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Luo M, Gan Q, Huang Z, Jiang Y, Li K, Wu M, Yang D, Shao H, Chen Y, Fu Y, Chen Z. Changes in Mental Health and EEG Biomarkers of Undergraduates Under Different Patterns of Mindfulness. Brain Topogr 2024; 37:75-87. [PMID: 38145437 PMCID: PMC10771601 DOI: 10.1007/s10548-023-01026-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 11/20/2023] [Indexed: 12/26/2023]
Abstract
The effects of short-term mindfulness are associated with the different patterns (autonomic, audio guided, or experienced and certified mindfulness instructor guided mindfulness). However, robust evidence for reported the impacts of different patterns of mindfulness on mental health and EEG biomarkers of undergraduates is currently lacking. Therefore, we aimed to test the hypotheses that mindfulness training for undergraduates would improve mental health, and increase alpha power over frontal region and theta power over midline region at the single electrode level. We also describe the distinction among frequency bands patterns in different sites of frontal and midline regions. 70 participants were enrolled and assigned to either 5-day mindfulness or a waiting list group. Subjective questionnaires measured mental health and other psychological indicators, and brain activity was recorded during various EEG tasks before and after the intervention. The 5-day mindfulness training improved trait mindfulness, especially observing (p = 0.001, d = 0.96) and nonreactivity (p = 0.03, d = 0.56), sleep quality (p = 0.001, d = 0.91), and social support (p = 0.001, d = 0.95) while not in affect. Meanwhile, the expected increase in the alpha power of frontal sites (p < 0.017, d > 0.84) at the single electrode level was confirmed by the current data rather than the theta. Interestingly, the alteration of low-beta power over the single electrode of the midline (p < 0.05, d > 0.71) was difference between groups. Short-term mindfulness improves practitioners' mental health, and the potentially electrophysiological biomarkers of mindfulness on neuron oscillations were alpha activity over frontal sites and low-beta activity over midline sites.
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Affiliation(s)
- Miaoling Luo
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
- Brain Science and Visual Cognition Research Center, Medical School of Kunming University of Science and Technology, Kunming, China
| | - Quan Gan
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
- Brain Science and Visual Cognition Research Center, Medical School of Kunming University of Science and Technology, Kunming, China
- Faculté de Médecine, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Ziyang Huang
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Yunxiong Jiang
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Kebin Li
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Minxiang Wu
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Dongxiao Yang
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Heng Shao
- Department of Geriatrics, The First People's Hospital of Yunnan Province, Kunming, China
| | - Yanmei Chen
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
- Brain Science and Visual Cognition Research Center, Medical School of Kunming University of Science and Technology, Kunming, China
| | - Yu Fu
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
- Brain Science and Visual Cognition Research Center, Medical School of Kunming University of Science and Technology, Kunming, China
| | - Zhuangfei Chen
- Medical Faculty, Kunming University of Science and Technology, Kunming, China.
- Brain Science and Visual Cognition Research Center, Medical School of Kunming University of Science and Technology, Kunming, China.
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Xin Y, Ma L, Xie T, Liang Y, Ma M, Chu T, Liu C, Xu A. Comparative analysis of the effect of electromyogram to bispectral index and 95% spectral edge frequency under remimazolam and propofol anesthesia: a prospective, randomized, controlled clinical trial. Front Med (Lausanne) 2023; 10:1128030. [PMID: 37608826 PMCID: PMC10442164 DOI: 10.3389/fmed.2023.1128030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/25/2023] [Indexed: 08/24/2023] Open
Abstract
Background Bispectral index (BIS), an index used to monitor the depth of anesthesia, can be interfered with by the electromyogram (EMG) signal. The 95% spectral edge frequency (SEF95) also can reflect the sedation depth. Remimazolam in monitored anesthesia care results in higher BIS values than propofol, though in the same sedation level assessed by Modified Observers Assessment of Alertness and Sedation (MOAA/S). Our study aims to illustrate whether EMG is involved in remimazolam causing higher BIS value than propofol preliminarily and to explore the correlations among BIS, EMG, and SEF95 under propofol and remimazolam anesthesia. Patients and methods Twenty-eight patients were randomly divided into propofol (P) and remimazolam (RM) groups. Patients in the two groups received alfentanil 10 μg/kg, followed by propofol 2 mg/kg and remimazolam 0.15 mg/kg. Blood pressure (BP), heart rate (HR), and oxygen saturation (SpO2) were routinely monitored. The BIS, EMG, and SEF95 were obtained through BIS VISTATM. The primary outcomes were BIS, EMG, and the correlation between BIS and EMG in both groups. Other outcomes were SEF95, the correlation between BIS and SEF95, and the correlation between EMG and SEF95. And all the statistical and comparative analysis between these signals was conducted with SPSS 26.0 and GraphPad Prism 8. Results BIS values, EMG, and SEF95 were significantly higher in the RM group than in the P group (all p < 0.001). There was a strong positive correlation between BIS and EMG in the RM group (r = 0.416). Nevertheless, the BIS in the P group showed a weak negative correlation with EMG (r = -0.219). Both P (r = 0.787) and RM group (r = 0.559) had a reasonably significant correlation coefficient between BIS and SEF95. SEF95 almost did not correlate with EMG in the RM group (r = 0.101). Conclusion Bispectral index can be interfered with high EMG intensity under remimazolam anesthesia. However, EMG can hardly affect the accuracy of BIS under propofol anesthesia due to low EMG intensity and a weak negative correlation between EMG and BIS. Moreover, SEF95 may have a great application prospect in predicting the sedation condition of remimazolam.
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Affiliation(s)
- Yueyang Xin
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Li Ma
- School of Information Engineering, Wuhan University of Technology, Wuhan, Hubei, China
| | - Tianli Xie
- School of Information Engineering, Wuhan University of Technology, Wuhan, Hubei, China
| | - Yuhui Liang
- School of Information Engineering, Wuhan University of Technology, Wuhan, Hubei, China
| | - Miao Ma
- School of Information Engineering, Wuhan University of Technology, Wuhan, Hubei, China
| | - Tiantian Chu
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Cheng Liu
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Aijun Xu
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Li F, Dang Y, Zhang X, Chen H, Lu Y, Yu Y. Age-dependent Electroencephalogram Characteristics During Different Levels of Anesthetic Depth. Clin EEG Neurosci 2022:15500594221142680. [PMID: 36503267 DOI: 10.1177/15500594221142680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Objective The monitoring of anesthetic depth based on electroencephalogram derivation is not currently adjusted for age. Here we analyze the influence of age factors on electroencephalogram characteristics. Methods Frontal electroencephalogram recordings were obtained from 80 adults during routine clinical anesthesia. The characteristics of electroencephalogram with age and anesthesia were observed during four kinds of anesthesia. Results The slow wave power, δ power, Bispectral Index (BIS) and approximate entropy can be used to distinguish different states of anesthesia (P < 0.05). In the deep and very deep anesthesia states, δ power decreased with age (P < 0.0001). In the very deep anesthesia state, θ power decreased with age (P < 0.05). In the deep and very deep anesthesia states, α power decreased with age (P = 0.0002). In the light and deep anesthesia states, β power decreased with age (P = 0.003). In the deep anesthesia state, γ power decreased with age (P = 0.002). In the very deep anesthesia state, permutation entropy increased significantly with age (P = 0.0001). In the very deep anesthesia state, BIS value increased with age (P = 0.006). The slow wave power, approximate entropy, and sample entropy did not show age-dependent changes. Conclusions The influence of age should be considered when using BIS and δ power to monitor the depth of anesthesia, while the influence of age should not be considered when using slow wave power and approximate entropy to monitor the depth of anesthesia.
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Affiliation(s)
- Feixiang Li
- Department of Anesthesiology, 74671Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin, China
- Department of Anesthesiology, 117865The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Yaoyao Dang
- Department of Anesthesiology, 117865The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Xuan Zhang
- Tianjin Medical University Cancer Institute and Hospital, 74675National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Huimin Chen
- Department of Anesthesiology, 117865The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Yuechun Lu
- Department of Anesthesiology, 117865The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Yonghao Yu
- Department of Anesthesiology, 74671Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin, China
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Mylonas D, Machado S, Larson O, Patel R, Cox R, Vangel M, Maski K, Stickgold R, Manoach DS. Dyscoordination of non-rapid eye movement sleep oscillations in autism spectrum disorder. Sleep 2022; 45:6505127. [DOI: 10.1093/sleep/zsac010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/13/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
Converging evidence from neuroimaging, sleep, and genetic studies suggest that dysregulation of thalamocortical interactions mediated by the thalamic reticular nucleus (TRN) contribute to autism spectrum disorder (ASD). Sleep spindles assay TRN function, and their coordination with cortical slow oscillations (SOs) indexes thalamocortical communication. These oscillations mediate memory consolidation during sleep. In the present study, we comprehensively characterized spindles and their coordination with SOs in relation to memory and age in children with ASD.
Methods
Nineteen children and adolescents with ASD, without intellectual disability, and 18 typically developing (TD) peers, aged 9–17, completed a home polysomnography study with testing on a spatial memory task before and after sleep. Spindles, SOs, and their coordination were characterized during stages 2 (N2) and 3 (N3) non-rapid eye movement sleep.
Results
ASD participants showed disrupted SO-spindle coordination during N2 sleep. Spindles peaked later in SO upstates and their timing was less consistent. They also showed a spindle density (#/min) deficit during N3 sleep. Both groups showed significant sleep-dependent memory consolidation, but their relations with spindle density differed. While TD participants showed the expected positive correlations, ASD participants showed the opposite.
Conclusions
The disrupted SO-spindle coordination and spindle deficit provide further evidence of abnormal thalamocortical interactions and TRN dysfunction in ASD. The inverse relations of spindle density with memory suggest a different function for spindles in ASD than TD. We propose that abnormal sleep oscillations reflect genetically mediated disruptions of TRN-dependent thalamocortical circuit development that contribute to the manifestations of ASD and are potentially treatable.
