Déjà vu phenomenon-related EEG pattern. Case report.

BACKGROUND: Déjà vu (DV, from French déjà vu - "already seen") is an aberration of psychic activity associated with transitory erroneous perception of novel circumstances, objects, or people as already known. OBJECTIVE: This study aimed to record the EEG pattern of déjà vu. METHODS: The subjects participated in a survey concerning déjà vu characteristics and underwent ambulatory EEG monitoring (12-16 h). RESULTS: In patients with epilepsy, DV episodes began with polyspike activity in the right temporal lobe region and, in some cases, ended with slow-wave theta-delta activity over the right hemisphere. There were no epileptic discharges in healthy respondents during DV. CONCLUSION: Two types of déjà vu are suggested to exist: "pathological-epileptic" déjà vu, characteristic of patients with epilepsy and equivalent to an epileptic seizure, and "nonpathological-nonepileptic" déjà vu, which is characteristic of healthy people and psychological phenomenon.

[Evoked skin sympathetic potentials and electroencephalography in the differential diagnosis of temporal and frontal epilepsy].

An aim of the study was to investigate indices of autonomous regulation (evoked skin sympathetic potentials--ESSP) and EEG in temporal and frontal epilepsy (TE and FE) before and after functional tests (physical, psychoemotional, hyperventilation). The study included 24 patients with TE, 20 patients with FE and 20 healthy controls. The enhance of sympathetic component of reaction was seen in FE and that of parasympathetic component--in TE. The sympathetic response to physical load and hyperventilation was insufficient in both forms of epilepsy that manifested itself in the reduced reaction amplitude and its longer duration. In the psychoemotional test, the reduction of sympathetic reaction amplitude and its later development was more characteristic of TE compared to FE. In conclusion, resting ESSP is more significant for differential diagnosis of TE and FE while in the functional test only quantitative differences between these forms were observed.

Pathophysiological aspects of the formation of neurological deficit in multiple sclerosis.

The results of complex studies were used to formulate a concept of the development of neurological impairments in multiple sclerosis (MS). Acutely developing impairments to spike propagation, reaching the level of conduction blockade, due to the active pathological process with demyelinating and axonal damage to the CNS lead to the formation of neurological impairments in exacerbations of MS, while complete or partial reversion (regression) of these symptoms in the stage of remission results from compensatory changes in the nature of conduction, which were not, however, accompanied by recovery of electrophysiological measures. The development of stable neurological deficit in secondary-progressive MS is determined by impairments to spike conduction processes associated with significant levels of demyelination and atrophic changes in the CNS, with myelin loss and axon death. Finally, the severity of cognitive changes is determined by differences in the severities of both the focal demyelinating process and diffuse damage to brain substance in MS, including the neurodegenerative component. The main factor in transient increases in symptoms is the universal lability of electrophysiological parameters, including those developing on the background of ion and neurotransmitter imbalance.

[Compressive-spectral analysis of EEG in patients with panic attacks in the context of different psychiatric diseases].

Panic disorders (PD) which develop in the context of different psychiatric diseases (neurotic, personality disorder and schizotypal disorders) have their own clinical and neurophysiological features. The results of compressive-spectral analysis of EEG (CSA EEG) in patients with panic attack were different depending on the specifics of initial psychiatric status. EEG parameters in patients differed from those in controls. The common feature for all PD patients was the lower spectral density of theta-, alpha- and beta-bands as well as total spectral density without any alterations of region distribution. The decrease of electrical activity of activation systems was found in the groups with neurotic and schizotypal disorders and that of inhibition systems - in the group with schizotypal disorders. The EEG results did not suggest any depression of activation systems in patients with specific personality disorders. The data obtained with CSA EEG mirror the integrative brain activity which determinad of the appearance of PA as well as of nosology of psychiatre disease.

[Structural and functional analysis of the cortico-spinal tract in multiple sclerosis].

