Tentative anatomoclinical classification

By correlating the preceding classification with anatomical observations on our own cases and others described in the literature, we have been able to distinguish four main anatomoclinical stages in prolonged coma (Fig.8).

The reactive apathic hypoperceptive syndrome

The word apathic is used here as the etymological opposite of hyperpathic. This syndrome corresponds to the one first described by Cairns et al. (1941) under the name of akinetic mutism. It concerns those subjects in whom perception is altered but not abolished (P3-P4). Reaction is normal (R l) and the orienting reaction is facilitated, hence the frequent ocular movements. Autonomic reac tions are normal but motor reactions to pain are partly lost. Even strong stimuli fail to elicit the characteristic facial mimic in response to pain. The lesions responsible for this syndrome spare the cortex but affect the thalamus (Cairns 1952; Jouvet and Dechaume 1961), the posterior part of the third ventricle; it can be a pineal tumour, a craniopharyngioma or an epidermoid cyst(Cairns 1952), occlusion of the vertebrobasilar system affecting the lower end of the brainstem but sparing most of the tegmentum (Kubik and Adams 1946; Cravioto et al. 1960; Girard et al. 1962). Finally, it can be a tumour of the cerebellum or of the posterior cranial fossa (Jefferson and Johnson 1950; Longman and Tenuto 1956; Daly and Love 1958). Of the cases reported of a kinetic mutism, only a few involve the cortex: cingular cortex (Nielsen and Jacobs 1951) and pallidum, by CO2 poisoning (Cravioto et al. 1960). It is also worth noting that in the majority of cases, the mesencephalic tegmentum and the reticular formation are virtually intact. It would appear therefore that the syndrome of akinetic mutism may result from a group of lesions primarily affecting the cingular cortex and the brain stem, damaging the extra pyramidal mechanisms concerned with the integration of motor responses to pain and to the spoken word.

The reactive hyperpathic-hypertonic aperceptivity syndrome

This is the equivalent of decortication in man. Perception is totally absent (P5) except if the occipItal. cortex is still intact, when the blink reaction may persist (P4). Reactivity is preserved (R1): Reactions to pain are normal, but, like the autonomic reactions, they may be exaggerated. There is always present a decortication rigidity with flexion of the upper limbs and frequently there is a positive Magnus-De Klein reflex. Finally, these subjects almost invariably keep their eyes open and appear awake all the time. Continuous recordings however show periodically a short lasting sleeping phase. The same signs were demonstrated in cases described by Rosenblath (1899) and by Kretschmer (1940) under the name "das appallische Syndrom", by Strich (1956,1957) under the name of "dementia from traumatic ence phalopathy", by Lundervold (1954) under the name of "loss of consciousness due to anoxia", by Zeman and Youngue (1957), Denst et al . (1958), Fischgold and Mathis (1959), Nystrom (1960), and by ourselves (Jouvet and Dechaume 1960; Trillet 1961).

In all the cases, the lesion is similar. There is either massive cortical involvement (Denst et al. 1958) or diffuse degenerative changes in the white matter of the cerebral hemispheres. The brainstem is intact in the majority of cases (with the exception of the pyramidal fibres which frequently show signs of degeneration).

The areactive apathic normotonic aperceptivity syndrome

This group concerns cases of very deep coma in which survival is usually limited to a few weeks. Perceptivity is lost (P5). Nonspecific reactions are altered (R2-R3) as well as reaction to pain (D2-D3), but autonomic reactions are normal. In most cases, there is no definite hypertonicity. Patients described by Jefferson (1952) under the name of parasomnia, by French (1952) under the name of prolonged uncounsciousness, and by Cravioto et al. (1958), and Trillet (1961), present the same symptomatology. The lesion common to all these patients is one affecting the upper part of the brainstem (mesencephalic reticular formation), but in most cases, there were also associated lesions of the cortex or white matter. It appears that total or subtotal destruction of the reticular system is responsible for the more severe losses of reactivity.

The aperceptivity areactive apathic and atonic syndrome

This syndrome, described only recently, is a result of modern resuscitation methods. In spite of diffuse damage to the encephalon (most often from anoxia) and of the development of massive aseptic necrosis, life can be maintained by arti ficial respiration and by continuous perfusion of hypertensive agents. This group consists of the cases of brain death (Wertheimer et al. 1959), sometimes called "coma dépassé" (Mollaret et al. 1959) or artificial survival (Bertrand et al. 1959). Such a clinical picture poses the problem of legal death (which is discussed elsewhere). We shall only mention, as a reminder, the various tests used to diagnose death ofthe nervous system and on the results of which one is entitled to stop artificial respiration (Fig.9):

• no spontaneous resumption of respiration when the respirator is switched off
• absence of recordable cortical and subcortical electrical activity from a deep electrode
• poikilothermia
• polyuria
• failure to fill the cerebral vascular tree by arteriography.

Next page