Influence of midazolam premedication on intraoperative EEG signatures in elderly patients

ObjectiveTo investigate the influence of midazolam premedication on the EEG-spectrum before and during general anesthesia in elderly patients.MethodsPatients aged ≥65 years, undergoing elective surgery were included in this prospective observational study. A continuous pre- and intraoperative frontal EEG was recorded in patients who received premedication with midazolam (Mid, n = 15) and patients who did not (noMid, n = 30). Absolute power within the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (12–25 Hz) frequency-bands was analyzed in EEG-sections before (pre-induction), and after induction of anesthesia with propofol (post-induction), as well as during general anesthesia with either propofol or volatile-anesthetics (intra-operative).ResultsPre-induction, α-power of Mid patients was lower compared with noMid-patients (α-power: Mid: −10.75 dB vs. noMid: −9.20 dB; p = 0.036). After induction of anesthesia Mid-patients displayed a stronger increase of frontal α-power resulting in higher absolute α-power at post-induction state, (α-power: Mid −3.56 dB vs. noMid: −6.69 dB; p = 0.004), which remained higher intraoperatively (α-power: Mid: −2.12 dB vs. noMid: −6.10 dB; p = 0.024).ConclusionMidazolam premedication alters the intraoperative EEG-spectrum in elderly patients.SignificanceThis finding provides further evidence for the role of GABAergic activation in the induction of elevated, frontal α-power during general anesthesia.Trial Registry NumberNCT02265263. 23 September 2014. Principal investigator: Prof. Dr. med. Claudia Spies. (https://clinicaltrials.gov/ct2/show/NCT02265263).     

A standardised assessment scheme for conventional EEG in preterm infants

ObjectiveTo develop a standardised scheme for assessing normal and abnormal electroencephalography (EEG) features of preterm infants. To assess the interobserver agreement of this assessment scheme.MethodsWe created a standardised EEG assessment scheme for 6 different post-menstrual age (PMA) groups using 4 EEG categories. Two experts, not involved in the development of the scheme, evaluated this on 24 infants <32 weeks gestational age (GA) using random 2 hour EEG epochs. Where disagreements were found, the features were checked and modified. Finally, the two experts independently evaluated 2 hour EEG epochs from an additional 12 infants <37 weeks GA. The percentage of agreement was calculated as the ratio of agreements to the sum of agreements plus disagreements.ResultsGood agreement in all patients and EEG feature category was obtained, with a median agreement between 80% and 100% over the 4 EEG assessment categories. No difference was found in agreement rates between the normal and abnormal features (p = 0.959).ConclusionsWe developed a standard EEG assessment scheme for preterm infants that shows good interobserver agreement.SignificanceThis will provide information to Neonatal Intensive Care Unit (NICU) staff about brain activity and maturation. We hope this will prove useful for many centres seeking to use neuromonitoring during critical care for preterm infants.     

The prognostic value of the EEG in asphyxiated newborns

Peripartal asphyxia is still one of the most important factors of neonatal morbidity and mortality and accounts for the majority of non-progressive neurological deficits seen in children. A set of evaluations that may consistently predict outcome in this patient population would be valuable. The purpose of the present retrospective study was to investigate the prognostic value of the early neonatal EEG and Sarnat scoring obtained in 23 asphyxiated term newborns. All infants met strict entrance criteria, regarding asphyxia, and received standard treatment. The relationship between the Sarnat scoring, the early EEG findings, and the clinical follow up examination (at 1, 5-7 years) were studied using the Pearson Correlation test and multiple regression. Our study clearly demonstrates a strong correlation between the early neonatal EEG and outcome, even regarding the prediction of minor sequelae (r = 0.79, p< 0.0001). The early neonatal EEG is more accurate in predicting the ultimate clinical outcome than the Sarnat scoring.     

