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1.
Br J Anaesth ; 121(6): 1290-1297, 2018 Dec.
Article de Anglais | MEDLINE | ID: mdl-30442256

RÉSUMÉ

BACKGROUND: Mismatch negativity (MMN) is the neurophysiological correlate of cognitive integration of novel stimuli. Although MMN is a well-established predictor of awakening in non-sedated comatose patients, its prognostic value in deeply sedated critically ill patients remains unknown. The aim of this prospective, observational pilot study was to investigate the prognostic value of MMN for subsequent awakening in deeply sedated critically ill patients. METHODS: MMN was recorded in 43 deeply sedated critically ill patients on Day 3 of ICU admission using a classical 'odd-ball' paradigm that delivers rare deviant sounds in a train of frequent standard sounds. Individual visual analyses and a group level analysis of recordings were performed. MMN amplitudes were then analysed according to the neurological status (awake vs not awake) at Day 28. RESULTS: Median (inter-quartile range) Richmond Assessment Sedation Scale (RASS) at the time of recording was -5 (range, from -5 to -4.5). Visual detection of MMN revealed a poor inter-rater agreement [kappa=0.17, 95% confidence interval (0.07-0.26)]. On Day 28, 30 (70%) patients had regained consciousness while 13 (30%) had not. Quantitative group level analysis revealed a significantly greater MMN amplitude for patients who awakened compared with those who had not [mean (standard deviation) = -0.65 (1.4) vs 0.08 (0.17) µV, respectively; P=0.003). CONCLUSIONS: MMN can be observed in deeply sedated critically ill patients and could help predict subsequent awakening. However, visual analysis alone is unreliable and should be systematically completed with individual level statistics.


Sujet(s)
Maladie grave , Sédation profonde , Vigilance , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Cognition , Conscience , Potentiels évoqués , Femelle , Humains , Mâle , Adulte d'âge moyen , Projets pilotes , Études prospectives
2.
Rev Neurol (Paris) ; 171(8-9): 646-54, 2015 Sep.
Article de Français | MEDLINE | ID: mdl-26321313

RÉSUMÉ

For intra-operative neurophysiological monitoring during spine and spinal cord surgery, the challenge is to detect, in real-time, the occurrence of neurological impairment at onset in order to remedy the problem as quickly as possible before it becomes definitely acquired and irreversible. The past three decades were marked by considerable technical progress. Feasibility and reliability have now reached a very high level. A multimodal approach combining simultaneous monitoring of somatosensory and motor pathways has enabled a considerable decline in the rate of false negatives reported in the 80s when somatosensory evoked potentials (SSEP) were monitored alone. Several methods of monitoring are described in the literature. Combining transcranial electric stimulation of muscle motor evoked potentials (mMEP) and cortical SSEP allows non-invasive and selective monitoring of the posterior columns and pyramidal tract. One of the most widely used techniques internationally backed by a broad consensus within the International Society of Intra-operative Neurophysiology (ISIN), this technique remains exceptional in French-speaking countries. We expose here the methodological aspects for the readers of La Revue Neurologique.


Sujet(s)
Complications peropératoires/diagnostic , Surveillance peropératoire/méthodes , Procédures de neurochirurgie , Tractus pyramidaux/physiologie , Traumatismes de la moelle épinière/diagnostic , Moelle spinale/chirurgie , Rachis/chirurgie , Anesthésie générale/effets indésirables , Anesthésie générale/méthodes , Vis orthopédiques/effets indésirables , Potentiels évoqués moteurs , Potentiels évoqués somatosensoriels , Humains , Complications peropératoires/étiologie , Complications peropératoires/physiopathologie , Complications peropératoires/prévention et contrôle , Examen neurologique , Soins préopératoires , Radiculopathie/diagnostic , Radiculopathie/étiologie , Radiculopathie/physiopathologie , Moelle spinale/physiologie , Traumatismes de la moelle épinière/étiologie , Traumatismes de la moelle épinière/physiopathologie , Traumatismes de la moelle épinière/prévention et contrôle
3.
Neurophysiol Clin ; 45(2): 131-42, 2015 May.
Article de Anglais | MEDLINE | ID: mdl-25957985

