[Emergency indications of EEG in the situation of a head injury in children and adults]. / Indications urgentes de l'EEG dans la situation d'un traumatisme crânien, chez l'enfant et chez l'adulte.

After initial loss of consciousness following brain injury, background EEG may show slowing and posterior slow waves are observed, consistent with the existence of commotio cerebri, particularly in children. However, discrepancies between cerebral electrogenesis and the clinical condition may also persist for several weeks. As EEG is correlated with the stage of posttraumatic coma, its reactivity to stimuli is of value. While important EEG impairment with paroxysmal abnormalities is frequent in children, the patients' outcome is poorly correlated with initial EEG record. In intensive care units, the use of continuous digitized EEG techniques has opened new avenues. Though in case of mild risks, EEG and clinical follow-up may be sufficient after brain injury, EEG recording is recommended when computerized tomography (CT-scan) is normal in case of severe risks. When consciousness impairment is unexplained by the importance of the brain injury, emergency CT-scan is recommended, searching for intracranial hematoma. If CT-scan proves to be normal EEG should then be recorded, searching for local injury. EEG may uncover non-convulsive status epilepticus, mainly in elderly patients. In case of early seizures, EEG recording should be done within the first 24 hours following brain injury. In the post-ictal period, EEG should be recorded in emergency in case of confusional state lasting more than 30 minutes, as potential non-convulsive status epilepticus should not be underestimated. EEG is not of good predictive value for posttraumatic epilepsy; however, the existence of paroxysmal, local abnormalities is a risk factor. Recording of abnormalities may be useful for the medico-legal expert.

[EEG spike focus topography: study of potential fields]. / Cartographie d'amplitude dans les foyers de pointes EEG: étude des champs de potentiels.

Mapping study of EEG spike focus was performed on 122 topographic maps, from 88 records of 72 subjects, classified in: F for "functional" (no epileptic seizure); EGI, EGS and EGC: respectively generalized idiopathic, symptomatic and cryptogenic epilepsies; EPI, EPS and EPC: respectively partial idiopathic, symptomatic and cryptogenic epilepsies--epilepsies with centro-temporal spikes (EPR) are predominant in this group--; EI: indeterminate epilepsies. The graphoelements study: morphology, localization, amplitude, time course (sites of appearance, culmination and disappearance) and of electrical fields: distribution, monopolar, bipolar or intermediary aspect was performed. In order to quantify the brain mapping data we established series of numeric parameters: maximal negative and positive values; sum of the negative and positive values; ratio of these values. EGS and EPS groups have very variable map imaging for a patient or from a patient to another, r1 ratio is lower to 0.33. Idiopathic epilepsies are characterised by the stability of imaging, in the EGI group aspect is frequently monopolar with a central negativity, r1 and r2 ratios are high (0.9 and 1.2); in the EPI group the aspect can be monopolar or bipolar, in the EPR the aspect is stable, longitudinal bipolar, r1 and r2 ratios are between 0.33 and 0.99. In the EGC, EPC and EI groups there is no typical imaging, the mapping aspect can be monopolar or bipolar, in EGC and EPC r1 ratio is between 0 and 0.99, in EI r1 and r2 ratios are low (r1 = r2 = 0.2). In the F group the monopolar aspect is frequent. We can note the stability of the electrical fields apportionment in idiopathic epilepsies which is explainable by the integrity of the cerebral potential propagation pathways in spite of a dysfunction responsible of the epileptic seizures, the presence of a lesion is one of the responsible factors of the instability of the brain mapping.

[Evoked potentials in HIV infection]. / Aspects des potentiels évoqués dans l'infection par le VIH.