The study aimed at comparison of transcranial magnetic stimulation (TMS) parameters to MRI data in multiple sclerosis (MS), taking into account clinical course of the disease. TMS was conducted in 56 patients and in 10 age- and sex-matched healthy controls. According to stage of activity and variant of the course, the patients were divided into 2 groups: one at the stage of exacerbation and another--at the stage of remission with secondary progressive MS. Latency of segmental evoked motor response was similar in patients and controls. Statistically significant between-group difference or trend toward changing of some TMS parameters were found that indicates a slow-down of the impulse conducting along the cortico-spinal tract, which is characteristic of demyelinization process. The changes were more pronounced in secondary-progressive MS. According to MRI data, a square of the spinal cord on the level of the intervertebral disk center C2/C3 was significantly smaller in the group of patients with secondary progressive MS than in that with exacerbation of the disease. The TMS parameters correlated both with the level of the focal demyelinization process and with the square of the spinal cord on a level selected. It allows to estimate expression of atrophic changes caused, in its turn, not only by myelin loss but also by axon loss.

[Clinical and neurophysiological aspects of epilepsy with photosensitivity]. / Kliniko-neirofiziologicheskie aspekty épilepsii s fotosensitivnost'iu.

Using mapping EEG with dipole source location, transcranial magnetic stimulation (TMS), and visual evoked potential (VEP), clinico-neurophysiological analysis of photosensitivity was carried out in 7 patients with different types of epilepsy. In all the patients, an increase of visual response amplitude in VEP assessment and location of photogenic and eye-closing spike activity was observed in parietal and occipital areas that suggested a significant role of the striate and para striate cortex, along with primary projection cortex, in photosensitivity. Although motor cortex excitability by TMS causes hypersynchronization of the background activity and increase of slow wave discharge on the EEG after TMS. TMS is supposed to cause an activation of antiepileptic system.

[Bifocal atypical rolandic epilepsy with speech dyspraxia]. / Bifokal'naia atipichnaia rolandicheskaia épilepsiia s apraksiei iazyka.

Clinical and neurophysiological analysis of a case of a 7 year old patient with typical benign partial seizures with rolandic spikes and speech disorder, differing from those in Landau-Kleffner syndrome and in typical benign partial epilepsy of childhood presenting as speech dyspraxia. Two independent foci (in the premotor cortex of the left front lobe (dominant hemisphere) and in the temporal lobe of the right hemisphere were found. Significant clinical improvement and electrographical positive effect in EEG were achiered after prednisolone and sodium valproate treatment.

Neurophysiological characterization of transitory global amnesia syndrome.

A total of 27 patients with transitory global amnesia (TGA) in the acute and late (from 7 days) periods and 31 patients with dyscirculatory encephalopathy and subjective memory impairments (control group) were studied. EEG data and assessment of the P300 cognitive evoked potential wave established differences in the nature of beta1 activity between these groups. The extent of beta1 activity on the EEG showed different relationships with the latent period of the P300 wave: in the control group, there were increases in beta1 activity with increases in the latent period (r = 0.43). while beta1 activity in TGA decreased with increases in latent period (r = -0.23). These changes were most marked in the frontocentral areas. The authors believe that these patterns of changes in EEG and cognitive evoked potentials in the acute period of TGA and at later periods, as well as in the control group, provide evidence of the functional nature of TGA syndrome, which is not related to any damaged brain structure.

[Mechanisms of lability of neurological symptoms in multiple sclerosis]. / Mekhanizmy labil'nosti nevrologicheskikh simptomov pri rasseiannom skleroze.

Pathophysiological peculiarities of demyelinated axons determine their high sensitivity to different exogenous factors and are the reason of instability of neurological signs in MS. One of the typical MS sing is high sensitivity to elevated temperature of the body. Even temporary elevation in body temperature may cause changes in impulse conduction in demyelinated fibres, which was proved by studies of evoked potentials and stabilometric studies. These disturbances may be associated with disorder of ions channels function. The role of other factors (metabolic and immunological disturbances, levels of cytokines and neurotransmitters) in temporary block of nerve conduction in MS is discussed. Further studies of the mechanisms of the lability of neurological sings in MS may lead to elaboration of new approaches to MS treatment.

