Physiological asymmetry of brain functions--its influence on the lateralization, symptomatology and course of the epileptic process.

Lateralization of the epileptic process in a group of 152 subjects and the relationship of epilepsy to the lateralization of brain functions was studied in smaller groups of 108 and 56 subjects. A unilateral epileptic process in the temporal limbic structures of the brain is localized in the left half of the brain twice (in 64.5%) to four times (in 80.8%) as often as in the right half. The greater the asymmetry of physiological brain functions--in particular motor and verbally symbolic functions--the more is this tendency pronounced. An epileptic process in temporal limbic structures of the left half of the brain is manifested more often in primarily generalized epileptic seizures with initial sudden and complete loss of consciousness. Episodic spike-and-wave activity, which is the typical electroencephalographic correlate of primarily generalized seizures, or of the thalamocortical aetiopathogenetic component of the epileptic process, is often asymmetrical in amplitude, which in 68.1% of these cases is twice as high over the left hemisphere. An epileptic process in subcortical structures of the right hemisphere impairs physiological asymmetry of emotive facial mimicry (with preponderance of mimic reactions on the left) and in 68.4% of the cases causes atypical preponderance of emotive mimicry in the right half of the face. A unilateral epileptic process in subcortical structures of the left half of the brain has a more favourable course and more hopeful prognosis in 70.4% of the cases, while the course of a right-sided process is worse in 67.6%.

Prophylactic treatment of posttraumatic epilepsy: results of a long-term follow-up in Czechoslovakia.

The results of a long-term study of prophylactic treatment of posttraumatic epilepsy performed in Czechoslovakia during the years 1963 through 1980 are reported. The prophylactically treated group of 144 patients with severe brain injuries was compared with a control group of 24 equally damaged cases without prophylactic treatment. The preventive treatment lasting 2 years in the great majority of cases was performed with relatively low doses of phenytoin (160--240 mg/day) and phenobarbital (30--60 mg/day) administered orally. The incidence of late posttraumatic epilepsy was 25% in the control and 2.1% in the prophylactically treated group. Only one patient (0.7%), however, developed seizures during the course of the prophylactic treatment. The efficiency of prophylactic pharmacotherapy has been proved in long-term observations lasting 8 to 13 years.

Activating effect of nasal and oral hyperventilation on epileptic electrographic phenomena: reflex mechanisms of nasal origin.

In experiments on animals, airflow through the nasal cavity elicits rhythmic synchronized activity that can trigger and/or elicit epileptic electrographic activities in the limbic structures of the brain. This could be demonstrated in studies of lower vertebrates (frogs and turtles). In the turtle the elicited paroxysmal activity often had the shape of regular high-voltage activity in the theta-frequency range (average frequency, 4.1 Hz). It was further proven in clinical experiments that nasal deep breathing with a closed mouth effectively activates epileptic electrographic phenomena of a temporal (limbic) origin. The activating effect was more pronounced on the side ipsilateral to the ventilated nasal meatus. It could also be evoked by air insufflation into the nasal cavity. This effect was suppressed by anesthesia of the mucous membrane in the upper nasal meatus. Possible mechanisms of this, probably reflex, phenomenon are discussed.

Activating effect of nasal air flow on epileptic electrographic abnormalities in the human EEG. Evidence for the reflect origin of the phenomenon.

Deep nasal breathing [with the mouth closed] activates [to a certain extent selectively], in the human EEG, epileptic abnormalities of diencephalotemporal origin [Servít et al. 1977]. This activating effect could be suppressed by local anaesthesia of the mucosa membrane in the superior nasal meatus. The same abnormalities could be elicited or activated by air insufflation into the upper nasal cavity, without pulmonary hyperventilation. These results speak in favour of the assumption that a neural [reflex] mechanism of the activating effect of nasal hyperventilation is involved, with a reflexogenic area in the superior nasal meatus.

Theta (RSA) activity in the brain of the turtle.

The existence of a synchronizing system generating theta (RSA) activity of an average frequency of 4 Hz has been demonstrated in the brain of the turtle Testudo Graeca. Three brain structures probably participate in the activity--the septum, amygdala and hippocampus. The septal region seems to play a leading role in this complex--lesions in this region abolished the generation of theta activity in 71% of experiments. This synchronizing system is functionally coupled with the olfactory generator of electrographic respiratory response (ERR), which is brought into activity by nasal air flow. This coupling can play a role in genesis of epileptic electrographic activities not only in the turtle, but also in phylogenetically higher species.

