Letter to the editor: Misperceptions exist about sleep attacks when driving.

Around half of all sleep related road crashes are caused by healthy adults aged under 30. We investigate many such crashes and find that most drivers deny having fallen asleep, and the evidence has to come from elsewhere. Other research shows that momentary sleep can go unnoticed. Moreover, these drivers usually deny knowledge of prior sleepiness, even those admitting to having fallen asleep. Ostensibly, it was an "unforewarned" sleep attack. Claims that drivers with Parkinson's disease are prone to unforewarned sleep attacks should therefore be treated cautiously. (Author/publisher)