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Allison DW, Balzer JR. Misconceptions in IONM Part I: Interleaved Intraoperative Somatosensory Evoked Potential Stimulation. Neurodiagn J 2022; 62:6-25. [PMID: 35061974 DOI: 10.1080/21646821.2022.2010471] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
A misconception in the field of intraoperative neurophysiological monitoring (IONM) is that continuous, multi-nerve (four-limb), interleaved somatosensory evoked potential (SSEP) stimulation, while advantageous, is not universally utilized due to variety of misunderstandings regarding this approach to SSEP stimulation. This article addresses the rationale for this misconception. We find that continuous, multi-nerve, interleaved SSEP stimulation is superior to all other stimulation paradigms in most operative scenarios, allowing the fastest acquisition of SSEPs at low stimulation repetition rates, which generate the highest amplitude cortical responses.
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Affiliation(s)
| | - Jeffrey R Balzer
- Department of Neurological Surgery, University of Pittsburgh Medical Centre, Pittsburgh, Pennsylvania
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MacDonald D, Dong C, Quatrale R, Sala F, Skinner S, Soto F, Szelényi A. Recommendations of the International Society of Intraoperative Neurophysiology for intraoperative somatosensory evoked potentials. Clin Neurophysiol 2019; 130:161-179. [DOI: 10.1016/j.clinph.2018.10.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/27/2018] [Accepted: 10/21/2018] [Indexed: 11/25/2022]
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Haley GE, Kroenke C, Schwartz D, Kohama SG, Urbanski HF, Raber J. Hippocampal M1 receptor function associated with spatial learning and memory in aged female rhesus macaques. AGE (DORDRECHT, NETHERLANDS) 2011; 33:309-320. [PMID: 20890730 PMCID: PMC3168603 DOI: 10.1007/s11357-010-9184-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 09/03/2010] [Indexed: 05/29/2023]
Abstract
Of the acetylcholine muscarinic receptors, the type 1 (M1) and type 2 (M2) receptors are expressed at the highest levels in the prefrontal cortex (PFC) and hippocampus, brain regions important for cognition. As equivocal findings of age-related changes of M1 and M2 in the nonhuman primate brain have been reported, we first assessed age-related changes in M1 and M2 in the PFC and hippocampus using saturation binding assays. Maximum M1 receptor binding, but not affinity of M1 receptor binding, decreased with age. In contrast, the affinity of M2 receptor binding, but not maximum M2 receptor binding, increased with age. To determine if in the elderly cognitive performance is associated with M1 or M2 function, we assessed muscarinic function in elderly female rhesus macaques in vivo using a scopolamine challenge pharmacological magnetic resonance imaging and in vitro using saturation binding assays. Based on their performance in a spatial maze, the animals were classified as good spatial performers (GSP) or poor spatial performers (PSP). In the hippocampus, but not PFC, the GSP group showed a greater change in T(2)*-weighted signal intensity after scopolamine challenge than the PSP group. The maximum M1 receptor binding and receptor binding affinity was greater in the GSP than the PSP group, but no group difference was found in M2 receptor binding. Parameters of circadian activity positively correlated with the difference in T(2)*-weighted signal intensity before and after the challenge, the maximum M1 receptor binding, and the M1 receptor binding affinity. Thus, while in rhesus macaques, there are age-related decreases in M1 and M2 receptor binding, in aged females, hippocampal M1, but not M2, receptor function is associated with spatial learning and memory and circadian activity.
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Affiliation(s)
- Gwendolen E. Haley
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Chris Kroenke
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Daniel Schwartz
- Portland Veterans Administration Medical Center, Division of Psychiatry, Oregon Health and Science University, Portland, OR 97239 USA
| | - Steven G. Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
| | - Henryk F. Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Jacob Raber
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
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Hansen HC. Sooner or later...? In search of the most useful components of the somatosensory evoked potential to define prognosis in critically ill patients with acute stroke. Clin Neurophysiol 2011; 122:1482-4. [PMID: 21330201 DOI: 10.1016/j.clinph.2011.01.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 12/31/2010] [Accepted: 01/05/2011] [Indexed: 10/18/2022]
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Joutsen A, Puumala P, Lyytikäinen LP, Pajulo O, Etelämäki A, Eskola H, Jäntti V. EEG sources of noise in intraoperative somatosensory evoked potential monitoring during propofol anesthesia. J Clin Monit Comput 2009; 23:237-42. [PMID: 19565340 DOI: 10.1007/s10877-009-9188-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 06/17/2009] [Indexed: 11/26/2022]
Abstract
OBJECTIVE It was hypothesized that somato- sensory evoked potentials can be achieved faster by selective averaging during periods of low spontaneous electroen- cephalographic (EEG) activity. We analyzed the components of EEG that decrease the signal-to-noise ratio of somatosensory evoked potential (SEP) recordings during propofol anesthesia. METHODS Patient EEGs were recorded with a high sampling frequency during deep anesthesia, when EEGs were in burst suppression. EEGs were segmented visually into bursts, spindles, suppressions, and artifacts. Tibial somatosensory evoked potentials (tSEPs) were averaged offline separately for burst, suppression, and spindle segments using a signal bandwidth of 30-200 Hz. Averages achieved with 2, 4, 8, 16, 64, 128, and 256 responses were compared both visually, and by calculating the signal-to-noise ratios. RESULTS During bursts and spindles, the noise levels were similar and significantly higher than during suppressions. Four to eight times more responses had to be averaged during bursts and spindles than during suppressions in order to achieve a similar response quality. Averaging selectively during suppressions can therefore yield reliable tSEPs in approximately one-fifth of the time required during bursts. CONCLUSION The major source of EEG noise in tSEP recordings is the mixed frequency activity of the slow waves of bursts that occur during propofol anesthesia. Spindles also have frequency components that increase noise levels, but these are less important, as the number of spindles is fewer. The fastest way to obtain reliable tSEPs is by averaging selectively during suppressions.
