Intraoperative seizures under general anesthesia are rare and our observation is the first to demonstrate a distinct electroencephalogram (EEG) pattern on the Narcotrend monitor.
We present the case ...of a 30-year-old man undergoing craniotomy for glioblastoma resection under general anesthesia who suffered tonic-clonic seizures captured in a specific pattern by the intraoperative EEG.
Our depth of anesthesia monitor recorded, before the seizure, a widening of the beta-wave performance in a distinct "triangular-shaped" pattern. This pattern was repeated before the second seizure. The patient had no previous history of seizures and following surgery no further seizures were recorded.
A spectrogram analysis showed a distinct increase in mean absolute beta power immediately prior to the first seizure. The EEG immediately prior to the second seizure was characterized by broadband noise. Both seizures were characterized by increased mean absolute delta, theta, and beta power.
The increase in EEG beta activity seen before the tonic-clonic movements may represent cortical irritability secondary to surgical manipulation, induced by electrical stimulation, reflecting progressive brain over-arousal. The attentive analysis of the relative beta power may have helped forecast the occurrence of the second seizure.
We report the use of a simple, inexpensive, and portable EEG-based monitoring device to assist seizure detection and decision making.
It is well-known that additive noise affects the stability of nonlinear systems. Using a network composed of two interacting populations , detailed stochastic and non-linear analysis demonstrates ...that increasing the intensity of iid additive noise induces a phase transition from a spectrally broad-band state to a phase-coherent oscillatory state. Corresponding coherence resonance-like system behaviour is described analytically for iid noise as well. Stochastic transitions and coherence resonance-like behaviour were also found to occur for non-iid additive noise induced by increased heterogeneity, corresponding analytical results complement the analysis. Finally, the results are applied to burst suppression-like patterns observed in electroencephalographic data under anaesthesia, providing strong evidence that these patterns reflect jumps between random and phase-coherent neural states induced by varying external additive noise levels.
Depth of anesthesia (DoA) monitors are widely used during general anesthesia to guide individualized dosing of hypnotics. Other than age and specific drugs, there are few reports on which ...comorbidities may influence the brain and the resultant electroencephalogram (EEG) of patients undergoing general anesthesia. We present a case of a patient undergoing 3 cardiac operations within 7 months with severe illness and comorbidity, leading to pronounced physical frailty and significant changes of frontal alpha power in the EEG and increased sensitivity to volatile anesthetics. These findings may have important clinical implications and should trigger further investigations on this topic.
Motor activity during general anesthesia (GA) without neuromuscular blockade is often interpreted as reflecting insufficient anesthesia. Here we present the case of an octogenarian undergoing deep ...sclerectomy with opioid-sparing electroencephalography (EEG)-guided anesthesia. Periodic leg movements (PLM) appeared during ongoing surgery while the patient's raw EEG displayed a pattern of deep anesthesia, evidenced by burst suppression. Recognizing PLM in the context of opioid-sparing GA is of importance for anesthesiologists, as deep anesthesia is not necessarily associated with a decrease in motor activity.
In multiple sclerosis (MS), the combination of visual, somatosensory and motor evoked potentials (EP) has been shown to be highly correlated with the Expanded Disability Severity Scale (EDSS) and to ...predict the disease course. In the present study, we explored whether the significance of the visual EP (VEP) can be improved with multichannel recordings (204 electrodes) and topographic analysis (tVEP). VEPs were analyzed in 83 MS patients (median EDSS 2.0; 52 % with history of optic neuritis; hON) and 47 healthy controls (HC). TVEP components were automatically defined on the basis of spatial similarity between the scalp potential fields (topographic maps) of single subjects’ VEPs and reference maps generated from HC. Non-ambiguous measures of latency, amplitude and configuration were derived from the maps reflecting the P100 component. TVEP was compared to conventional analysis (cVEP) with respect to reliability in HC, validity using descriptors of logistic regression models, and sensitivity derived from receiver operating characteristics curves. In tVEP, reliability tended to be higher for measurement of amplitude (
p
= 0.06). Regression models on diagnosis (MS vs. HC) and hON were more favorable using tVEP- versus cVEP-predictors. Sensitivity was increased in tVEP versus cVEP: 72 % versus 60 % for diagnosis, and 88 % versus 77 % for hON. The advantage of tVEP was most pronounced in pathological VEPs, in which cVEPs were often ambiguous. TVEP is a reliable, valid, and sensitive method of objectively quantifying pathological VEP in particular. In combination with other EP modalities, tVEP may improve the monitoring of disease course in MS.
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