EEG source imaging in pediatric epilepsy surgery: a new perspective in presurgical workup

PURPOSE: Epilepsy is a relatively frequent disease in children, with considerable impact on cognitive and social life. Successful epilepsy surgery depends on unambiguous focus identification and requires a comprehensive presurgical workup, including several neuroimaging techniques [magnetic resonance imaging, positron emission tomography (PET), and single-photon emission computed tomography (SPECT)]. These may be difficult to apply in younger or developmentally delayed children or both, requiring sedation, and hence, a significant workforce. Modern electric source imaging (ESI) provides accurate epileptic source-localization information in most patients, with minimal patient discomfort or need for cooperation. The purpose of the present study was to determine the usefulness of ESI in pediatric EEG recordings performed with routine electrode arrays. METHODS: Preoperative EEGs recorded from 19 to 29 scalp electrodes were reviewed, and interictal epileptiform activity was analyzed by using a linear source-imaging procedure (depth-weighted minimum norm) in combination with statistical parametric mapping. RESULTS: In 27 (90%) of 30 patients, the ESI correctly localized the epileptogenic region. These numbers compare favorably with the results from other imaging techniques in the same patients (PET, 82%; ictal SPECT, 70%). In extratemporal epilepsy, ESI was correct in all cases, and in temporal lobe epilepsy, in 10 of 13 cases. In two temporal lobe patients showing less-accurate ESI results, 128-electrode data could be analyzed, and in both cases, the 128-electrode ESI was correct. CONCLUSIONS: ESI with standard clinical EEG recordings provides excellent localizing information in pediatric patients, in particular in extratemporal lobe epilepsy. The lower yield in temporal lobe epilepsy seems to be due to undersampling of basal temporal areas with routine scalp recordings.     

Synchronous occurrence of EEG bursts and heart rate acceleration in preterm infants

Continuous and simultaneous registration of electroencephalogram (EEG) and heart rate (HR) pattern in preterm infants can give information about the functioning of central nervous system and the integrity of the autonomic nervous system. The developmental and behavioural state determine the pattern of EEG activity. A discontinuous EEG activity also known as ‘Tracé alternant’ (TA) in preterm infants is accompanied by a low heart rate variability (HRV). It was found that electroencephalographic bursts of slow waves during TA are coupled with an acceleration of the HR. In this study, this synchronous behaviour of EEG bursts and HR is described for the first time in a group of preterm infants with a mean conceptional age (CA) of 36 weeks.     

Sleep and EEG features of newborns with 18 and 13 trisomy syndromes

Serial polygraphic recordings of two to three hours duration were made in five full-term newborns with trisomy 18 and one full-term newborn with trisomy 13 syndrome. The newborns with 18 trisomy syndrome were poor sleepers with long periods of wakefulness and/or drowsiness. There were no consistent abnormalities in the sleep profile characteristic of 18 or 13 trisomy syndrome. These infants had some difficulty in organizing a stable sleep cycle especially during the immediate neonatal period. There was poor correlation between EEG patterns and states. After one to two weeks, cyclic organization of sleep showed some tendency towards normalization, although there were more trace alternant and fewer high voltage slow patterns in quiet sleep even around and after 44 weeks conceptional age. Other abnormal features of sleep often observed were an increase of indeterminate sleep, a decrease of quiet sleep, and an increase or decrease of active sleep in some records.     

Extrauterine life duration and ontogenic EEG parameters in preterm newborns with and without major ultrasound brain lesions

OBJECTIVE: To determine whether extrauterine life duration is associated with different ontogenic electroencephalographic (EEG) patterns in premature infants compared with neonates born at later gestational ages (GAs). METHODS: We included 97 preterm infants of 24-36 weeks GA. We performed neurosonography and EEG recordings at week 1 and 2 of postnatal life, then every two weeks until term conceptional age (CA). We analyzed background EEG and sleep states and compared them at matched CA. RESULTS: In the group of infants without major ultrasound lesion (MUL), those <29 weeks GA showed increased sawtooth at 32-36 weeks CA and delta brushes from 34 to 40 weeks CA compared to infants > or =29 weeks GA. Infants with MUL compared to those without MUL showed significantly longer interburst intervals, shorter minimum burst duration at 2 and 4 weeks postnatal life, and higher incidence of sawtooth and delta brushes from 34 weeks CA to term. In addition, those of <29 weeks GA had higher rates of indeterminate sleep until 32 weeks CA. The type of MUL most frequently associated with dysmature EEG patterns was persistent ventricular dilatation. CONCLUSIONS: Premature infants without MUL showed prolonged dysmature EEG patterns as from early CAs (> or =29 weeks). This finding was more evident in those with MUL. SIGNIFICANCE: Extrauterine EEG development in prematures may differ from that of babies born at a later GA.     

