title: Coma Recovery Scale-Revised: evidentiary support for hierarchical grading of level of consciousness.
abstract: OBJECTIVE
  To investigate the neurobehavioral pattern of recovery of consciousness as reflected by performance on the subscales of the Coma Recovery Scale-Revised (CRS-R).
  
  
  METHODS
  Retrospective item response theory (IRT) and factor analysis.
  
  
  METHODS
  Inpatient rehabilitation facilities.
  
  
  METHODS
  Rehabilitation inpatients (N=180) with posttraumatic disturbance in consciousness who participated in a double-blinded, randomized, controlled drug trial.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Scores on CRS-R subscales.
  
  
  RESULTS
  The CRS-R was found to fit factor analytic models adhering to the assumptions of unidimensionality and monotonicity. In addition, subscales were mutually independent based on residual correlations. Nonparametric IRT reaffirmed the finding of monotonicity. A highly constrained confirmatory factor analysis model, which imposed equal factor loadings on all items, was found to fit the data well and was used to estimate a 1-parameter IRT model.
  
  
  CONCLUSIONS
  This study provides evidence of the unidimensionality of the CRS-R and supports the hierarchical structure of the CRS-R subscales, suggesting that it is an effective tool for establishing diagnosis and monitoring recovery of consciousness after severe traumatic brain injury.
authors.affiliation: Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, MA.
authors.forename: Paul
authors.initials: P
authors.lastname: Gerrard
authors.affiliation: Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, MA.
authors.forename: Ross
authors.initials: R
authors.lastname: Zafonte
authors.affiliation: Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, MA. Electronic address: jgiacino@partners.org.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Giacino
mesh_terms: D000328:Adult; D001143:Arousal; D032882:Comprehension; D003243:Consciousness / Q000502:physiology*; D003244:Consciousness Disorders / Q000503:physiopathology* / Q000534:rehabilitation; D005163:Factor Analysis, Statistical; D005260:Female; D006309:Hearing; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011597:Psychomotor Performance; D012189:Retrospective Studies; D013060:Speech; D014796:Visual Perception; D055815:Young Adult
keywords: Disorders of consciousness; Psychometrics; Rehabilitation; Traumatic brain injury