Revisiting the diagnostic criteria for emergence from the minimally conscious state: An empirical investigation

Objective To determine whether consistent command-following (CCF) should be added to the diagnostic criteria for emergence from the minimally conscious state (MCS) Design Retrospective cohort study Setting Inpatient rehabilitation hospital Participants Patients with severe acquired brain injury and disorders of consciousness (DoC) admitted to a specialized rehabilitation program Main Outcome Measure Difference between time to recovery of CCF and time to recovery of functional object use [FOU] or functional communication [FC] (the two existing criteria for emergence from MCS) as measured by the Coma Recovery Scale – Revised [CRS-R]). Results Of 214 patients (median [interquartile range] age: 53 [34, 66] years, male: 134 (62.6%), traumatic etiology: 115 (53.7%), admission CRS-R total score: 10 [7, 13]) admitted to rehabilitation without CCF, FO, or FC, 162 (75.7%) recovered CCF and FOU or FC during the eight-week observation period. On average, recovery of CCF, FOU, and FC was observed within one day of one another, approximately 46 [38.25, 58] days post-injury. One hundred and sixteen patients (71.6%) recovered FOU or FC prior to or at the same time as CCF. Conclusions In patients recovering from DoC, CCF reemerges around the same time as FOU and FC. This finding likely reflects the shared dependency of these behaviors on cognitive procecess (e.g., language comprehension, attention, motor control) that are essential for effective interpersonal interaction and social participation. Our results support the addition of CCF to the existing diagnostic criteria for emergence from MCS.