Vegetative State (VS)

Published articles are available on the articles page.

Reports in the medical literature of duration of survival in VS are conflicting, in part because they seldom take account of risk factors. Important risk factors include:

• age,
  
  
• time since onset of VS,
  
  
• need for special aids such as gastrostomy tube and respirator/ventilator, and
  
  
• secular trend (there has been some improvement in the life expectancy over the last 15 years, other things being equal).

Our latest publications details these new findings, and summarize the literature on long-term survival of persons in vegetative or minimally conscious states.

Abstract: We studied life expectancy and risk factors for mortality of persons in the vegetative state (VS). Subjects were 1021 California patients in the VS during a 1981-1996 study period. Because of the large sample we were able to use multivariate methods to assess the effect of several risk factors on mortality. We found a strong secular trend in infant mortality, rates in the mid 1990's being only a third of those in the early 1980's (p < .01). A smaller secular trend was observed for children aged 2-10, and none for older patients. Mortality risk for older patients fell by approximately 8% for each year since onset of the VS. The need for gastrostomy feeding was associated with a substantially higher risk, especially for infants and older patients (p < .01). Ventilator dependence also appeared to be a risk factor. Based on recent mortality rates, life expectancy in the VS is frequently higher than has been generally thought. For example, it is 10.5 additional years (+- 2 years) for a patient aged 15 who has been in the VS for one year, and 12.2 years for a 15 year-old who has been in the VS for 4 years.

Abstract: We determined estimates of survival in children, 3-15 years of age, in the vegetative state (VS) (n = 564), immobile minimally conscious state (MCS) (n = 705), and mobile MCS (n = 3,806). Data were extracted from the annual Client Development Evaluation Reports of the California Department of Developmental Services between 1988 and 1997 using the operational definitions for these three states on the basis of 15 descriptive behavioral categories. Patients were also categorized according to the following four etiologies: acquired (traumatic and nontraumatic) brain injury; perinatal/genetic; degenerative; and unknown/undetermined. The percentage of patients surviving 8 years was 63%, 65%, and 81%, for the VS, immobile MCS, and mobile MCS, respectively. Children in the VS and MCSs with acquired brain injury had lower mortality rates and those with degenerative diseases the highest mortality rates. We observed little difference in survival between patients in the VS and immobile MCS, suggesting that the presence of consciousness is not a critical variable in determining life expectancy. Furthermore, survival was much greater for patients in the mobile MCS than for those in the immobile MCS, suggesting that mobility is more important in predicting survival than the level of consciousness.