The study of the literature data on the multimodal evoked potentials in HIV infected patients shows many abnormalities as well in asymptomatic subjects without AIDS as in AIDS subjects with or without neurological signs. Visual evoked potentials (VEPs) reveal prolonged P100 wave latency in 22% of HIV asymptomatic subjects and in 26% of HIV symptomatic subjects; brainstem auditory evoked potentials (BAEPs) reveal an increase of the interpeak latency I-V in 16% of asymptomatic subjects and in 32% of symptomatic subjects; somatosensory evoked potentials (SEPs) by median nerve stimulation reveal prolonged central conduction time in 6% of asymptomatic subjects and in 11% of symptomatic subjects; somatosensory evoked potentials (SEPs) by tibial nerve stimulation reveal prolonged central conduction time in 4% of asymptomatic subjects and in 45% of symptomatic subjects; motor evoked potentials (MEPs) by magnetic stimulation reveal prolonged central motor conduction time in 46% of asymptomatic subjects.

[Multimodal evoked potentials in partial epilepsy in children]. / Etude des potentiels évoqués multimodalitaires dans les épilepsies partielles de l'enfant.

A multimodal evoked potential study was realised in three groups of children or adolescents 5 to 15 years old. The first group included 25 normal non-epileptic subjects; the second group was composed of 27 subjects with partial idiopathic epilepsy (PIE) (benign childhood epilepsy with centro-temporal spike; childhood epilepsy with occipital paroxysms); the third group was formed of 20 subjects with partial symptomatic epilepsy (PSE) without patent anatomical lesion or with anatomical lesion. Recording for each subject included: flash visual evoked potentials, pattern visual evoked potentials, brainstem auditory evoked potentials and somatosensory evoked potentials. Each curve obtained was studied for the response morphology, the measure of the different wave latencies, the inter-peak latencies (conduction time) and the amplitudes. A statistical treatment of the data was performed to evaluate the significance of variation of the different parameter values obtained for the various groups. Among the significantly modified parameters, we found: an increase of the amplitudes in the PIE and a decrease in the PSE, specially when an anatomical lesion exists; an asymmetrical amplitude of the somatosensory responses in the PIE with centro-temporal spike; an increase of the central somatosensory conduction time in the PSE with anatomical lesion.

Sensory evoked potentials in herpes simplex encephalitis.

Flash visual potentials (FEPs), somatosensory evoked potentials (SEPs) and auditory brainstem responses (ABR) were recorded in a 66-year-old patient presenting with clinical, EEG and CT brain scan features of herpes simplex encephalitis (HSE). At the time of evoked potential study (10 days after onset of the disease) the patient was treated with iv barbiturate on controlled respiration (lidocaine and phenytoin were not utilized); core temperature was 37 degrees C and pupils were dilated and nonreactive. Cortical FEPs were not recognizable on 02 lead, whereas they were clearly evident on 01 with normal latency of early N1, P1, N2 waves and delayed P2 component. SEPs showed normal peripheral and central conduction times, but N20 peak was bilaterally absent with unrecognizable (on P3) or delayed (on P4) N33 wave. No ABR (including wave I) were found on stimulation of the right ear, whereas delayed wave V with prolonged interpeak I-V latency was found on stimulation of the left ear. In conclusion, changes in sensory evoked potentials in HSE seem to be caused either by necrotic-hemorrhagic damage (with the disappearance of some cortical responses), by coma (with alterations in middle-latency cortical responses) and by increased intracranial pressure (with subsequent ABR abnormalities).

[Spatial orienting of attention: a study of reaction time during pointing movement]. / Orientation spatiale de l'attention: étude des temps de réaction lors du mouvement de pointage.