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Affiliation(s)
- Dimitrios Mylonas
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | - Sasha Machado
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Olivia Larson
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA,USA
| | - Rudra Patel
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Roy Cox
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam,The Netherlands
| | - Mark Vangel
- Department of Biostatistics, Massachusetts General Hospital, Harvard Medical School, Boston, MA,USA
| | - Kiran Maski
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Robert Stickgold
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Dara S Manoach
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
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Chaudhuri S, Banerjee S, Chattopadhyay U, Hussain S. Comparison of recovery times by using bispectral index monitoring versus end-tidal agent concentration monitoring in patients undergoing inhalational general anaesthesia. Indian J Anaesth 2022; 66:S161-S168. [PMID: 35774240 PMCID: PMC9238234 DOI: 10.4103/ija.ija_716_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 04/18/2022] [Accepted: 04/29/2022] [Indexed: 11/06/2022] Open
Abstract
Background and Aims: End-tidal anaesthetic gas concentration (ETAG) and bispectral index (BIS) are both used to monitor depth of anaesthesia. Maintaining an accurate depth of anaesthesia helps in early post-operative recovery. This study compared the recovery times from sevoflurane–nitrous oxide anaesthesia using ETAG monitoring with BIS monitoring. Methods: Four hundred and two patients undergoing elective surgeries under sevoflurane- nitrous oxide anaesthesia were enroled in this double blinded parallel group prospective randomised trial and allocated into two groups. The depth of anaesthesia was monitored using BIS in BIS group (n = 202) and end-tidal sevoflurane concentration (EtSevo) in ETAG group (n = 200). The time to extubation and recovery were compared between the groups. Parametric, non-parametric and categorical variables were compared using Student’s ‘t’ test, Wilcoxon’s rank sum test and Chi-square test, respectively. Results: Time to extubation (min) [BIS group – 10, 5; ETAG group – 10, 5 (median, inter-quartile range, IQR), P = 0.32] and time to recovery (min) [BIS group – 14, 6; ETAG group – 13.5, 7 (median, IQR), P = 0.34] did not differ significantly between the two groups. The EtSevo concentration (vol%) was significantly higher in the BIS group at 5 min [BIS group – 1.2, 0.4; ETAG group – 1.0, 0.4 (median, IQR), P < 0.001], 30 min [BIS group – 1.1, 0.4; ETAG group – 1.0, 0.3 (median, IQR), P = 0.002] and 120 min [BIS group – 1.11 ± 0.28; ETAG group – 0.96 ± 0.27 (mean ± standard deviation), P = 0.014] after induction of anaesthesia. Conclusions: BIS and ETAG monitoring are associated with comparable recovery profiles. ETAG monitoring is associated with significantly less sevoflurane consumption.
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The impact of bolus versus continuous infusion of intravenous ketamine on bispectral index variations and desflurane administration during major surgery: The KETABIS study. Eur J Anaesthesiol 2021; 38:1168-1179. [PMID: 34474441 DOI: 10.1097/eja.0000000000001588] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although ketamine, a NMDA-receptor antagonist, tends to increase the bispectral index (BIS), it remains a widely used analgesic whenever administered in low doses during major surgery. OBJECTIVE The objective of this study was to compare the impact of intravenous ketamine (given either as a continuous infusion or as a bolus) on BIS and to compare desflurane administration and postoperative outcomes between the groups. DESIGN Prospective, randomised, parallel-group, open-label study. SETTING University hospital, operating room. PARTICIPANTS Fifty patients, scheduled for major abdominal surgery. INTERVENTIONS AND MAIN OUTCOMES MEASURES Patients were randomised into two groups: ketamine by intravenous continuous infusion - group (KI) and ketamine by i.v. bolus - group (KB). In the KI group, ketamine at a rate of 0.25 mg kg-1 h-1 was commenced at skin incision (T0) and maintained at this rate for the duration of surgery. In group KB, a ketamine bolus of 0.25 mg kg-1was administered at T0 and repeated every hour. The difference in BIS between the groups was compared from T0 onwards. The amount of desflurane administered to keep BIS within the usual recommended range (40-60) was compared, as were the doses of phenylephrine and remifentanil. Postoperative pain and recovery outcomes were also assessed. RESULTS After T0, the BIS increased significantly from baseline in group KB compared with group KI: the rise in BIS was 20 ± 8 vs. 11 ± 6, respectively (P = 0.0001). The between-group mean difference (95% confidence interval (CI), was 9 (5 to 13). In group KB, desflurane administration significantly increased for the first 15 min after T0: 6.3 ± 1.8 vs. 3.8 ± 1.3 ml (P < 0.0001) with a mean intergroup group difference (95% CI) of 2.4 (1.5 to 3.4) ml. There was no difference in desflurane administration when considering the full hour from T0 to T60 min: 16 ± 9 vs. 15 ± 5 ml (P = 0.63) with a mean intergroup difference (95% CI) of 1 (-3 to 5) ml. After surgery, pain scores, opioid consumption, incidence of nausea and vomiting and recovery scores were similar between groups. CONCLUSION Compared with a continuous ketamine infusion, a ketamine bolus significantly increased the BIS after T0. In order to keep the BIS below 60, significantly more desflurane was administered from T0 to T15 min in group KB. To prevent such higher desflurane administration and its related atmospheric pollution, our results suggest administering intra-operative intravenous ketamine as an infusion rather than a bolus. TRIAL REGISTRATION Clinicaltrials.gov registration identifier: NCT03781635.
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Dahaba AA, Lin H, Ye XF, Zhang N, Wang K, Reibnegger G, Lian QQ. Propofol-Bispectral Index (BIS) Electroencephalography (EEG) Pharmacokinetic-Pharmacodynamic Model in Patients With Post-Cerebral Hemorrhage Hydrocephalus. Clin EEG Neurosci 2021; 52:351-359. [PMID: 32527157 DOI: 10.1177/1550059420932042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Background. Titrating hypnotic agents for patients who suffer from a cerebral insult is a challenging task. To date there is no real gold standard to precisely quantify electroencephalography (EEG) response in a fashion that could be utilized for patients with post-cerebral hemorrhage hydrocephaly. While we must administer "as per usual" analgesics for noxious stimuli, we have to administer the hypnotic agents more "sparingly" due to lack of objective monitoring. Methods. We compared 15 adult post-cerebral hemorrhage hydrocephalus patients undergoing ventriculo-peritoneal shunt placement with 15 controls matched for gender and approximate age. We set propofol target controlled infusion estimated plasma concentrations (Cp) to gradually reach 4 µg/mL over 4 minutes. To precisely quantify post-cerebral hemorrhage mental dysfunction, we used electronically retrieved bispectral index (BIS) and propofol Cp data points to create individual inhibitory monophasic mathematical model for each patient that incorporates an independent hysteresis "lag" function. Results. In post-cerebral hemorrhage patients Cp-BIS curve, C50 (propofol concentration associated with inhibitory 50% BIS response) cutoff point was significantly shifted to the left by 39%. Whereas before infusion and at stable propofol 4 µg/mL aneurismal surgical sides ipsilateral (75 ± 13, 25 ± 9) and contralateral (73 ± 15, 27 ± 9) mean ± SD BIS values were significantly lower than ipsilateral (95 ± 3, 46 ± 12) and contralateral (94 ± 3, 46 ± 12) matched controls. Conclusions. Using BIS as surrogate marker of propofol hypnotic effect, BIS monitoring in patients with post-cerebral hemorrhage hydrocephaly showed a pattern of change and trend that was similar albeit 39% significantly lower than subjects without.
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Affiliation(s)
- Ashraf A Dahaba
- Department of Anaesthesiology and Intensive Care Medicine, Suez Canal University, Ismailia, Egypt
| | - Han Lin
- Department of Anesthesiology, Critical Care and Pain Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wen Zhou, Zhejiang, People's Republic of China
| | - Xue Fei Ye
- Department of Anesthesiology, Critical Care and Pain Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wen Zhou, Zhejiang, People's Republic of China
| | - Nu Zhang
- Department of Neurosurgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wen Zhou, Zhejiang, People's Republic of China
| | - Kun Wang
- Laboratory of Pharmacometrics, Shanghai Qiangshi Information Technology Co Ltd, Shanghai, People's Republic of China
| | - Gilbert Reibnegger
- Otto-Loewi Research Center for Physiological Chemistry, Medical University of Graz, Graz, Austria
| | - Qing Quan Lian
- Department of Anesthesiology, Critical Care and Pain Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wen Zhou, Zhejiang, People's Republic of China
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Dehnavi F, Koo-Poeggel PC, Ghorbani M, Marshall L. Spontaneous slow oscillation - slow spindle features predict induced overnight memory retention. Sleep 2021; 44:6277833. [PMID: 34003291 PMCID: PMC8503833 DOI: 10.1093/sleep/zsab127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 05/06/2021] [Indexed: 11/13/2022] Open
Abstract
Study Objectives Synchronization of neural activity within local networks and between brain regions is a major contributor to rhythmic field potentials such as the EEG. On the other hand, dynamic changes in microstructure and activity are reflected in the EEG, for instance slow oscillation (SO) slope can reflect synaptic strength. SO-spindle coupling is a measure for neural communication. It was previously associated with memory consolidation, but also shown to reveal strong interindividual differences. In studies, weak electric current stimulation has modulated brain rhythms and memory retention. Here, we investigate whether SO-spindle coupling and SO slope during baseline sleep are associated with (predictive of) stimulation efficacy on retention performance. Methods Twenty-five healthy subjects participated in three experimental sessions. Sleep-associated memory consolidation was measured in two sessions, in one anodal transcranial direct current stimulation oscillating at subjects individual SO frequency (so-tDCS) was applied during nocturnal sleep. The third session was without a learning task (baseline sleep). The dependence on SO-spindle coupling and SO-slope during baseline sleep of so-tDCS efficacy on retention performance were investigated. Results Stimulation efficacy on overnight retention of declarative memories was associated with nesting of slow spindles to SO trough in deep nonrapid eye movement baseline sleep. Steepness and direction of SO slope in baseline sleep were features indicative for stimulation efficacy. Conclusions Findings underscore a functional relevance of activity during the SO up-to-down state transition for memory consolidation and provide support for distinct consolidation mechanisms for types of declarative memories.
