On the nature of brain stem disorders in severe head injured patients. II. A study on caloric vestibular reactions and neurotransmitter treatment.

The results of electro-oculographic recordings made after caloric vestibular stimulation (C.O.G.) in severe head injured patients are discussed. It was found that: 1. The C.O.G. correlates with the state of consciousness of the patients. 2. The rate of improvement of the C.O.G. correlates with the rate of the clinical improvement. 3. A prediction of the duration of unconsciousness can be made by repeated C.O.G. scores as well as by repeated scoring of the clinical state. 4. In all patients a paradoxical response is present except in those who have regained clear consciousness and in those persisting in a vegetative state, so the presence of a paradoxical response indicates the possibility of further improvement. It was supposed that in patients with a paradoxical response a functional brain dysfunction was present, which was at least partly caused by disturbed neurotransmitter metabolism. Therapeutic trials with L-DOPA and physostigmine were successful in patients with a paradoxical response, but without any result in those without this phenomenon. The responses to L-DOPA and to physostigmine are related respectively to motor pattern and to verbal or non-verbal communication.