.5. This impairment was no greater than that tolerated in other segments of the 'higher-risk' driving population (drivers aged 16 to 21 and those driving under the influence of alcohol at a blood alcohol concentration [less than]0.08%). Drivers with AD at a severity of CDR 1 were observed to pose a significant traffic safety problem from crashes and from driving performance measurements. There is clear evidence that, the risk of crashes increases in patients with AD who continue to drive.

The committee recommends:

* Patients and their families should be told that patients with AD, with a severity of CDR 1 or greater, have a substantially increased rate of accidents and driving performance errors, and therefore should not drive.

* Patients and their families should be told that patients with possible AD with a severity of CDR 0.5 pose a significant traffic safety problem.

* A driving performance evaluation by a qualified examiner should be considered.

* Due to the high likelihood of progression to a severity of CDR 1 within a few years, clinicians should reassess dementia severity and appropriateness of continued driving every six months.

Evaluation of fitness to drive: The physician's role in assessing elderly or demented patients. Kakaiya R, Tisovec R, Fulkerson P. Postgraduate Medicine 2000; 107:229-236

This article addresses the various considerations that are important in assessing and counseling patients, especially the elderly and those with dementia, and offers suggestions for implementing and easing the decision to terminate a patient's driving privileges.

Factors to consider in evaluating fitness to drive include:

* Crash rates per miles driven;

* Modification of driving (fewer miles driven per month, limiting driving to familiar roads, daytime hours, or good weather);

* Driving history which includes getting lost in familiar surroundings, near misses or near crashes, and traffic violation tickets;

* Medications used;

* Impairment of faculties needed for safe driving, for example contraction of visual fields, or decline in resistance to glare;

* The Mini-Mental State Examination (MMSE) provides a rough correlation with on-road results, however, consensus was not reached on the use of cutoff scores;

* On-road testing by a driver's licensing authority may be considered;

* The effects of terminating the patient's right to drive, including depression, should be considered.

Evaluating Driving Performance of Outpatients with Alzheimer Disease. Cox DJ, Quillian WC, Thorndike FP, et al. J Am Board Earn Pract 1998; 11:264-71

This study evaluated driving performance of patients with Alzheimer's disease (AD) and its relation to patient scores on the Mini-Mental State Exam (MMSE). Twenty-nine outpatients with probable AD were compared with 21 age-matched control participants on an interactive driving simulator to determine how the tow groups differed and how these differences related to mental status.

The patients with AD were less likely to comprehend and operate the simulator cognitively. They drove off the road more often, spent more time driving considerably slower than the posted speed limit and less time driving faster than the speed limit. These patients applied less brake pressure in stop zones, spent more time negotiating left turns, and drove more poorly overall. Those patients who could not drive the simulator because of confusion and disorientation (n=10), had lower MMSE scores and drove fewer miles annually. AD patients who had stopped driving also scored lower on the MMSE, but did not perform more poorly on the driving simulator. The computed total driving score correlated substantially with MMSE scores (r = -0.403, P = .011).

Fitness to drive in older drivers with cognitive impairment. Withaar FR Brouwer WH, van Zomeren AH. J Int Neuropsychol Soc 2000 May; 6(4) :480-490

This is a literature review on assessment of fitness to drive in elderly drivers with cognitive impairment. The studies demonstrated that cognitively impaired people as a group performed significantly worse than controls on both neuropsychological and driving measures. A high prevalence of cognitive impairment was seen in older drivers involved in traffic accidents and crashes. Low to moderate correlations were established between neuropsychological test results and on-road driving performance, making it difficult to discriminate between cognitively impaired subjects who are fit or unfit to drive.

The review concluded with a discussion of methodological difficulties in the area of dementia and driving, including participant selection, the choice of neuropsychological tests, and the operationalization of driving performance.

Simulators for assessing driving skills in demented patients. Bylsma FW. Alzheimer Dis Assoc Disord 1997 Jun; 11 (Suppl 1):17-20.

The use of simulators to assess driving abilities in individuals with dementing illnesses is discussed in this review. The key points addressed include: the definition of a driving simulator, the strengths and weaknesses of various types of simulators, and the potential role of using simulators to predict future driving safety.

Cognitive change, medical illness, and crash risk among older drivers: an epidemiological consideration. Wallace RB. Alzheimer Dis Assoc Disord 1997 Jun; 11 (Suppl 1):31-37

Selected issues concerning the natural history of cognitive change among older persons and potential effects on driving safely are discussed in this review. Data are reviewed from large population-referent epidemiological studies that have sought direct association between medical conditions and treatments and crash risk. The review identified several medical risk factors that should be considered along with the assessment of cognitive decline and dementia when evaluating safety issues on older drivers.

Attentional problems and older drivers. Ball K. Alzheimer Dis Assoc Disord 1997 Jun; 11 (Suppl 1):42-47

Research aimed at finding ways to distinguish drivers who may pose a threat to their own safety, as well as the safety of other road users, is discussed in this review. The studies indicated that measures of visual attention and cognitive function have been successful in distinguishing between these groups. The paper also addresses the fact that because visual attention skills can be improved with training, there are important implications for further evaluation of intervention to enhance the skills that underlie safe driving.

The role of selective attention in driving and dementia of the Alzheimer type. Duchek JM, Hunt L, Ball K, et al. Alzheimer Dis Assoc Disord 1997 Jun; 11 Suppl 1:48-56

The relationship between cognitive processes and driving in dementia of the Alzheimer type is discussed in this review. Included are results from several studies that have explored the relationship between neuropsychological test performance and various indications of driving safety. Screening measures are included that emphasize the ability to selectively attend to relevant information and inhibit irrelevant information in order to identify mildly demented individuals who are at risk for unsafe driving.

