The JFK Coma Recovery Scale-Revised: Measurement characteristics and diagnostic utility

Objective: To determine the measurement properties and diagnostic utility of the JFK Coma Recovery Scale-Revised (CRS-R). Design: Analysis of interrater and test-retest reliability, internal consistency, concurrent validity, and diagnostic accuracy. Setting: Acute inpatient brain injury rehabilitation hospital. Participants: Convenience sample of 80 patients with severe acquired brain injury admitted to an inpatient Coma Intervention Program with a diagnosis of either vegetative state (VS) or minimally conscious state (MCS). Interventions: Not applicable. Main Outcome Measures: The CRS-R, the JFK Coma Recovery Scale (CRS), and the Disability Rating Scale (DRS). Results: Interrater and test-retest reliability were high for CRS-R total scores. Subscale analysis showed moderate to high interrater and test-retest agreement although systematic differences in scoring were noted on the visual and oromotor/verbal subscales. CRS-R total scores correlated significantly with total scores on the CRS and DRS indicating acceptable concurrent validity. The CRS-R was able to distinguish 10 patients in an MCS who were otherwise misclassified as in a VS by the DRS. Conclusions: The CRS-R can be administered reliably by trained examiners and repeated measurements yield stable estimates of patient status. CRS-R subscale scores demonstrated good agreement across raters and ratings but should be used cautiously because some scores were underrepresented in the current study. The CRS-R appears capable of differentiating patients in an MCS from those in a VS.