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Early functional evaluation and prognosis of patients with disorders of consciousness is a major challenge that clinical assessments alone cannot solve. Objective measures of brain activity could help resolve this uncertainty. We used electroencephalogram at bedside to detect voluntary attention with a paradigm previously validated in healthy subjects.Using auditory-oddball sequences, our approach rests on detecting known attentional modulations of Event Related Potentials that reflect compliance with verbal instructions. Sixty-eight unresponsive patients were tested in their first year after coma onset (37 coma and 31 first year post-coma patients). Their evolution 6 months after the test was considered.Fourteen of the 68 patients, showed a positive response. Nine were in a coma and 5 in a minimally conscious state (MCS). Except for one who died early, all responders evolved to exit-MCS within 6 months (93%), while 35 (65%) among non-responders only.Among those patients for whom the outcome is highly uncertain, 21% responded positively to this simple but cognitively demanding test. Strikingly, some coma patients were among responders.The proposed paradigm revealed cognitive-motor dissociation in some coma patients. This ability to sustain attention on demand predicted awakening within 6 months and represents an immediately useful information for relatives and caregivers.

Study Analysis Group 21 (SAG21) of NASA's Exoplanet Exploration Program Analysis Group (ExoPAG) was organized to study the effect of stellar contamination on space-based transmission spectroscopy, a method for studying exoplanetary atmospheres by measuring the wavelength-dependent radius of a planet as it transits its star. Transmission spectroscopy relies on a precise understanding of the spectrum of the star being occulted. However, stars are not homogeneous, constant light sources but have temporally evolving photospheres and chromospheres with inhomogeneities like spots, faculae, plages, granules, and flares. This SAG brought together an interdisciplinary team of more than 100 scientists, with observers and theorists from the heliophysics, stellar astrophysics, planetary science, and exoplanetary atmosphere research communities, to study the current research needs that can be addressed in this context to make the most of transit studies from current NASA facilities like HST and JWST. The analysis produced 14 findings, which fall into three Science Themes encompassing (1) how the Sun is used as our best laboratory to calibrate our understanding of stellar heterogeneities ("The Sun as the Stellar Benchmark"), (2) how stars other than the Sun extend our knowledge of heterogeneities ("Surface Heterogeneities of Other Stars") and (3) how to incorporate information gathered for the Sun and other stars into transit studies ("Mapping Stellar Knowledge to Transit Studies"). In this invited review, we largely reproduce the final report of SAG21 as a contribution to the peer-reviewed literature., Invited review in press at RASTI. Based on the ExoPAG SAG21 report (arXiv:2201.09905v1) and refined via feedback from three reviewers. 75 pages, 30 figures, 5 tables

Resume La frequence de l’arret cardiaque au cours de la grossesse est de l’ordre de 1/12 000. Les principales causes sont l’hemorragie de la delivrance et l’embolie amniotique. La reanimation de l’arret cardiaque a certaines particularite : deplacement manuel de l’uterus gravide et surtout realisation rapide et prioritaire de la cesarienne sur place apres 20–24 semaines d’amenorrhee.

Objective To provide national guidelines for the management of women with severe pre-eclampsia. Design A consensus committee of 26 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE(r)) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Methods The last SFAR and CNGOF guidelines on the management of women with severe pre-eclampsia were published in 2009. The literature is now sufficient for an update. The aim of this expert panel guidelines is to evaluate the impact of different aspects of the management of women with severe preeclampsia on maternal and neonatal morbidities separately. The experts studied questions within 7 domains. Each question was formulated according to the PICO (Patients Intervention Comparison Outcome) model and the evidence profiles were produced. An extensive literature review and recommendations were carried out and analysed according to the GRADE(r) methodology. Results The SFAR/CNGOF experts panel provided 25 recommendations: 8 have a high level of evidence (GRADE 1+/−), 9 have a moderate level of evidence (GRADE 2+/−), and for 7 recommendations, the GRADE method could not be applied, resulting in expert opinions. No recommendation was provided for 3 questions. After one scoring round, strong agreement was reached between the experts for all the recommendations. Conclusions There was strong agreement among experts who made 25 recommendations to improve practices for the management of women with severe pre-eclampsia.

Resume Les consequences d’une breche de la dure-mere ne resument pas les causes de cephalees dans le post-partum. Les cephalees primaires sont les plus frequentes, les cephalees de tension et les migraines en representent les premieres etiologies. Si la semiologie est inhabituelle, le diagnostic de cephalee secondaire doit etre evoque rapidement. Les cephalees secondaires ont souvent une origine circulatoire : pre-eclampsie, encephalopathie posterieur reversible, thrombose veineuse cerebrale, accident vasculaire thrombotique voire hemorragique, syndrome de vasoconstriction reversible. Le diagnostic est souvent aide par l’IRM qui doit etre effectuee quand les signes cliniques de la cephalee sont atypiques ou associees a d’autres signes.

Resume La frequence de l’arret cardiaque au cours de la grossesse est de l’ordre de 1/12 000. Les principales causes sont l’hemorragie de la delivrance et l’embolie amniotique. La reanimation de l’arret cardiaque a certaines particularite : deplacement manuel de l’uterus gravide et surtout realisation rapide et prioritaire de la cesarienne sur place apres 20–24 semaines d’amenorrhee.

Objective To provide national guidelines for the management of women with severe pre-eclampsia. Design A consensus committee of 26 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Methods The last SFAR and CNGOF guidelines on the management of women with severe pre-eclampsia were published in 2009. The literature is now sufficient for an update. The aim of this expert panel guidelines is to evaluate the impact of different aspects of the management of women with severe preeclampsia on maternal and neonatal morbidities separately. The experts studied questions within 7 domains. Each question was formulated according to the PICO (Patients Intervention Comparison Outcome) model and the evidence profiles were produced. An extensive literature review and recommendations were carried out and analysed according to the GRADE® methodology. Results The SFAR/CNGOF experts panel provided 25 recommendations: 8 have a high level of evidence (GRADE 1+/−), 9 have a moderate level of evidence (GRADE 2+/−), and for 7 recommendations, the GRADE method could not be applied, resulting in expert opinions. No recommendation was provided for 3 questions. After one scoring round, strong agreement was reached between the experts for all the recommendations. Conclusions There was strong agreement among experts who made 25 recommendations to improve practices for the management of women with severe pre-eclampsia.