EEG alpha and theta signatures of socially and non-socially cued working memory in virtual reality

In this preregistered study (https://osf.io/s4rm9) we investigated the behavioural and neurological [electroencephalography; alpha (attention) and theta (effort)] effects of dynamic non-predictive social and non-social cues on working memory. In a virtual environment realistic human-avatars dynamically looked to the left or right side of a table. A moving stick served as a non-social control cue. Kitchen items were presented in the valid cued or invalid un-cued location for encoding. Behavioural findings showed a similar influence of the cues on working memory performance. Alpha power changes were equivalent for the cues during cueing and encoding, reflecting similar attentional processing. However, theta power changes revealed different patterns for the cues. Theta power increased more strongly for the non-social cue compared to the social cue during initial cueing. Furthermore, while for the non-social cue there was a significantly larger increase in theta power for valid compared to invalid conditions during encoding, this was reversed for the social cue, with a significantly larger increase in theta power for the invalid compared to valid conditions, indicating differences in the cues’ effects on cognitive effort. Therefore, while social and non-social attention cues impact working memory performance in a similar fashion, the underlying neural mechanisms appear to differ.     

Peri-ictal EEG in infants with PRRT2-related self-limited infantile epilepsy

Objective

Pathogenic PRRT2 variants cause self-limited (familial) infantile epilepsy (SeLIE), which is responsive to sodium channel blocking antiseizure medications. The interictal EEG is typically normal. We describe a cohort of infants with PRRT2-related SeLIE with striking peri-ictal EEG abnormalities.

Methods

We included all infants diagnosed with PRRT2-related SeLIE during July 2020 to November 2021 at the Royal Children's Hospital, Melbourne. Clinical features and results of aetiologic investigations were collected from electronic medical records. All EEGs were reviewed independently by two epileptologists.

Results

Ten infants presented with focal seizures at a median age of 5 months (range: 3–6 months). Eight had a family history of epilepsy, paroxysmal kinesigenic dyskinesia (PKD) or hemiplegic migraine. Seven of the eight infants with an EEG performed within 24 h of the most recent seizure had epileptiform discharges. Their EEGs showed focal sharp waves, spikes, polyspikes or fast activity independently over the left and right temporo-occipital regions. Conversely, the two infants with last known seizure greater than 24 h prior to their EEG had no epileptiform discharges. Oxcarbazepine was commenced in two infants and was effective. Eight infants were initially treated with levetiracetam, and all were subsequently switched to oxcarbazepine due to ongoing seizures or side effects.

Significance

Posterior polymorphic focal epileptiform discharges on a peri-ictal EEG recording are a feature of PRRT2-related SeLIE. This finding, particularly in the presence of a family history of infantile epilepsy, PKD or hemiplegic migraine, suggests a diagnosis of PRRT2-related SeLIE and has important treatment implications.     

禁睡加睡眠脑电图

本组对６５例临床诊断癫痫而脑电图正常或界限异常的患者行禁睡加睡眠脑电图检查。其癫痫波出现率为７８．４％。禁睡活化率与发作类型、年龄、病程有关，而与发作频率、治疗与否无关。禁睡后清醒和禁睡后睡眠脑电图活化率比较有极显著性差异（Ｐ＜０．００１）。对照组１５例，均系正常脑电图，无１例出现痫性放电。癫痫患者虽经其他诱发试验，仍有３４％患者为正常脑电图，而行此法检查，痫性波活化率较高，以强直－阵挛性发作者尤高（活化率８３．８％）。因此我们认为此法简单易行，活化率较高，值得临床推广。     

EEG findings in minor head trauma as a clue for indication to CT scan

In order to investigate the role of EEG in minor head traumata in the pediatric age, EEG and CT scan findings were compared in a series of 103 consecutive cases of children hospitalized within 24 h after head trauma. The EEGs were classified as normal in 50 patients, borderline in 10 patients, and abnormal in 43 patients. CT scan showed contusion in 6 patients and extracerebral hematoma in 4. All cases of abnormal CT scans were reported for patients with frankly abnormal EEG findings. In contrast, no pathological findings were found in CT scans for patients with normal EEG. The data suggest that EEG findings can play a major role in the diagnostic workup of patients with minor head traumata. Specifically, in the case of asymptomatic patients with normal EEG findings, it is likely that the CT scan will also be normal.Presented at the 11th Meeting of the European Society for Paediatric Neurosurgery, Naples 1988     

EEG features of absence seizures in idiopathic generalized epilepsy: Impact of syndrome, age, and state

