Sociedad española de electroencefalografia y neurofisiologia clínica

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ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY

SOCIETY

PROCEEDINGS

S O C I E D A D E S P A N O L A DE ELECTROENCEFALOGRAFIA Y

NEUROFISIOLOGIA CLiNICA Barcelona, December 11-12, 1964

Secretary:

DR. J. CARBONELL

Gran Hospital, Diego de Le6n, Madrid (Spain) 1. The EEG as a unifying pattern in 14 cases of subacute selerosing leucoencephalitis. - - D. Marmol (Seville). An analytical study is made of the electroencephalographic development of 14 cases of subacute sclerosing leucoencephalitis, pointing out the importance of periodic slow paroxysms, which have served as a unifying pattern and a clinical identification datum in each case. In the longitudinal study we review changes in background activity and the presence of irritative signs or neuronal deficiency. The importance and teaching of a longitudinal study are given more emphasis than the establishment of transverse electro-clinical correlations. 2. EEG study in respiratory insufficiency. - - J. Vanrell and R. Vifies (Barcelona). Eight cases are presented of patients with a syndrome of chronic respiratory insufficiency, which showed an evident neurological symptomatology and which were studied from the EEG point of view. A short clinical and EEG description of each case is given. The EEG records are classified according to the degree of the observed alterations; each is described separately. The EEG discoveries are compared with others published, giving consideration to r~curo-physiological factors. 3. Abnormal EEG in functional digestive disorders. - - R. Vifies and J. Vanrell (Barcelona). Thirteen patients, whose reasons for consultation were digestive disorders such as epigastralgia, vomiting, incontinence, etc., were studied from the EEG point of view. Not finding an obvious direct digestive aetiology, the general practitioner or the neurologist recommended an EEG study; in all of them a clearly abnormal record was found, generally paroxysmal, focal or centrencephalic. Anticonvulsive medication abolished or greatly improved the symptoms of these patients. 4. Paroxysmal EEG abnormalities in temporal regions of healthy people. - - J. A. Brafia (Madrid). EEG records of 330 healthy adult males, of an age between 22 and 33 years, without epileptogenic, pathological antecedents and without clinical manifestations of any type, and obviously without paroxysmal phenomena of any kind, were studied. Several EEG records were made of a great number of them, especially those who presented irregularities or abnormalities of the

record. Ten of these individuals presented localized hypersynchronous paroxysmal abnormalities or a clear predominance in one temporal region. These abnormalities appeared as spikes, sharp waves or very sharp pseudo-rhythmic theta activity of a much bigger voltage than 80 pV, which appeared at rest and especially with hyperventilation. The published work is reviewed and the possible meaning and importance of these discoveries are discussed. 5. Bilateral discharges of spike and wave complexes with intermittent photie stimulation in non-epileptic individuals. - - P. de Castro (Madrid). The published work on paroxysmal discharges of bilaterally synchronous spike and wave complexes over the whole of the two hemispheres, provoked by intermittent photic stimulation, in individuals without epileptic clinical manifestations, is briefly reviewed. Our experience of the percentages of this electrographic abnormality in different pathological conditions and in healthy persons is presented and electro-clinical correlations are established. We especially emphasize the relative frequency of this type of paroxysm in children with clinical symptomatology of banal vaso-vagal syncopes, vascular headaches and character disturbances, and examine the spontaneous evolution and the effect of anticonvulsive treatment on clinical and electrographic manifestations. The possible meaning of these findings and their practical importance are discussed. 6. Development of focal paroxysmal discharges in the EEGs of patients with chronic cerebral insufficiency. J. M. Sacristfin (Madrid). A group of patients with cerebral circulatory insufficiency, with or without infarct, especially due to arteriosclerosis, is studied from the etectrographic and clinical points of view, with special emphasis on those who present focal paroxysmal abnormalities in the EEG. The morphology, localization and development of these abnormalities are analysed, establishing electro-clinical correlations. 7. Posterior slow rhythms of petit mal and their possible relation to cerebral dominance. - - L. Oiler Daurella - and E. Mas6 Subirana (Barcelona). At the recent meeting of the International Institution of Electroencephalography, the problem was presented of the relationship of some posterior slow rhythms, especially

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SPANISH EEG SOCIETY those which are frequently observed in petit mal, with hemisphere dominance. The authors reviewed a group of epileptics who presented this type of rhythm several times, either before the beginning of treatment or during it, and subjected them to different tests for the study of cerebral dominance. The results are discussed, pointing out that the possible localization of these rhythms in the minor hemisphere does not diminish their importance as a bioelectrical phenomenon in the diagnosis of the different types of epilepsy and of petit mal. 8.