[Role of multimodal evoked potentials in evaluations of persistent vegetative state of nontraumatic origin]. / Rol' mul'timodal'nykh vyzvannykh potentsialov v otsenke persistiruiushchego vegetativnogo sostoiania netravmaticheskogo geneza.

Persistent vegetative state (PVS) is a kind of release from coma, manifesting by absence of any signs of cognitive activity. Progress in reanimatology leads to an increase in the number of patients with PVS, thus creating a new medical and social problem. Study of atraumatic PVS acquires special importance because of a drastic increase in its incidence, necessitating definition of criteria of this state formation and its prognostic signs. Multimodal evoked potentials (MEP) now play an important role in diagnosis and prediction of PVS. The impact of acoustic stem (ASEP), visual (VEP), somatosensory (SSEP), and cognitive (CEP) evoked potentials is analyzed and early diagnostic and prognostic neurophysiological criteria are defined. Results of dynamic examinations of 23 patients (9 men and 14 women) aged 10-67 years with atraumatic PVS are presented. According to neurophysiological data, PVS in the majority of patients is characterized by absence of cognitive responses to a significant stimulus (wave P300) during examinations of CEP and of cortical response during examination of SSEP. VEP and long latent acoustic evoked potentials are as rule intact in atraumatic PVS. According to ASEP, stem functions were intact or slightly changed in the examined patients with PVS. Prognostically unfavorable and relatively favorable signs in the time course of MEP are defined.

[Change of bioelectric brain activity registered at the distance from the focus of cerebral tissue injury]. / Izmeneniia bioélektricheskoi aktivnosti mozga, registriruemye na rasstoianii ot ochaga porazheniia tserebral'noi tkani.

The focal delta-waves and the remote influences of the stroke in the form of the sinusoidal flashes of delta-waves with a maximal amplitude exceeding an amplitude of the focal delta-waves (frontal flashes--FF) in frontal-polar leads were investigated in 51 patients (22 men, 29 women) by means of mapping, dipole location (BrainLoc) and LORETA methods. The patients were examined in dynamics during the acute period of hemispheric stroke on days 1-3, 14 and 21 after the onset of the disease. The usage of the modern computer methods of EEG analysis permits to consider FF as an independent electrophysiological phenomenon and to localize a zone of the sources of such flashes, which does not coincide with the zone of generation of the focal delta-activity that corresponds to the perifocal zone of the stroke. According to the data of the three-dimensional location a probable zone of FF generation corresponds to the frontal pole and medial-basal areas of the frontal lobe. Comparison with the MRI data leads to the conclusion that a damage of anterior white substance was the most frequent cause of FF development, probably by deafferentation mechanism. FF may be an electrophysiological manifestation of the influence of the damage of the different brain structures on the frontal lobes according to diaschisis mechanism.

[Treatment and prevention of cognitive dysfunction in patients with arterial hypertension and atherosclerosis: results of a randomized double-blind placebo-controlled trial of cerebrolysin]. / Lechenie i preduprezhdenie rasstroistv poznavatel'noi funktsii u bol'nykh arterial'noi gipertoniei i aterosklerozom: rezul'taty randomizirovannogo dvoinogo slepogo platsebo-kontroliruemogo issledovaniia tserebrolizina.

AIM: To assess therapeutic and prophylactic effect of large-dose cerebrolysin (15 ml/day for 28 days) in hypertensive and atherosclerotic patients with cognitive disorders. MATERIAL AND METHODS: Cerebrolysin was given annually (15 ml/day for 28 days) for 2 years to 42 patients in a randomized double-blind placebo-controlled study. The effect was stated by clinical status, neuropsychological and neurophysiological data. RESULTS: In mild disturbances of cognitive functions in patients with arterial hypertension and atherosclerosis courses of cerebrolysin with one-year interval produce stable improvement of subjective status, productivity of memory, attention and thinking which persist for at least a year after the course. The clinical data agree with positive trend in neurophysiological parameters of cognitive component of the response of evoked potentials P-300. CONCLUSION: A course of 28-day annual treatment with cerebrolysin (15 ml/day) of patients with mild defects of cognitive functions stabilizes the process, leads to regression of cognitive disorders predicting vascular dementia.