Purpose:   Factors influencing the electroencephalography (EEG) features of absence seizures in newly presenting children with idiopathic generalized epilepsy (IGE) have not been rigorously studied. We examined how specific factors such as state, provocation, age, and epilepsy syndrome affect the EEG features of absence seizures.
Methods:   Children with untreated absence seizures were studied using video-EEG recording. The influence of state of arousal, provocation (hyperventilation, photic stimulation), age, and epilepsy syndrome on specific EEG features was analyzed.
Results:   Five hundred nine seizures were evaluated in 70 children with the following syndromes: childhood absence epilepsy (CAE) 37, CAE+ photoparoxysmal response (PPR) 10, juvenile absence epilepsy (JAE) 8, juvenile myoclonic epilepsy (JME) 6, and unclassified 9. Polyspikes occurred in all syndromes but were more common in JME. They were brought out by drowsiness and sleep in fragments of generalized spike and wave (GSW). Polyspikes were more likely to occur during photic stimulation, but were not influenced by age independently. GSW was more likely to be disorganized in JME than JAE, and in JAE than CAE. Increasing age and levels of arousal were more likely to result in organized GSW. Factors specific to each child independently influenced EEG features; the nature of these factors has not been identified.
Discussion:   The EEG features of absence seizures are influenced by a complex interaction of age, epilepsy syndrome, level of arousal, provoking factors, and other intrinsic factors. Epilepsy syndrome alone cannot predict specific features of GSW; however, JME is more frequently associated with polyspikes and disorganization of the paroxysm.     

Facial expressions and EEG in infants of intrusive and withdrawn mothers with depressive symptoms

When intrusive and withdrawn mothers with depressive symptoms modeled happy, surprised, and sad expressions, their 3-month-old infants did not differentially respond to these expressions or show EEG changes. When a stranger modeled these expressions, the infants of intrusive vs. withdrawn mothers looked more at the surprised and sad expressions and showed greater relative right EEG activity in response to the surprise and sad expressions as compared to the happy expressions. These findings suggest that the infants of intrusive mothers with depressive symptoms showed more differential responding to the facial expressions than the infants of withdrawn mothers. In addition, the infants of intrusive vs. infants of withdrawn mothers showed increased salivary cortisol following the interactions, suggesting that they were more stressed by the interactions.     

EEG hyper-connectivity in high-risk infants is associated with later autism

Background

It has been previously reported that structural and functional brain connectivity in individuals with autism spectrum disorders (ASD) is atypical and may vary with age. However, to date, no measures of functional connectivity measured within the first 2 years have specifically associated with a later ASD diagnosis.

Methods

In the present study, we analyzed functional brain connectivity in 14-month-old infants at high and low familial risk for ASD using electroencephalography (EEG). EEG was recorded while infants attended to videos. Connectivity was assessed using debiased weighted phase lag index (dbWPLI). At 36 months, the high-risk infants were assessed for symptoms of ASD.

Results

As a group, high-risk infants who were later diagnosed with ASD demonstrated elevated phase-lagged alpha-range connectivity as compared to both low-risk infants and high-risk infants who did not go on to ASD. Hyper-connectivity was most prominent over frontal and central areas. The degree of hyper-connectivity at 14 months strongly correlated with the severity of restricted and repetitive behaviors in participants with ASD at 3 years. These effects were not attributable to differences in behavior during the EEG session or to differences in spectral power.

Conclusions

The results suggest that early hyper-connectivity in the alpha frequency range is an important feature of the ASD neurophysiological phenotype.

Electronic supplementary material

The online version of this article (doi:10.1186/1866-1955-6-40) contains supplementary material, which is available to authorized users.     

Prognostic value of EEG performed at term age in preterm infants

Rationale Electroencephalography (EEG) was performed at term age on 32 infants born prematurely (25–32 weeks). EEG was assessed looking for overall background activity and transients.Methods A quantitative analysis was performed, selecting 5-min epochs of tracé alternant free of artefacts during quiet sleep. EEG findings were compared with cranial ultrasound (US) findings at term age and with neurodevelopmental outcome at 2 years (Students t-test).Results The overall EEG background activity was not always related to the outcome or to the severity of cranial US. Infants with normal US and normal outcome had longer synchrony percentage of bursts, longer maximum duration of bursts and shorter mean of abnormal transients per interbursts than children with major lesions and abnormal outcome. Infants with minor lesions, who all had normal outcome, also had better results than those with major lesions and abnormal outcome, but the range of the EEG findings was more variable.Conclusion Our results suggest that the EEG performed at term age does not provide additional prognostic information compared to cranial US.