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Affiliation(s)
- Fereshteh Dehnavi
- Department of Electrical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Ping Chai Koo-Poeggel
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee, Lübeck, Germany.,Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck
| | - Maryam Ghorbani
- Department of Electrical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.,Rayan Center for Neuroscience and Behavior, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Lisa Marshall
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee, Lübeck, Germany.,Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck
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Sleep Spindles Preferentially Consolidate Weakly Encoded Memories. J Neurosci 2021; 41:4088-4099. [PMID: 33741722 DOI: 10.1523/jneurosci.0818-20.2021] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 01/22/2023] Open
Abstract
Sleep has been shown to be critical for memory consolidation, with some research suggesting that certain memories are prioritized for consolidation. Initial strength of a memory appears to be an important boundary condition in determining which memories are consolidated during sleep. However, the role of consolidation-mediating oscillations, such as sleep spindles and slow oscillations, in this preferential consolidation has not been explored. Here, 54 human participants (76% female) studied pairs of words to three distinct encoding strengths, with recall being tested immediately following learning and again 6 h later. Thirty-six had a 2 h nap opportunity following learning, while the remaining 18 remained awake throughout. Results showed that, across 6 h awake, weakly encoded memories deteriorated the fastest. In the nap group, however, this effect was attenuated, with forgetting rates equivalent across encoding strengths. Within the nap group, consolidation of weakly encoded items was associated with fast sleep spindle density during non-rapid eye movement sleep. Moreover, sleep spindles that were coupled to slow oscillations predicted the consolidation of weak memories independently of uncoupled sleep spindles. These relationships were unique to weakly encoded items, with spindles not correlating with memory for intermediate or strong items. This suggests that sleep spindles facilitate memory consolidation, guided in part by memory strength.SIGNIFICANCE STATEMENT Given the countless pieces of information we encode each day, how does the brain select which memories to commit to long-term storage? Sleep is known to aid in memory consolidation, and it appears that certain memories are prioritized to receive this benefit. Here, we found that, compared with staying awake, sleep was associated with better memory for weakly encoded information. This suggests that sleep helps attenuate the forgetting of weak memory traces. Fast sleep spindles, a hallmark oscillation of non-rapid eye movement sleep, mediate consolidation processes. We extend this to show that fast spindles were uniquely associated with the consolidation of weakly encoded memories. This provides new evidence for preferential sleep-based consolidation and elucidates a physiological correlate of this benefit.
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Hayase K, Kainuma A, Akiyama K, Kinoshita M, Shibasaki M, Sawa T. Poincaré Plot Area of Gamma-Band EEG as a Measure of Emergence From Inhalational General Anesthesia. Front Physiol 2021; 12:627088. [PMID: 33633587 PMCID: PMC7900422 DOI: 10.3389/fphys.2021.627088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/05/2021] [Indexed: 12/18/2022] Open
Abstract
The Poincaré plot obtained from electroencephalography (EEG) has been used to evaluate the depth of anesthesia. A standalone EEG Analyzer application was developed; raw EEG signals obtained from a bispectral index (BIS) monitor were analyzed using an on-line monitoring system. Correlations between Poincaré plot parameters and other measurements associated with anesthesia depth were evaluated during emergence from inhalational general anesthesia. Of the participants, 20 were adults anesthetized with sevoflurane (adult_SEV), 20 were adults anesthetized with desflurane (adult_DES), and 20 were pediatric patients anesthetized with sevoflurane (ped_SEV). EEG signals were preprocessed through six bandpass digital filters (f0: 0.5–47 Hz, f1: 0.5–8 Hz, f2: 8–13 Hz, f3: 13–20 Hz, f4: 20–30 Hz, and f5: 30–47 Hz). The Poincaré plot-area ratio (PPAR = PPA_fx/PPA_f0, fx = f1∼f5) was analyzed at five frequency ranges. Regardless of the inhalational anesthetic used, there were strong linear correlations between the logarithm of PPAR at f5 and BIS (R2 = 0.67, 0.79, and 0.71, in the adult_SEV, adult_DES, and ped_SEV groups, respectively). As an additional observation, a part of EMG activity at the gamma range of 30–47 Hz probably influenced the calculations of BIS and PPAR_f5 with a non-negligible level. The logarithm of PPAR in the gamma band was most sensitive to state changes during the emergence process and could provide a new non-proprietary parameter that correlates with changes in BIS during measurement of anesthesia depth.
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Affiliation(s)
- Kazuma Hayase
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Kainuma
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Koichi Akiyama
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Mao Kinoshita
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Masayuki Shibasaki
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Teiji Sawa
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Garbe J, Eisenmann S, Kantelhardt JW, Duenninghaus F, Michl P, Rosendahl J. Capability of processed EEG parameters to monitor conscious sedation in endoscopy is similar to general anaesthesia. United European Gastroenterol J 2021; 9:354-361. [PMID: 32921270 PMCID: PMC8259428 DOI: 10.1177/2050640620959153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/20/2020] [Indexed: 11/23/2022] Open
Abstract
Background Reliable and safe sedation is a prerequisite for endoscopic interventions. The current standard is rather safe, yet, an objective device to measure sedation depth is missing. To date, anaesthesia monitors based on processed electroencephalogram (EEG) have not been utilised in conscious sedation. Objective To investigate EEG parameters to differentiate consciousness in endoscopic propofol sedation. Methods In total, 171 patients aged 21–83 years (ASA I–III) undergoing gastrointestinal and bronchial endoscopy were enrolled. Standard monitoring and a frontotemporal two‐channel EEG were recorded. The state of consciousness was identified by repeated requests to squeeze the investigator's hand. Results In total, 1132 state‐of‐consciousness (SOC) transitions were recorded in procedures ranging from 5 to 69 min. Thirty‐four EEG parameters from the frequency domain, time‐frequency domain and complexity measures were calculated. Area under the curve ranged from 0.51 to 0.82 with complexity and optimised frequency domain parameters yielding the best results. Conclusion Prediction of the SOC with processed EEG parameters is feasible, and the results for sedation in endoscopic procedures are similar to those reported from general anaesthesia. These results are insufficient for a clinical application, but prediction capability may be increased with optimisation and modelling. Electroencephalogram (EEG)‐based anaesthesia monitors, like the Bispectral Index, have been investigated as an adjunct to monitor propofol sedation in the endoscopy ward. These studies showed very limited benefit. Capability of processed EEG parameters to differentiate the state of consciousness (SOC) in endoscopy is similar to general anaesthesia. However, artefacts arising from the less controlled endoscopy environment as compared to anaesthesia limit their use in sedation monitoring. The Bispectral Index and its underlying parameters are ineffective in the determination of the SOC in sedation during endoscopic procedures.
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Affiliation(s)
- Jakob Garbe
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Stephan Eisenmann
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Jan W Kantelhardt
- Institute of Physics, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Florian Duenninghaus
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Patrick Michl
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Jonas Rosendahl
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
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12
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Cox R, Fell J. Analyzing human sleep EEG: A methodological primer with code implementation. Sleep Med Rev 2020; 54:101353. [PMID: 32736239 DOI: 10.1016/j.smrv.2020.101353] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/30/2020] [Accepted: 04/30/2020] [Indexed: 12/15/2022]
Abstract
Recent years have witnessed a surge in human sleep electroencephalography (EEG) studies, employing increasingly sophisticated analysis strategies to relate electrophysiological activity to cognition and disease. However, properly calculating and interpreting metrics used in contemporary sleep EEG requires attention to numerous theoretical and practical signal-processing details that are not always obvious. Moreover, the vast number of outcome measures that can be derived from a single dataset inflates the risk of false positives and threatens replicability. We review several methodological issues related to 1) spectral analysis, 2) montage choice, 3) extraction of phase and amplitude information, 4) surrogate construction, and 5) minimizing false positives, illustrating both the impact of methodological choices on downstream results, and the importance of checking processing steps through visualization and simplified examples. By presenting these issues in non-mathematical form, with sleep-specific examples, and with code implementation, this paper aims to instill a deeper appreciation of methodological considerations in novice and non-technical audiences, and thereby help improve the quality of future sleep EEG studies.
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Affiliation(s)
- Roy Cox
- Department of Epileptology, University of Bonn, 53127 Bonn, Germany.
| | - Juergen Fell
- Department of Epileptology, University of Bonn, 53127 Bonn, Germany
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Dahaba AA. Benefits and boundaries of processed electroencephalography (pEEG) monitors when they do not concur with standard anesthetic clinical monitoring: lights and shadows. Minerva Anestesiol 2020; 86. [DOI: 10.23736/s0375-9393.19.13959-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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14
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Xing Y, Xu D, Xu Y, Chen L, Wang H, Li S. Effects of Neuromuscular Blockages on Entropy Monitoring During Sevoflurane Anesthesia. Med Sci Monit 2019; 25:8610-8617. [PMID: 31729355 PMCID: PMC6873634 DOI: 10.12659/msm.917879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background There are no data available on the effects of different degrees of neuromuscular blockade on spectral entropy during sevoflurane anesthesia. This study aimed to observe the effects of different degrees of neuromuscular blockade on state and response entropy during sevoflurane anesthesia. Material/Methods Eighty-one female patients were randomized to 9 groups (n=9 per group) according to the concentration of sevoflurane and degree of neuromuscular blockade. Response and state entropy were monitored. The endpoints were: 1) impact of neuromuscular blockade on state entropy and response entropy, and the difference between response entropy and state entropy; and 2) the response of entropy after cutaneous tetanic electrical noxious stimulation to the ulnar nerve under different degrees of neuromuscular blockade and concentrations of sevoflurane. Results These were no significant differences in response entropy or state entropy, or differences between response entropy and state entropy among the groups in the awake state (P>0.05). Without noxious stimulation, sevoflurane concentrations and neuromuscular blockade had no significant effects on response entropy or state entropy, or on the difference between response entropy and state entropy (all P>0.05), but sevoflurane concentrations showed a significant effect on state entropy (P<0.05). After noxious stimulation, sevoflurane concentrations and neuromuscular blockade had significant effects on response entropy and state entropy, and on the difference between response entropy and state entropy. Conclusions Response entropy and state entropy decreased with increasing sevoflurane concentration. Neuromuscular blockade did not affect entropy without noxious stimulation. With stimulation, muscle relaxants significantly reduced the changes in entropy, and there were significant effects of neuromuscular blockade and sevoflurane on entropy.