AIM: The aim of this study was to investigate how advance information both explicit and implicit provided prior to movement may affect the spatial orientation and the internal attention control processes in normal adult subjects. The originality of this work compared to the test of Posner, lies essentially in the methodology used to study the attentional systems. The use of three procedures of reaction time (RT) allowed us to study the setting concerned of the specific and non-specific components of the attention in the motor preparation. By associating of these three procedures of RT, we have evaluated the effects of the explicit and implicit components of advance information on motor preparation. The use of advance information to the movement requires the implication of the attentional systems. MATERIAL AND METHODS: Experiments were carried out using a simple reaction time (RT) procedure involving the use of an orientation cue and two choice reaction time situations: one with a neutral preparatory cue and one with a priming cue giving the likelihood of the preparatory stimulus (S1) being compatible with the imperative stimulus (S2). The mechanisms underlying the subjects' vigilance and the orientation of their attention were studied by assessing the effects on their reaction times of the preparatory signal and those of the cue giving the likelihood of S1 and S2 being compatible. The preparatory signal was designed to explicitly attract the subjects' attention towards the position of the forthcoming pointing target, whereas the cue giving the compatibility between S1 and S2 was intended to mobilize the subject's attention more implicitly. Prior to performing the pointing movement towards a visual target, the subjects' attention was therefore mobilized by the advance information containing two components: the explicit information about the position of S1 and the implicit information about the probability of S1 and S2 being compatible. RESULTS AND CONCLUSION: The results obtained here on 17 normal adult subjects show that the subjects significantly improved their RTs by using the explicit component of the information provided. The implicit information available was also used in the choice reaction situations: a priming effect was found to occur, which resulted in the shortening of the primed "compatible cue" reaction times in comparison with the "neutral cue" reaction times, and in the correlation which was found to exist between the reaction time performances and the degree of compatibility between the preparatory signal and the imperative signal. These results suggest that various components of the attentional system may participate in processing the advance information provided prior to the movement in reaction time tasks of the kind used here. The explicit information provided prior to the movement may mobilize the subject's vigilance and spatially orients his attention; whereas the implicit information available may rather subserve the internal control of the subject's attention.

[Early cerebral MRI in preterm infants: correlations with EEG and outcome]. / Intérêt de la réalisation d'une IRM cérébrale précoce chez le prématuré: corrélation avec l'EEG et le devenir.

AIM OF THE STUDY: Assess the potential benefits of performing an early cerebral MRI to evaluate the gravity of cerebral lesions among premature neonates at risk of neurologic sequels and establish correlations between EEG findings, abnormal neuroimaging findings and neurodevelopment. METHODS: A MRI was performed in 34 premature newborn babies with abnormal neurological clinical signs, and/or with two abnormal EEG and/or with two abnormal cerebral ultrasound scans. The mean age and the adjusted age of our population were 5 weeks (range 1-11 weeks) and 35 weeks of adjusted age (range 29-40 weeks) respectively. The neuroimaging findings were correlated to the results of three EEGs (recorded before 15 days old, between 15 days and one month old, and after the first month of life) and to neurodevelopment. RESULTS: Two statically significant correlations were found between: 1) the severity of brain injuries observed in MRI and the results of the latest EEG (sensitivity 100%, specificity 60%), 2) the severity of brain injuries observed in MRI and abnormal neurodevelopment (sensitivity 75%, specificity 80%). There was no correlation between the abnormal development and the results of EEG recordings. CONCLUSION: Early cerebral MRI is justified in a selected premature population. It is useful for the diagnosis, the evaluation of the severity of brain injury and for the management of these children. The correlation with EEGs traces allows the detection of the majority of prematures babies that will develop sequels.

Disappearance of periodic sharp wave complexes in Creutzfeldt-Jakob disease.

Periodic sharp wave complexes (PSWC) are sensitive and specific of Creutzfeldt-Jakob disease (CJD). Once they have emerged, PSWC may exceptionally disappear in the terminal stage of the disease, as a consequence of the flattening of scalp electroencephalogram (EEG). We document the disappearance of PSWC in serial EEG during the clinical course in two women (57 and 70 years of age) with pathologically proven CJD. Despite PSWC disappearance, diffuse theta-delta activity was still well recognizable. Moreover, external stimuli failed to trigger PSWC. The absence of PSWC in CJD might be due to the timing and frequency of EEG recordings. PSWC disappearance should not be interpretated as evidence against the diagnosis of CJD.

