For professionals

Abstract

One of the worst consequences of acquired brain injury is the vegetative state, recently renamed "unresponsive vigilance syndrome" (VS/UWS). A patient in VS/UWS exhibits reflexive behaviors such as spontaneous eye opening and breathing, but no signs of awareness of themselves or the environment.

We conducted a systematic review of VS/UWS prevalence studies and assessed their reliability. Medline, Embase, the Cochrane Library, CINAHL, and PsycINFO were searched in April 2013 for crosssectional point or period prevalence studies that explicitly stated the prevalence of VS/UWS due to acute causes within the general population. In addition, we checked bibliographies and consulted experts in the field to obtain 'grey data' such as government reports. Relevant publications underwent quality assessment and data extraction.

We collected 1032 papers, of which 14 met the inclusion criteria. Prevalence rates ranged from 0.2 to 6.1 VS/UWS patients per 100,000 members of the population. However, the methodological quality of the publications differed considerably, in particular with regard to the inclusion criteria and the verification of the diagnosis. The reliability of the US/UWS prevalence rates is poor. Methodological shortcomings in available prevalence studies, the fact that 5/14 of the studies predate the identification of the Minimally Conscious State (MCS) as a separate entity in 2002, and insufficient verification of included cases may lead to both overestimation and underestimation of the true number of patients in VS/UWS.

Keywords
disorders of consciousness, epidemiology, postanoxic encephalopathy, rehabilitation, vegetative state