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Affiliation(s)
- Atte Joutsen
- Department of Biomedical Engineering, Tampere University of Technology, Tampere, Finland.
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Murrell JC, Waters D, Johnson CB. Comparative effects of halothane, isoflurane, sevoflurane and desflurane on the electroencephalogram of the rat. Lab Anim 2008; 42:161-70. [PMID: 18435874 DOI: 10.1258/la.2007.06019e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inhalant anaesthetic agents are commonly used in studies investigating the electroencephalographic (EEG) effects of noxious stimuli in animals. Halothane causes less EEG depression than isoflurane, however, the EEG effects of halothane, isoflurane, sevoflurane and desflurane have not been compared in the same model. This study aimed to compare the EEG effects of these inhalational agents in the rat. Forty male Sprague-Dawley rats were assigned to four groups and anaesthetized with halothane, isoflurane, sevoflurane or desflurane. EEG was recorded from the left and right somatosensory cortices for 5 min at three different multiples of minimal alveolar concentration (MAC) (1.25, 1.5 and 1.75). Median, 95% spectral edge frequency and total power were derived and a single mean value for each was calculated for the first 60 s of each recording period. When the raw EEG contained burst suppression (BS), the BS ratio (BSR) over 60 s was calculated. No BS was found in EEG recorded from the halothane group at any concentration. BS was present at all concentrations with the other anaesthetic agents. BS was almost complete at all concentrations of isoflurane, whereas BSR increased significantly with increasing concentrations of sevoflurane and desflurane. No significant differences were found between the BSR due to the 1.75 MAC multiple of isoflurane, sevoflurane or desflurane. Halothane causes significantly less depression of cortical activity than the newer inhalant agents at equivalent multiples of MAC. These data support the hypothesis that halothane has a fundamentally different mechanism of action than the other inhalant agents.
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Affiliation(s)
- J C Murrell
- Comparative Anatomy and Physiology, Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
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Tirschwell DL. COMA IN THE INTENSIVE CARE UNIT. Continuum (Minneap Minn) 2006. [DOI: 10.1212/01.con.0000290437.80323.d2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Liu EHC, Wong HK, Chia CP, Lim HJ, Chen ZY, Lee TL. Effects of isoflurane and propofol on cortical somatosensory evoked potentials during comparable depth of anaesthesia as guided by bispectral index. Br J Anaesth 2004; 94:193-7. [PMID: 15516356 DOI: 10.1093/bja/aei003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The aim of this study was to determine if propofol caused less suppression of cortical somatosensory evoked potentials (SSEPs) during spine surgery compared with isoflurane during comparable depth of anaesthesia as guided by bispectral index (BIS) measurements. METHODS This was a randomized controlled trial of propofol and isoflurane involving 60 patients undergoing elective spine surgery. BIS monitoring was used to guide a consistent and comparable depth of anaesthesia, the index was maintained at between 40 and 50 during anaesthesia. The cortical SSEP P40-N50 peak-to-peak amplitude and latency time to the P40 peak were measured before induction of anaesthesia, after induction of anaesthesia, at the start of skin incision, at the start of pedicle screw insertion and at the start of rod insertion, by a neurophysiologist blinded to drug allocation. RESULTS Both propofol and isoflurane decreased SSEP amplitude and increased latency during the course of anaesthesia. After achieving a comparable depth of anaesthesia, the SSEP amplitude was significantly lower with isoflurane, 1.5 (1.0) vs 2.4 (1.4) muV (P=0.005). Latency was significantly longer with isoflurane, 39.5 (3.9) vs 37.3 (3.1) ms (P=0.024). Isoflurane was associated with greater variability of SSEP amplitude during the course of anaesthesia and surgery, coefficient of variation 35.4 (18.0) vs 21.2 (10.2)% (P=0.008). CONCLUSIONS Propofol anaesthesia caused less suppression of the cortical SSEP, with better preservation of SSEP amplitude, and less variability at an equivalent depth of anaesthesia.