Objectives Several studies have shown that bilateral abolition of somatosensory evoked potentials after a nontraumatic coma has 100% specificity for nonawakening with ethical consequences for active care withdrawal. We propose to evaluate the prognostic value of bilateral abolished cortical components of SEPs in severe vascular coma. Methods A total of 144 comatose patients after subarachnoid haemorrhage were evaluated by multimodal evoked potentials (EPs); 7 patients presented a bilateral abolition of somatosensory and auditory EPs. Their prognosis value was interpreted with respect to brainstem auditory EPs, EEG, and structural imaging. Results One patient emerged from vegetative state during follow-up; 6 patients did not return to consciousness. The main neurophysiological difference was a cortical reactivity to pain preserved in the patient who returned to consciousness. This patient had focal sub-cortical lesions, which could explain the abolition of primary cortical components by a bilateral deafferentation of somatosensory and auditory pathways. Conclusions This is the first report of a favourable outcome after a multimodal abolition of primary cortex EPs in vascular coma. For the 3 cases of vascular coma with preserved brainstem function, EEG reactivity and cortical EPs were abolished by a diffuse ischaemia close to cerebral anoxia. Significance The complementarity of EPs, EEG, and imaging must be emphasised if therapeutic limitations are considered to avoid over-interpretation of the prognosis value of EPs.

Cancer risk assessment is performed generally in relation to assessment of the safety of new medical products or environmental exposures, especially when DNA modification is a factor. The risk assessment paradigms used for products subject to regulatory review are independent of specific cancers, multiple exposures, and individual risk factors. A default cancer risk assessment for regulatory review includes “uncertainty factors” to account for differential susceptibility and other variables involved in extrapolating from experimental systems to human risk. However, there is a growing amount of evidence that suggests differing risk for different types of cancer as well as the importance of combinations of risk factors not limited to genetic or environmental effects. In the era of personalized medicine and cancer genomics, can we begin to assess personalized cancer risk, instead of overall cancer risk? What models would assist in this paradigm shift? There are several cancers for which specific genetic, environmental, viral and other associations have been established and could be used in personalized cancer risk assessments, including colon, liver, and lung cancer. A search was conducted on PubMed for available literature on epidemiology, genetic susceptibility, and risk factors associated with the major types of cancer, including ~25 pathological types of cancer in 17 different organs. Risk factors associated with each included chemical exposures and tobacco, as well as genetic, epigenetic, microbial, viral, dietary, exercise, and other factors known for involvement in the development of cancer in humans. The diversity of cancers and evidence for specific risk factors is summarized. Common risk factors, including smoking and obesity, are supplemented with a substantial set of individual, often non-overlapping risk factors for diverse cancers. Surprisingly, little evidence was found that genetic-environmental interactions are significant risk factors for most cancers. From this assessment we can begin to ask whether and for what cancers a personalized risk approach seems feasible. Disclaimer: The findings and conclusions in this presentation are those of the authors and should not be construed to represent any agency determination or policy. Citation Format: Rosalie K. Elespuru, Catherine Fischer. Personalized cancer risk and prevention: analysis of risk factors for specific cancers and integration into cancer risk assessment paradigms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2612.

Active paradigms requiring subjects to engage in a mental task on request have been developed to detect consciousness in behaviorally unresponsive patients. Using auditory ERPs, the active condition consists in orienting patient's attention toward oddball stimuli. In comparison with passive listening, larger P300 in the active condition identifies voluntary processes. However, contrast between these two conditions is usually too weak to be detected at the individual level. To improve test sensitivity, we propose as a control condition to actively divert the subject's attention from the auditory stimuli with a mental imagery task that has been demonstrated to be within the grasp of the targeted patients: navigate in one's home. Twenty healthy subjects were presented with a two-tone oddball paradigm in the three following condition: (a) passive listening, (b) mental imagery, (c) silent counting of deviant stimuli. Mental imagery proved to be more efficient than passive listening to lessen P300 response to deviant tones as compared with the active counting condition. An effect of attention manipulation (oriented vs. diverted) was observed in 19/20 subjects, of whom 18 showed the expected P300 effect and 1 showed an effect restricted to the N2 component. The only subject showing no effect also proved insufficient engagement in the tasks. Our study demonstrated the efficiency of diverting attention using mental imagery to improve the sensitivity of the active oddball paradigm. Using recorded instructions and requiring a small number of electrodes, the test was designed to be conveniently and economically used at the patient's bedside.

Resume Le mode Programmed Intermittent Epidural Bolus (PIEB) est une nouvelle technique disponible pour l’entretien de l’analgesie obstetricale qui permet l’administration automatique, a intervalles programmes de bolus d’une solution anesthesique, associee aux injections controlees par la patiente (PCEA). Le mode PIEB, par comparaison au mode PCEA avec un debit continu, permet une epargne de la dose d’anesthesique local consommee, diminue le recours aux interventions complementaires et ameliore la satisfaction maternelle. L’injection automatique intermittente des bolus diminue le recours aux injections declenchees par les patientes surtout au cours du 1er stade du travail. L’amelioration de la qualite de l’analgesie s’accompagne d’une reduction de l’incidence et de l’intensite du bloc moteur, surtout en fin de travail, avec un effet benefique sur la duree du 2e stade du travail et une reduction du risque d’accouchement instrumental. Les etudes in vitro montrent que la diffusion de la solution anesthesique est plus etendue et plus homogene si le produit est injecte en dose unique avec une certaine vitesse et un certain degre de pression. En pratique clinique, la qualite et l’extension du bloc sensitif sont meilleures lorsque la meme dose est injectee en bolus par rapport a une perfusion continue. Plusieurs types de programmation sont possibles selon les intervalles bolus et selon la priorisation choisie entre le bolus patient ou le bolus automatique, ces elements restent a evaluer. Des etudes complementaires sont necessaires pour preciser et confirmer ces avancees mais il semble que le mode PIEB soit superieur au mode PCEA avec debit continu.

An unsexed, 16-year-old blue-and-gold macaw (Ara ararauna) was presented for evaluation of rapidly growing subcutaneous masses at the left tibiotarso-tarsometatarsal joint. Results of incisional biopsy were diagnostic for an intermediate-grade soft-tissue sarcoma. A distal-femoral amputation was performed and the leg was submitted for histopathology. Histopathologic examination confirmed the biopsy diagnosis and revealed neoplastic spread into the bone marrow cavity of the tibiotarsus. Excisional margins were complete. The macaw recovered and did well until it died suddenly 32 months after surgery. At necropsy, death was attributed to acute hepatic hemorrhage. No recurrence or metastasis of the sarcoma was identified.

Resume La grossesse est un facteur de risque important de la maladie thromboembolique veineuse. Les indications des traitements thromboprophylactiques sont precisees par des recommandations d’experts selon le niveau de risque tenant compte de facteurs cliniques et biologiques, les heparines de bas poids moleculaire sont utilisees en 1re intention. Dans le cadre de la prophylaxie, une interruption programmee du traitement permet le plus souvent de realiser une anesthesie perimedullaire pour l’accouchement. La prise en charge d’une patiente sous traitement a dose curative est plus complexe et necessite une concertation pluridisciplinaire pour chaque patiente, notamment pour l’organisation de l’accouchement qui doit etre programme dans le cadre d’un schema d’interruption du traitement beaucoup plus strict. Dans ce cas, l’acces a l’anesthesie locoregionale est plus aleatoire et l’incidence des complications hemorragiques en peri-partum est plus elevee.