Deprivation of sleep as an activating method of the E E G in epilepsy. - - L. Oiler Daurella (Barcelona).

The author has used deprivation of sleep as a method to activate the EEG of epileptics. The studies carried through by other authors on normal persons, and on epileptics whose attacks have appeared after a long time without sleep, have led him to submit epileptics with normal or not very demonstrative EEGs to this test. The results obtained are discussed. 9.

E E G exploration of a cranioencephalic post-traumatic series. - - J. Jim~nez Castellanos, D. Marmol, F. Castellanos and M. Cabezas (Seville).

Examined from the EEG point of view are 156 cranioencephalic post-traumatic cases, 76 of which have normal records and 80 abnormal records. Among these alterations predominate frequency changes, observed in 70 cases; nevertheless there are abnormal elements in 21 and amplitude changes are detected only once. We have tried to evaluate the clinical data, as well as the electrical results, emphasizing the following points: (a) degree and duration of disturbances of consciousness which accompany tile trauma; (b) special consideration of the kind and location of trauma, comparing it with the possible electroencephalographic focal activity; (c) time elapsed between the accident and the EEG; (d) post-traumatic clinical symptomatology, with special reference to the reason for exploration; (e) individual events, specially age and sex. 10. Deep eleetroeneephalography. - - J. Jim~nez Castellanos, M. Murga, J. L. Ramps, D. Marmol and A. Rodriguez (Seville).

Tile tirst clinical results of deep electroencephalographic control are presented thanks to the stereotaxic approach to subcortical brain structures. The double value of this technique is emphasized: first, it allows us to mention important differences in bioelectrical activity, which may guarantee a functional topographic control, with great efficiency and utility, for common localization and for the differentiation of pallidal, and especially thalamic, structures. Secondly, even more interesting is its auxiliary role in the localization of deep epileptogenic foci which may be the reason for a later stereotaxic destruction or for a wider direct surgical resection. 11. Some considerations about tetany in adults. - Subirana and E. M a s 6 Subirana (Barcelona).

A.

The authors reviewed quickly the clinical symptomatology of 24 cases with E M G signs of tetany. All of them were

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patients who had been studied twice or more often from the E M G point of view and in whom the adequate therapy had provoked total or partial disappearance of the symptomatology. Paraesthesiae, especially brachial and essentially nocturnal, are the most frequent clinical expression. Secondly, there are psychic symptoms: anxiety syndromes, depression, etc. Less often appears another symptom series: headaches, functional crises, morphological disturbances, etc. In this connection, we studied in more detail two brothers with EMG and clinical signs of tetany and one case which showed the classic symptomatology of this illness with morphological disturbances. 12. Echoencephalography. Important comments on a particular case. - - J. Vila Bad6 and J. M. Sams6 Dies (Barcelona).

This is a general review of our experience in the use of this cerebral exploratory method, which gives important information, particularly when it is compared with electroencephalographic data. We comment on one case in which the echoencephalogram showed a peculiar aspect. 13. Focal crisis of localized paroxysmal expression as the prologue to hypsarrhythmia. - - L. Oiler Daurella, J. M. Sams6 Dies and J. Vila Bad6 (Barcelona).

Epilepsy in the infant sometimes presents greatly misleading characteristics. The authors comment on the observation made by two of them (J. M.S. and V.B.) of a 10 days infant with focal crises in the right extremities which showed in the EEG as spike discharges in the contralateral hemisphere; the intercritical record presented a low ~oltage and lack of organization of cerebral rhythms. This patient was seen 12 months later by the other author (L.O.D.) with a typical clinical and EEG symptomatology of hypsarrhythmia, including spasms in flexion, accompanied by typical paroxysmal depression of short duration. The different types of hypsarrhythmia and its various aetiologies are discussed and the interest of a closer relation between the different electroencephalographic services is shown. 14. Cybernetic hypothesis on the organization of epileptogenic foci. - - J. M. Sams6 Dies and J. Vila Bad6 (Barcelona).

