The Vegetative and Minimally Conscious States: A Comparison of Clinical Features and Functional Outcome

Abstract

Objective: 

To compare the vegetative (VS) and minimally conscious states (MCS) with regard to the incidence of specific clinical features and differences in functional outcome across the first year post injury. It was hypothesized that patients diagnosed with MCS on admission to rehabilitation would have more favorable outcomes at 1 year post injury relative to patients diagnosed with VS and that this difference would be more pronounced for traumatic (TBI) versus nontraumatic brain injury (NTB1). Design: Retrospective analysis of clinical findings collected using a standardized methodology (ie, Coma Recovery Scale). Findings were utilized to determine diagnosis and functional outcome at 1, 3, 6, and 12 months post injury. Setting: Acute and extended care brain injury rehabilitation hospital. Patients: 104 patients (62 male, 42 female; mean age = 37 years; mean weeks post injury to admission = 10) with severe TBI or NTB1 (VS = 55; MCS = 49) admitted to a rehabilitation-based coma intervention program. Results: Functional outcome at 3,6, and 12 months post Injury was significantly more favorable for patients diagnosed with MCS relative to those with an admitting diagnosis of VS, and this difference was greatest for patients in MCS following TBI. Visual tracking and motor agitation were found to occur in VS but were of low frequency in comparison to MCS. Conclusions: In patients with severe disorders of consciousness, those diagnosed with MCS show more continuous improvement and attain significantly more favorable outcomes by 1 year post injury than those diagnosed with VS. The presence of specific clinical features, particularly visual tracking, may contribute additional information to differential diagnosis in patients whose level of behavioral responsiveness is severely diminished.