Aims Several high-sensitivity cardiac troponin (hs-cTn) assays have recently been developed. It is unknown which hs-cTn provides the most accurate prognostic information and to what extent early changes in hs-cTn predict mortality. Methods and results In a prospective, international multicentre study, cTn was simultaneously measured with three novel [high-sensitivity cardiac Troponin T (hs-cTnT), Roche Diagnostics; hs-cTnI, Beckman-Coulter; hs-cTnI, Siemens] and a conventional assay (cTnT, Roche Diagnostics) in a blinded fashion in 1117 unselected patients with acute chest pain. Patients were followed up 2 years regarding mortality. Eighty-two (7.3%) patients died during the follow-up. The 2-year prognostic accuracy of hs-cTn was most accurate for hs-cTnT [area under the receivers operating characteristic curve (AUC) 0.78 (95% CI: 0.73–0.83) and outperformed both hs-cTnI (Beckman-Coulter, 0.71 (95% CI: 0.65–0.77; P = 0.001 for comparison), hs-cTnI (Siemens) 0.70 (95% CI: 0.64–0.76; P < 0.001 for comparison)] and cTnT 0.67 (95% CI: 0.61–0.74; P < 0.001 for comparison). Absolute changes of hs-cTnT were more accurate than relative changes in predicting mortality, but inferior to presentation values of hs-cTnT. Combining changes of hs-cTnT within the first 6 h with their presentation values did not further improve prognostic accuracy. Similar results were obtained for both hs-cTnI assays regarding the incremental value of changes. Hs-cTn concentrations remained predictors of death in clinically challenging subgroups such as patients with pre-existing coronary artery disease, impaired renal function, and patients older than 75 years. Conclusion High-sensitivity cardiac Troponin T is more accurate than hs-cTnI in the prediction of long-term mortality. Changes of hs-cTn do not seem to further improve risk stratification beyond initial presentation values.

Resume La thrombopenie gestationnelle concerne environ 10 % des femmes enceintes. Dans 75 % des cas, il s’agit d’une thrombopenie gestationnelle benigne, sans consequence et sans risque hemorragique. Cependant, elle peut reveler des pathologies graves comme la preeclampsie, le hemolysis elevated liver enzyme and low platelets (HELLP) syndrome et les redoutables microangiopathies thrombotiques. Elle peut aussi s’inscrire dans le cadre d’un purpura thrombopenique auto-immun ou d’une autre affection auto-immune comme le lupus ou le syndrome des anticorps antiphospholipides. Le risque hemorragique et les consequences fœtomaternels sont variables en fonction de ces pathologies, ce qui impose un diagnostic etiologique precis. Les examens complementaires ne sont pas systematiques et doivent etre orientes en fonction des signes associes. Le diagnostic differentiel entre purpura thrombopenique auto-immun et thrombopenie gestationnelle n’est pas biologique, mais clinique et anamnestique. La strategie therapeutique et l’attitude vis-a-vis de la realisation de l’anesthesie/analgesie locoregionale est fonction de chaque pathologie.

Resume Les infections severes sont rares au cours de la grossesse ou en postpartum, malgre une forte incidence de bacteriemies chez les femmes enceintes. Les germes les plus souvent en cause sont l’ Escherichia coli et le streptocoque B, mais les infections sont souvent polymicrobiennes. Une recrudescence des infections graves a streptocoque A est responsable d’une augmentation recente de la part relative des infections impliquees dans la mortalite maternelle des pays industrialises. Le statut physiologique et la faible incidence des comorbidites expliquent la rarete du choc septique chez la femme enceinte ; en l’absence de donnees specifiques au cours de la grossesse, la prise en charge initiale s’appuie sur les principes de reanimation precoce en tenant compte des modifications hemodynamiques et pulmonaires, responsables notamment d’une defaillance respiratoire. L’antibiotherapie a large spectre doit etre ultraprecoce. L’extraction fœtale peut etre indiquee pour des motifs obstetricaux mais ne modifie pas le pronostic maternel, excepte en cas d’arret cardiorespiratoire.

Case Description—A 5-year-old spayed female cat was evaluated because of lethargy of 3 days' duration, acute respiratory distress, and anemia. Clinical Findings—Physical examination revealed the cat was in good body condition but had pale mucous membranes and elevated heart and respiratory rates. Results of hematologic analysis indicated the cat had severe anemia (Hct, 0.07 L/L; reference range, 0.28 to 0.49 L/L) and marked rubricytosis (19.0 × 109 cells/L; reference value, 0 cells/L). Results of serologic and PCR assays for detection of FeLV and FIV and PCR assays for detection of Mycoplasma spp were negative. Cytologic evaluation of a bone marrow aspirate and histologic evaluation of a biopsy specimen revealed a predominance of rubriblasts and rubricytes with granulocytopenia. Cytologic evaluation of fine-needle aspirates of the spleen and liver also revealed numerous rubriblasts. Treatment and Outcome—The cat received transfusions of packed RBCs, and supportive treatment was administered. Analysis of test results yielded a diagnosis of acute myeloid leukemia (erythroid subtype). Because of continued hemolysis and anemia in combination with the diagnosis of erythroleukemia (which has a poor prognosis), the cat was euthanized. Clinical Relevance—To the authors' knowledge, erythroleukemia has only been reported in cats infected with FeLV. However, results of all diagnostic assays for FeLV were negative in the cat reported here, which suggested that erythroleukemia can develop in cats in the absence of FeLV infection.

Objective To assess markers of cognition, if any, in patients in a permanent vegetative state (PVS). Methods Event-related potential (ERP) mapping was performed on 27 patients in permanent (4–261 months after coma onset) vegetative (PVS, n = 16) or minimally conscious states (MCS, n = 11) due to anoxia ( n = 18) or other aetiologies ( n = 9). Mismatch negativity (MMN) to duration-deviant tones and novelty P3 (nP3) to the subject’s own name were recorded according to a paradigm previously validated in healthy volunteers and comatose patients. SEPs, MLAEPs and BAEPs were also recorded. Results MMN was present in 5/27 and nP3 in 7/27 patients. ERPs were not related to the time from coma onset and not different in MCS and in PVS. Normal SEPs and MLAEPs, and present nP3s were less frequent in anoxia than in other aetiologies. Conclusions Irrespective of their clinical assessment, a few patients are likely to process sound deviance (MMN) or novelty (nP3), mainly when their state is not due to anoxia. Significance Some PVS patients may be able to put certain awareness marker processes to work. The diagnostic criteria for PVS or MCS, currently based on mere behaviour, should also include functional brain investigations, such as ERPs, related to the aetiology.

