scholarly journals Interictal epileptiform activity in sleep and wakefulness in patients with temporal lobe epilepsy

2019 ◽  
pp. 21-26
Author(s):  
A.G. Broutian ◽  
A.I. Belyakova-Bodina ◽  
S.M. Dolgova ◽  
T.N. Pushkar ◽  
A.A. Abramova
Keyword(s):  
Cortical Neurons ◽  
Epileptiform Activity ◽  
Nrem Sleep ◽  
Epileptiform Discharge ◽  
Sleep Stages ◽  
Recording Time ◽  
Temporal Epilepsy ◽  
Major Mechanism ◽  
Eeg Recordings ◽  
Sleep Recording

Sleep is an important activator of epileptiform activity, with epileptiform discharge (ED) probability varying among sleep stages. The aim of our study was to analyze the association between epileptiform activity and sleep stages or wakefulness in adults with temporal discharges. We analyzed 32 long-term overnight EEG recordings. All focal discharges were marked, and the entire sleep was staged. Absolute general epileptiform discharge index (EDI), defined as a ratio of total ED number to the full recording time in hours, as well as absolute EDIs for REM, N1, N2 and N3 stages were calculated. The majority of patients (28) had the highest EDI in N3. EDI increased significantly while sleep progressed to deeper stages, reaching its peak in N3. In REM sleep, EDI sharply declined (p < 0.01) reaching the levels of wakefulness. Increasing synchronization of cortical neurons is thought to be the major mechanism of EDI rise in NREM sleep. Hence, N3 seems to be the most sensitive stage to capture EDs, which highlights the importance of deep sleep recording in patients with temporal epilepsy.

NREM Sleep and Antiepileptic Medications Modulate Epileptiform Activity by Altering Cortical Synchrony

2018 ◽  
Vol 49 (6) ◽  
pp. 417-424 ◽  
Author(s):  
Chetan S. Nayak ◽  
N. Mariyappa ◽  
Kaushik K. Majumdar ◽  
G. S. Ravi ◽  
Pradeep D. Prasad ◽  
...  
Keyword(s):  
Phase Synchronization ◽  
Focal Epilepsy ◽  
Sleep Stage ◽  
Epileptiform Activity ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Epileptiform Discharges ◽  
Drug Naïve ◽  
Antiepileptic Medications

Introduction. The activating role of non–rapid eye movement (NREM) sleep on epileptic cortex and conversely, the seizure remission brought about by antiepileptic medications, has been attributed to their effects on neuronal synchrony. This study aims to understand the role of neural synchrony of NREM sleep in promoting interictal epileptiform discharges (IEDs) in patients with epilepsy (PWE) by assessing the peri-IED phase synchrony during awake and sleep states. It also studies the role played by antiepileptic drugs (AEDs) on EEG desynchronization in the above cohort. Methods. A total of 120 PWE divided into 3 groups (each n = 40; juvenile myoclonic epilepsy [JME], temporal lobe epilepsy [TLE]. and extratemporal lobe epilepsy [Ex-TLE]) were subjected to overnight polysomnography. Each patient group was subdivided into drug-naive and on treatment (Each n = 20). EEG phase synchronization analysis was performed to compare peri-IED phase synchronization indices (SI) during awake and sleep stages and between drug naïve and on treatment groups in 4 frequency bands, namely delta, theta, alpha, and beta. The mean ± SD of peri-IED SI among various subgroups was compared employing a multilevel mixed effects modeling approach. Results. Patients with JME had increased peri-IED cortical synchrony in N3 sleep stage, whereas patients with partial epilepsy had increased IED cortical synchrony in N1 sleep stage. On the other hand, peri-IED synchrony was lower during wake and REM sleep. We also found that peri-IED synchronization in patients with JME was higher in drug-naive patients compared with those on sodium valproate monotherapy in theta, alpha, and beta bands. Conclusion. The findings of this study suggest that sleep stages can alter cortical synchrony in patients with JME and focal epilepsy, with NREM IEDs being more synchronized and wake/REM IEDs being less synchronized. Furthermore, it also suggests that AEDs alleviate seizures in PWE by inhibiting cortical synchrony.