RÉSUMÉ

BACKGROUND: Somatosensory evoked potentials (SSEPs) are increasingly performed for the assessment of peripheral neuropathies, but no practical guidelines have yet been established in this specific application. STUDY AIM: To determine the relevant indication criteria and optimal technical parameters for SSEP recording in peripheral neuropathy investigation. METHODS: A survey was conducted among the French-speaking practitioners with experience of SSEP recording in the context of peripheral neuropathies. The results of the survey were analyzed and discussed to provide recommendations for practice. RESULTS: SSEPs appear to be a second-line test when electroneuromyographic investigation is not sufficiently conclusive, providing complementary and valuable information on central and proximal peripheral conduction in the somatosensory pathways. CONCLUSIONS: Guidelines for a standardized recording protocol, including the various parameters to be measured, are proposed. CLINICAL RELEVANCE: We hope that these proposals will help to recognize the value of this technique in peripheral neuropathy assessment in clinical practice.


Sujet(s)
Potentiels évoqués somatosensoriels , Neuropathies périphériques/diagnostic , Stimulation électrique/méthodes , France , Humains , Conduction nerveuse , Guides de bonnes pratiques cliniques comme sujet , Enquêtes et questionnaires
5.
Neurophysiol Clin ; 43(4): 217-27, 2013 Oct.
Article de Anglais | MEDLINE | ID: mdl-24094907

RÉSUMÉ

AIMS OF THE STUDY: A brain-computer interface aims at restoring communication and control in severely disabled people by identification and classification of EEG features such as event-related potentials (ERPs). The aim of this study is to compare different modalities of EEG recording for extraction of ERPs. The first comparison evaluates the performance of six disc electrodes with that of the EMOTIV headset, while the second evaluates three different electrode types (disc, needle, and large squared electrode). MATERIAL AND METHODS: Ten healthy volunteers gave informed consent and were randomized to try the traditional EEG system (six disc electrodes with gel and skin preparation) or the EMOTIV Headset first. Together with the six disc electrodes, a needle and a square electrode of larger surface were simultaneously recording near lead Cz. Each modality was evaluated over three sessions of auditory P300 separated by one hour. RESULTS: No statically significant effect was found for the electrode type, nor was the interaction between electrode type and session number. There was no statistically significant difference of performance between the EMOTIV and the six traditional EEG disc electrodes, although there was a trend showing worse performance of the EMOTIV headset. However, the modality-session interaction was highly significant (P<0.001) showing that, while the performance of the six disc electrodes stay constant over sessions, the performance of the EMOTIV headset drops dramatically between 2 and 3h of use. Finally, the evaluation of comfort by participants revealed an increasing discomfort with the EMOTIV headset starting with the second hour of use. CONCLUSION: Our study does not recommend the use of one modality over another based on performance but suggests the choice should be made on more practical considerations such as the expected length of use, the availability of skilled labor for system setup and above all, the patient comfort.


Sujet(s)
Interfaces cerveau-ordinateur , Encéphale/physiologie , Électroencéphalographie/méthodes , Potentiels évoqués cognitifs P300 , Adulte , Études croisées , Électrodes , Électroencéphalographie/instrumentation , Femelle , Humains , Mâle , Adulte d'âge moyen , Jeune adulte
6.
Neurophysiol Clin ; 43(4): 243-50, 2013 Oct.
Article de Anglais | MEDLINE | ID: mdl-24094910

