[Prognostic evaluation of sleep in patients in a vegetative state]

Coma in the genuine sense is a dreamlike state that lasts not more than 3 weeks, thereafter it progresses to a vegetative stage of consciousness recovery, except when a patient has died or regained conscious wakefulness. Among those who have achieved the vegetative state progress to the following stage of recovery: mal consciousness or completely return to the initial cognitive level. Others remain in a persistent vegetative state. The registered cases of the vegetative state is as high as 100 per million population (S. Ashwal et al., 1996). This patient category remains terra incognita even for interdisciplinary analysis by neurologists and reanimatologists. Nonetheless, the emotional and financial support to manage this patient category is high. In searching for prognostic criteria for the outcome of a vegetative state, the authors attempted to analyze sleep, one of the earliest phylogenetic autonomic functions. Based on the hypothesis that the cognitive status cannot be regained if sleep is not recovered, the authors conducted a polysomnographic study in 64 patients. Preserved sleep patterns were observed in 27 (96%) of 28 patients with a good outcome versus 11 (31%) of 36 patients with a poor outcome. It is concluded that it is expedient to incorporate polysomnographic monitoring into the examination protocol for patients in a vegetative state.