Summary Purpose Indication of gamma-knife surgery (GKS) in temporal lobe epilepsy (TLE) remains a matter of debate. Either positive or negative results have been reported in studies with a maximum follow-up of 24 months. No long-term data have been published yet. Methods We collected data from 15 TLE patients who underwent GKS and whose follow-up was longer than 24 months. Localisation and extension of the epileptogenic zone (EZ) were assessed by SEEG in eight patients. Ten patients were presenting with mesial TLE (mTLE) while in the other five SEEG showed that the EZ was extending beyond mesio-temporal structures. GKS procedure was targeted to the EZ at a dose of 21.1 ± 2.6 Gy at the margin. Results The mean duration of the follow-up was 60 ± 22.3 months. At last follow-up, seven patients (46.7%) were free of disabling seizure. The last seizure following GKS occurred on average after a delay of 19.75 ± 20.62 months. No patient suffered recurrent seizures after a long period free of disabling seizures. No significant prognostic predictor could be individualized in this population. However, 6 of the 10 patients with mTLE (60%) were seizure free whereas only 1 of the 5 (20%) whose EZ was more extended exhibited the same seizure outcome. Conclusion When a positive outcome is achieved, the risk of seizure recurrence remains low at long term. In patients with typical mTLE, long-term GKS results may be closed to those observed after conventional surgery. Conversely, this procedure should not be proposed to patients in whom SEEG results suggest that the EZ is not restricted to mesial temporal structures.

Vagus Nerve Stimulation (VNS) is recognized as an efficient procedure for controlling seizures in patients with drug-refractory epilepsies. It is used as a palliative procedure as a complement to conventional treatment by antiepileptic (AE) drugs and, according to literature, 40 to 50p.cent of patients report a decrease in seizures frequency >or=50p.cent, which is usually accepted to classify patients as responders in add on AE drug trials. The objectives of this study based on retrospective analysis of 50 consecutive patients with partial (39) or generalized (11) refractory epilepsy non eligible for surgery were; firstly to evaluate the global long term VNS efficacy and secondly to identify potential predictors of the VNS effects on seizure frequency. No patient has been seizure free at any moment of the follow up (2.8+/-1.8 years, max: 6 years) and the AE has been maintained in all. During follow up 44, 66, 61 and 58p.cent of patients were classified as responders at 6 months, 1, 2 and 3 years, respectively. Logistic regression analysis showed that: the percentage of responders at 6 months of follow up and later was significantly higher than that before 6 months (p=0.002); generalized epilepsy was predictive of a better outcome as compared to partial epilepsy (p=0.03); there was a trend for a better outcome in partial epilepsies symptomatic of a focal lesion than in those with normal brain MRI (p=0.06). These results are in line with previously published data in terms of global efficiency and confirm that seizures control does not reach its maximal level before at least one year of VNS. In severe generalized epilepsies (either secondary or cryptogenic) manifesting by frequent falls due to atonic or tonic-clonic generalized seizures VNS is a useful palliative procedure, which entails much les of surgical risk than callosotomy. The better VNS effects in patients with partial epilepsy possibly reflect the high incidence in our series of Malformations of Cortical Development, which have been identified as one the few variables possibly predictive of a response over 50p.cent of seizures frequency reduction.

To evaluate the utility of sensory and event-related evoked potentials for the prediction of awakening/nonawakening in severe anoxic coma and to design a decision tree helping decision for any patient in this condition.Prospective cohort study.Clinical neurophysiology unit and intensive care unit of a French university hospital.Sixty-two consecutive severe comatose patients after out-of-hospital cardiac arrest.None.We gathered clinical variables and recorded the somatosensory, auditory, and cognitive evoked potentials within an average period of 8 days after cardiac arrest. The patients were followed for 12 months and classified as awake or nonawake (permanent vegetative state or death). The statistical study included measurements of specificity, sensitivity, and positive and negative predictive value for each clinical and electrophysiologic variable recorded at the early stage of coma. Furthermore, a tree-based classification analysis was performed.All patients in whom somatosensory evoked potentials or middle-latency auditory evoked potentials were abolished did not awaken (100% specificity). All patients in whom mismatch negativity (MMN) was present awakened (100% specificity). MMN was superior to somatosensory evoked potentials for the prediction of awakening and had the best specificity and positive predictive value for awakening. On the decision tree, the awakening/nonawakening explicative variables were, by order of importance, MMN, pupillary reactivity, and somatosensory evoked potentials.There is a need to predict early and accurately awakening or nonawakening in postanoxic comas. Using sensory and cognitive evoked potentials to assess the functional condition of the brain, a prognostic tree for the prediction of awakening/nonawakening in severe anoxic coma has been designed. It is applicable to any patient in this condition and offers the possibility to predict with very high probability awakening when MMN, the earliest component of event-related potentials, is present and nonawakening when MMN and pupillary light reflex are absent or cortical components of somatosensory evoked potentials are abolished.

Hearing one's own first name automatically elicits a robust electrophysiological response, even in conditions of reduced consciousness like sleep. In a search for objective clues to superior cognitive functions in comatose patients, we looked for an optimal auditory stimulation paradigm mobilizing a large population of neurons. Our hypothesis was that wider ERPs would be obtained in response to the subject's own name (SON) when a familiar person uttered it. In 15 healthy awake volunteers, we tested a passive oddball paradigm with three different novels presented with the same probability (P = 0.02) : SON uttered by a familiar voice (FV) or by an unknown voice (NFV) and a non-vocal stimulus (NV) which preserved most of the physical characteristics of SON FV. ERP (32 electrodes) and scalp current density (SCD) maps were analyzed. SON appeared to generate more robust responses related to involuntary attention switching (MMN/N2b, novelty P3) than NV. When uttered by a familiar person, the SON elicited larger response amplitudes in the late phase of novelty P3 (after 300 ms). Most important differences were found in the late slow waves where two components could be temporally and spatially dissociated. A larger parietal component for FV than for NFV suggested deeper high-level processing, even if the subjects were not required to explicitly differentiate or recognize the voices. This passive protocol could therefore provide a valuable tool for clinicians to test residual superior cognitive functions in uncooperative patients.