[Hypoxic-ischemic encephalopathy in the full-term newborn. Contribution of electroencephalography and MRI or computed tomography to its prognostic evaluation. Apropos of 26 cases]. / Encéphalopathie hypoxo-ischémique du nouveau-né à terme. Apport de l'électroencéphalogramme et de l'IRM ou de la TDM à l'évaluation pronostique. A propos de 26 observations.

OBJECTIVES: Perinatal asphyxia complicated by hypoxic ischemic brain injury still remains the source of neurological lesions often serious and definitive. A major aim of neonatologists is to appreciate the severity of the hypoxic ischemic brain injury in the first days of life and to evaluate the forecast. The purpose of this work is to establish a relation between clinical signs, EEG, neuroimaging (MRI and CTS) and neuro-development. MATERIALS AND METHODS: 26 neonates from paediatric resuscitation unit (Hospital North, Marseille) were enrolled in a retrospective study since February 1994 to December 1997. All the newborns had at least one anamnestic criteria of perinatal asphyxia, an early electroencephalogram in the first two days of life and another between the third and the seventh day of life, and neuroimaging in the first 15 days of life: CTS in five cases and MRI in 21 cases. RESULTS: There was a good electro-clinic (P: 0.01) and prognostic (P: 0.03) correlation in patients within stage 3 of the "Sarnat classification". In the stage 2, the EEG did not provide valuable information about severity of the injury, and neuroimaging (especially MRI) allowed better prognosis. Diffuse brain injury or lesions of basal ganglia in MRI were associated, independently of clinical settings and EEG tracings, with a poor neurodevelopmental outcome (P: 0.02). The MRI was diagnostic in four cases of congenital encephalopathy complicated with neonatal suffering. CONCLUSION: Our study confirms the interest of the association of clinical settings, EEG tracings and MRI in the diagnosis and the prognostic of the hypoxic-ischemic encephalopathy in term neonate.

Facial reflex myoclonus induced by language: a neuropsychological and neurophysiological study.

We studied a 53 year old right-handed patient who presented isolated myoclonus of right facial muscles induced exclusively by language. Twitching significantly hindered speaking and reading performance. MRI and CT-scan revealed no brain lesion. Conventional EEG showed a few spike-waves predominantly in the left hemisphere. Spike-waves increased during drowsiness. An EEG-EMG polygraphic study was performed during stimulation tests which included linguistic tasks and non-verbal/non-linguistic tests. Myoclonus was triggered by speaking and writing but not by non-linguistic tasks. The severity of myoclonus was dependent on the complexity of the language task. Back-averaging of right facial EMG bursts failed to show a reliable EEG-EMG correlation. However, the facial reflex myoclonus might have originated from the left rolandicopercular cortex, as it was triggered by complex language activities. Findings in this case are compared with those reported for other forms of reflex seizure and myoclonus.

Electroencephalographic and anatomo-clinical evidences of posterior cerebral damage in hypertensive encephalopathy.

The authors describe two patients suffering from hypertensive encephalopathy associated with epileptic seizures and anatomo-clinical evidences of posterior cerebral damage. The concordant electroencephalographic features with clinical signs and anatomic lesions of these two patients are discussed, in order to make some considerations about the role played by the blood-brain-barrier damage on the physiopathology of the hypertensive encephalopathy.

Brainstem auditory evoked responses in Lafora disease.

Brainstem auditory-evoked responses (BAERs) have been studied in five patients suffering from Lafora-type of progressive myoclonus epilepsy proven by skin biopsy and in ten healthy volunteers. At the time of examination the patients were not taking benzodiazepines and showed myoclonic jerks. In all patients the central conduction time (interpeak latencies I-V, I-III, III-V) and the amplitude (amplitude ratio I/V) of BAERs were within the +/- 2 S.D. limits of the normal values. Since Lafora disease is a neuropathologically prevalent grey-matter illness (typical inclusion bodies are stored intraneuronally) these data indicate that diseases primarily affecting the brainstem grey-matter are usually associated with normal BAERs.

