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University of Iowa News Release

March 16, 2004

Study Aims To Predict Driver Safety For Parkinson's Patients

Certain conditions and illnesses can drastically affect a person's driving capabilities. However, determining if an illness-related impairment makes someone an unsafe driver is a complicated decision. Ideally, that decision should be based on an ability to accurately predict how certain aspects of a disease contribute to risky driving.

Using a five-year, $1.6 million grant from the National Institute of Neurological Disorders and Stroke, a team of University of Iowa researchers will study how Parkinson's disease affects driver safety. The team, led by principal investigator Ergun Uc, M.D., (left) assistant professor of neurology in the UI Roy J. and Lucille A. Carver College of Medicine, and co-principal investigator Matthew Rizzo, M.D., UI professor of neurology, engineering and public policy, aims to generate data that will help predict driver safety for individuals with this condition.

"Parkinson's disease affects people in many ways that can have an impact on their ability to drive," Uc said. "Most people know about the motor effects of the disease -- the tremors and difficulty walking -- but the disease affects lots of systems in the brain and the body. Mental functions -- including the ability to think and make decisions, memory and attention -- are affected, as are reaction times. Parkinson's disease also can affect psychology, causing depression and anxiety, and can alter sleep rhythms and vision."

Uc also noted that the medications designed to alleviate tremors and stiffness caused by the disease can actually worsen other functions by making the patient sleepy or decreasing attention span.

The UI study will enroll 115 individuals with Parkinson's disease and follow each patient for three years. Various tests will assess the severity of motor, mental and visual symptoms of Parkinson's disease in these patients at the beginning of the study. The tests also will allow the researchers to track the decline in those functions over the three years. The patients' driving ability will be assessed over the study period using three different methods.

Patients will drive an instrumented vehicle known as ARGOS (Automobile for Research in Ergonomics and Safety) on the road. This vehicle is an ordinary car, but is fitted with monitors, cameras and computers that record the driver's responses. Tests given to the participants while they are driving, including following a given route, or recognizing significant signs, will assess driver skills, memory, attention, decision making and multitasking abilities.

A driving simulator, SIREN (Simulator for Interdisciplinary Research in Ergonomics and Neuroscience), will test drivers' reactions to potential accident-causing situations by using virtual reality to mimic dangerous traffic encounters.

"The simulator makes it possible to test the driver's response to dangerous situations and determine, safely, whether a driver is likely to have an accident," Uc said.

Finally, to try and measure how well these drivers are able to cope with real danger on the roads, the researchers will examine Department of Transportation (DOT) records of crashes and moving violations for the participants over the duration of the study.

As a comparison, the driving ability of 115 normal individuals also will be assessed using the same three methods.

"At the end, we want to be able to say how the severity of different problems caused by Parkinson's disease affect driving ability and safety," Uc said. "We are trying to relate the severity of the disease in each of its aspects with the patient's safeness as a driver and their true risk for accidents. The strength of our study is that we are looking at many aspects of Parkinson's disease at the same time in a longitudinal manner in a large number of patients and controls and comparing these to the driving abilities assessed with state-of-the-art methods."

When there is a question about retaining or renewing the driver's license of a person with Parkinson's disease, the patient and his or her physician complete a form. The DOT uses that information to decide if to renew and how frequently the individual should undergo a driving test to monitor their abilities.

Uc notes, however, that a standard driving test may not be the best way to evaluate driver safety because it is designed to evaluate a novice driver's abilities rather than to specifically test functions that might be impaired by Parkinson's disease.

"If we can come up with strong predictive guidelines, it will be easier for doctors, the DOT and patients themselves to decide whether to drive or how best to limit driving to stay safe," Uc added.

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at

STORY SOURCE: University of Iowa Health Science Relations, 5141 Westlawn, Iowa City, Iowa 52242-1178

CONTACT: Jennifer Brown, (319) 335-9917

PHOTOS/GRAPHICS: A photo of Dr. Uc is available at

OTHER INFORMATION: (Uc is pronounced "Ooch")