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Affiliation(s)
- Yian Xing
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
| | - Dian Xu
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
| | - Yanyifang Xu
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
| | - Lianhua Chen
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
| | - Hong Wang
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
| | - Shitong Li
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China (mainland)
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Eagleman SL, Chander D, Reynolds C, Ouellette NT, MacIver MB. Nonlinear dynamics captures brain states at different levels of consciousness in patients anesthetized with propofol. PLoS One 2019; 14:e0223921. [PMID: 31665174 PMCID: PMC6821075 DOI: 10.1371/journal.pone.0223921] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/01/2019] [Indexed: 12/31/2022] Open
Abstract
The information processing capability of the brain decreases during unconscious states. Capturing this decrease during anesthesia-induced unconsciousness has been attempted using standard spectral analyses as these correlate relatively well with breakdowns in corticothalamic networks. Much of this work has involved the use of propofol to perturb brain activity, as it is one of the most widely used anesthetics for routine surgical anesthesia. Propofol administration alone produces EEG spectral characteristics similar to most hypnotics; however, inter-individual and drug variation render spectral measures inconsistent. Complexity measures of EEG signals could offer better measures to distinguish brain states, because brain activity exhibits nonlinear behavior at several scales during transitions of consciousness. We tested the potential of complexity analyses from nonlinear dynamics to identify loss and recovery of consciousness at clinically relevant timepoints. Patients undergoing propofol general anesthesia for various surgical procedures were identified as having changes in states of consciousness by the loss and recovery of response to verbal stimuli after induction and upon cessation of anesthesia, respectively. We demonstrate that nonlinear dynamics analyses showed more significant differences between consciousness states than spectral measures. Notably, attractors in conscious and anesthesia-induced unconscious states exhibited significantly different shapes. These shapes have implications for network connectivity, information processing, and the total number of states available to the brain at these different levels. They also reflect some of our general understanding of the network effects of consciousness in a way that spectral measures cannot. Thus, complexity measures could provide a universal means for reliably capturing depth of consciousness based on EEG changes at the beginning and end of anesthesia administration.
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Affiliation(s)
- Sarah L. Eagleman
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
| | - Divya Chander
- Department of Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Christina Reynolds
- Department of Neurology, Oregon Health Sciences University, Portland, Oregon, United States of America
- National Radio Astronomy Observatory, Charlottesville, VA, United States of America
| | - Nicholas T. Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California, United States of America
| | - M. Bruce MacIver
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California, United States of America
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Dubost C, Humbert P, Benizri A, Tourtier JP, Vayatis N, Vidal PP. Selection of the Best Electroencephalogram Channel to Predict the Depth of Anesthesia. Front Comput Neurosci 2019; 13:65. [PMID: 31632257 PMCID: PMC6779712 DOI: 10.3389/fncom.2019.00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 09/06/2019] [Indexed: 11/13/2022] Open
Abstract
Precise cerebral dynamics of action of the anesthetics are a challenge for neuroscientists. This explains why there is no gold standard for monitoring the Depth of Anesthesia (DoA) and why experimental studies may use several electroencephalogram (EEG) channels, ranging from 2 to 128 EEG-channels. Our study aimed at finding the scalp area providing valuable information about brain activity under general anesthesia (GA) to select the more optimal EEG channel to characterized the DoA. We included 30 patients undergoing elective, minor surgery under GA and used a 32-channel EEG to record their electrical brain activity. In addition, we recorded their physiological parameters and the BIS monitor. Each individual EEG channel data were processed to test their ability to differentiate awake from asleep states. Due to strict quality criteria adopted for the EEG data and the difficulties of the real-life setting of the study, only 8 patients recordings were taken into consideration in the final analysis. Using 2 classification algorithms, we identified the optimal channels to discriminate between asleep and awake states: the frontal and temporal F8 and T7 were retrieved as being the two bests channels to monitor DoA. Then, using only data from the F8 channel, we tried to minimize the number of features required to discriminate between the awake and asleep state. The best algorithm turned out to be the Gaussian Naïve Bayes (GNB) requiring only 5 features (Area Under the ROC Curve - AUC- of 0.93 ± 0.04). This finding may pave the way to improve the assessment of DoA by combining one EEG channel recordings with a multimodal physiological monitoring of the brain state under GA. Further work is needed to see if these results may be valid to asses the depth of sedation in ICU.
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Affiliation(s)
- Clement Dubost
- Department of Anesthesiology and Intensive Care, Begin Military Hospital, Saint-Mande, France
- Cognac-G Cognition and Action Group, CNRS, Université Paris Descartes, SSA, Paris, France
| | - Pierre Humbert
- Centre de Mathematiques et de Leurs Applications, CNRS, ENS Paris-Saclay, Université Paris-Saclay, Cachan, France
| | - Arno Benizri
- Cognac-G Cognition and Action Group, CNRS, Université Paris Descartes, SSA, Paris, France
| | - Jean-Pierre Tourtier
- Department of Anesthesiology and Intensive Care, Begin Military Hospital, Saint-Mande, France
| | - Nicolas Vayatis
- Centre de Mathematiques et de Leurs Applications, CNRS, ENS Paris-Saclay, Université Paris-Saclay, Cachan, France
| | - Pierre-Paul Vidal
- Cognac-G Cognition and Action Group, CNRS, Université Paris Descartes, SSA, Paris, France
- Institute of Information and Control, Hangzhou Dianzi University, Zhejiang, China
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17
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Abstract
Bispectral index (BIS), a useful marker of anaesthetic depth, is calculated by a statistical multivariate model using nonlinear functions of electroencephalography-based subparameters. However, only a portion of the proprietary algorithm has been identified. We investigated the BIS algorithm using clinical big data and machine learning techniques. Retrospective data from 5,427 patients who underwent BIS monitoring during general anaesthesia were used, of which 80% and 20% were used as training datasets and test datasets, respectively. A histogram of data points was plotted to define five BIS ranges representing the depth of anaesthesia. Decision tree analysis was performed to determine the electroencephalography subparameters and their thresholds for classifying five BIS ranges. Random sample consensus regression analyses were performed using the subparameters to derive multiple linear regression models of BIS calculation in five BIS ranges. The performance of the decision tree and regression models was externally validated with positive predictive value and median absolute error, respectively. A four-level depth decision tree was built with four subparameters such as burst suppression ratio, power of electromyogram, 95% spectral edge frequency, and relative beta ratio. Positive predictive values were 100%, 80%, 80%, 85% and 89% in the order of increasing BIS in the five BIS ranges. The average of median absolute errors of regression models was 4.1 as BIS value. A data driven BIS calculation algorithm using multiple electroencephalography subparameters with different weights depending on BIS ranges has been proposed. The results may help the anaesthesiologists interpret the erroneous BIS values observed during clinical practice.
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18
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Kim D, Ahn JH, Jung H, Choi KY, Jeong JS. Effects of neuromuscular blockade reversal on bispectral index and frontal electromyogram during steady-state desflurane anesthesia: a randomized trial. Sci Rep 2019; 9:10486. [PMID: 31324862 PMCID: PMC6642209 DOI: 10.1038/s41598-019-47047-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/10/2019] [Indexed: 02/06/2023] Open
Abstract
The degree of neuromuscular blockade reversal may affect bispectral index (BIS) value. One possible reason is that the reverse of neuromuscular blockade affects electromyographic (EMG) signals of fascial muscle. Another reason is, the afferentation theory, the reverse of neuromuscular blockade relieves block signals generated in muscle stretch receptors from accessing the brain through afferent nerve pathways and induces arousal. Inaccurate BIS value may lead to overdose of drugs or the risk of intraoperative awareness. We compared changes in BIS and EMG values according to neuromuscular blockade reversal agents under steady-state desflurane anesthesia. A total of 65 patients were randomly allocated to receive either neostigmine 0.05 mg/kg, sugammadex 4 mg/kg, or pyridostigmine 0.25 mg/kg for neuromuscular blockade reversal under stable desflurane anesthesia, and 57 patients completed the study. The primary outcome was change in BIS and EMG values before and after administration of neuromuscular blockade reversal agents (between train-of-four [TOF] count 1-2 and TOF ratio 0.9). The change in BIS and EMG values before and after administration of neuromuscular blockade reversal agents were statistically different in each group (BIS: Neostigmine group, P < 0.001; Sugammadex group, P < 0.001; Pyridostigmine group, P = 0.001; EMG: Neostigmine group, P = 0.001; Sugammadex group, P < 0.001; Pyridostigmine group, P = 0.001; respectively). The BIS and EMG values had a positive correlation (P < 0.001). Our results demonstrate that the EMG and BIS values have increased after neuromuscular blockade reversal under desflurane anesthesia regardless of the type of neuromuscular blockade reversal agent. BIS should be applied carefully to measure of depth of anesthesia after neuromuscular blockade reversal.
