The Prognostic Value of 48-h Continuous EEG During Therapeutic Hypothermia After Cardiac Arrest

Background

The aim of this study was to evaluate the prognostic value of continuous electroencephalogram (cEEG) during the first 48 h following cardiac arrest (CA) in patients treated with targeted temperature management (TTM).

Methods

We reviewed data from 92 comatose post-CA patients over a 6 year-period; cEEG recordings were performed during TTM and restoration of normothermia. EEG findings were divided into four time-periods: 0–8, 8–16, 16–24, and 24–48 h after CA. Background EEG findings were defined as moderate encephalopathy (diffuse slowing with reactivity/variability), severe encephalopathy (diffuse slowing without reactivity/variability), burst suppression or suppression, and dichotomized as malignant (suppression/burst suppression/severe encephalopathy) or benign (moderate encephalopathy). Epileptiform activity was defined as the presence of seizures, sporadic epileptiform discharges, or periodic discharges. Neurological outcome was assessed at 3 months using the cerebral performance categories (CPC) score (good outcome: CPC 1–2).

Results

26/92 (28 %) patients had a good outcome. Malignant patterns were associated with a poor outcome at all time-points, with a high positive predictive value (94–97 %) but a poor negative predictive value (44–56 %). Epileptiform activity did not influence the prognostic value of EEG patterns. All patients with moderate encephalopathy and seizures or generalized periodic discharges had a poor outcome.

Conclusions

cEEG can identify patients with poor outcome from the first hours following CA, with limited predictive value for good outcome. Epileptiform activity did not improve the prognostic accuracy of EEG, but seizures and generalized periodic discharges were associated with poor outcome even when developing on a benign EEG pattern.

     

Electroencephalography in pediatric moyamoya disease: reappraisal of clinical value

Purpose

The clinical value of electroencephalography (EEG) in pediatric moyamoya disease has been underestimated, though the characteristic patterns are well known. We undertook this study to evaluate the clinical value of EEG as a diagnostic and postoperative follow-up modality in pediatric moyamoya disease.

Methods

We retrospectively reviewed the pre and postoperative EEG with effective hyperventilation in 127 pediatric moyamoya patients and compared their patterns with hemodynamic images.

Results

One hundred and two patients (80.3 %) among 127 showed abnormal EEG findings before revascularization surgery. The typical rebuild-up phenomenon was observed in 82 (64.6 %) and localized build-up in 32 (25.2 %) without any significant clinical ischemic events during and after hyperventilation. The rebuild-up was observed more frequently in younger age groups (less than 13 years) and Suzuki stages III. The location of the rebuild-up distribution and asymmetric build-up was consistent with the area showing hemodynamic abnormalities on single photon emission computed tomography and/or perfusion magnetic resonance imaging. Postoperative follow-up EEGs were performed in 41 patients. Six patients with remaining rebuild-up in postoperative follow-up EEG showed poorer postoperative clinical outcomes.

Conclusions

This study may reappraise EEG as an easy, safe, and adjunctive diagnostic and postoperative follow-up modality for evaluation of hemodynamic status and clinical outcome, especially in children with moyamoya disease.     

Intracortical EEG for the Detection of Vasospasm in Patients with Poor-Grade Subarachnoid Hemorrhage

Background

To study the feasibility of utilizing intracortical electroencephalography (ICE) including quantitative EEG (qEEG) analysis for the detection of vasospasm in five consecutive poor-grade SAH patients.

Methods

Intracortical electroencephalography (ICE) was obtained via a single miniature parenchymal 8-contact depth electrode placed at the bedside. Quantitative EEG parameters, calculated on surface EEG and ICE, included alpha/delta ratio (ADR), mean amplitude, suppression percent, and total power. Percent changes between averaged values over 4–6 h of baseline EEG and EEG prior to angiography were calculated. The entire continuous qEEG recording for each patient was then reviewed to determine optimal automated alarm criteria.

Results

ICE ADR was the most accurate for predicting angiographic vasospasm (5/5). ICE ADR decreased between baseline and follow-up by 42% (from 0.56 ± 0.07 to 0.32 ± 0.03) for those with vasospasm (N = 3) compared to 17% (0.62 ± 0.06 to 0.51 ± 0.03) for those without (N = 2). A sustained decrease in the ICE ADR from baseline (>25% for ≥4 h) occurred in all three patients with angiographically confirmed vasospasm and not in the two without; this decline occurred 1–3 days prior to angiographic confirmation.

