Cortical sources of resting-state alpha rhythms are abnormal in persistent vegetative state patients

Claudio Babiloni, Marco Sarà, Fabrizio Vecchio, Francesca Pistoia, Fabio Sebastiano, Paolo Onorati, Giorgio Albertini, Patrizio Pasqualetti, Giuseppe Cibelli, Paola Buffo, Paolo Maria Rossini

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: High power of pre-stimulus cortical alpha rhythms (about 8-12 Hz) underlies conscious perception in normal subjects. Here we tested the hypothesis that these rhythms are abnormal in persistent vegetative state (PVS) patients, who are awake but not aware of self and environment. Methods: Clinical and resting-state, eyes-closed electroencephalographic (EEG) data were taken from a clinical archive. These data were recorded in 50 PVS subjects (level of cognitive functioning - LCF score: I-II) and in 30 cognitively normal subjects. Rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). Cortical sources were estimated by low-resolution electromagnetic tomography (LORETA). Based on LCF score at 3-months follow-up, PVS patients were retrospectively divided into three groups: 30 subjects who did not recover (NON-REC patients; follow-up LCF: I-II), 8 subjects classified as minimally conscious state patients (MCS patients; follow-up LCF: III-IV), and 12 subjects who recovered (REC patients; follow-up LCF: V-VIII). Results: Occipital source power of alpha 1 and alpha 2 was high in normal subjects, low in REC patients, and practically null in NON-REC patients. A Cox regression analysis showed that the power of alpha source predicted the rate of the follow up recovery, namely the higher its power, the higher the chance to recover consciousness. Furthermore, the MCS patients showed intermediate values of occipital alpha source power between REC and NON-REC patients. Conclusions: These results suggest that cortical sources of alpha rhythms are related to the chance of recovery at a 3-months follow-up in patients in persistent vegetative state. Significance: Cortical sources of resting alpha rhythms might predict recovery in PVS patients.

Original languageEnglish
Pages (from-to)719-729
Number of pages11
JournalClinical Neurophysiology
Volume120
Issue number4
DOIs
Publication statusPublished - Apr 2009

Keywords

  • Consciousness
  • Human cerebral cortex
  • Low-resolution brain electromagnetic source tomography (LORETA)
  • Persistent vegetative state (PVS)
  • Resting-state electroencephalography (EEG)

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Physiology (medical)
  • Sensory Systems

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