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Affiliation(s)
- Doyeon Kim
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jin Hee Ahn
- Department of Anaesthesiology and Pain Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hyunjoo Jung
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ka Young Choi
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ji Seon Jeong
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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Neumann E, Rudolph U, Knutson DE, Li G, Cook JM, Hentschke H, Antkowiak B, Drexler B. Zolpidem Activation of Alpha 1-Containing GABA A Receptors Selectively Inhibits High Frequency Action Potential Firing of Cortical Neurons. Front Pharmacol 2019; 9:1523. [PMID: 30687091 PMCID: PMC6333667 DOI: 10.3389/fphar.2018.01523] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 12/12/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: High frequency neuronal activity in the cerebral cortex can be induced by noxious stimulation during surgery, brain injury or poisoning. In this scenario, it is essential to block cortical hyperactivity to protect the brain against damage, e.g., by using drugs that act as positive allosteric modulators at GABAA receptors. Yet, cortical neurons express multiple, functionally distinct GABAA receptor subtypes. Currently there is a lack of knowledge which GABAA receptor subtypes would be a good pharmacological target to reduce extensive cortical activity. Methods: Spontaneous action potential activity was monitored by performing extracellular recordings from organotypic neocortical slice cultures of wild type and GABAAR-α1(H101R) mutant mice. Phases of high neuronal activity were characterized using peri-event time histograms. Drug effects on within-up state firing rates were quantified via Hedges' g. Results: We quantified the effects of zolpidem, a positive modulator of GABAA receptors harboring α1-subunits, and the experimental benzodiazepine SH-053-2'F-S-CH3, which preferably acts at α2/3/5- but spares α1-subunits. Both agents decreased spontaneous action potential activity but altered the firing patterns in different ways. Zolpidem reduced action potential firing during highly active network states. This action was abolished by flumazenil, suggesting that it was mediated by benzodiazepine-sensitive GABAA receptors. SH-053-2'F-S-CH3 also attenuated neuronal activity, but unlike zolpidem, failed to reduce high frequency firing. To confirm that zolpidem actions were indeed mediated via α1-dependent actions, it was evaluated in slices from wild type and α(H101R) knock-in mice. Inhibition of high frequency action potential firing was observed in slices from wild type but not mutant mice. Conclusion: Our results suggest that during episodes of scarce and high neuronal activity action potential firing of cortical neurons is controlled by different GABAA receptor subtypes. Exaggerated firing of cortical neurons is reduced by positive modulation of α1-, but not α2/3/5-subunit containing GABAA receptors.
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Affiliation(s)
- Elena Neumann
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Guanguan Li
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Harald Hentschke
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Bernd Antkowiak
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Berthold Drexler
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
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Hayashi K, Sawa T. The fundamental contribution of the electromyogram to a high bispectral index: a postoperative observational study. J Clin Monit Comput 2019; 33:1097-1103. [PMID: 30607805 DOI: 10.1007/s10877-018-00244-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/22/2018] [Indexed: 12/19/2022]
Abstract
The electromyogram (EMG) activity has been reported to falsely increase BIS. Conversely, EMG seems necessary to constitute the high BIS indicative of an awake condition, and may play a fundamental role in calculating BIS, rather than distorting the appropriate BIS. However, exactly how EMG is associated with a high BIS remains unclear. We intended to clarify the respective contributions of EMG and various electroencephalogram (EEG) parameters to high BIS. In 79 courses of anaesthesia, BIS monitor-derived EMG parameters (EMGLOW), and other processed EEG parameters [SEF95 (spectral edge frequency 95%), SynchFastSlow (bispectral parameter), BetaRatio (frequency parameter), total power subtypes in five frequency range], were obtained simultaneously with BIS, every 3 s. These EEG parameters were used for receiver operating characteristic (ROC) analysis of detecting three BIS levels (BIS > 80, BIS > 70, and BIS > 60) to assess their diagnosabilities. A total of 218,418 data points derived from 79 cases were used for analysis. Area under the ROC curve (AUC) was calculated and optimal cut-off (threshold) was determined by Youden index. As the results, for detecting BIS > 80, the AUC of EMGLOW was 0.975 [0.974-0.977] (mean [95% confidence interval]), significantly higher than any other processed EEG parameters such as BetaRatio (0.832 [0.828-0.835]), SEF95 (0.821 [0.817-0.826]) and SynchFastSlow (0.769 [0.764-0.774]) (p < 0.05 each). The threshold of EMGLOW for detecting BIS > 80 was 35.7 dB, with high sensitivity (92.5%) and high specificity (96.5%). Our results suggest EMG contributes considerably to the diagnosis of high BIS, and is particularly essential for determining BIS > 80.
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Affiliation(s)
- Kazuko Hayashi
- Department of Anesthesiology, Kyoto Chubu Medical Center, Yagi Ueno 25, Nantan, Kyoto, 629-0917, Japan.
| | - Teiji Sawa
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Haghighi SJ, Komeili M, Hatzinakos D, Beheiry HE. 40-Hz ASSR for Measuring Depth of Anaesthesia During Induction Phase. IEEE J Biomed Health Inform 2018; 22:1871-1882. [DOI: 10.1109/jbhi.2017.2778140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Eagleman SL, Vaughn DA, Drover DR, Drover CM, Cohen MS, Ouellette NT, MacIver MB. Do Complexity Measures of Frontal EEG Distinguish Loss of Consciousness in Geriatric Patients Under Anesthesia? Front Neurosci 2018; 12:645. [PMID: 30294254 PMCID: PMC6158339 DOI: 10.3389/fnins.2018.00645] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/29/2018] [Indexed: 12/04/2022] Open
Abstract
While geriatric patients have a high likelihood of requiring anesthesia, they carry an increased risk for adverse cognitive outcomes from its use. Previous work suggests this could be mitigated by better intraoperative monitoring using indexes defined by several processed electroencephalogram (EEG) measures. Unfortunately, inconsistencies between patients and anesthetic agents in current analysis techniques have limited the adoption of EEG as standard of care. In attempts to identify new analyses that discriminate clinically-relevant anesthesia timepoints, we tested 1/f frequency scaling as well as measures of complexity from nonlinear dynamics. Specifically, we tested whether analyses that characterize time-delayed embeddings, correlation dimension (CD), phase-space geometric analysis, and multiscale entropy (MSE) capture loss-of-consciousness changes in EEG activity. We performed these analyses on EEG activity collected from a traditionally hard-to-monitor patient population: geriatric patients on beta-adrenergic blockade who were anesthetized using a combination of fentanyl and propofol. We compared these analyses to traditional frequency-derived measures to test how well they discriminated EEG states before and after loss of response to verbal stimuli. We found spectral changes similar to those reported previously during loss of response. We also found significant changes in 1/f frequency scaling. Additionally, we found that our phase-space geometric characterization of time-delayed embeddings showed significant differences before and after loss of response, as did measures of MSE. Our results suggest that our new spectral and complexity measures are capable of capturing subtle differences in EEG activity with anesthesia administration-differences which future work may reveal to improve geriatric patient monitoring.
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Affiliation(s)
- Sarah L. Eagleman
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
| | - Don A. Vaughn
- UCLA Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA, United States
- Department of Psychology, University of Santa Clara, Santa Clara, CA, United States
| | - David R. Drover
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
| | | | - Mark S. Cohen
- UCLA Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA, United States
- UCLA Departments of Psychiatry, Neurology, Radiology, Psychology, Biomedical Physics and Bioengineering, California Nanosystems Institute, Los Angeles, CA, United States
| | - Nicholas T. Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
| | - M. Bruce MacIver
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
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Eagleman SL, Drover CM, Drover DR, Ouellette NT, MacIver MB. Remifentanil and Nitrous Oxide Anesthesia Produces a Unique Pattern of EEG Activity During Loss and Recovery of Response. Front Hum Neurosci 2018; 12:173. [PMID: 29867405 PMCID: PMC5950731 DOI: 10.3389/fnhum.2018.00173] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 04/12/2018] [Indexed: 12/14/2022] Open
Abstract
Nitrous oxide (N2O) and remifentanil (remi) are used along with other anesthetic and adjuvant agents for routine surgical anesthesia, yet the electroencephalogram (EEG) changes produced by this combination are poorly described. N2O administered alone produces EEG spectral characteristics that are distinct from most hypnotics. Furthermore, EEG frequency-derived trends before and after clinically relevant time points vary depending on N2O concentration. Remifentanil typically increases low frequency and decreases high frequency activity in the EEG, but how it influences N2O's EEG effect is not known. Previous attempts to characterize EEG signals of patients anesthetized with N2O using frequency-derived measures have shown conflicts and inconsistencies. Thus, in addition to determining the spectral characteristics of this unique combination, we also test whether a newly proposed characterization of time-delayed embeddings of the EEG signal tracks loss and recovery of consciousness significantly at clinically relevant time points. We retrospectively investigated the effects of remi and N2O on EEG signals recorded from 32 surgical patients receiving anesthesia for elective abdominal surgeries. Remifentanil and N2O (66%) were co-administered during the procedures. Patients were tested for loss and recovery of response (ROR) to verbal stimuli after induction and upon cessation of anesthesia, respectively. We found that the addition of remifentanil to N2O anesthesia improves the ability of traditional frequency-derived measures, including the Bispectral Index (BIS), to discriminate between loss and ROR. Finally, we found that a novel analysis of EEG using nonlinear dynamics showed more significant differences between states than most spectral measures.
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Affiliation(s)
- Sarah L Eagleman
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
| | | | - David R Drover
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
| | - Nicholas T Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
| | - M Bruce MacIver
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
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Cox R, Schapiro AC, Manoach DS, Stickgold R. Individual Differences in Frequency and Topography of Slow and Fast Sleep Spindles. Front Hum Neurosci 2017; 11:433. [PMID: 28928647 PMCID: PMC5591792 DOI: 10.3389/fnhum.2017.00433] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/15/2017] [Indexed: 11/25/2022] Open
Abstract
Sleep spindles are transient oscillatory waveforms that occur during non-rapid eye movement (NREM) sleep across widespread cortical areas. In humans, spindles can be classified as either slow or fast, but large individual differences in spindle frequency as well as methodological difficulties have hindered progress towards understanding their function. Using two nights of high-density electroencephalography recordings from 28 healthy individuals, we first characterize the individual variability of NREM spectra and demonstrate the difficulty of determining subject-specific spindle frequencies. We then introduce a novel spatial filtering approach that can reliably separate subject-specific spindle activity into slow and fast components that are stable across nights and across N2 and N3 sleep. We then proceed to provide detailed analyses of the topographical expression of individualized slow and fast spindle activity. Group-level analyses conform to known spatial properties of spindles, but also uncover novel differences between sleep stages and spindle classes. Moreover, subject-specific examinations reveal that individual topographies show considerable variability that is stable across nights. Finally, we demonstrate that topographical maps depend nontrivially on the spindle metric employed. In sum, our findings indicate that group-level approaches mask substantial individual variability of spindle dynamics, in both the spectral and spatial domains. We suggest that leveraging, rather than ignoring, such differences may prove useful to further our understanding of the physiology and functional role of sleep spindles.
