Predictors of recovery of responsiveness in prolonged anoxic vegetative state

The number of patients in prolonged postanoxic vegetative state (VS) is increasing. However, little information is available about prognostic markers of long-term outcome in patients who remain in VS more than 1 month postonset. The present 2-year prospective clinical study aimed to identify prognostic markers, recorded in the chronic phase, that might be useful for predicting recovery of responsiveness in a cohort of postanoxic VS patients.

We enrolled 43 inpatients with prolonged anoxic VS (23 female; age range 12-83 years). We collected data about medical history, clinical findings, and neurophysiological assessments at study entry (1-6 months postonset), and assessed their relationships with outcome at 24 months postonset; for defining outcome, patients were classified as responsive or unresponsive on the basis of clinical criteria and on Coma Recovery Scale-Revised (CRS-R).

Nine patients had recovered responsiveness (but 2 of them died after awakening), whereas 12 patients remained in VS and 22 had died in VS. Functional abilities were severely affected in all responsive survivors. Responsive patients were significantly younger and showed higher CRS-R total score and lower Disability Rating Scale score at study entry than patients who did not recover. All responsive survivors had spared pupillary light reflex and nociceptive response, and paroxysmal sympathetic hyperactivity. Logistic regression analysis showed that the presence of median nerve somatosensory evoked potentials and CRS-R total score ≥ 6 were significant predictors of recovery of responsiveness.

Clinical features and evoked potentials are useful predictors of long-term recovery of responsiveness in patients with prolonged postanoxic VS.