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Affiliation(s)
- E H C Liu
- Department of Anaesthesia, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074
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Wiedemayer H, Schaefer H, Armbruster W, Miller M, Stolke D. Observations on intraoperative somatosensory evoked potential (SEP) monitoring in the semi-sitting position. Clin Neurophysiol 2002; 113:1993-7. [PMID: 12464339 DOI: 10.1016/s1388-2457(02)00302-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Former case reports suggest that monitoring of median nerve somatosensory evoked potentials (M-SEP) is unreliable in patients operated in the semi-sitting position due to the occurrence of evoked potential changes unrelated to neurological damage. This study was designed to analyze these changes in greater detail and confirm that these changes are not caused by neurological damage. METHODS M-SEP monitoring findings of 50 patients with surgery in the semi-sitting position were analyzed and compared with a group of 50 patients who underwent surgery in the supine position. M-SEP amplitudes and latencies at distinct steps of the monitoring procedure were used for further analysis. In 10 of the 50 semi-sitting patients, M-SEP were recorded additionally after surgery with the anesthetized patient in the supine position. RESULTS Significant M-SEP changes occurred in the semi-sitting patients only. An amplitude loss of greater than 50% on at least one side was observed in 24 patients. The magnitude and the time course of the amplitude loss was considerably variable. A complete loss of the evoked potential was not observed in any case. In all 10 patients, M-SEP recovered completely when recorded in the supine position. CONCLUSIONS In about half of the patients with M-SEP monitoring in the semi-sitting position, a significant amplitude loss occurs which is unrelated to neurological damage and presumably caused by subdural gas collections. There is no characteristic pattern of M-SEP changes which enables a differentiation of these 'artificial' alterations from true events. The only appropriate criterion to indicate an impending neurological damage in these patients seems to be a complete loss of the M-SEP potential.
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Affiliation(s)
- Helmut Wiedemayer
- Department of Neurosurgery, University of Essen Medical School, Hufelandstr. 5545122, Essen, Germany.
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MacDonald DB. Individually optimizing posterior tibial somatosensory evoked potential P37 scalp derivations for intraoperative monitoring. J Clin Neurophysiol 2001; 18:364-71. [PMID: 11673702 DOI: 10.1097/00004691-200107000-00008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
This investigation sought the optimal (highest amplitude) derivation for monitoring the posterior tibial P37 for each side in each individual, and determined whether this may change intraoperatively. Fifty monitored patients were studied using a partial P37 map consisting of FPz, Fz, Cz, Cz', Pz, POz, C4', and C3' to a noncephalic reference. From this, the highest amplitude scalp derivation was determined for each side. Of 100 tibial nerves, the initial optimal input 1 was Cz' in 52%, Pz in 28%, and Cz or iC' in 10%, and optimal input 2 was cC' in 69% and FPz in 31%. The optimal derivation was the same for each side in 34% of patients and different in 66%. Of 31 patients with at least one subsequent trial later during surgery, P37 topography changed in 14 and affected optimal inputs in 12. This occurred regularly during sitting-position posterior fossa surgery because of intracranial air, but sometimes occurred during other surgeries as well. The most common change consisted of FPz replacing cC' as optimal input 2. Input 1 changes were predominantly in an anterior or posterior sagittal direction. The results demonstrate great inter- and intraindividual P37 variability, and document intraoperative topographic changes. Both phenomena can be addressed by a practical method to refine intraoperative monitoring by individually optimizing scalp derivations and identifying topographic P37 changes during surgery.
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Affiliation(s)
- D B MacDonald
- Department of Neurosciences, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
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Vaugha DJ, Thornton C, Wright DR, Fernandes JR, Robbins P, Doré C, Brunner MD. Effects of different concentrations of sevoflurane and desflurane on subcortical somatosensory evoked responses in anaesthetized, non-stimulated patients. Br J Anaesth 2001; 86:59-62. [PMID: 11575411 DOI: 10.1093/bja/86.1.59] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Twenty-four patients were recruited and given either sevoflurane or desflurane as their sole anaesthetic. Each patient was given sequentially increasing or decreasing doses at 0.5 MAC intervals, and the median nerve somatosensory evoked response recorded after an equilibration at each concentration. The N20-P25 and P25-N35 amplitudes decreased with increasing agent concentration. However, for both agents the P15-N20 amplitude response was quadratic in shape. The peak inflection points were at 3.2% for sevoflurane and 4.9% for desflurane. There were no differences between the ascending and descending groups. This increase in activity in the midbrain at 'surgical' end-tidal anaesthetic concentrations suggests more complex neuroelectrical responses to anaesthesia than simple global suppression.