Sleep electroencephalogram at the early stage of Creutzfeldt-Jakob disease.

We describe sleep EEG studies in three patients at the early stage of Creutzfeldt-Jakob disease. Little work has been devoted to the study of the sleep EEG in the course of the CJ disease: disorganized sleep architecture was noted, associated with a decrease in stage 4 and an almost complete disappearance of the REM stage. Our patients were considered to have normal stage 2; yet spindles and K complexes were rare at this stage. No evolution towards stage 4 was noted. The percentage of rapid eye movement sleep was significantly low in two cases and normal in one case. Sleep disturbances in the other dementing disorders are reported.

Pure left hemianacousia: clinical and neurophysiological study.

Hemianacousia is a pure sensory deficit revealed by an abnormality of dichotic listening test associated with an asymmetry of late auditory evoked potentials. We report a case of a patient with pure left hemianacousia. LAEPs, MLAEPs and P300 were recorded. Left hemisphere N90 wave amplitude was significantly reduced over the right hemisphere. CT scan revealed a right temporal hematoma which seemed to correspond to area 41.

Brainstem auditory evoked potentials in alternating hemiplegia: ictal vs interictal assessment in one case.

The authors report a case of alternating hemiplegia (AH) in a 3yr 6m old boy who had presented, from the age of 4 months on, episodes of alternating hemi- or quadriplegia. Brainstem auditory evoked potentials were recorded both in the interictal state and, for the first time, during an attack. There was no significant difference between the two states. These findings suggest that a massive involvement of the posterior vascular territory is not likely to be associated with attacks in AH.

Subacute spongiform encephalopathy with periodic paroxysmal activities: clinical evolution and serial EEG findings in 20 cases.

Evolution of both clinical and EEG abnormalities was analyzed in 20 (16 pathologically confirmed) patients suffering from subacute spongiform encephalopathy with periodic paroxysmal activities (PPA) on the EEG. Illness duration was less than 4 and greater than 17 months in 65% and 10% of cases, respectively. All data but EEG were utilized to assess 3 conventional clinical stages in 20 patients. The early clinical stage was characterized by gradual presentation of gait disturbances, mental deterioration, sensory or autonomic disorders. In contrast with other reports, no PPA were observed in 10 EEG recordings from 7 patients examined at the early clinical stage. Both clinical and EEG findings were not in contrast with a hypothetic subcortical onset of disease. Similar to recent data in the literature, early PPA appeared within 12 weeks of disease evolution in 88% of patients who underwent EEG recordings in the first 3 months of disease. Nonetheless, these early PPA always occurred at an intermediary stage, when our patients showed a marked worsening of the clinical picture. Focal, segmental and/or generalized myoclonic jerks were observed in 15%, 53% and 100% of cases at prodromal, intermediary and terminal stages respectively. Different kinds of PPA were observed: bi-tri-phasic periodic complexes (PC), periodic complexes with multiphasic configuration (PPC) and periodic polyspiking discharges (PPD). Abnormal "pacing" of PC by slowly repeated flashes was found in 4 patients presenting visual hallucinations or cortical blindness. Burst-suppression activity was frequently found at the terminal stage in decorticate patients.

Epileptic nystagmus: electroclinical study of a case.

Epileptic nystagmus (EN) is a rare form of nystagmus that occurs only during epileptic seizures. We report a case in which EN was first noted in an 8 year-old boy. Neuro-imaging was normal. Sharp waves from the left occipital lobe characterised the interictal EEG. Ictal video-EEG showed the aspects of electric seizures during clinical manifestations e.g. nystagmus. Ambulatory EEG displayed numerous diurnal and nocturnal seizures, but exclusively in REM sleep. After two weeks of sodium valproate treatment, the seizures, EEG focus spikes and nystagmus, as well as the squint, disappeared. During a two-year follow-up the child had no further seizures, EEG was normal and the school performance was unaffected. This case has the main features of benign epilepsy, although there are unusual features such as epileptic nystagmus, permanent squint, reduction of EEG paroxysmal abnormalities during NREM, and the presence of seizures during REM sleep. The observation and the significance of EN are discussed with reference to the literature.