Summary: Purpose: Several animal studies suggest that the thalamus might be involved in the maintenance and propagation of epileptic seizures. However, electrophysiologic evidence for this implication in human partial epileptic seizures is still lacking. Considering the rich and reciprocal connectivity of the medial pulvinar (PuM) with the temporal lobe, we evaluated a potential participation of this thalamic nucleus in temporal lobe epilepsy (TLE). Methods: The electrophysiologic activity of PuM was recorded during stereoelectroencephalographic exploration of spontaneous temporal lobe seizures in 14 patients referred for presurgical assessment of refractory TLE. Results: We recorded PuM ictal activity in 80% of the 74 seizures that we analyzed. This activity was characterized by rhythmic slow-waves or rhythmic spikes (RSW-RS) or both or by low-voltage fast activity (LVFA) in 64% and 36% of seizures, respectively. RSW-RS occurred mostly in seizures arising from mesiotemporal structures, whereas LVFA was more frequently observed in seizures of neocortical origin. In the 15 seizures without PuM ictal activity, spreading of the seizure outside the onset zone never occurred, whereas it did in 78% of seizures with PuM ictal involvement. Discharge propagation was systematic when PuM involvement corresponded to LVFA, whatever the seizure onset zone was, whereas it represented only 66% of the seizures when PuM exhibited RSW-RS. Conclusions: This study shows that ictal changes in PuM activity are frequently observed during temporal lobe seizures and suggests that this thalamic nucleus might participate in their propagation.

Objective To assess pre-attentive detection mechanisms indexed by MMN component of auditory Event-Related Potentials (ERPs) in Multiple Sclerosis (MS) patients. Methods 46 MS patients (mean age 43.7 years, mean disease duration 10.1 years, mean EDSS 4.6) and 46 matched controls were assessed with ERPs elicited by a passive oddball paradigm using duration deviants. Auditory P50, N1, P2 components were recorded. MMN and P3a components were calculated as the difference potential between deviants and standard stimuli. Eighteen of these 46 patients underwent also global psychometrical assessment and were sorted in cognitively normal and impaired patients. ERPs of these two groups of patients were compared. Results MS patients showed reduced MMN and P3a areas as compared to controls, besides exogenous N1–P2 complex amplitude reduction. Among the 18 patients investigated with neuropsychological testings, six were cognitively impaired and 12 cognitively unimpaired. Patients with a global cognitive impairment had reduced MMN as compared to cognitively unimpaired patients. Conclusions Auditory MMN and P3a components of auditory ERPs are altered in MS patients. MMN alterations are more pronounced in cognitively impaired patients. Significance MMN and P3a areas reduction suggests that MS patients are prone to pre-attentive auditory information processing deficits, besides previously described controlled information processing difficulties. Moreover, MMN alterations may represent an objective index of cognitive disturbances in MS patients.

We studied the surgical outcome, and the complications in a group of 100 consecutive adult patients with medically refractory epilepsy arising from the temporo-mesial structures.Hundred patients were treated surgically between 1994 and 2003 for drug-resistant epilepsy involving the temporo-mesial structures. All of them underwent a comprehensive noninvasive presurgical evaluation. Fourty-eight of them underwent depth electrodes recordings (according to the Talairach's StereoElectroEncephaloGraphic (SEEG) methodology) because the noninvasive investigations were not congruent enough to identify the epileptic zone. The patients presenting with any space-occupying lesion, or with a cavernoma, or with a strictly lateral neocortical epileptic focus, were excluded. The MRI-examination was abnormal in 87 cases, displaying a hippocampal atrophy in 69 cases. The extent of temporal resection was planned according to the results of the presurgical investigation in each particular patient. Consequently, this "tailored" resection varied from selective amygdalo-hippocampectomy (6 cases), to anterior temporal lobectomy (76 cases), or to total temporal lobectomy (18 cases).The mean post-operative follow-up period was 53 months. 85 patients were found to be in Engel's class I post-operatively (free of disabling seizures), among them 74 were in class Ia (totally seizure free). Nine patients were in Engel's class II and six were in Engel's class III or IV (failures). There was no surgical mortality. Three patients had a postoperative hematoma; two patients required a shunt insertion; in three patients meningitis occurred; and two patients had postoperative ischaemia of the anterior choroidal artery territory, which resulted in a mild permanent hemiparesis. Neuropsychological complications are not addressed in detail in this article.These data indicate that "tailored" resective surgery for temporo-mesial epilepsy can be performed with a low rate of morbidity, and is highly efficacious. The use of invasive presurgical investigation (SEEG) may explain this high rate of success.

Summary: Purpose: The lateralizing value of ictal head deviation (HD) in frontal lobe epilepsy (FLE) is a matter of debate. Although FLE is typically associated with tonic or clonic HD contralateral to seizure onset, ipsilateral HD has been noted in numerous reports. Whether both types of HD can be distinguished according to their clinical patterns has not yet been specifically investigated. Methods: We studied the clinical pattern and time of occurrence of HD of 129 seizures in 13 consecutive patients, who underwent successful surgery for FLE, including 12 investigated with an intracerebral stereotactic EEG procedure. Results: Ictal HD was ipsilateral to the epileptogenic zone (EZ) in four (30%) patients and 27 (20.9%) seizures and contralateral in five (38%) patients and 15 (11.6%) seizures. Ipsilateral HD was rarely tonic and never associated with clonic manifestation. Contralateral HD was always tonic, unnatural, and associated with hemifacial clonic movements in 86% of seizures. Ipsilateral HD occurred earlier than contralateral HD (p < 0.03), with a mean delay of 1 ± 2s after the first detectable ictal sign, as compared with a delay of 17 ± 11 s for contralateral HD. Moreover, ipsilateral HD always occurred before contralateral HD when both signs coexisted in the same seizure. Our patients with ipsilateral HD demonstrated either an anterior or dorsolateral frontal EZ. Conclusions: Ipsilateral HD is a common ictal sign during FLE and can be distinguished from contralateral HD by its time of occurrence at or immediately after seizure onset and its lacking association with clonic movements. Ke yW ords: Version— Head deviation—Frontal lobe epilepsy.

While source localization methods are increasingly developed to identify brain areas underlying scalp electro/magnetoencephalographic data (EEG/MEG), these methods have not yet been used to identify the sources of intracerebral signals which offer highly detailed information. Here, we adapted the minimum current estimates method to intracranial data in order to localize supratemporal sources of intracerebral auditory 1-kHz-tone-evoked potentials occurring within 100 ms after stimulus onset. After an evaluation of localization method and despite inter-subject variability, we found a common spatiotemporal pattern of activities, which involved the first Heschl's gyrus (H1) and sulcus (HS), the Planum Temporale (PT), H2/H3 when present, and the superior temporal gyrus (STG). Four time periods of activity were distinguished, corresponding to the time range of the scalp components P0, Na, Pa/Pb, and N100. The sources of the earliest components P0 (16–19 ms) and Na (20–25 ms) could be identified in the postero-medial portion of HS or H1. Then, several areas became simultaneously active after 25 ms. The Pa/Pb time range (30–50 ms) was characterized by a medio-lateral and postero-anterior propagation of activity over the supratemporal plane involving successively H1/HS, the Planum Temporale, H2/H3 when present, and the STG. Finally, we found to a large extent that the N100 (55–100 ms) involved almost the same areas as those active during the Pa/Pb complex, with a similar propagation of activities. Reconstructing scalp data from these sources on fictive EEG/MEG channels reproduced classical auditory evoked waveforms and topographies. In conclusion, the spatiotemporal pattern of activation of supratemporal auditory areas could be identified on the individual anatomy using current estimates from intracerebral data. Such detailed localization approach could also be used prior to epilepsy surgery to help identify epileptogenic foci and preserve functional cortical areas.