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Affiliation(s)
- D J Vaugha
- Department of Anaesthesia, Imperial College School of Anaesthesia at Northwick Park Hospital, Harrow, Middlesex, UK
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Nikouline VV, Wikström H, Linkenkaer-Hansen K, Kesäniemi M, Ilmoniemi RJ, Huttunen J. Somatosensory evoked magnetic fields: relation to pre-stimulus mu rhythm. Clin Neurophysiol 2000; 111:1227-33. [PMID: 10880798 DOI: 10.1016/s1388-2457(00)00291-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Brain responses to auditory and visual stimuli have been previously shown to depend on the level of spontaneous brain activity in the 8-13 Hz range. Our aim was to determine whether somatosensory evoked responses are influenced by ongoing rhythmic activity in the 8-13 Hz frequency range originating in the sensorimotor cortex (mu rhythm). METHODS We used a whole-head 122 channel magnetoencephalography (MEG) system to record somatosensory evoked fields (SEFs) in response to median nerve stimulation in 11 subjects. Spontaneous oscillations in the 8-13 Hz band over the contralateral sensorimotor cortex were evaluated in 3 different pre-stimulus time intervals using wavelet analysis. RESULTS The N20m SEF deflection did not depend on pre-stimulus activity, while the amplitude of the P35m deflection, and to a lesser extent that of the P60m deflection, showed a small positive correlation with the amplitude of the pre-stimulus mu rhythm. Although the amplitude of the mu rhythm varied by a factor of 2.3-5, the maximum variations in P35m and P60m amplitude were only 21 and 12%, respectively. The latencies of the peaks were not affected by the strength of the pre-stimulus mu rhythm. CONCLUSIONS It appears that the first excitatory cortical response (N20m) is independent of the oscillatory state (8-13 Hz frequency range) of the sensorimotor cortex. Later parts of the response (P35m and P60m) are also relatively stable compared with the large variations in mu rhythm.
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Affiliation(s)
- V V Nikouline
- BioMag Laboratory, Medical Engineering Centre, Helsinki University Central Hospital, Helsinki, Finland.
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Jäntti V, Yli-Hankala A. Chapter 11 Neurophysiology of anaesthesia. CLINICAL NEUROPHYSIOLOGY AT THE BEGINNING OF THE 21ST CENTURY, 11TH INTERNATIONAL CONGRESS OF ELECTROMYOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 2000. [DOI: 10.1016/s1567-424x(09)70142-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Jäntti V, Sonkajärvi E, Mustola S, Rytky S, Kiiski P, Suominen K. Single-sweep cortical somatosensory evoked potentials: N20 and evoked bursts in sevoflurane anaesthesia. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 108:320-4. [PMID: 9607521 DOI: 10.1016/s0168-5597(98)00005-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cortical evoked responses to median nerve stimulation were recorded from 21 subjects during sevoflurane anaesthesia at the level of burst suppression in EEG. The N20/P22 wave had the typical form of a negative wave postcentrally, and positive precentrally. The amplitude exceeded 4 microV in all patients, making it easily visible without averaging on the low-amplitude suppression. These results show that two kinds of somatosensory evoked potential can be studied without averaging during EEG suppression in deep anaesthesia. One is the localised N20/P22 wave, which is seen regularly during suppression after stimuli with intervals exceeding 1 s. The other is the burst, involving the whole cortex, which is not evoked by every stimulus. We suggest that somatosensory evoked potentials can be monitored during sevoflurane-induced EEG suppression, and often can be evaluated reliably from a couple of single sweeps with stimulation interval exceeding 1 s. The enhancement of early cortical components of SEP, their adaptation to repeated stimuli, and the disappearance of later polysynaptic components during EEG suppression, give new possibilities to study the generators of SEP and the different effects of anaesthetics.
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Affiliation(s)
- V Jäntti
- Department of Clinical Neurophysiology, Oulu University Hospital, Finland.
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Guérit JM. [International literature review concerning evoked potentials in 1997]. Neurophysiol Clin 1998; 28:73-9. [PMID: 9563000 DOI: 10.1016/s0987-7053(97)89579-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- J M Guérit
- Unité d'explorations électrophysiologiques du système nerveux, cliniques universitaires Saint-Luc, université catholique de Louvain, Bruxelles, Belgique
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