scholarly journals Primary sleep enuresis in childhood: polysomnography evidences of sleep stage and time modulation

1993 ◽  
Vol 51 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Rubens Reimäo ◽  
Laércio C. Pachelli ◽  
Ricardo Carneiro ◽  
Guido Faiwichow
Keyword(s):  
Sleep Disorders ◽  
Normal Distribution ◽  
Sleep Stage ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Recording Time ◽  
Time Modulation ◽  
Drug Free ◽  
Sleep Cycles

The objective of this study was to evaluate enuretic events and its relations to sleep stages, sleep cycles and time durations in a selected group of children with primary essential sleep enuresis. We evaluated 18 patients with mean age of 8.2 years old (ranging from 5 to 12 years); 10 were males and 8 females (n.s.). They were referred to the Sleep Disorders Center with the specific complaint of enuresis since the first years of life (primary). Pediatric, urologic and neurologic workup did not show objective abnormalities (essential). The standard all-night polysomnography including an enuresis sensor attached to the shorts in the crotch area was performed. Only enuretic events nights were included. All were drug free patients for two weeks prior to polysomnography. In this report, only one polysomnography per patient was considered. The enuretic events were phase related, occurring predominantly in non-REM (NREM) sleep (p<0.05). There was no predominance of enuretic events among the NREM stages (n.s.). A tendency of these events to occur in the first two sleep cycles was detected but may be due to the longer duration of these cycles. The events were time modulated, adjusted to a normal distribution with a mean of 213.4 min of recording time.

scholarly journals Interhemispheric asymmetry during NREM sleep in the dog

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vivien Reicher ◽  
Anna Kis ◽  
Péter Simor ◽  
Róbert Bódizs ◽  
Márta Gácsi
Keyword(s):  
Hemispheric Asymmetry ◽  
Nrem Sleep ◽  
Sleep Cycle ◽  
Interhemispheric Asymmetry ◽  
Frequency Range ◽  
Non Invasive ◽  
Eeg Recordings ◽  
Sleep Recording ◽  
Slow Frequency ◽  
Sleep Cycles

AbstractFunctional hemispheric asymmetry was evidenced in many species during sleep. Dogs seem to show hemispheric asymmetry during wakefulness; however, their asymmetric neural activity during sleep was not yet explored. The present study investigated interhemispheric asymmetry in family dogs using non-invasive polysomnography. EEG recordings during 3-h-long afternoon naps were carried out (N = 19) on two occasions at the same location. Hemispheric asymmetry was assessed during NREM sleep, using bilateral EEG channels. To include periods with high homeostatic sleep pressure and to reduce the variance of the time spent in NREM sleep between dogs, the first two sleep cycles were analysed. Left hemispheric predominance of slow frequency range was detected in the first sleep cycle of sleep recording 1, compared to the baseline level of zero asymmetry as well as to the first sleep cycle of sleep recording 2. Regarding the strength of hemispheric asymmetry, we found greater absolute hemispheric asymmetry in the second sleep cycle of sleep recording 1 and 2 in the frequency ranges of alpha, sigma and beta, compared to the first sleep cycle. Differences between sleep recordings and consecutive sleep cycles might be indicative of adaptation-like processes, but do not closely resemble the results described in humans.

scholarly journals Endogenous memory reactivation during sleep in humans is clocked by slow oscillation-spindle complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Thomas Schreiner ◽  
Marit Petzka ◽  
Tobias Staudigl ◽  
Bernhard P. Staresina
Keyword(s):  
Memory Function ◽  
Nrem Sleep ◽  
Stimulus Category ◽  
Learning Material ◽  
Memory Reactivation ◽  
Eeg Recordings ◽  
Surface Eeg ◽  
Function Of Sleep ◽  
Prior Experiences

