Intracranial pressure and muscle activity in patients with decerebrate rigidity.

The authors analyse the relationship between the muscle activity during paroxysms of decerebration and the intracranial pressure. These relationships differ, and depend upon the presence or absence of mesencephalic herniation and patency of the perimesencephalic cisterns, as well as on whether the decerebration posturing has been spontaneous or induced by external stimulus. It is suggested that the magnitude of ICP reaction during decerebration is connected with the possibility of compensating the increased intracranial volume and with the strain imposed upon the brain stem at the mesencephalic level. Close correlations between the vegetative variables occuring during spontaneous DR paroxysms suggest a common excitatory neuronal mechanism. In cases when decerebration is provoked by external stimuli the response becomes more complex and not uniform.