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Affiliation(s)
- Roy Cox
- Department of Psychiatry, Beth Israel Deaconess Medical CenterBoston, MA, United States.,Department of Psychiatry, Harvard Medical SchoolBoston, MA, United States
| | - Anna C Schapiro
- Department of Psychiatry, Beth Israel Deaconess Medical CenterBoston, MA, United States.,Department of Psychiatry, Harvard Medical SchoolBoston, MA, United States
| | - Dara S Manoach
- Department of Psychiatry, Harvard Medical SchoolBoston, MA, United States.,Department of Psychiatry, Massachusetts General HospitalCharlestown, MA, United States.,Athinoula A. Martinos Center for Biomedical ImagingCharlestown, MA, United States
| | - Robert Stickgold
- Department of Psychiatry, Beth Israel Deaconess Medical CenterBoston, MA, United States.,Department of Psychiatry, Harvard Medical SchoolBoston, MA, United States
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Location of the Mesopontine Neurons Responsible for Maintenance of Anesthetic Loss of Consciousness. J Neurosci 2017; 37:9320-9331. [PMID: 28821646 DOI: 10.1523/jneurosci.0544-17.2017] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 08/06/2017] [Accepted: 08/09/2017] [Indexed: 12/14/2022] Open
Abstract
The transition from wakefulness to general anesthesia is widely attributed to suppressive actions of anesthetic molecules distributed by the systemic circulation to the cerebral cortex (for amnesia and loss of consciousness) and to the spinal cord (for atonia and antinociception). An alternative hypothesis proposes that anesthetics act on one or more brainstem or diencephalic nuclei, with suppression of cortex and spinal cord mediated by dedicated axonal pathways. Previously, we documented induction of an anesthesia-like state in rats by microinjection of small amounts of GABAA-receptor agonists into an upper brainstem region named the mesopontine tegmental anesthesia area (MPTA). Correspondingly, lesioning this area rendered animals resistant to systemically delivered anesthetics. Here, using rats of both sexes, we applied a modified microinjection method that permitted localization of the anesthetic-sensitive neurons with much improved spatial resolution. Microinjected at the MPTA hotspot identified, exposure of 1900 or fewer neurons to muscimol was sufficient to sustain whole-body general anesthesia; microinjection as little as 0.5 mm off-target did not. The GABAergic anesthetics pentobarbital and propofol were also effective. The GABA-sensitive cell cluster is centered on a tegmental (reticular) field traversed by fibers of the superior cerebellar peduncle. It has no specific nuclear designation and has not previously been implicated in brain-state transitions.SIGNIFICANCE STATEMENT General anesthesia permits pain-free surgery. Furthermore, because anesthetic agents have the unique ability to reversibly switch the brain from wakefulness to a state of unconsciousness, knowing how and where they work is a potential route to unraveling the neural mechanisms that underlie awareness itself. Using a novel method, we have located a small, and apparently one of a kind, cluster of neurons in the mesopontine tegmentum that are capable of effecting brain-state switching when exposed to GABAA-receptor agonists. This action appears to be mediated by a network of dedicated axonal pathways that project directly and/or indirectly to nearby arousal nuclei of the brainstem and to more distant targets in the forebrain and spinal cord.
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Yin YQ, Wang LF, Chen C, Gao T, Zhao ZF, Li CH. In vivo field recordings effectively monitor the mouse cortex and hippocampus under isoflurane anesthesia. Neural Regen Res 2016; 11:1951-1955. [PMID: 28197191 PMCID: PMC5270433 DOI: 10.4103/1673-5374.197136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2016] [Indexed: 02/05/2023] Open
Abstract
Isoflurane is a widely used inhaled anesthetic in the clinical setting. However, the mechanism underlying its effect on consciousness is under discussion. Therefore, we investigated the effect of isoflurane on the hippocampus and cortex using an in vivo field recording approach. Our results showed that 1.3%, 0.8%, and 0.4% isoflurane exerted an inhibitory influence on the mouse hippocampus and cortex. Further, high frequency bands in the cortex and hippocampus showed greater suppression with increasing isoflurane concentration. Our findings suggest that in vivo field recordings can monitor the effect of isoflurane anesthesia on the mouse cortex and hippocampus.
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Affiliation(s)
- Yi-qing Yin
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Li-fang Wang
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Chao Chen
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Teng Gao
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Zi-fang Zhao
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Cheng-hui Li
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
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Schneider G, Pilge S. Restrict relaxants, be aware, and know the limitations of your depth of anaesthesia monitor. Br J Anaesth 2015; 115 Suppl 1:i11-i12. [PMID: 26174295 DOI: 10.1093/bja/aev148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- G Schneider
- Department of Anaesthesiology, HELIOS Clinic Wuppertal, Witten/Herdecke University, Heusnerstr. 40, Wuppertal 42283, Germany
| | - S Pilge
- Department of Anaesthesiology, HELIOS Clinic Wuppertal, Witten/Herdecke University, Heusnerstr. 40, Wuppertal 42283, Germany
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Jindal A, Sharma BC, Sachdeva S, Chawla R, Srivastava S, Maharshi S. Bispectral index monitoring for diagnosis and assessment of severity of hepatic encephalopathy in cirrhotic patients. Dig Liver Dis 2015; 47:769-74. [PMID: 26022229 DOI: 10.1016/j.dld.2015.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 02/25/2015] [Accepted: 04/28/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Recent evidence suggests that bispectral index may aid in the diagnosis of hepatic encephalopathy. We evaluated its utility to diagnose, grade and monitor clinical course of hepatic encephalopathy in patients with cirrhosis. METHODS 200 patients (70.5% males, mean age 39.5±9.1 years) with cirrhosis and 20 healthy controls were enrolled prospectively. Cirrhotic patients were divided into groups based on encephalopathy grades I-IV assessed by West Haven criteria; minimal encephalopathy was assessed by psychometric tests. Bispectral index was measured at baseline and after one week of lactulose therapy in patients with overt encephalopathy, and after 3 months in patients with minimal encephalopathy. RESULTS Bispectral index scores were significantly different in patients with different grades of encephalopathy; 79.5±4.2, 67.5±4.3, 56.4±3.5, 44.8±3.9 and 85.0±4.3 respectively for grade I, II, III, IV overt and minimal hepatic encephalopathy, but similar (92.6±3.7 vs 93.75±2.8) in cirrhotics without encephalopathy and healthy controls. Bispectral scores' cut off values for minimal and overt encephalopathy grade I, II, III, IV were 90.5 and 77.5, 70.5, 60.5, 50.5, respectively. Changes in bispectral index after treatment corresponded to cut-off scores for grades of overt and minimal hepatic encephalopathy. CONCLUSIONS Bispectral index was found to be useful in diagnosis, grading and monitoring of treatment response in cirrhotic patients with hepatic encephalopathy.
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Affiliation(s)
- Amit Jindal
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India
| | - Barjesh Chander Sharma
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India.
| | - Sanjeev Sachdeva
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India
| | - Rajiv Chawla
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India
| | - Siddharth Srivastava
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India
| | - Sudhir Maharshi
- Department of Gastroenterology and Anaesthesiology, G.B. Pant Hospital, New Delhi, India
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Noda T, Kanzaki R, Takahashi H. Population activity in auditory cortex of the awake rat revealed by recording with dense microelectrode array. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:1538-41. [PMID: 24109993 DOI: 10.1109/embc.2013.6609806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cortical mechanisms of auditory perception include temporal interaction between neuronal ensembles in a functional cortical structure such as a place code of frequency, or tonotopic map. To investigate the mechanism, a recording method is needed to densely map spatio-temporal activity pattern within the predefined tonotopic organization specifically in the awake condition. The present study has proposed and developed an experimental system that is capable of simultaneous neural recording with a grid array of 100 sites with 400-µm inter-electrode distance in the 4(th) layer of auditory cortex of awake rat. Both multiunit activities (MUA) and local field potentials (LFPs) confirmed the tonotopic map in the auditory cortex. In addition, spectral powers in higher frequency components (4-120 Hz) were enhanced and a lower frequency component (1-4 Hz) was reduced during waking. Phase synchronization between recording sites in the gamma-band oscillatory activity was generally smaller in the awake cortex than in the anesthetized cortex. These results have proven the feasibility of our recording and will open a new avenue to investigate neural activities in the functional map of awake cortex.
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Wang K, Steyn-Ross ML, Steyn-Ross DA, Wilson MT, Sleigh JW. EEG slow-wave coherence changes in propofol-induced general anesthesia: experiment and theory. Front Syst Neurosci 2014; 8:215. [PMID: 25400558 PMCID: PMC4212622 DOI: 10.3389/fnsys.2014.00215] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/10/2014] [Indexed: 11/13/2022] Open
Abstract
The electroencephalogram (EEG) patterns recorded during general anesthetic-induced coma are closely similar to those seen during slow-wave sleep, the deepest stage of natural sleep; both states show patterns dominated by large amplitude slow waves. Slow oscillations are believed to be important for memory consolidation during natural sleep. Tracking the emergence of slow-wave oscillations during transition to unconsciousness may help us to identify drug-induced alterations of the underlying brain state, and provide insight into the mechanisms of general anesthesia. Although cellular-based mechanisms have been proposed, the origin of the slow oscillation has not yet been unambiguously established. A recent theoretical study by Steyn-Ross et al. (2013) proposes that the slow oscillation is a network, rather than cellular phenomenon. Modeling anesthesia as a moderate reduction in gap-junction interneuronal coupling, they predict an unconscious state signposted by emergent low-frequency oscillations with chaotic dynamics in space and time. They suggest that anesthetic slow-waves arise from a competitive interaction between symmetry-breaking instabilities in space (Turing) and time (Hopf), modulated by gap-junction coupling strength. A significant prediction of their model is that EEG phase coherence will decrease as the cortex transits from Turing-Hopf balance (wake) to Hopf-dominated chaotic slow-waves (unconsciousness). Here, we investigate changes in phase coherence during induction of general anesthesia. After examining 128-channel EEG traces recorded from five volunteers undergoing propofol anesthesia, we report a significant drop in sub-delta band (0.05-1.5 Hz) slow-wave coherence between frontal, occipital, and frontal-occipital electrode pairs, with the most pronounced wake-vs.-unconscious coherence changes occurring at the frontal cortex.
