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

Abstract

Giacino JT, Kalmar K, Whyte J. 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.