Circadian rhythms in the vegetative state

Brain Inj. 2009 Oct;23(11):915-9. doi: 10.1080/02699050903283197.


Objective: To evaluate whether vegetative state patients maintain circadian rhythms.

Research design: An observational study of five single cases.

Methods and procedures: Five chronic vegetative state patients underwent clinical and neurological evaluations and 2-week continuous temperature measurements.

Main outcomes and results: The two patients with traumatic brain injury showed well-formed circadian temperature rhythms and had more reflexive behaviours and relatively low cortical and sub-cortical atrophy, whereas the three patients from anoxic-hypoxic origin demonstrated no cycles or rhythmic behaviour.

Conclusions: The presence of periods of wakefulness does not imply preserved sleep-wake cycling capacity, nor preserved circadian rhythms and it should not be taken as a distinguishing feature for the definition of the vegetative state.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Body Temperature Regulation / physiology*
  • Brain Injuries / complications
  • Brain Injuries / physiopathology*
  • Circadian Rhythm / physiology*
  • Female
  • Humans
  • Hypoxia, Brain / physiopathology*
  • Male
  • Middle Aged
  • Persistent Vegetative State / physiopathology*
  • Wakefulness / physiology*
  • Young Adult