Measurement of impaired consciousness in the neurological intensive care unit: a new test

Neurological deterioration in alert patients with an acute CNS disorder can be subtle, but current coma scales may not clearly capture changes in level of alertness. Many coma scales include components such as eye opening and content of speech, features that are difficult to assess in intubated patients and patients with facial trauma. Two new tools have been devised by the authors. The components are a continuous performance test (patient is asked to raise his hand every time he hears a certain letter in a standardised sentence) and the three consecutive hand position test ("thumbs up-fist-victory sign"). Variation within and between observers was assessed with three neurologists, two junior neurology residents, and two neuroscience nurses, and compared with the Glasgow coma score. The average agreements had comparable ranges for both scores, 65% to 89% for both tests and 60% to 88% for the Glasgow coma score. On the first visit 49% of all tests with a maximum Glasgow coma score had a negative continuous performance test as opposed to 13% of tests with a less than maximum Glasgow coma score. For the consecutive hand position test, these numbers were respectively 25% and 2%. These tests may be a reasonable alternative to the Glasgow coma score to monitor patients, in particular when the verbal and eye response cannot be reliably tested.