Active cochlear micromechanisms, involved in auditory sensitivity, are modulated by the medial olivocochlear efferent system, which projects directly onto the organ of Corti. Both processes can be assessed non-invasively by means of evoked otoacoustic emissions. Animal experiments have revealed top-down control from the auditory cortex to peripheral auditory receptor, supported by anatomical descriptions of descending auditory pathways from auditory areas to the medial olivocochlear efferent system and organ of Corti. Through recording of evoked otoacoustic emissions during presurgical functional brain mapping for refractory epilepsy, we showed that corticofugal modulation of peripheral auditory activity also exists in humans. In 10 epileptic patients, electrical stimulation of the contralateral auditory cortex led to a significant decrease in evoked otoacoustic emission amplitude, whereas no change occurred under stimulation of non-auditory contralateral areas. These findings provide evidence of a cortico-olivocochlear pathway, originating in the auditory cortex and modulating contralateral active cochlear micromechanisms via the medial olivocochlear efferent system, in humans.

Summary: Purpose: Depth electrodes recordings may be required in some cases of epilepsy surgery to delineate the best region for cortical resection. We usually implant depth electrodes according to Talairach’s stereoelectroencephalography (SEEG) method. By using these permanently implanted depth electrodes, we are able to perform radiofrequency (RF)-thermolesions of the epileptic foci. We report the technical data required to perform such multiple cortical thermolesions, as well as preliminary results in terms of seizure outcome in a group of 20 patients. Methods: Lesions were performed by using 100- to 110-mA bipolar current (50 V), applied for 10 to 50 s. Each thermocoagulation produced a 5- to 7-mm diameter cortical lesion. In total, two to 16 lesions were performed in each of the 20 patients. Lesions were placed without anesthesia. No general or neurologic complication occurred during the procedures. Two transient postprocedure side effects, consisting of paresthetic sensations in the mouth and mild apraxia of the hand, were observed. Results: At a follow-up time of 8 to 31 months (mean, 19 months), 15% of the patients became seizure free, 40% experienced a ≥80% reduction of their seizure frequency, and 45% were not significantly improved. Conclusions: SEEG-guided RF thermolesions is a safe technique. Our preliminary results indicate that such lesions can lead to a significant reduction of seizure frequency and could be proposed as a palliative procedure if no resective surgery is possible. A randomized controlled trial is needed to determine which patients are likely to respond to SEEG-guided RF ther

OBJECTIVE The nerve function of Cranial Nerve VIII is at risk during microvascular decompression for hemifacial spasm. Intraoperative monitoring of brainstem auditory evoked potentials (BAEPs) can be a useful tool to decrease the danger of hearing loss. The aim of this study was 1) to assess the side effects of surgery on hearing and describe the main intraoperative BAEP changes observed in the authors' series, and 2) to define warning values beyond which the probability of hearing impairment rises significantly. These values were calculated by correlating the (possible) postoperative hearing disturbances evaluated in terms of pure tone average with intraoperative BAEP changes (especially delay in Wave V latency). METHODS This series included 84 consecutive patients affected with hemifacial spasm who underwent microvascular decompression during which BAEPs were monitored. During surgery, Wave I, I to V interpeak interval, latency, and amplitude of Wave V were recorded and measured. Auditory function was studied before and after surgery and expressed as a pure tone average in all patients. Then, correlations were made between hearing impairment after surgery and intraoperative BAEP changes in an attempt to define warning values. RESULTS Seventy-four patients (88%) had no hearing loss after surgery (Group 1). Eight patients (9.5%) had hearing impairment with a decrease in pure tone average of more than 20 dB (Group 2). Two patients (2.3%) experienced a definitive and complete hearing loss on the side operated on (Group 3). Among intraoperative BAEP changes, latency of Peak V was the most frequently observed and the most significant phenomenon, especially during cerebellar retraction and the decompression step of the microvascular decompression procedure. In the group of patients without hearing loss (Group 1), the mean delay in latency of Peak V was 0.61 millisecond (standard deviation, +/-0.36 ms); in the group with hearing decrease (Group 2), the mean delay was 1.05 milliseconds (standard deviation, +/-0.64 ms); and in the group with deafness (Group 3), Wave V was abolished. CONCLUSION From a practical standpoint, three warning values, based on delay in latency of Peak V, were established for use during surgery: an initial one at 0.4 millisecond ("watching" signal) at the safety limit; a second one at 0.6 millisecond (risk "warning" signal), which is the mean value corresponding to the group of patients without postoperative hearing loss; and an ultimate one at 1 millisecond ("critical" warning), before irreversibility. These warnings should help the surgeon to avoid or correct maneuvers that are dangerous for hearing function, which is mandatory in functional surgery.

We describe documented simultaneous intracerebral auditory evoked potentials from the auditory cortex and medial geniculate body (MGB) of a human patient. The MGB response lasted > 300 ms, with an initial negativity at 13.5 ms (N13), two positive peaks P21 and P29, and two broader negativities N50 and N200. P21 and N50 amplitudes were strongest for lowest tone frequencies, suggesting possible MGB tonotopic organization. Thalamic peaks were strongly interlaced with cortical activities recorded in Heschl’s gyri before 30 ms: N13 preceded the first cortical component by 3.5 ms, then P21 and P29 preceded and lagged, respectively, the following two cortical polarity reversals by 1.5‐2 ms. This study provides new functional data on the human MGB, and supports a more complex than simply relay-like role of the thalamus in sound perception.