RÉSUMÉ

OBJECTIVE: Transcranial electric stimulation elicited muscle motor evoked potentials (TESmMEPs) is one of the best methods for corticospinal tract's function monitoring during spine and spinal cord surgeries. A train of multipulse electric stimulation is required for eliciting TESmMEPs under general anaesthesia. Here, we investigated the best stimulation parameters for eliciting and recording tibialis anterior's TESmMEPs during paediatric scoliosis surgery. PATIENTS AND METHODS: Numbers of pulses (NOP), inter-stimulus intervals (ISI) and current intensities allowing the best size tibialis anterior muscle's TESmMEPs under general anaesthesia, were tested and collected during 77 paediatric scoliosis surgery monitoring procedures in our hospital. Individual pulse duration was kept at 0.5 ms and stimulating electrodes were positioned at C1 and C2 (International 10-20-EEG-System) during all the tests. RESULTS: The NOP used for eliciting the best tibialis anterior TESmMEPs response was 5, 6, and 7 respectively in 21 (27%), 47 (61%) and 9 (12%) out of the 77 patients. The ISI was 2, 3 and 4 ms respectively in 13 (17%), 55 (71%) and 9 (12%) of them. The current intensity used varied from 300 to 700 V (mean: 448±136 V). CONCLUSION: Most patients had 6 as best NOP (61%) and 3 ms as best ISI (71%). These findings support that a NOP of 6 and an ISI of 3 ms should be preferentially used as optimal stimulation settings for intraoperative tibialis anterior muscle's TESmMEPs eliciting and recording during paediatric scoliosis surgery.


Sujet(s)
Potentiels évoqués moteurs/physiologie , Surveillance peropératoire , Scoliose/chirurgie , Stimulation magnétique transcrânienne/méthodes , Adolescent , Enfant , Femelle , Humains , Mâle , Muscles squelettiques/physiologie , Tractus pyramidaux/physiologie , Jeune adulte
7.
Orthop Traumatol Surg Res ; 99(6 Suppl): S319-27, 2013 Oct.
Article de Anglais | MEDLINE | ID: mdl-23972785

RÉSUMÉ

Intraoperative spinal cord monitoring consists in a subcontinuous evaluation of spinal cord sensory-motor functions and allows the reduction the incidence of neurological complications resulting from spinal surgery. A combination of techniques is used: somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), neurogenic motor evoked potentials (NMEP), D waves, and pedicular screw testing. In absence of intraoperative neurophysiological testing, the intraoperative wake-up test is a true form of monitoring even if its latency long and its precision variable. A 2011 survey of 117 French spinal surgeons showed that only 36% had neurophysiological monitoring available (public healthcare facilities, 42%; private facilities, 27%). Monitoring can be performed by a neurophysiologist in the operating room, remotely using a network, or directly by the surgeon. Intraoperative alerts allow real-time diagnosis of impending neurological injury. Use of spinal electrodes, moved along the medullary canal, can determine the lesion level (NMEP, D waves). The response to a monitoring alert should take into account the phase of the surgical intervention and does not systematically lead to interruption of the intervention. Multimodal intraoperative monitoring, in presence of a neurophysiologist, in collaboration with the anesthesiologist, is the most reliable technique available. However, no monitoring technique can predict a delayed-onset paraplegia that appears after the end of surgery. In cases of preexisting neurological deficit, monitoring contributes little. Monitoring of the L1-L4 spinal roots also shows low reliability. Therefore, monitoring has no indication in discal and degenerative surgery of the spinal surgery. However, testing pedicular screws can be useful. All in all, thoracic and thoracolumbar vertebral deviations, with normal preoperative neurological examination are currently the essential indication for spinal cord monitoring. Its absence in this indication is a lost opportunity for the patient. If neurophysiological means are not available, intraoperative wake-up test is a minimal obligation.


Sujet(s)
Monitorage neurophysiologique peropératoire/méthodes , Maladies de la moelle épinière/chirurgie , Moelle spinale/physiopathologie , France , Humains , Reproductibilité des résultats , Moelle spinale/chirurgie , Maladies de la moelle épinière/physiopathologie
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