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Biomedical subjects

S A Chkhenkeli

Publications and source records attributed to S A Chkhenkeli.

At least 19 recordsLinked to original sources
PubMed1997

Effects of therapeutic stimulation of nucleus caudatus on epileptic electrical activity of brain in patients with intractable epilepsy.

The effects of electrostimulation of caput nuclei caudati (CNC) were investigated in 57 patients. Long-term implanted multicontact electrodes were used in 38 patients. In 23 cases, completely implanted neurostimulators and in the remaining 15 cases externalized electrodes were used. Investigations demonstrated that a low-frequency (4-6 Hz) stimulation of certain points of the ventral part of CNC reliably led to (1) a decrease of interparoxysmal activity in the neocortical and mesial temporal epileptic foci; (2) a decrease of focal discharges in the aforementioned areas, and (3) abrupt cessation of spreading and generalized discharge.

Amygdala↗
PubMed1990

Clinical experience in intraoperational determination of brain inhibitory structures and application of implanted neurostimulators in epilepsy.

Therapeutic brain stimulation was applied in 74 patients with resistant forms of epilepsy. It was shown that low frequency stimulation of certain zones of the head of the caudate nucleus and higher frequency stimulation of the dentate nucleus of the cerebellum lead to a marked suppression of interparoxysmal epileptic activity and to a disruption of both focal and generalized epileptic discharges. It is necessary to determine, by means of stereo-electroencephalography, the variability for localizing the inhibitory zones of the structures to implant the neurostimulators exactly.

Caudate Nucleus↗
PubMed1987

[The problem of neuroroentgenologic diagnosis of an epileptic focus in so-called temporal lobe epilepsy].

The size of individual elements of temporal cornua of the lateral ventricles of the normal human brain has been determined. The topic diagnostic informative value of preoperative pneumoencephalography has been found inadequate for determining the degree of morphological alterations in the mediobasal brain structures. On the basis of the findings from preoperative pneumoencephalograms and operative positive ventriculograms of 80 patients the author has demonstrated the necessity of a detailed ventriculographic examination of the brain using the technique of orthogonal teleroentgenography and administration of positive contrasting agents. The ventriculographic criteria for locating the epileptic focus, verified by stereoelectroencephalographic studies, have been described.

Adolescent↗
PubMed1981

[Effectiveness and current principles of pharmacologic diagnosis of epileptic focus using short- and ultrashort-acting analeptics and barbiturates].

An analysis of the results of examining 50 operated epileptic patients has shown that the use of short- and ultrashort-acting analeptics and barbiturates makes it possible to specify not only the location of the epileptic focus, but also to disclose the character of the interrelations between the elements of the epileptic system. Especially valuable data can be obtained with the use of brietal. The use of analeptics is the most promising in the course of operation, and, therefore, it should be limited to the preoperational period. It is suggested that the method of implanting permanent intracerebral electrodes acquires now not only diagnostic, but primarily therapeutic importance.

Amygdala↗
PubMed1979

[Telemetric electroencephalographic and stereoelectroencephalographic studies in the topical diagnosis of an epileptic focus].

Telemetrical recordings of the EEG and stereoelectroencephalographic (SEEG) studies of patients with generalized epilepsy demonstrated a high informativeness of these techniques. The existence of focal changes in the routine EEG recording require an obligatory control by telemetrical EEG studies. An absence of focal changes in the EEG and teleEEG recording may serve as an indication for teleSEEG studies with the use of durative deep electrodoes. In patients with generalized seizures a trigger focus in the frontal or temporal lobe may be found quite frequently.

Electroencephalography↗
PubMed1979

["Forced normalization" EEG phenomenon and several mechanisms of psychopathologic symptoms in epileptic patients].

Some electrophysiological correlations of periodically exacerbating psychopathological manifestations in epilepsy are discussed. It was established that in phenomenon of a "forced normalization" of the EEG deep structures of the lymbic system may show active foci of epileptical bioelectrical activity. It is suggested that such pictures of bioelectrical activity in the different brain structures are formed as a result of dissociated inhibitory influences of the brain stem. The necessity of a stereoelectroencephalographic study in this group of patients is emphasized in order to assess the possibilities of a successful surgical operation.