[Neurophysiological characteristics of transitory global amnesia syndrome]. / Neirofiziologicheskaia kharakteristika sindroma tranzitornoi global'noi amnezii.

Twenty seven patients with transitory global amnesia (TGA) in acute and remote (after 7 and more days) stages and 31 dyscircular encephalopathy patients with subjective memory disturbances (control group) have been examined. According to electroencephalographical (EEG) data and wave P300 cognitive evoked potential evaluation, the differences in the beta 1-activity between these groups have been found. beta 1-Activity expression on EEG correlated in different ways with latent P300 periods, increasing together with latent period (r = 0.43) in control group and decreasing in TGA (r = -0.23). The most distinct, changes were expressed in central cerebral regions. The authors hold that the relationship between changes of EEG and cognitive evoked potential in acute and remote TGA stages, as well as in control group, indicate functional character of TGA syndrome, being unrelated to cerebral structure damage.

[Acoustic brain stem and cognitive evoked potentials (P300) in patients with hepatolenticular degeneration]. / Akusticheskie stvolovye i kognitivnye vyzvannye potentsialy (P300) u bol'nykh gepatolentikuliarnoi degeneratsiei.

18 patients with hepatolenticular degeneration (Wilson's disease, WD) aged 15-38 years were subjected to an overall clinical and neurophysiologic examinations. As a result, the data obtained enable to evaluate functional reserves of CNS of the WD patients in correlation with the illness duration and severity of neurologic symptoms. Correlation between an increase of interpeak I-V and the degree of neurological deficit and, also, level of ceruloplasmin was established (r = -0.45; p < 0.05). Correlation between an increase of latency P300 and the degree of manifestation of neurologic symptoms was identified as well (r = 0.63; p < 0.05). Positive dynamics of evoked potentials was followed in 4 WD patients during copper-eliminative drugs treatment.

[Evoked potentials in assessing the sensory, activating and cognitive functions of the normal human brain and in cortical and subcortical types of vascular dementia]. / Vyzvannye potentsialy v otsenke sensornykh, aktiviruiushchikh i kognitivnykh funktsii mozga cheloveka v norme i pri sosudistoi dementsii korkovogo i podkorkovogo tipa.

Characteristics of the auditory EP under conditions of stimulus recognition (the P300 technique) and parameters of the visual "nonspecific" EP to light flash were studied in healthy subjects of the wide age range (18-78 years old) and patients with vascular dementia of different severity. It was shown that P300 parameters depended on age in healthy patients and on expression of cognitive dysfunction in demented patients. The changes were more pronounced in dementia of the cortical type. The P300 to nonrelevant stimulus was not age-dependent and slightly changed at cognitive dysfunction. Parameters of the nonspecific visual responses (the latency and duration--the index of homeostatic regulation) and maximal amplitude (reflecting the extent of activation processes) were not age-dependent and changed both in subcortical and cortical dementia types (increase in response latency and duration). In cognitive dysfunctions of subcortical origin homeostatic changes in the form of increase in time of homeostatic regulation and deterioration of stabilization of brain electrical processes were more pronounced.

[In vivo diagnosis of Creutzfeldt-Jakob disease]. / Prizhiznennaia diagnostika bolezni Kreitzfel'dta-Iakoba.

The paper presents the data concerning usage of some original method of vital laboratory diagnostics of Creutzfeldt-Jacob disease that belongs to the group of prionic diseases. The method consisted in the inoculation of inoculative culture of rat Gasser ganglion's neurinoma by biologic materials investigated (serum and clot of blood) with the following passivation and investigation of the contaminated culture by means of both morphologic and electron microscopic methods. As an example of vital verificated case the wide pathomorphologic analysis of the biopsy sample of brain was presented. Besides, the efficiency of the investigation of cognitive evoked potentials (P300) together with EEG was also demonstrated as the method of objectification of the development of dementia in this disease.