Implicit Memory Varies as a Function of Hypnotic Electroencephalogram Stage in Surgical Patients

Münte, Sinikka; Münte, Thomas F.; Grotkamp, Jörg; Haeseler, Gertrud; Raymondos, Konstantinos; Piepenbrock, S.; Kraus, G.

doi:10.1213/01.ane.0000068828.76045.c3

Cited by 21 publications

(14 citation statements)

References 22 publications

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“…Münte reported intraoperative preservation of implicit memory as indicated by an increased postoperative reading speed for stories presented during light to moderate but not deep hypnotic stages as evidenced by Narcotrend [31]. Deeprose reported significant implicit memory during adequate anaesthesia with propofol in two studies [15, 16].…”

Section: Discussionmentioning

confidence: 99%

Comparative effects of sevoflurane and propofol based general anaesthesia for elective surgery on memory

Flouda¹,

Pandazi²,

Papageorgiou³

et al. 2013

aoms

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IntroductionUnconscious processing of words during general anaesthesia has been suggested. We used the process dissociation procedure (PDP) to test memory performance during sevoflurane and propofol anaesthesia in relation to hypnotic depth.Material and methodsOne hundred participants anaesthetised for elective surgery (50 with propofol and 50 with sevoflurane) and 50 non-anaesthetized listened to a list of words. The bispectral index (BIS) of the anaesthetised patients was recorded. Within 36 h after word presentation, memory was assessed using a word stem completion task, based on Buchner's model applied on the PDP.ResultsThere was evidence of memory for words presented during light (BIS 61-80) (p = 0.001) and adequate (BIS 41-60) (p = 0.008) but not deep anaesthesia (BIS 21-40) (p = 0.09). The PDP showed a significant implicit but not explicit memory contribution (mean total explicit memory scores: 0.04 ±0.07 in all BIS categories; mean implicit memory scores: 0.01 ±0.04, 0.1 ±0.08, and 0.05 ±0.09 at BIS = 21-40, 41-60, and 61-80, respectively). There was a statistically significant difference between the mean implicit memory score (I) of the propofol and sevoflurane group in the BIS category 41-60 in general (p = 0.016), and after incision (IA.I.) (p = 0.005) in particular, with propofol depressing I more than sevoflurane in both cases. Memory performance of nonanaesthetized participants was better, with a higher contribution of explicit and a comparable contribution of implicit memory.ConclusionsDuring general anaesthesia, implicit memory persists even in adequate hypnotic states. Sevoflurane affects the implicit memory of adequately anaesthetised subjects less than propofol.

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Section: Discussionmentioning

confidence: 99%

Comparative effects of sevoflurane and propofol based general anaesthesia for elective surgery on memory

Flouda¹,

Pandazi²,

Papageorgiou³

et al. 2013

aoms

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“…The automatic classification of the EEG monitor Narcotrend using the EEG stages A to F 1 (version 2.0) has been validated in various studies [6,10,12,16,19,20].…”

Section: Discussionmentioning

confidence: 99%

The Narcotrend Index: Classification Algorithm, Correlation with Propofol Effect-Site Concentrations, and Comparison with Spectral Parameters / Der Narcotrend-Index: Klassifikationsalgorithmus, Korrelation mit Propofol-Effekt-Site-Konzentrationen und Vergleich mit Spektralparametern

Schultz¹,

Grouven²,

Beger³

et al. 2004

Biomedizinische Technik/Biomedical Engineering

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A reliable assessment of the depth of hypnosis during sedation and general anaesthesia using the EEG is a subject of current interest. The Narcotrend Index implemented in the latest version 4.0 of the EEG monitor Narcotrend provides an automatic classification of the EEG on a scale ranging from 100 (awake) to 0 (very deep hypnosis, EEG suppression). The classification algorithms implemented in the EEG monitor Narcotrend are described. In a study the correlation of the propofol effect-site concentration with the Narcotrend Index and with the traditional spectral parameters total power, relative power in the standard frequency bands delta, theta, alpha, and beta, median frequency, 95% spectral edge frequency, burst-compensated spectral edge frequency, and spectral entropy was investigated. The Narcotrend Index had the highest average correlation with the propofol effect-site concentration and the smallest variability of the individual correlation values. Moreover, the Narcotrend Index was the only parameter which showed a monophasic trend over the whole investigated time period. The Narcotrend monitor can make a significant contribution to the improvement of the quality of anaesthesia by adjusting the dosage of hypnotics to individual patient needs.

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“…It has been shown that implicit memory is related to the hypnotic electroencephalographic stage in surgical patients. 29 Although the risk of awareness in propofolremifentanil anesthesia seems to be low, 30 this field warrants further investigation. 31 In this article, only the amount of remifentanil was changed.…”

Section: Fig 4 the R Scale Values At Different Endpoints (Loss Of Cmentioning

confidence: 99%

Remifentanil Modifies the Relation of Electroencephalographic Spectral Changes and Clinical Endpoints in Propofol Anesthesia

et al. 2008

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Implicit Memory Varies as a Function of Hypnotic Electroencephalogram Stage in Surgical Patients

Cited by 21 publications

References 22 publications

Comparative effects of sevoflurane and propofol based general anaesthesia for elective surgery on memory

Comparative effects of sevoflurane and propofol based general anaesthesia for elective surgery on memory

The Narcotrend Index: Classification Algorithm, Correlation with Propofol Effect-Site Concentrations, and Comparison with Spectral Parameters / Der Narcotrend-Index: Klassifikationsalgorithmus, Korrelation mit Propofol-Effekt-Site-Konzentrationen und Vergleich mit Spektralparametern

Remifentanil Modifies the Relation of Electroencephalographic Spectral Changes and Clinical Endpoints in Propofol Anesthesia

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