[Stuporous state in an epileptic treated with sodium valproate. Diagnostic problems]. / Etat stuporeux chez un épileptique traité par le valproate de sodium. Problèmes diagnostiques.

The authors report a case of stupor secondary to valproic acid, in a patient treated with this drug and phenobarbital for a complex partial form of epilepsy. The pathogeny of this rare complication is discussed. In this patient, a paradoxical epileptic reactivation is excluded, and the authors favor a metabolic mechanism: either hyperammoniemia or a perturbation in cerebral neuro-transmitter systems are proposed.

[Treatment of epilepsy in rural areas in Mali]. / Traitement des épileptiques en milieu rural au Mali.

Epilepsy is a public health problem in Africa due to prevalence and social exclusion. We report a follow-up protocol for epileptic patients treated at home in rural areas of Mali. The objectives were: education for the patient, family, and village leaders in orders to achieve good compliance, uninterrupted supply of generic phenobarbitol, follow-up visits once a month for one year then every two months if good compliance with a country physician with delivery of phenobarbitol in sufficient quantity to reach the next visit, verification of correct drug dosage and use, supervision of treatment effect. After two years, the follow-up visits showed that 57.4% of the patients had been seizure free for at least 24 months (more than 4 monthly seizures before treatment). Rate of seizures decreased in 15.7% of the patients. Results were excellent with no seizures, clear physical, psychic and social improvement (work, married life, school attendance). Very few side effects were observed. There were no cases of poisoning. The management scheme is very cost effective: 1.5 USD per month per patient, including phenobarbitol and implementation. There is a need for anti-epilepsy programs in Africa which should be implemented on the local (rural medicalisation), national and international level ("Epilepsy out of the shadows" campaign).

[Multimodal evoked potentials in human immunodeficiency virus infection]. / Potentiels évoqués multimodaux dans l'infection par le virus de l'immunodéficience humaine.

We have studied 95 HIV seropositive patients (77 males and 18 females; mean age: 31 years): 67 had no neurological symptoms or signs, 28 had various neurological symptoms and signs. This study included a full multimodal evoked potentials (MEP) assessment: visual evoked potentials by flash and reversal checkerboard; brainstem auditory evoked potentials; somatosensory evoked potentials obtained by stimulation of the median nerve. Patient evaluation further included: electroencephalography, electromyography with measurement of conduction velocities and neuroimaging (brain CT scan and/or MRI). We found abnormal MEP for all modalities. The prevalence of abnormal results was high in neurological symptomatic patients; in non neurological ones, the changes tended to be more frequent with the progression of the HIV infection. Whatever the stage of the disease, the various modes were equally affected. MEP were abnormal in 54.7 p. 100 of the cases: in 41.8 p. 100 (28/67) of patient without neurological signs (in 4/12 of fully asymptomatic subjects, 11/34 ARC patients and 13/21 AIDS patients) vs 85.7 p. 100 of neurological symptomatic patients. In neurological asymptomatic patients, a similar proportion of abnormal MEP was found in asymptomatic and ARC patients, while the evolution into AIDS was associated with a higher prevalence of abnormal MEP. In the latter group, MEP changes were nearly as frequent as in neurological symptomatic patients. Comparison between MEP and other electrophysiological procedures (EEG, EMG) and with neuroimaging techniques (CT Scan, MRI) showed the high sensitivity of the MEP technique at all stages of the disease. EMG was a sensitive method and complementary to MEP. The EEG and neuroimaging techniques showed abnormalities principally at the neurological symptomatic stage. Previous studies could not be properly compared.(ABSTRACT TRUNCATED AT 250 WORDS)