People with Parkinson's disease may make errors in driving test.

Parkinson's disease impairs movement and has other symptoms such as memory and vision problems. You might expect the condition to impair driving ability and a team at the University of Iowa has shown this to be the case - at least for some Parkinson's patients.

The study involved an on-road driving test involving 71 people with mild to moderate Parkinson's disease who were current drivers. They were compared to 147 people of similar age who had no neurological problems. While driving, the participants were given a verbal addition test. This simulates the amount of distraction that is involved in talking while driving - including on a mobile phone.

During the distraction, 28 per cent of those with Parkinson's disease made driving errors compared to 16 per cent of the controls. Those who made the errors tended to have memory, vision and balance problems. They were also more likely to experience daytime sleepiness. The researchers noted that the better known movement problems, such as tremor, were in fact less likely to affect driving than the lesser known problems listed above. People with Parkinson's disease and their families should be aware that driving may be affected as the condition progresses and should be prepared to watch out for this.

Source
Neurology 28th November 2006