Parkinson’s disease (PD) has multiple effects on motor, cognitive, and visual functioning, all of which can impair a person’s ability to drive.
The typical motor symptoms of PD, including rigidity of the arms, slowness of movement, and lack of coordination, can make driving complicated. Several studies have supported this, with on-road assessments showing drivers with PD having significantly worse driving performance than healthy controls.
In addition to the motor symptoms, PD can cause difficulties in making decisions and the ability to think clearly, as well as changes to visual perception. These symptoms can make it difficult for someone living with PD to drive safely and may increase the risk of driving accidents.1
Impaired vision in early stages
Research has found that the ability to drive safely may be impaired even in the early stages of Parkinson's, as visual symptoms like decreased contrast sensitivity become noticeable. Contrast sensitivity is the ability to distinguish between objects and their backgrounds. This is especially challenging in situations of low light, such as fog, glare, or at night.1,2
Assessing driving ability
There are currently no evidence-based parameters for physicians to guide their assessment of driving fitness in their patients with PD. The American Medical Association recommends that physicians base their evaluation of driving abilities on the patient’s motor and cognitive changes, their response to medications, and any side effects the patients are experiencing as a result of those medications.
The National Highway Traffic Safety Administration and the Federal Motor Carrier Safety Administration suggest assessments be done on a case-by-case basis since PD affects individual people differently and each person’s disease progresses at its own rate. Without official guidelines, doctors must make their own personal judgments regarding whether their patients should drive. However, research has shown that doctors often overestimate the driving ability of their patients.1
Some hospitals offer driving assessment clinics, in which medical symptoms that may impact driving skills can be assessed. Occupational therapists can provide some rehabilitation and teach skills to help with impairments. One example is the use of a “bioptic telescope” which can enhance vision.3
Questions to consider
Driving plays an important role in an individual’s sense of independence, personal control, and self-reliance, and giving up driving can be very difficult. People living with Parkinson's should consider the following questions when deciding whether or not to drive:4,5
- How is my vision? Can I see well at night? Can I distinguish colors, such as in traffic lights?
- Would I be putting my passenger (friend or loved one) at risk?
- How fast is my reaction time? Could I safely avoid a surprise obstacle in the road?
- Has anyone (friend or family member) commented negatively on my ability to drive?
- Can I handle multiple activities at the same time (whether driving or not)?
- Can I effectively and quickly turn the wheel or step on the brake with enough strength?
- Do my medications for PD (or other conditions) cause side effects like sleepiness, dizziness, blurred vision, or confusion?
In addition to considering these questions in a self-assessment, drivers can get an on-road assessment by a Driving Rehabilitation Specialist or at their local Department of Motor Vehicles. When it is time to give up driving, people living with PD have options.
They can use public transportation, ask a friend or family member for a ride, or look into special shuttle services through local organizations and community centers.4