Introduction The purpose of this monocentric study was to assess the long-term outcome of a group of severe traumatic brain-injured patients and explore the prognostic values of some clinical and paraclinical parameters available at the initial stage. Methodology The patients included were victims of severe traumatic brain injuries in 2007 or 2008. A standardized assessment was performed for each patient including clinical, radiological, and electrophysiological data collected at the initial stage, The outcomes were assessed at least 2 years after injury. Depending on the patients’ availability and ability to communicate, the assessments included measures of dependency for activities of daily living (ADL), cognitive functions, behaviour, mood, and quality of life. Results Eighteen patients were included, of whom ten were autonomous for ADL at the time of assessment. Memory complaints, attentional deficits, anxiety, and irritability were the main long-term impairments observed. A correlation analysis showed significant correlations between the dependency level (as rated by the Functional Independence Measure) and each of length of coma, length of the post-traumatic amnesia, and the N100 auditory evoked potentials. Discussion These results confirm the uniqueness of each patient regarding the long-term consequences of a traumatic brain injury and the multi-determined nature of each prognosis.

Objective To investigate automatic event-related potentials (ERPs) to an auditory change in migraine patients. Methods Auditory ERPs were recorded in 22 female patients suffering from menstrually-related migraine and in 20 age-matched control subjects, in three sessions: in the middle of the menstrual cycle, before and during menses. In each session, 200 trains of tone-bursts each including two duration deviants were presented in a passive listening condition. Results In all sessions, duration deviance elicited a mismatch negativity (MMN) showing no difference between the two groups. However, migraine patients showed an increased N1 orienting component to all incoming stimuli and a prolonged N2b to deviance. They also presented a different modulation of P3a amplitude along the menstrual cycle, which tended to normalise during migraine attacks. None of the studied ERP components showed a default of habituation. Conclusions This passive paradigm highlighted increased automatic attention orienting to auditory changes but normal auditory sensory processing in migraineurs. Significance Our observations suggest normal auditory processing up to attention triggering but enhanced activation of attention-related frontal networks in migraineurs.

Event-related potentials (ERPs) were recorded in 10 adult volunteers, who were asked to view pictures of faces with different emotional expressions, i.e. fear, happiness, disgust, surprise and neutral expression [Ekman, P. & Friesen, W.V. (1975). Pictures of Facial Affect. Consulting Psychologist Press, Palo Alto, CA]. ERPs were recorded during two different tasks with the same stimuli. Firstly, subjects were instructed to pay attention to the gender of the faces by counting males or females. Secondly, they had to focus on facial expressions by counting faces who looked surprised. The classical scalp 'face-related potentials', i.e. a vertex-positive potential and a bilateral temporal negativity, were recorded 150 ms after the stimulus onset. Significant differences were found, firstly between late-latency ERPs to emotional faces and to neutral faces, between 250 and 550 ms of latency and, secondly, among the ERPs to the different facial expressions between 550 and 750 ms of latency. These differences appeared only during the expression discrimination task, not during the gender discrimination task. Topographic maps of these differences showed a specific right temporal activity related to each emotional expression, some particularities being observed for each expression. This study provides new data concerning the spatio-temporal features of facial expression processing, particularly a late-latency activity related to specific attention to facial expressions.

Object of the Study: In some candidates for epilepsy surgery in whom the decision to operate is difficult to make, invasive presurgical investigations, namely depth electrode recordings, may be needed. The SEEG (StereoElectroEncephaloGraphy) method consists of stereotactic orthogonal implantation of depth electrodes (5 to 15, 11 on average). The object of this study is to clarify the indications for SEEG, to expose its complications, and to display its usefulness in terms of surgical strategy and results. Patients and Methods: 100 patients, suffering from drug-resistant epilepsy and selected as candidates for surgical resection, underwent SEEG between 1996 and 2000. A total of 1,118 electrodes were implanted. For each single case, the sites of implantation of the electrodes were chosen in order to determine either the side of the onset of seizures, or the uni- or multilobar feature of them, or a possible operculo-insular propagation from a temporal onset, and also, using direct electrode stimulation, the proximity of speech or motor area. Results: Complications occurred in 5 patients (2 superficial infections, 2 breakages of electrodes, and 1 intracerebral hematoma responsible for death). SEEG was helpful in most (84%) of the 100 patients to confirm or annul surgical indication, and to adjust the extent of the resection. In some cases (14%), SEEG allowed to propose a resection that might have been disputable based solely on noninvasive investigation data. For frontal epilepsy, SEEG was crucial in all cases to delineate the extent of resection. Conclusion: SEEG proved to be a relatively safe and a very useful method in ‘difficult’ candidates for epilepsy surgery. In addition, in some cases the implanted electrodes can be used to perform therapeutic RF thermocoagulation of epileptic foci or networks.

Background This study compared the administration of 0.1% ropivacaine and 0.5 microg/ml sufentanil with that of 0.1% bupivacaine and 0.5 microg/ml sufentanil via patient-controlled epidural analgesia route during labor. Methods Two hundred healthy pregnant women at term with a single fetus with a vertex fetal presentation were randomized in a double-blind fashion to receive either 0.1% ropivacaine and 0.5 microg/ml sufentanil or 0.1% bupivacaine and 0.5 microg/ml sufentanil using a patient-controlled epidural analgesia pump (5-ml bolus dose, 10-min locked-out period, no basal infusion). Pain score on a visual analog scale, Bromage score (0-3), level of sensory block, patient-controlled epidural analgesia ratio, drug use, supplemental boluses, and side effects were recorded at 30 min and then hourly. Mode of delivery, duration of first and second stages of labor, umbilical cord pH, Apgar scores of the newborn, and a measure of maternal satisfaction were recorded after delivery. Results No differences were seen between the two groups for pain scores on a visual analog scale during labor, volume of anesthetic solution used, mode of delivery, or side effects. Motor block during the first stage of labor was significantly less in the ropivacaine group than in the bupivacaine group (no motor block in 97.8 of patients vs. 88.3%, respectively; P < 0.01). Duration of the second stage of labor was shorter in the ropivacaine group (1.3 +/- 1.0 vs. 1.5 +/- 1.2 h [mean +/- SD]; P < 0.05). Maternal satisfaction was greater in the bupivacaine group (91 +/- 13 mm for contraction, 89 +/- 19 mm for delivery on a visual scale: 0 = not satisfied at all, 100 = fully satisfied) than in the ropivacaine group (84 +/- 21 and 80 +/- 25 mm; P < 0.0001). Patients in the ropivacaine group requested more supplemental boluses to achieve analgesia during the second stage of labor than those in the bupivacaine group (29.7 vs. 19.8%, respectively, requested one or more supplemental boluses; P < 0.05). Conclusions Delivered as patient-controlled epidural analgesia, 0.1% ropivacaine and 0.5 microg/ml sufentanil produce less motor block but are clinically less potent than 0.1% bupivacaine and 0.5 microg/ml sufentanil.

