Clinical neurologic assessment tool: development and testing of an instrument to index neurologic status.

The clinical neurologic assessment tool (CNA) is a 21-item instrument assessing response to verbal and tactile stimulation, ability to follow commands, muscle tone, body position, movement, chewing, and yawning in the patient with head trauma. The CNA was developed to detect subtle changes in the patients' neurologic status that may indicate transitions in the comatose state. The CNA has been extensively pilot tested. Reliability determined by using Cronbach's alpha revealed an internal consistency of 0.96. Concurrent validity testing with the Glasgow Coma Scale indicated a strong positive correlation, r = 0.94. Construct validity was assessed with factor analysis using 0.50 for a loading criterion. Three factors were demonstrated: general level of consciousness, muscle tone and resistance, and chewing or yawning. Discriminant function analysis revealed that the CNA scores correctly classified 95.1% of the patient observations into their respective Glasgow Coma Scale categories. The CNA is reliable, valid, convenient, and easily scored and captures the subtle changes in the patient with head trauma.