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Anesthesia and the Patient with Epilepsy
Published in Stanley R. Resor, Henn Kutt, The Medical Treatment of Epilepsy, 2020
Samantha L. Mullis, A. Donald Finek
High-dose intravenous fentanyl (SO to 100 pg/kg) has been used extensively for cardiac anesthesia because of its ability to produce a high degree of hemodynamic stability. The effects of such large doses upon the EEG in patients undergoing cardiac surgery has been examined by a variety of authors who report that the consistent EEG changes are produced (67). The EEG appearance is predominantly one of depression and is quite similar to that seen during the normal progression of sleep, though K-complexes are not seen.
The biological and evolutionary foundations of sleep and dreams
Published in Frederick L. Coolidge, Ernest Hartmann, Dream Interpretation as a Psychotherapeutic Technique, 2018
Frederick L. Coolidge, Ernest Hartmann
Stage 2 also has a second distinctive brain wave known as a K-complex which usually consists of a single large voltage burst beginning with a negative deflection followed by a smaller positive one. K-complexes do occur during wakefulness but usually only in response to some external stimuli. Their purpose during stage 2 sleep is unknown.
Fibromyalgia and the neurobiology of sleep
Published in S.R. Pandi-Perumal, Meera Narasimhan, Milton Kramer, Sleep and Psychosomatic Medicine, 2017
Between 2% and 15% of any given population and 60% and 90% of FM patients have non-restorative sleep.16 First reported with FM in the 1970s by Moldofsky’s group in Toronto, alpha-wave intrusion into delta-wave sleep is noted on polysomnograms during stages 2–4 of non-rapid eye movement (non-REM) sleep.2 Other findings noted include increases in stage 1 sleep, reductions in delta sleep, and increases in the number of arousals.17,18 This leads to one being in bed for 8 hours or so, but waking up not feeling rested. Moldofsky’s group has identified three distinct patterns of alpha sleep activity in FM: phasic alpha–delta activity (50%); tonic alpha continuous throughout nonREM sleep (20%); and low alpha in the remaining 30%.19 The phasic group had the greatest number of symptoms and lowest sleep time. Increased fragmented sleep has also been documented by greater numbers of arousals and alpha–K complexes (which promote arousal, fatigue, and muscular symptoms) in the syndrome. Electrocardiograms demonstrate increased sympathetic nervous system activity overnight, while healthy individuals report a decline with sleep. FM and pain have been associated with a higher proportion of stage 1 non-REM sleep, fewer sleep spindles, and less sleep spindle frequency activity (usually seen in phase 2 sleep), suggesting that the mechanism relates to thalamocortical mechanisms of spindle, generation. Cyclic altering patterns during sleep, which express the instability of the level of vigilance that manifests as the brain’s fatigue in preserving and regulating the macrostructure of sleep, is more often present in FM.20
EEG coherence and power spectra during REM sleep related to melatonin intake in mild-to-moderate Alzheimer’s disease: a pilot study
Published in International Journal of Neuroscience, 2023
Manuel Alejandro Cruz-Aguilar, Ignacio Ramírez-Salado, Marisela Hernández-González, Miguel Angel Guevara, Ana Paula Rivera-García
In humans, sleep is divided into rapid eye movement (REM) and non-rapid eye movement (No-REM) stages. No-REM sleep is associated with a synchronized EEG pattern in which sleep spindles, K complexes, and high-voltage low-wave activity can be recorded over the entire cortical surface. As No-REM sleep deepens, slow-wave oscillations appear in EEGs and muscle tone is low but not abolished [11]. Compared to the wakefulness state, in No-REM sleep levels of acetylcholine and monoamines are reduced, while the level of GABA increases [12–16]. During REM sleep, muscle activity is strongly suppressed and sleep EEGs show low amplitude, fast activity, and sporadic τ activity, which in humans oscillates between 4-7 Hz. This EEG band plays a role in the consolidation of memory, spatial memory, spatial learning, and emotional memories in the hippocampus, amygdala and prefrontal cortex [17]. Several studies using magnetoencephalography and intracranial electroencephalography in humans have indicated that the hippocampus has a basal frequency of τ oscillations which have been linked to memory and spatial learning [18]. Likewise, the τ coherence between the hippocampus and amygdala is related to the presence of ponto-geniculo-occipital waves and the processing of emotional memory in the hippocampus during REM sleep [17]. Scarpelli et al. [19] showed that τ oscillations in the final minutes of REM sleep predict the retrieval of the memory of subsequent sleep.
Prognostic and clinicopathological value of CDK12 mutation in prostate cancer: a meta-analysis
Published in Expert Review of Anticancer Therapy, 2023
Wenjian Zhang, Lushan Zhou, Jianzhong Di
As Viswanathan et al. [25] speculated, the alteration of CDK12 drives tumorigenesis and contributes to cancer development. It is considered that loss or mutation of CDK12 leads to genomic instability, which contributes to PCa. CDK12 mutation interferes with the formation of CDK12/cyclin K complex and directly affects the expression of homologous recombination (HR)-related (DNA repair) genes downstream [26–31]. Recent studies show that the inactivation of CDK12 is associated with tandem duplication phenotype [25,31], leading to high copy-number gains of prostate cancer-relevant oncogenes (e.g. MYC, AR, and CCND1) [26]. CDK12 in mCRPC is characterized by focal tandem duplications (FTDs) that lead to increased gene fusions and marked differential gene expression. FTDs associated with CDK12 loss result in highly recurrent gains at loci of genes involved in the cell cycle and DNA replication and increased fusion-induced chimeric open reading frames across multiple genes [22].
Subacute sleep disturbance in moderate to severe traumatic brain injury: a systematic review
Published in Brain Injury, 2020
Bianca Fedele, Gavin Williams, Dean McKenzie, Edwina Sutherland, John Olver
Wiseman-Hakes et al. (54) individually reported PSG results in six patients, where two were in PTA. All patients displayed normal components of sleep (e.g. all sleep stages, sleep spindles and k-complexes) and on average, sleep duration, sleep efficiency and proportion of non-REM Stage 3 sleep (slow-wave sleep) tended to be lower in these two patients (54). Makley et al. (16) and Duclos et al. (12) utilized actigraphy. In Makley et al. (16), sleep efficiency (the ratio of time spent asleep compared with time spent in bed) was significantly worse for patients in PTA compared to patients out of PTA. Increased sleep efficiency was also a statistically significant predictor for increasing recovery of continuous memory (16). In Duclos et al. (12), activity levels over 24 h was used to determine whether rest-activity cycles (a measure of sleep–wake cycles) were consolidated (characterized as ≥80% of the activity occurring during the daytime). Patients in PTA at discharge had lower mean daytime activity ratio (69.1% versus 78.9%) and less improvement in daytime activity ratio over time (1.9% versus 14.9%) (12). Although this difference was not statistically significant, this could be due to the small sample size.