The demented driver: the doctor's dilemma. Fitten LJ. Alzheimer Dis Assoc Disord 1997 Jun; 11 (Suppl 1):57-61

A discussion of reporting cognitively impaired drivers to the appropriate licensing bodies is presented in this review. The problem of timely and effective screening for the cognitively impaired driver is raised, and alternative approaches to the screening process are discussed.

The 1994 International Consensus Conference on Dementia and Driving: A Brief Report. Johansson K, Lundberg C. Alzheimer Dis Assoc Disord 1997; 11:62-69

In September 1994, the Swedish National Road Administration invited representatives from research groups in North America and Europe to prepare a consensus statement on dementia and driving. Dementia might contribute significantly to the increased crash risk of older drivers. The consensus statement is considered provisional because the field of investigation continues to evolve. The following points are included:

* Individuals with dementing diseases pose a problem to clinicians because many continue to drive after the diagnosis has been made and after experiencing specific difficulties due to impairments.

* Decisions concerning driving aptitude are formed on uncertain grounds. It is difficult to make reliable estimations of the risk of accidents in patients with dementia.

* The precise point in time at which the risk for accidents for patients with dementing diseases becomes unacceptable is yet to be determined.

The Concept of Acceptable Risk

* There is no absolute level of acceptable risk for accidents because it depends on several factors: views on individual freedom versus public safety, access to alternative transportation, and the general traffic environment.

* Among policy-makers the level of acceptable risk will vary considerably in different counties, states, and countries.

* The physician should always inform the patient of a possible increased risk of accidents.

How Cognitive Impairment in Dementia Affects Driving

* Dementing diseases cause impairments of visuospatial skills, attention, memory, and judgment -- important functions for safe driving.

* Visuospatial skills are required for appropriate positioning of the vehicle, estimating distances, and interpreting a current traffic situation and predicting its outcome.

* Selective, divided, and sustained attention are necessary to foresee potential hazards, to deal with competing stimuli at intersections and to maintain optimal alertness on long trips.

* Memory is always impaired in dementia and often language disturbances are found. Intact immediate or short-term memory functions allow the driver to retain information obtained, for example, when looking at the rear-view mirror. Memory deficits that are often combined with visuospatial impairments can contribute to getting lost, thus leading to driving errors and violations. Language deficits may influence the route the driver chooses or anticipated maneuvers regarding traffic signs.

* Impaired judgment applies not only to the driving task, but also to the awareness of deficits, making compensatory behavior possible.

Suggested Decision Process for the Physician Dealing with Cognitively Impaired Driving Patients

A. Information about cognitive function and driving status

* A physician should always be informed of the driving status of the patient, regardless of suspicions of a dementing disease, since some medical conditions and pharmaceutical treatments can also affect driving performance.

* The Mini-Mental State Examination of Folstein et al (1975) may be used as a screening test if there is uncertainty of any cognitive impairment. Consensus could not be reached by the panel on the use of cutoff scores on the MMSE because this instrument does not capture judgement and impulse control. If a cutoff score were to be used, it might take precedence over the physician's qualified clinical judgement, resulting in negative consequences. There is also a risk that all patients with "sufficient" scores would automatically be viewed as safe drivers.

* The physician should determine which cognitive functions are involved. A decline in cognition in combination with other impairments, such as poor vision is of special interest. Physicians should question reliable relatives for additional information when there is a suspicion or confirmed cognitive impairment.

B. Recommended action if a patient has cognitive impairment and drives.

* Patients with questionable cognitive impairment often perform differently on different occasions and often appear to be quite unimpaired in the physician's office. A conclusion should not be based on any single observation. A thorough assessment of driving and driving-related abilities should be conducted if a patient shows signs of a functional deterioration, manifested as breakdown of instrumental activities of daily living (IADL) skills, especially combined with other impairments, such as poor visual acuity or poor motor function.

* Before making a decision about driving, the etiology of the cognitive impairment or diagnosis must be clear.

* If driving poses an imminent danger to the patient or other drivers, reporting the situation to the authorities is recommended. Moderate to severe dementia is sufficient to warrant an immediate cessation of driving.

* Driving fitness may often be compromised in patients who were assessed at a dementia clinic, but did not receive a diagnosis of a dementing disease. Driving cessation should not be determined without specialized assessment. As long as a mildly impaired nondemented patient has a stable functional level, a periodic follow-up is sufficient.

* The patient should be referred for more specialized assessment when the physician is uncertain of the extent of the patient's cognitive impairment and its influence on driving.

* Physicians are urged to refer patients to professionals with expertise in comprehensive assessment of driving competence, such as driving instructors or driving examiners.

Consensus Group Conclusions

* Individuals with moderate and severe dementia should not drive.

* Continued research is necessary to determine when patients with mild dementia should cease driving.

* In the meantime, mild cases of dementia should be carefully evaluated in an individualized manner.

The full text of this conference is published in Alzheimer Disease and Associated Disorders: The 1994 International Consensus Conference on Dementia and Driving: A Brief Report. Johansson K, Lundberg C. Alzheimer Disease and Associated Disorders 1997; Vol 11 (Suppi 1): 62-69.

(*.) Prepared by Elaine McLellan-Holm.