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Affiliation(s)
- Kaier Wang
- School of Engineering, The University of WaikatoHamilton, New Zealand
| | | | - D. A. Steyn-Ross
- School of Engineering, The University of WaikatoHamilton, New Zealand
| | - Marcus T. Wilson
- School of Engineering, The University of WaikatoHamilton, New Zealand
| | - Jamie W. Sleigh
- Waikato Clinical School, The University of Auckland, Waikato HospitalHamilton, New Zealand
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Different Propofol–Remifentanil or Sevoflurane–Remifentanil Bispectral Index Levels for Electrocorticographic Spike Identification during Epilepsy Surgery. Anesthesiology 2013; 119:582-92. [DOI: 10.1097/aln.0b013e3182976036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Abstract
Background:
Medical therapy, the cornerstone of managing epilepsy, still fails a substantial portion of patients. Little information is available regarding the potential impact of different bispectral index (BIS) levels on electrocorticographic spike identification for surgical epileptic foci resection.
Methods:
Twenty-two intractable epilepsy subjects were randomly allocated to the propofol–remifentanil or sevoflurane–remifentanil groups, and were further randomized to four BIS85 (BIS 71–85), BIS70 (BIS 56–70), BIS55 (BIS 41–55), and BIS40 (BIS ≤40) sequence order.
Results:
Two-way ANOVA revealed no differences between groups in spike frequency (P = 0.720), spike amplitude (P = 0.647), or number of spiking leads (P = 0.653). In the propofol and sevoflurane groups, decreasing BIS levels increased mean ± SD spike/min frequency (P < 0.001 and P < 0.001) at BIS85 (10 ± 12 and 10 ± 8), BIS70 (19 ± 17 and 17 ± 15), BIS55 (22 ± 17 and 18 ± 8), and BIS40 (25 ± 15 and 23 ± 17). Furthermore, in the propofol and sevoflurane groups, decreasing BIS levels increased spike microvolt amplitude (P = 0.006 and P = 0.009) at BIS85 (1,100 ± 400 and 750 ± 400), BIS70 (1,200 ± 460 and 850 ± 490), BIS55 (1,300 ± 560 and 940 ± 700), and BIS40 (1,400 ± 570 and 1,300 ± 700). Whereas, in the propofol and sevoflurane groups, there was no difference in the location or number of spiking leads (P = 0.057 and P = 0.109) at the four BIS levels. Compared with BIS85, spike frequency in the propofol and sevoflurane groups increased 100 and 170% at BIS70, 116 and 180% at BIS55, and 132 and 230% at BIS40. Compared with BIS85, spike amplitude increased 108 and 113% at BIS70, 121 and 125% at BIS55, and 128 and 170% at BIS40.
Conclusion:
Decreasing BIS levels in the propofol and sevoflurane groups enhanced epileptogenic spike frequency and amplitude with the same location and number of spiking leads.
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Zanatta P, Toffolo GM, Sartori E, Bet A, Baldanzi F, Agarwal N, Golanov E. The human brain pacemaker: Synchronized infra-slow neurovascular coupling in patients undergoing non-pulsatile cardiopulmonary bypass. Neuroimage 2013; 72:10-9. [DOI: 10.1016/j.neuroimage.2013.01.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 01/17/2013] [Accepted: 01/20/2013] [Indexed: 11/27/2022] Open
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Glen J, Porr B, Hamilton R, Tait L. Proof of concept evaluation of the electroencephalophone as a discriminator between wakefulness and general anaesthesia. Br J Anaesth 2013; 111:400-5. [PMID: 23533253 DOI: 10.1093/bja/aet067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Depth of anaesthesia (DOA) monitors based on the electroencephalogram (EEG) are commonly used in anaesthetic practice. Their technology relies on mathematical analysis of the EEG waveform, generally resulting in a number which corresponds to anaesthetic depth. We have created a novel method of interpreting the EEG, which retains its underlying complexity. This method consists of turning the EEG into a sound: the electroencephalophone (EEP). METHODS In a pilot study, we recorded awake and anaesthetized EEGs from six patients. We transformed each EEG into an audio signal using a ring buffer with a write frequency of 1 kHz and a read frequency of 48 kHz, thus elevating all output frequencies by a factor of 48. In essence, the listener hears the previous 12 s of EEG data compressed into 250 ms, updated every 250 ms. From these data, we generated a bank of 5 s audio clips, which were then used to train and test a sample of 23 anaesthetists. RESULTS After training, 21 of the 23 anaesthetists were able to use the EEP to correctly identify the conscious state of >5 of 10 randomly selected patients (P<0.001). The median score was 8 out of 10, with an inter-quartile range of 7-9. CONCLUSIONS The EEP shows promise as a DOA monitor. However, extensive validation would be required in a variety of clinical settings before it could be accepted into mainstream clinical practice.
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Affiliation(s)
- J Glen
- Southern General Hospital, Glasgow, UK.
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Arefian N, Seddighi AS, Seddighi A, Zali AR. Accuracy of combined EEG parameters in prediction the depth of anesthesia. IRANIAN RED CRESCENT MEDICAL JOURNAL 2013; 14:833-7. [PMID: 23482427 PMCID: PMC3587877 DOI: 10.5812/ircmj.1502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 05/13/2012] [Accepted: 05/28/2012] [Indexed: 11/22/2022]
Abstract
Background The importance of proper qualitative evaluation of EEG parameters during surgery has been recognized since many years. Although none of the characteristics based on the frequency, entropy, and Bi spectral characteristics have been regarded as a good predictor for detection of the depth of anesthesia alone. So it seems necessary to study multiple characteristics together. Objectives In this study we tried to introduce the best combination of the mentioned characteristics. Materials and Methods EEG data of 64 patients undergoing general anesthesia with the same anesthesia protocol (total intravenous anesthesia) were recorded in all anesthetic stages in Shohada Tajrish Hospital. Quantitative EEG characteristics are classified into 4 categories: time, frequency, bi spectral and entropy based characteristics. Their sensitivity, specificity and accuracy in determination of the depth of anesthesia are yielded by comparison with recorded reference signal in awake, light anesthesia, deep anesthesia and brain death patients. Then, with combining 2, 3, 4 and 5 of characteristics and using coded algorithm we determined the error degree and introduced the combination yielding the least error. Results Fifteen vectors (of dimension two to five) which yielded the best results were introduced. Vectors combined of entropy based characteristics obtained 100% specificity and sensitivity during all 4 stages. Conclusions The combination entropy based characteristics had high accuracy in predicting the depth of anesthesia. Reevaluation of classic indices cortical status index and BIS seems necessary. The next step is to find a system to simplify the evaluation of this information for technicians.
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Affiliation(s)
- Nourmohammad Arefian
- Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Amir Saied Seddighi
- Shohada Tajrish Hospital, Functional Neurosurgery Research Center of Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Afsoun Seddighi
- Shohada Tajrish Hospital, Functional Neurosurgery Research Center of Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Ali Reza Zali
- Shohada Tajrish Hospital, Functional Neurosurgery Research Center of Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
- Corresponding author: Ali Reza Zali, Shohada Tajrish Hospital, Functional Neurosurgery Research Center of Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Tel.: +98-2188265188, Fax: +98-2188265188, E-mail:
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Bang JO, Son HJ, Lee EH, Hahm KD, Choi IC. Falsely increased bispectral index score during deep hypothermic circulatory arrest in cardiac surgery. Korean J Anesthesiol 2012; 63:372-3. [PMID: 23115694 PMCID: PMC3483500 DOI: 10.4097/kjae.2012.63.4.372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jae Ouk Bang
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Kortelainen J, Jia X, Seppänen T, Thakor N. Increased electroencephalographic gamma activity reveals awakening from isoflurane anaesthesia in rats. Br J Anaesth 2012; 109:782-9. [PMID: 22907339 DOI: 10.1093/bja/aes265] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Animal studies often require reliable measures for anaesthetic drug effects. Lately, EEG-based depth of anaesthesia estimation has been widely applied to rat models. This study investigated the reliability of different EEG spectral properties in revealing awakening from isoflurane anaesthesia in rats. METHODS Adult Wistar rats with previously implanted frontal epidural electrodes were anaesthetized using isoflurane. The anaesthesia was slowly lightened until awakening, as observed by the first spontaneous movement, after which anaesthesia was induced again by increasing the isoflurane concentration. EEG was recorded during the recovery and induction periods, and the spectrograms and 23 quantitative spectral parameters used in the depth of anaesthesia estimation were calculated from the signals. RESULTS The awakening was accompanied by a decrease in EEG activity at frequencies below 25 Hz, while the activity at higher frequencies (25-150 Hz) was increased. Whereas the behaviour of parameters used to measure activity in the lower frequencies was subject to variability between animals, the increase in higher frequency activity was more consistent, resulting in a statistically significant change in the relative gamma power parameters at the moment of awakening. CONCLUSIONS The increase in frontal relative gamma activity, especially in the 50-150 Hz frequency band, seems to be the most reliable EEG indicator for the awakening of a rat from isoflurane anaesthesia. A number of other spectral measures can also be used to detect this event. However, the role of gamma frequencies in the performance of these parameters is crucial.
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Affiliation(s)
- J Kortelainen
- Department of Computer Science and Engineering, University of Oulu, Oulu, Finland.