AbstractSleep is thought to support memory consolidation via reactivation of prior experiences, with particular electrophysiological sleep signatures (slow oscillations (SOs) and sleep spindles) gating the information flow between relevant brain areas. However, empirical evidence for a role of endogenous memory reactivation (i.e., without experimentally delivered memory cues) for consolidation in humans is lacking. Here, we devised a paradigm in which participants acquired associative memories before taking a nap. Multivariate decoding was then used to capture endogenous memory reactivation during non-rapid eye movement (NREM) sleep in surface EEG recordings. Our results reveal reactivation of learning material during SO-spindle complexes, with the precision of SO-spindle coupling predicting reactivation strength. Critically, reactivation strength (i.e. classifier evidence in favor of the previously studied stimulus category) in turn predicts the level of consolidation across participants. These results elucidate the memory function of sleep in humans and emphasize the importance of SOs and spindles in clocking endogenous consolidation processes.

Vigilance states, EEG spectra, and cortical temperature in the guinea pig

1993 ◽  
Vol 264 (6) ◽  
pp. R1125-R1132 ◽  
Author(s):  
I. Tobler ◽  
P. Franken ◽  
K. Jaggi
Keyword(s):  
Guinea Pig ◽  
Rem Sleep ◽  
Guinea Pigs ◽  
Process Model ◽  
Dark Period ◽  
Nrem Sleep ◽  
Light Period ◽  
Recording Time ◽  
Cortical Temperature ◽  
Eeg Power

Vigilance states, electroencephalogram (EEG) power spectra (0.25-25.0 Hz), and cortical temperature (TCRT) were obtained in nine guinea pigs for 24 h in a 12:12-h light-dark (LD 12:12) schedule. Sleep was markedly polyphasic and fragmented and amounted to 32% of recording time, which is a low value compared with sleep in other rodents. There was 6.8% more sleep in the light period than in the dark period. EEG power density in non-rapid eye movement (NREM) sleep showed no significant temporal trend within the light or the dark period. The homeostatic aspects of sleep regulation, as proposed in the two-process model, can account for the slow-wave activity (SWA) pattern also in the guinea pig: The small 24-h amplitude of the sleep-wakefulness pattern resulted in a small, 12% decline of SWA within the light period. In contrast to more distinctly nocturnal rodents, SWA in the dark period was not higher than in the light period. TCRT showed no difference between the light and the dark period. TCRT in REM sleep and waking was higher than TCRT in NREM sleep. TCRT increased after the transition from NREM sleep to either REM sleep or waking, and decreased in the last minute before the transition and after the transition from waking to NREM sleep. Motor activity measured in six animals for 11 days in constant darkness showed no apparent rhythm in three animals and a significant circadian rhythm in three others. Our data support the notion that guinea pigs exhibit only a weak circadian rest-activity rhythm.

Effects of exercise on sleep

1978 ◽  
Vol 44 (6) ◽  
pp. 945-951 ◽  
Author(s):  
J. M. Walker ◽  
T. C. Floyd ◽  
G. Fein ◽  
C. Cavness ◽  
R. Lualhati ◽  
...  
Keyword(s):  
Eye Movement ◽  
Slow Wave Sleep ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Absolute Amount ◽  
Rapid Eye Movement ◽  
Personality Profiles ◽  
Experimental Conditions ◽  
Strong Trend ◽  
Delta Activity

We tested the hypothesis that EEG sleep stages 3 and 4 (slow-wave sleep, SWS) would be increased as a function of either acute of chronic exercise. Ten distance runners were matched with 10 nonrunners, and their sleep was recorded under both habitual (runners running and nonrunners not running, 3 night) and abruptly changed (runners not running and nonrunners running, 1 night) conditions. Analyses of both visually scored SWS and computer measures of delta activity during non-rapid eye-movement (NREM) sleep failed to support the SWS-exercise hypothesis. The runners showed a significantly higher proportion and a greater absolute amount of NREM sleep than the nonrunners. The runners showed less rapid eye-movement activity during sleep than the nonrunners under both experimental conditions, indicating a strong and unexpected effect of physical fitness on this measure. Modest afternoon exercise in nonrunners was associated with a strong trend toward elevated heart rate during sleep. Mood tests and personality profiles revealed few differences, either between groups or within groups, as a function of exercise.

