[Unexplained electrographic temporal discharges (author's transl)]. / Décharges électrographiques temporales inexpliquées.

Unilateral or bilateral electrographic temporal discharges at 5 Hz were analyzed in relation to their morphological characteristics, their topography, and their evolution in II subjects. The clinical context, in which there was no evidence of epileptic disorder, was also analyzed. These discharges were compared to other infraclinical critical phenomena reported in the literature, and related to similar manifestations described by the Gibbs "school" as "Psychomotor variant type of discharge", or by Hughes group as "Rhythmic mid Temporal discharges".

[Lambda waves in the neonate (author's transl)]. / Ondes lambda chez le nouveau-né.

Different types of sharp elements can be observed over the occipital regions from the 2nd postnatal week in the open-eyed child, with active eye movement but practically no body movement. Certain of these sharply localised elements in the occipital midlin are identical to adult lambda waves. Their early occurrence calls to mind the emergence of visual function and attention, these latter occurring at the end of the neonatal period between 7 and 9 days.

[Density and dynamic of frontal sharp waves (encoches pointues frontales) during sleep in new-borns and infants (author's transl)]. / Densité et dynamique des encoches pointues frontales dans le sommeil du nouveau-né et du nourrisson.

Frontal sharp waves (encoches pointues frontales) identified by Monod (1960) were studied in 110 neonates and infants. Three pattern were described: typical, related and degraded. They were recorded in all subjects, the reason why the frequency of each pattern varied was discussed. Pathological states did not increase the occurrence of those frontal sharp waves since most of them were recorded in children either normal or suffering from a minor pathology. Incidence of maturation seemed to be probable since the highest proportion of frontal sharp waves occurred in infants whose gestational and legal age were respectively greater than 43 weeks and between 20 and 40 days at the time of investigation. Typical and degraded forms were predominant in transitional period towards quiet sleep; they were less numerous during falling asleep in active sleep and totally absent during active sleep following quiet sleep. This could suggest that the two states of active sleep are different in nature.

[Action of ketamine of paroxysmal discharges provoked by air emboli in the baboon Papio papio]. / Action de la kétamine sur les décharges paroxystiques provoquées par embolie aerique chez le babouin Papio-papio

Ketamine was administered to 18 baboons (Papio papio) to disrupt epileptic discharges elicited through intracarotid air injection. Discharge suppression was obtained in all animals but could be preceded by a phase of enhancement of the epileptic patterns, which rendered necessary the injection of a supplementary dose. The mechanisms of Ketamine action are discussed, in connection with data from the literature. Some of the latter suggest that its use in proved epileptics facilitates paroxystic patterns or even convulsions while others emphasize its antiepileptic action. Present data corroborate the ambivalent action of this drug. However, its dominant depressant effect obtained with increasing doses is somewhat favourable to its administration to epileptic patients.

[EEG and craniofacial injuries]. / E.E.G. et traumatismes cranio-faciaux

The number of cases studied was too small to be really representative of the role of the E.E.G. in the assessment of cranio-facial trauma cases. The following points may nevertheless be stressed: -The usefulness of negative findings. The E.E.G. may be used to confirm that a purely facial impact, or one without any severe cranial involvement, has only minor or quite negligeable cerebral repercussions. -The presence of significant E.E.G. changes indicates marked cerebral involvement. The nature of the latter (contusion, haematoma etc.) cannot be determined by the E.E.G. alone but any obvious localising signs (e.g. severe frontal deterioration) should indicate the possibility of a lesion requiring urgent neurosurgical treatment. In particular, sub-frontal extra-dural haematomas are associated with abnormalities clearly localised in the fronto-polar regions (R. Vigouroux et al., 1962). Apart from such specific collections, the type of damage described in operative reports easily explains the major disturbances in the frontal tracing which are almost invariably encountered. -The value of an early E.E.G. examination and of repeated studies. The first record gives an indication of the cerebral "state" and of possible "functional" disturbances which may exist later after the accident. Above all, it represents a valuable prognostic indication, in particular in patients who are in coma, precisely reflecting the depth of the latter and its potential reversibility. The course and progress of initial abnormalities is also an element in prognosis. In our patients, it was surprising to note the ease with which certain initial major disturbances resolved. However the persistence of minor alterations should lead to reserve with regard to the recovery of complete cerebral integrity and such subjects should be carefully followed up.

[EEG effects of sodium nitroprusside and hemodynamic references]. / Effets EER du nitroprussiate de sodium et references hemodynamiques

A study was performed on baboons (Papio papio) of various hemodynamic and EEG effects of sodium nitroprussiate (SNP), substance with powerful vasodilator action. Three different procedures of drug injection were used: (1) in isolation, either in doses close to those used in clinical practice or in high doses; (2) after neuroleptanalgesia (NLA); (3) after causing vasospasm. With isolated SNP, effects on blood pressure were unstable; in certain cases hypotension could be maintained only with toxic doses. Hypotension was facilitated when NLA had been previously induced. At low doses the cerebral blood flow (CBF) was practically unmodified, whereas at toxic doses it first increased then decreased. In animals under NLA, the CBF drop was only moderate, suggesting persistence of adequate spasm, CBF was significantly improved through SNP. The EEG did not undergo sizeable change at low SNP doses given in isolation; toxic doses always induced alterations with peculiar morphology, but developing only tardily after SNP perfusion was begun. This lag may indicate that hypotensive and toxic SNP effects are dissociated. These alterations suggest that screening of the EEG is necessary during prolonged administration of SNP, e.g., in surgical procedures. Combining NLA and SNP (at low doses) causes EEG deceleration, but no great alteration of the rhythms, as observed during other types of controlled experimental hypotension. Hence, cerebral circulation may be relatively well protected during SNP hypotension.

[Experimental study of the cerebrovascular effects of sodium nitroprusside in the baboon Papio papio. Its action on the experimental vasospasm]. / Etude expérimentale des effets cérébro-vasculaires du nitroprussiate de soude chez le babouin Papio papio. Son action sur le vasospasme expérimental

Sodium nitroprusside (SNP) has been suggested as hypotensive agent in the surgery of cerebral aneurysms. As a preliminary step to neurosurgery, a study of its cerebro-vascular and EEG action had been carried out in 42 papio-papio baboons. On the unanaesthetized analgesic-free animal, doses below 20 mumg/kg/min. induce only a moderate decrease of mean arterial blood pressure (MABP), a slight rise of intracranial pressure (ICP) and a neat fall of cerebro-vascular resistance (CVR) without EEG modifications. Doses above 50 mumg/kg/min. induce a neat fall of MABP with a rise of cerebral blood flow (CBF), of ICP and signs of poisoning with metabolic acidosis and prolonged EEG disturbances. Beyond 90 mumg/kg/min. irreversible hypotension occured accompanied by metabolic acidosis and progressive abolition of cerebral electrogenesis. The hypotensive action of SNP is potentiated by neuroleptanalgesic drugs (phenoperidine and dehydrobenzoperidol). Using this combination marked hypotension was achieved with non toxic doses of SNP (6 to 10 mumg/kg/min.). During those hypotensions cerebral auto-regulation was maintained up to a MABP of 50 mmHg. Deeper brief hypotensions up to a MABP of 25 to 45 mmHg induce a 23% fall of CBF (p less than 0, 05) but without major EEG alterations. During experimental arterial spasms induced by injection of blood in the cisterna magna or serotonin infusion, SNP has a vasodilating action. It induces a significant rise of CBF (p less than 0, 01) for doses between 8 and 19 mumg/kg/min.