[Etiopathogenetical diagnosis and therapy of epilepsy (tentative application of some neurophysiological data)(author's transl)]. / Atiopathogenetische Diagnostik und Therapie der Epilepsie (Versuch einer Anwendung physiologischer Erkenntnisse).

A purely symptomatological classification of epilepsies can be substituted by diagnostical determination of etiopathogenetical components, which take part in the origin and evolution of the pathological process in individual cases. Usually it can be done by simple diagnostical processing. The etiopathogenetical diagnosis can also contribute to a less empirical and more rational use of therapeutical means.

Activation of epileptic electrographic phenomena in the human EEG by nasal air flow.

The activating effect of deep oral breathing (with the nose closed) and nasal hyperventilation (with mouth closed) was examined in 62 patients with three different kinds of epileptic EEG abnormalities: unilateral localized temporal (fronto-temporal, occipito-temporal) abnormalities - group F, bilateral episodic theta-delta abnormalities - group TH, and bilaterally synchronous spike and wave abnormalities - group SW. Nasal hyperventilation was much more effective in group F and TH. Its effect was already significant 30-60 seconds after the start of deep breathing. In the group SW there were no statistically significant differences between the effects of nasal and oral hyperventilation. Unilateral nasal hyperventilation (the other nasal cavity being closed by tamponade) demonstrated a more pronounced activating effect on ipsilateral localized temporal EEG abnormalities. These effects of deep nasal breathing can hardly be explained by metabolic-vascular mechanisms, which probably are involved in the course of oral hyperventilation. On the other hand they are in agreement with animal experiments demonstrating that the mechanical stimulus of nasal air flow operates as a synchronizing impulse for certain rhinencephalic structures.

The effect of acetyldexphenmetrazine and dexphenmetrazine on the susceptibility to audiogenic seizures in mice.

The antiepileptic effect of dexphenmetrazine (DP) and acetyldexphenmetrazine (ADP) was tested on audiogenic seizures in a 100% susceptible strain of mice. DP had no antiepileptic effect, however, it markedly suppressed the postparoxysmal motor inhibition. ADP had a distinct anticonvulsive effect--it suppressed the convulsive component of the seizure, leaving its running component unaffected. The results are compared with the effect of both drugs on electrographic epileptic phenomena in the turtle brain (Servít and Strejcková 1976).

The effect of dexphenmetrazine and acetyldexphenmetrazine upon epileptic electrographic activities in the brain of the turtle.

The effect of acetyldexphenmetrazine (ADP) and dexphenmetrazine (DP) on normal and epileptic electrographic activities in the cortical and thalamic structures of the turtle brain were studied in curarized and artificially ventilated animals. Both drugs almost exclusively influenced cortical activities. The effect of low doses of ADP and DP was similar--they desynchronized cortical activity and suppressed the activity of a cortical penicillin focus. They also elevated the cortical response to optic stimuli. Higher doses of ADP continued to suppress both normal and epileptic cortical activities. Higher doses of DP had a two phase effect with enhancement of epileptic activity in the first phase. Continuous trains of theta activity appeared after low doses of ADP and very often after both low and high doses of DP. The findings are discussed in terms of comparative physiology of the brain.

Influence of nasal respiration upon normal EEG and epileptic electrographic activities in frog and turtle.

The electrographic respiratory response (ERR) was elicited by nasal air flow in the brain of the frog and turtle. It had the shape of a spindle of high voltage rhythmic activity and was propagated from the olfactory bulb predominantly into the ipsilateral hippocampal region in the frog and into the pyriform cortex in the turtle. In both animals, thalamic propagation of the ERR was also found. In both animals epileptic electrographic phenomena, were enhanced, created by local penicillin application. In the turtle epileptic electrographic manifestations were also elicited in the intact brain by simple nasal air insufflation. Diazepam (intraperitoneal administration) had no effect either on the ERR or on its triggering effect on epileptic phenomena. The possible physiological and pathophysiological interpretations of these findings are discussed.