Engagement of Rat Striatal Neurons by Cortical Epileptiform Activity Investigated With Paired Recordings

2004 ◽  
Vol 92 (5) ◽  
pp. 2725-2737 ◽  
Author(s):  
Enrico Bracci ◽  
Diego Centonze ◽  
Giorgio Bernardi ◽  
Paolo Calabresi
Keyword(s):  
Cortical Neurons ◽  
Epileptiform Activity ◽  
Brain Slices ◽  
Brain Structures ◽  
Extracellular Potassium ◽  
Striatal Neurons ◽  
Cholinergic Interneurons ◽  
Medial Agranular Cortex ◽  
The Impact ◽  
Oblique Slices

The striatum is thought to play an important role in the spreading of epilepsy from cortical areas to deeper brain structures, but this issue has not been addressed with intracellular techniques. Paired recordings were used to assess the impact of cortical epileptiform activity on striatal neurons in brain slices. Bath-application of 4-amynopyridine (100 μM) and bicuculline (20 μM) induced synchronized bursts in all pairs of cortical neurons (≤5 mm apart) in coronal, sagittal, and oblique slices (which preserve connections from the medial agranular cortex to the striatum). Under these conditions, striatal medium spiny neurons (MSs) displayed a strong increased spontaneous glutamatergic activity. This activity was not correlated to the cortical bursts and was asynchronous in pairs of MSs. Sporadic, large-amplitude synchronous depolarizations also occurred in MSs. These events were simultaneously detected in glial cells, suggesting that they were accompanied by considerable increases in extracellular potassium. In oblique slices, cortically driven bursts were also observed in MSs. These events were synchronized to cortical epileptiform bursts, depended on non– N-methyl-d-aspartate (NMDA) glutamate receptors, and persisted in the cortex, but not in the striatum, after disconnection of the two structures. During these bursts, MS membrane potential shifted to a depolarized value (59 ± 4 mV) on which an irregular waveform, occasionally eliciting spikes, was superimposed. Thus synchronous activation of a limited set of corticostriatal afferents can powerfully control MSs. Cholinergic interneurons located <120 μm from simultaneously recorded MSs, did not display cortically driven bursts, suggesting that these cells are much less easily engaged by cortical epileptiform activity.

scholarly journals P.129 Bi-insular Responsive Neurostimulation Artifact on Scalp Electroencephalogram

2021 ◽  
Vol 48 (s3) ◽  
pp. S56-S56
Author(s):  
EM Paredes-Aragón ◽  
M Chávez-Castillo ◽  
GL Barkley ◽  
JG Burneo ◽  
A Suller-Martí
Keyword(s):  
Scientific Literature ◽  
Seizure Activity ◽  
Epileptiform Activity ◽  
Scalp Eeg ◽  
Proven Efficacy ◽  
Eeg Recordings ◽  
Scalp Electroencephalogram ◽  
Intracranial Electroencephalography

Background: Background: Responsive Neurostimulation (RNS) has proven efficacy in treating medically resistant epilepsy as an intracranial system detecting, recording and treating seizures automatically. No information exists pertaining to artifact characteristics of RNS findings in scalp EEG. Methods: A 30 year-old female was diagnosed using intracranial electroencephalography(iEEG), with bi-insular epilepsy, of unknown cause. She presented large number of focal unaware non-motor seizures and seizures with progression to bilateral tonic-clonic. She was implanted with bi-insular RNS. Results: During scalp EEG recordings, a prominent artifact was seen corresponding to an automatized discharge suspectedly evoked by the RNS trying to minimize the frequent epileptiform activity in her case. Figure 1 and 2 depict these findings. Conclusions: Artifact seen by the RNS in scalp EEG has not been previously described in scientific literature. These findings must be identified to better characterize the role of the RNS in EEG and treatment of seizure activity visible on scalp recordings.

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