) - Impairments in motor function are not the primary obstacle to
safe driving for patients with Parkinson's disease, even for those
with relatively early-stage disease, researchers reported here
during the 132nd annual meeting of the American Neurological
Association. Errors in judgment, easy distractibility and an
inability to multitask can be more significant, according to Dr.
Ergun Y. Uc.

Dr. Uc, of the University of Iowa, Iowa City, and colleagues are
conducting an ongoing longitudinal study of driving safety in 230
drivers, 79 of whom have Parkinson's disease with a median Hoehn-
Yahr stage 2, indicating relatively mild disease.

At baseline, Parkinson's patients "performed significantly worse
than control drivers on all motor, cognitive, visual tests and
driving experiments," Dr. Uc said.

On road tests, Parkinson's patients made more safety errors during
verbal distraction, were unable to identify targets, made more wrong
turns and got lost more often than controls, he reported.

In a driving simulator, drivers with Parkinson's disease had worse
vehicular control while simultaneously performing simple motor tasks
and were at higher risk of crashes under foggy conditions when faced
with an oncoming vehicle making an illegal turn.

The poorer driving ability of Parkinson's patients, compared with
controls, "was predicted by deficits in attention, executive
functions, memory, visual perception and visuospatial abilities
rather than motor dysfunction," Dr. Uc said.

He said the findings show that Parkinson's disease negatively
affects cognition and visuospatial ability, apart from the more
distinguishing deficits in motor function, "even in relatively early
stages of Parkinson's disease."

The findings suggest, he said, "the need for a multidisciplinary
approach to predict safety of drivers with Parkinson's disease."

Date updated: October 09, 2007
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WASHINGTON, DC (Reuters Health