Monitoring of the level of neurological response is an essential component of the diagnostic and therapeutic process in the management of craniocervical injury and neurological catastrophes. When Hippocrates reminded us that “No Head Injury is so mild that it can be neglected,” he cannot have been aware of the significance of the lethal factors of cerebral swelling and intracranial hematoma contributing to poor survival. Neither can he have known how these factors could be detected. Coma scales have evolved to indicate when deterioration is likely and intervention indicated.

Many hospitals use simple grades of responsiveness for their unconscious patients, but the widespread habit of recording the level of response in an abstract manner is as meaningless as measuring temperature in units of feverishness. There is a requirement for a device which can be expressed in numerical terms and, when necessary, related to an analogue or graphical mode.