The progressive establishment of loci in patients with epilepsy, especially based on EEG foci and experimental anatomo-pathological discoveries, suggests a great probability of the fundamental and unitary organization of the epileptic focus. This theory, based on the conjunction of neuronal metabolic functional auto-regulation and on the systemic auto-regulation of energy or the vascular contribution in tissues according to its supply by negative feedback action, may explain the organization of epileptogenie loci in the following stages: neuronal aggression, hypoxia, anoxia, metabolic deficit, neuronal necrobiosis, cicatricial gliosis. The epileptogeny will exist in functionally active neuronal cells next to gliosis, due to hypoxia or chronic metabolic deficit, due to a deficient w~scular supply, because of belonging to a tissue with an approximately 10 times smaller oxygen consumption than that

Electroenceph. clin. Neurophysiol., 1966, 20 : 620-622

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SOCIETY PROCEEDINGS

necessary for neuronal tissue. The chronic metabolic deficit of the neurones mentioned causes an increase of excitability which facilitates the probability of autochthonous discharges in the affected neurones, typical of the epileptic unitary discharge, synchronous discharges of high frequency and with temporal grouping. The discharge determined in neuronal groups greatly interrelated through synaptic connections may cause functional discharges which will produce a secondary focus; this, by an opposite mechanism, vascular consumption during the convulsive discharge, will cause a vascular degeneration, with neuronal necrobiosis and cicatricial gliosis, which will be the exponent of the organic lesion to which the functional secondary focus may arrive. The authors suggest this hypothesis as a possible starting point of an experimental working method to determine its sufficiency or its deficient points in the creation of experimental foci and the logical explanation of the secondary focus at a distance in these cases, in which a real organic alteration can be shown in the course of time. 15. The E E G in 68 cases of posterior fossa lesions. - - J. Santoni and J. Carbonell (Madrid).

Cerebello-pontine angle tumours mostly showed normal or bilaterally, non-specifically altered records. Some showed lateralizing features which always coincided with the affected side. Cerebellar hemisphere tumours evoked bilateral abnormalities but, out of 17, 8 had homolateral localizing signs, whereas 4 had contralateral signs. Unilateral theta emphasis seemed more reliable than delta

asymmetry in the correct lateralization. Cerebellar midline and IVth ventricle lesions showed some loss of alpha rhythm with bilateral paroxysms of frontal or occipital delta rhythm. All brain-stem tumours evoked similar discharges. The striking general features were: notching of rhythmic delta waves, reminiscent at times of spike and wave complexes, the frequent number of isolated high voltage occipital sharp waves, and less frequent hypersynchronous bursts of high voltage alpha rhythm. 16. Evaluation of some periodic activities in the EEG. - J. Carboneli, J. Santoni and S. Hortig6n (Madrid). A review of periodic activities studied during the last 6 months in our service. We have usually found this kind of activity: in subacute sclerosing encephalitis, in some cases of myoclonic epilepsy, in the last stages of some generalized fits, in 1 case of Nevin Jones, in some stages during cardiac surgery with extracorporeal circulation and hypothermia, etc. We emphasize the varied aetiology of these cases and, nevertheless, the similarines among the above records. We think that periodic activities in the EEG mean particularly the existence of diffuse cerebral damage, which may be transitory or permanent at a cortical and deep level. The deep structures afl'ected will modulate periodically the cortical activit?y. This modulating mechanism, not well known, which appears at times in some patients after sensory stimulation, will have a longer autonomy in some illnesses, The necessary corticosubcortical interaction for periodic activity appears evident.

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SOUTHERN ELECTROENCEPHALOGRAPHIC SOCIETY Charlottesville, Va., November 19-21, 1965

Secretary: L. F. STEWART, M . D . Neurological Service, University of Virginia Hospital, Charlottesz~ille, Va. (U.S.A.) 1.

Stimulation and electrographic recording from multiple subcortical areas in alert man. - - B. S. Nashold Jr. and W. P. Wilson (Durham, N. C.).

A series of observations in alert man will be presented in which electrical stimulation and electrographic recordings were made from electrodes chronically implanted in the thalamus, subthalamus and midbrain. By means of stereotactic neurosurgery, depth electrodes can be introduced into specific subcortical areas for long periods of time. The techniques are safe and electrophysiological data can be gathered when the patient is in a normal state without effects of anesthesia or the duress of the surgical procedure. The electrodes are multiple contact with specific distances between each contact point. They are small enough to produce minimal

brain damage and can be left in the brain for periods up to 4 weeks with safety. Multiple electrodes are implanted with as many as 36 separate recording points. Persons suffering from epilepsy, involuntary motor disorders and central pain have been studied in this manner. Evidence will be presented on the presence of caudate spindles after depth stimulation from the thalamus, globus pallidus, head of the caudate nucleus and interna I capsule. Epileptiform discharges have been recorded from the mesencephalic tegmentum in a person with central pain. The discharges occurred in synchrony with the pain. A person with mirror epileptic loci in the frontal region was studied with multiple depth electrodes in each frontal lobe followed by bilateral cortical resections. Details of these observations will be discussed.

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