Being told it's time to stop driving with Alzheimer's is often the "straw that breaks the camel's back." I've treated many patients with dementia whose emotional health held up remarkably well until the loss of driving privileges led to an episode of depression and a decline in other areas of functioning. While often taken for granted as a routine part of adult life, driving is a strong symbol of independence and competence.
Brain Functions That Affect Driving Ability
If you can imagine what goes into actually driving a motor vehicle safely, you can see that there are many higher level cognitive abilities required. Appropriate judgment is essential, as is orientation and reaction time. The ability to multitask is important, as is visuospatial ability.Other aspects of executive functioning such as planning, logical thinking, and self-restraint are also important in safe driving, and unfortunately these are often impaired in Alzheimer's disease.
Warning Signs to Stop Driving
There are certain signs that may indicate that someone with dementia should stop driving. These include:- Failing to observe traffic signals
- Hitting curbs
- Signaling incorrectly
- Driving at inappropriate speeds
- Moving into the wrong lane
- Confusing the brake and gas pedals
- Stopping in traffic for no apparent reason
Tests to Determine Driving Ability
If the above signs are noticed, it may be appropriate for a screening test to be conducted. Many healthcare professionals use a dementia screening test called the Mini Mental State Examination (MMSE), but it was never designed to be, nor has it been validated as, a predictor of driving safety. In fact, studies have shown it to be inconclusive as a predictor of crash risk. Updated guidelines published by the American Academy of Neurology in April 2010 recommend that doctors use the Clinical Dementia Rating (CDR) Scale to identify people with dementia who are at increased risk of unsafe driving.
While other tests have been used for driver evaluation in dementia, it is known that cognitive tests alone are not sufficient to determine fitness to drive. On-road driving assessments by experienced driving evaluators are considered the gold standard to evaluate driving abilities in people with dementia.
Sources:
Iverson DJ, MD et al. "Practice Parameter Update: Evaluation and management of driving risk in dementia." Neurology 2010;74:1316-1324.
National Highway Traffic Safety Association. Accessed: March 17, 2010. Community Mobility in Dementia
Odenheimer GL, MD. "Safe Driving for Seniors." American Geriatrics Society Patient Education Forum. Accessed: March 17, 2010. Safe Driving For Seniors