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Dahaba A, Bornemann H, Hopfgartner E, Ohran M, Kocher K, Liebmann M, Wilfinger G, Metzler H. Effect of sugammadex or neostigmine neuromuscular block reversal on bispectral index monitoring of propofol/remifentanil anaesthesia. Br J Anaesth 2012; 108:602-606. [DOI: 10.1093/bja/aer495] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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Kang MH, In CB, Kim MH, Lim KJ, Park EY, Lee HM, Lee SK. Inappropriate elevation of bispectral index values in robot assisted thyroidectomy with electromyographic endotracheal tube -A case report-. Korean J Anesthesiol 2011; 61:511-4. [PMID: 22220230 PMCID: PMC3249575 DOI: 10.4097/kjae.2011.61.6.511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/09/2011] [Accepted: 08/25/2011] [Indexed: 12/04/2022] Open
Abstract
We report a case of an erroneously elevated bispectral index (BIS) during robot assisted thyroidectomy using an electromyographic endotracheal tube (EMG tube), which is safe and useful for laryngeal electromyographic monitoring. Ten minutes after start of the operation, a sudden increase of BIS value up to 98 was noticed. The BIS values were not decreased to < 65 with supplemental anesthetics. The anesthetic method was changed from total intravenous anesthesia to balanced anesthesia. The BIS sensor and monitor were changed and other models were used. These interventions did not alter BIS values. BIS levels remained between 60 and 70 throughout the main procedure and intermittently increased to the mid-90s without any trace of poor signal quality. At the end of the surgery, the BIS values returned to normal range. The patient did not complain of intraoperative recall. Knowledge of potential interference from the use of an EMG tube must be considered when interpreting BIS.
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Affiliation(s)
- Mae-Hwa Kang
- Department of Anesthesiology and Pain Medicine, College of Medicine, Hallym University, Anyang, Korea
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Chazot T, Dumont G, Le Guen M, Hausser-Hauw C, Liu N, Fischler M. Sugammadex administration results in arousal from intravenous anaesthesia: a clinical and electroencephalographic observation. Br J Anaesth 2011; 106:914-6. [DOI: 10.1093/bja/aer142] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Differential effects of isoflurane on high-frequency and low-frequency γ oscillations in the cerebral cortex and hippocampus in freely moving rats. Anesthesiology 2011; 114:588-95. [PMID: 21293253 DOI: 10.1097/aln.0b013e31820ad3f9] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cortical γ oscillations are thought to play a role in conscious cognitive functions. Suppression of 40-Hz γ activity was implicated in the loss of consciousness during general anesthesia. However, several experimental studies found that γ oscillations were preserved in anesthesia. The authors investigated the concentration-dependent effect of isoflurane on spontaneous γ oscillations in two frequency bands and three distinct brain regions in the rat. METHODS Adult Sprague-Dawley rats were chronically implanted with epidural and coaxial depth electrodes to record cortical field potentials in frontal cortex, visual cortex, and hippocampus in waking and at steady-state isoflurane concentrations of 0.4, 0.8, and 1.2%. The γ power was calculated for the frequency bands 30-50 and 70-140 Hz. Temporal variation and interregional synchrony of γ activity were analyzed using wavelet transform. Loss of consciousness was indexed by the loss of righting reflex. RESULTS Rats lost their righting reflex at 0.8 ± 0.1% isoflurane. High-frequency γ power was decreased by isoflurane in a concentration-dependent manner (P < 0.001, 50% decrease at 0.8% isoflurane) in all brain regions. Low-frequency γ power was unaffected by isoflurane. The duration and interregional synchrony of high-frequency γ bursts was also reduced (P l < 0.001, 40% decrease at 0.8% isoflurane). CONCLUSIONS Distinction between high- and low-frequency γ bands is important when evaluating the effect of general anesthetics on brain electrical activity. Spontaneous 40-Hz γ power does not indicate the state of consciousness. The attenuation and interregional desynchronization of high-frequency γ oscillations appear to correlate with the loss of consciousness.
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Monitoring the depth of anaesthesia. SENSORS 2010; 10:10896-935. [PMID: 22163504 PMCID: PMC3231065 DOI: 10.3390/s101210896] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 09/29/2010] [Accepted: 11/22/2010] [Indexed: 11/25/2022]
Abstract
One of the current challenges in medicine is monitoring the patients’ depth of general anaesthesia (DGA). Accurate assessment of the depth of anaesthesia contributes to tailoring drug administration to the individual patient, thus preventing awareness or excessive anaesthetic depth and improving patients’ outcomes. In the past decade, there has been a significant increase in the number of studies on the development, comparison and validation of commercial devices that estimate the DGA by analyzing electrical activity of the brain (i.e., evoked potentials or brain waves). In this paper we review the most frequently used sensors and mathematical methods for monitoring the DGA, their validation in clinical practice and discuss the central question of whether these approaches can, compared to other conventional methods, reduce the risk of patient awareness during surgical procedures.
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Javaid MA, Weeden J, Flom P, Avitable M, Glazman S, Bodis-Wollner I. Perisaccadic gamma modulation in Parkinson disease patients and healthy subjects. Clin EEG Neurosci 2010; 41:94-101. [PMID: 20521492 DOI: 10.1177/155005941004100209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We quantified the anterior-posterior distribution of the gamma modulation index (GMI), an index of perisaccadic phasic modulation of the gamma (35-45 Hz) range electroencephalogram (EEG), in healthy human subjects and Parkinson disease (PD) patients. The EEG was recorded over the frontal, parietal, temporal and occipital sites in 11 idiopathic PD patients (age 50-70 years, four females), 4 age matched healthy volunteers (1 female) and 17 young healthy controls (age 21-30 years, four females) Eye movements were recorded with EOG and ISCAN camera. Subjects executed saccades to a mark at right and back to fixation point and vice versa. The saccades directed away from center/fixation (centrifugal CF) were analyzed. Two minutes of EEG were obtained from each subject for the two possible saccade types (centrifugal rightwards and leftwards at 15 degrees). Each perisaccadic EEG segment was analyzed using continuous wavelet transform for quantifying the power and time course of gamma EEG ranges for each saccade type. A three way ANOVA was used for statistical analysis. Perisaccadic GMI (peak intrasaccadic power divided by mean power) in healthy subjects was higher over the contralateral hemisphere to the saccade direction, for both centrifugal saccades at anterior, posterior and occipital recording sites. Contrary to the healthy subject GMI remained near one in PD, i.e., there was no evidence of intrasaccadic gamma power increase in PD patients.
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Affiliation(s)
- M A Javaid
- Clinical Neurophysiology Lab, National Parkinson Foundation, COEX, USA
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Doufas AG, Komatsu R, Orhan-Sungur M, Sengupta P, Wadhwa A, Mascha E, Shafer SL, Sessler DI. Neuromuscular Block Differentially Affects Immobility and Cortical Activation at Near–Minimum Alveolar Concentration Anesthesia. Anesth Analg 2009; 109:1097-104. [DOI: 10.1213/ane.0b013e3181af631a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs during induction of anaesthesia with propofol. Res Vet Sci 2009; 87:287-91. [DOI: 10.1016/j.rvsc.2009.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 01/06/2009] [Accepted: 02/10/2009] [Indexed: 11/19/2022]
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Dahaba AA, Xu GX, Liu QH, Xue JX, Metzler H. Bispectral Index Monitoring of a Narcolepsy-Cataplexy Episode During Regional Anesthesia. Anesth Analg 2009; 108:613-5. [DOI: 10.1213/ane.0b013e31818ec932] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Odri A, Cavalcanti A, Billard V. Un indice bispectral étrangement élevé. ACTA ACUST UNITED AC 2008; 27:945-8. [DOI: 10.1016/j.annfar.2008.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 08/25/2008] [Indexed: 12/20/2022]
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Dissociating the effects of nitrous oxide on brain electrical activity using fixed order time series modeling. Comput Biol Med 2008; 38:1121-30. [DOI: 10.1016/j.compbiomed.2008.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 04/24/2008] [Accepted: 08/22/2008] [Indexed: 11/21/2022]
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Kawaguchi M, Takamatsu I, Masui K, Kazama T. Effect of landiolol on bispectral index and spectral entropy responses to tracheal intubation during propofol anaesthesia. Br J Anaesth 2008; 101:273-8. [DOI: 10.1093/bja/aen162] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Forgacs PB, von Gizycki H, Selesnick I, Syed NA, Ebrahim K, Avitable M, Amassian V, Lytton W, Bodis-Wollner I. Perisaccadic Parietal and Occipital Gamma Power in Light and in Complete Darkness. Perception 2008; 37:419-32. [DOI: 10.1068/p5875] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Our objective was to determine perisaccadic gamma range oscillations in the EEG during voluntary saccades in humans. We evaluated occipital perisaccadic gamma activity both in the presence and absence of visual input, when the observer was blindfolded. We quantified gamma power in the time periods before, during, and after horizontal saccades. The corresponding EEG was evaluated for individual saccades and the wavelet transformed EEG averaged for each time window, without averaging the EEG first. We found that, in both dark and light, parietal and occipital gamma power increased during the saccade and peaked prior to reaching new fixation. We show that this is not the result of muscle activity and not the result of visual input during saccades. Saccade direction affects the laterality of gamma power over posterior electrodes. Gamma power recorded over the posterior scalp increases during a saccade. The phasic modulation of gamma by saccades in darkness—when occipital activity is decoupled from visual input—provides electrophysiological evidence that voluntary saccades affect ongoing EEG. We suggest that saccade-phasic gamma modulation may contribute to short-term plasticity required to realign the visual space to the intended fixation point of a saccade and provides a mechanism for neuronal assembly formation prior to achieving the intended saccadic goal. The wavelet-transformed perisaccadic EEG could provide an electrophysiological tool applicable in humans for the purpose of fine analysis and potential separation of stages of ‘planning’ and ‘action’.
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Affiliation(s)
| | | | - Ivan Selesnick
- Department of Electrical & Computer Engineering, Polytechnic University, Brooklyn, NY 11201, USA
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