Amygdala↗
PubMed1977

[Several electrophysiologic variants of temporal lobe epilepsy].

The study discusses the diagnostic value of some electrophysiological methods of investigating patients with temporal lobe epilepsy. It is emphasized that routine EEG, basal and tympanic leads are not informative enough. Special attention is paid to the study of stereoelectroencephalographic activity of deep epileptic foci and "secondary" synchronization phenomena. It is suggested that SEEG is a necessary component of preoperative study. It is also pointed out that a bitemporal pathological activity should not be considered a contraindication to a surgical treatment of epilepsy.

Amygdala↗
PubMedDate not supplied

[Clinico-experimental research on the electrophysiological and polarographic characteristics of the cerebral cortex in hypoxia].

Electrocorticography, measurement of tissue PO2, local cerebral blood flow, and sodium ion concentration in the extracellular fluid of the cerebral cortex, as well as study of dynamics of the response of the cortex to its direct electrical stimulation, conducted during neurosurgical operations on patients with tumors of the brain and in experiment revealed two stages in the changes of excitability of the cortex: first stage--its sharp increase and second stage--its suppression. Electrophysiological and polarographic characteristics of these stages of edema and excitability of the cerebral cortex are shown. The results of the research are discussed from the standpoint of the pathomechanisms of the occurrence and cessation of epileptic seizures in the development of brain edema.

Animals↗
PubMedDate not supplied

[Analysis of coordinate systems of intracerebral structures and optimization of sterotaxic computations for the posterior longitudinal approach to the hippocampus].

In studying the three-dimensional interrelationship of the thalamic and temporal systems of co-ordinates it was proved that one of them cannot be used in calculating the stereotaxic co-ordinates of structures associated with the other. In combined stereotaxic operations it is necessary to construct combined independent systems of co-ordinates. The possibility of exact construction of the co-ordinate systems of intracerebral structures depends to a great measure on the positive contrasting of the ventricular system.

Cerebral Ventriculography↗
PubMedDate not supplied

[Complex characteristics of an epileptogenic focus in intracerebral space-occupying processes according to the findings of electrocorticography, polarographic studies and electron microscopy].

The work discusses the results of a study of the overall electric activity of the cerebral cortex, its frequency analysis and integration in brain tumors attended with epileptic seizures. The changes in electric activity are correlated with the cortical ultrastructure and the oxygen balance in the brain tissue. The possible mechanisms responsible for the development, cessation or absence of epileptic seizures in the clinical picture of brain tumors are analysed. Data are presented in evidence of the important role of hypoxia of various degrees in these mechanisms. It is established that activation of the synaptic apparatus may be considered as an ultrastructural correlator of hyperexcitation in the epileptic focus.

Brain Chemistry↗
PubMedDate not supplied

[Results of surgical treatment of severe forms of temporal epilepsy].

The work deals with the results of surgical management of 61 patients with temporal-lobe epilepsy. The indications for the use of various types of operative interventions in this pathological condition are discussed. Positive results of treatment were obtained in 90.8--80.65% of cases. Deterioration in the patients' condition was not noted. It is emphasized that indications for surgical treatment must be determined as early as possible.

Adolescent↗
PubMedDate not supplied

[Analysis of several causes of inadequate surgical treatment of epilepsy].

From the analysis of 100 cases with stereotaxic and "classical" surgical treatment of epilepsy several premises are drawn. The source of possible errors in the topical diagnosis of an epileptic focus may be overestimation in some case of the results of routine neuroradiological examination, and the possibility of the existence of reciprocal interrelationship of the epileptic foci and the activation of one of them in removal of the other. The authors suggests a method of control over the activity of intact foci after removal of the dominating elements of the epileptic systems. Some doubt is expressed concerning the diagnostic value of control (i. e. after removal of the focus) ECG examination and the conviction is stated for the need of widen the volume of single-stage stereotaxic operations by combining the destruction of the most active elements of the epileptic systems.

Adult↗