Summary: Purpose: We report the results of 75 intracortical electrical stimulations of the insular cortex performed in 14 patients during stereo-electroencephalography (SEEG) investigation of drug-resistant partial epilepsy. The insular cortex was investigated on electroclinical arguments suggesting the possibility of a perisylvian spread or a rapid multilobar diffusion of the discharges during video EEG. Methods: In these 14 patients, 27 stereotactically implanted transopercular electrodes reached the insular cortex (11 the right insula, 16 the left insula). Square pulses of current were applied between the two deepest adjacent contacts of each transopercular electrode using low (1 Hz) or high-frequency (50 Hz) stimulation. Only symptoms evoked in the absence of afterdischarges were analyzed. Results: Clinical responses were evoked in 10 of the 14 patients (in 20 of the 27 insular sites) and showed a clear topographic specificity inside the insular cortex. Viscerosensitive and visceromotor responses, similar to those evoked by temporomesial stimulation, were evoked by anterior insular stimulation and somesthetic sensation, similar to those evoked by opercular cortex stimulation, by posterior insular stimulation. Conclusions: The topographic organization of the induced responses within the insular cortex suggest that two different cortical networks, a visceral network extending to the temporomesial structures and a somesthetic network reaching the opercular cortex, are disturbed with stimulation of the anterior or the posterior insula, respectively. Thus ictal symptoms associated with the spread of the epileptic discharges to the insular cortex might be difficult to distinguish from those usually reported during temporomesial or opercular discharges.

Continuous long-term recording of brainstem (BAEPs), middle-latency (MLAEPs) and long-latency auditory evoked potentials, including the mismatch negativity (MMN), brings additional information on the immediate functional state and the outcome of patients in coma or recovering after surgery, in relation with clinical observations and therapeutics. A recently designed monitoring system is introduced, aimed at the continuous recording of late auditory potentials (N100 and MMN) as well as BAEPs and MLAEPs. Specific methodological aspects are emphasized. Long-term monitoring data from one patient recorded in the recovery room after surgery are displayed, allowing an illustration of the techniques used and of the problems raised.

Objectives : The purpose of this study was to assess the patterns of mismatch negativity (MMN) and N100 component in comatose patients and to evaluate their prognostic value vis-a-vis return of consciousness. Methods : MMN and auditory (early, middle-latency and late) evoked potentials were recorded in 52 normals and in 128 comatose patients (comas due to neurosurgical and neurological problems). At the time of recording, all patients scored lower than 8 on the Glasgow scale. Results : Visually detected N100 and MMN were confirmed by cross-correlation of sub-averages. The MMN was present in 33/128 patients and the N100 component in 84/128. The amplitudes of MMN and N100 waves detected in comatose patients were statistically different from those of normal subjects. By 3 months after the onset of coma, 95 patients had returned to consciousness, most of them with moderate to severe disability. A ratio of 30/33 patients with MMN and 70/84 with N100 had regained consciousness. The presence of a MMN together with a N100 component was more specific (90.9%) than the presence of a N100 component irrespective of MMN (57.6%) in terms of predicting return to consciousness, but its sensitivity was lower (respectively 31.6% for MMN and 73.7% for N100). The mean period that elapsed between the recording of evoked potentials and a return to consciousness was 6.3±4 days. MLAEPs were also highly specific, but BAEPs were not. Conclusion : MMN and auditory evoked potentials provide a reliable assessment of the functional status of comatose patients. When present, MMN and the N100 differ from those found in normal subjects in terms of latencies and amplitudes. As a predictor of return of consciousness MMN had high specificity and low sensitivity, whereas the N100 had high sensitivity and low specificity. This study demonstrates that the recording of MMN and the auditory N100 can be a very useful aid in the assessment of coma and in predicting whether or not a patient will regain consciousness.

This study aimed at assessing the effects of midazolam (MDZ) sedation on auditory brainstem (BAEP) and middle latency (MLAEP) evoked potentials in intensive care conditions. Ten ventilated comatose patients were receiving an intravenous MDZ bolus dose (0.2 mg/kg) followed by a 2 h continuous infusion (0.1 mg/kg/h). MLAEPs and BAEPs elicited by clicks (90 dB HL + masking) were simultaneously and continuously monitored during the first 6 h and for 30 min the next morning. We found no effect of MDZ sedation on BAEPs. Only MLAEP components were modified. However, none of the patients presented any total abolition of the MLAEPs. Bolus injection led to very early alteration of cortical responses, beginning after 5 min and lasting almost 1 h (maximum Pa latency increase, 3.1 ms; maximum Pa-Nb amplitude decrease, 46%). During continuous infusion, MLAEPs remained slightly, although significantly, altered (Pa latency, +1.3 ms; Pa-Nb amplitude, 27%). The Nb wave seemed to be modified earlier and to return to normality later than the Pa wave. These findings incite a careful interpretation of MLAEP tracings acquired during the first hour following MDZ bolus injection. If possible, MDZ should be administered as continuous infusion for reliable interpretation of evoked potential changes in intensive care unit, or during surgery.

Le bilan neurophysiologique tient une place importante dans l’evaluation du pronostic d’eveil des patients comateux [4] . Dans la legislation francaise, la mort cerebrale, evoquee sur des criteres cliniques, peut etre confirmee grâce a deux electroencephalogrammes realises a 4 h d’intervalle ; les potentiels evoques (PE) auditifs precoces peuvent egalement contribuer au diagnostic. A la phase aigue d’un coma anoxique, le bilan neurophysiologique aide a la prise de decision collegiale de limitation des therapeutiques actives, une abolition bilaterale des reponses du cortex somesthesique primaire sur les PES etant predictive d’une evolution vers le deces ou l’EVP dans pres de 100 % des cas. Si les reponses des cortex primaires somesthesique et/ou auditif sont preservees, les reponses evoquees tardives apportent des informations supplementaires [3] : la presence d’une negativite de discordance et/ou d’une reponse au propre prenom traduit un engagement dans le processus d’eveil sans prejuger des sequelles neurologiques et cognitives ulterieures. Dans les comas non anoxiques, une evaluation au cas par cas est indispensable, incluant les criteres cliniques, neurophysiologiques et d’imagerie, avec necessite d’un suivi longitudinal, les resultats du bilan initial n’ayant pas de signification pronostique definitive. L’evaluation neurophysiologique peut etre completee par des protocoles passifs plus sophistiques comme l’influence de la musique sur la reponse au propre prenom [2] ou un protocole de stimulation « local/global » [1] (irregularite « locale » entre des stimuli auditifs frequents et rares associee a une irregularite « globale » entre plusieurs sequences de stimulation). Ces tests permettent une exploration plus precise de la conscience et des circuits attentionnels, emotionnels et mnesiques. L’interet de protocoles actifs est en cours d’etude : la modulation des reponses corticales de type P300 en fonction de tâches specifiques demandees au sujet pourrait aider a evaluer les capacites de comprehension et de communication des patients en etat de conscience alteree.