Evaluation of coma and vegetative states.

The Coma/Near-Coma (CNC) scale was designed to measure small clinical changes in patients with severe traumatic and nontraumatic brain injuries who were functioning at very low levels characteristic of near-vegetative and vegetative states. In 20 patients followed for 16 weeks the scale identified 25% who ultimately showed modest improvement. Interrater reliability was high (r = .95); validity was supported by significant correlations between CNC- and brain-multimodality evoked potential abnormality scores as well as between scores on the CNC and the Disability Rating Scale. The CNC scale was easily learned and it could be completed quickly and cost effectively. Staff found it useful in recognizing among relatively homogeneous low-level patients those most likely to respond to further rehabilitation care. The CNC appears to be useful for justifying ongoing intensive rehabilitation and for preventing premature transfer to lower levels of care.