Conclusions

Intracortical EEG is promising for detecting ischemia from vasospasm in poor-grade SAH patients, may be superior to scalp EEG, and allow automated detection, particularly using the ADR. Larger studies are needed to better define the effectiveness of this approach.     

Clinical Outcome After a Reactive Hypothermic EEG Following Cardiac Arrest

Background

Reactive electroencephalography (EEG) background during therapeutic hypothermia (TH) is related to favorable prognosis after cardiac arrest (CA), but its predictive value is not 100 %. The aim of this study was to investigate outcome predictors after a first reactive EEG recorded during TH after CA.

Methods

We studied a cohort of consecutive comatose adults admitted between February 2008 and November 2012, after successful resuscitation from CA, selecting patients with reactive EEG during TH. Outcome was assessed at three months, and categorized as survivors and non-survivors (no patient was in vegetative state). Demographics, clinical variables, EEG features, serum neuron-specific enolase (NSE) and procalcitonin, were compared using uni- and multivariable analyses.

Results

A total of 290 patients were treated with TH after cardiac arrest; 146 had an EEG during TH, which proved reactive in 90 of them; 77 (86 %) survived and 13 (14 %) died (without recovery from coma). The group of non-survivors had a higher occurrence of discontinuous EEG (p = 0.006; multivariate analysis p = 0.026), and a higher serum NSE peak (p = 0.021; multivariate analysis p = 0.014); conversely, demographics, and other clinical variables including serum procalcitonin did not differ.

Conclusions

A discontinuous EEG and high serum NSE are associated with mortality after CA in patients with poor outcome despite a reactive hypothermic EEG. This suggests more severe cerebral damage, but not to higher extent of systemic disease.     

High Risk for Seizures Following Subarachnoid Hemorrhage Regardless of Referral Bias

Background

To investigate the frequency, predictors, and clinical impact of electrographic seizures in patients with high clinical or radiologic grade non-traumatic subarachnoid hemorrhage (SAH), independent of referral bias.

Methods

We compared rates of electrographic seizures and associated clinical variables and outcomes in patients with high clinical or radiologic grade non-traumatic SAH. Rates of electrographic seizure detection before and after institution of a guideline which made continuous EEG monitoring routine in this population were compared.

Results

Electrographic seizures occurred in 17.6 % of patients monitored expressly because of clinically suspected subclinical seizures. In unselected patients, seizures still occurred in 9.6 % of all cases, and in 8.6 % of cases in which there was no a priori suspicion of seizures. The first seizure detected occurred 5.4 (IQR 2.9–7.3) days after onset of subarachnoid hemorrhage with three of eight patients (37.5 %) having the first recorded seizure more than 48 h following EEG initiation, and 2/8 (25 %) at more than 72 h following EEG initiation. High clinical grade was associated with poor outcome at time of hospital discharge; electrographic seizures were not associated with poor outcome.

Conclusions

Electrographic seizures occur at a relatively high rate in patients with non-traumatic SAH even after accounting for referral bias. The prolonged time to the first detected seizure in this cohort may reflect dynamic clinical features unique to the SAH population.     

Aktivierung epileptischer Aktivit?t durch Etomidat?

Objective

Pharmacological activation of focal epileptic discharges is employed during presurgical evaluation to increase the yield of epileptic activity. Administration of etomidate has been shown to increase focal epileptic activity recorded by foramen ovale electrodes and by magnetoencephalography (MEG). However, results from simultaneous MEG and electroencephalography (MEG/EEG) recordings suggest that sensitivity of surface EEG for epileptic spikes might be diminished due to generalized theta/delta activity caused by etomidate. This project aimed to show differences between epilepsy patients and a control group with respect to clinical and EEG changes after administration of etomidate.

Methods

A total of 11 patients with focal epilepsy underwent activation with etomidate with simultaneous video EEG monitoring during presurgical evaluation. In addition activation with etomidate was performed in a control group of four patients without epilepsy under surveillance with simultaneous video EEG monitoring during anesthetization for spinal surgery.

Results

All patients except three epilepsy patients became unconscious after administration of etomidate. Motor symptoms of the eyes, the face and the limbs unrelated to the semiology of their habitual seizures occurred in the epilepsy patients. No clinical symptoms beyond sedation were observed in patients of the control group. In epilepsy patients no epileptic activity was recorded after injection of etomidate, however, generalized delta/theta activity occurred in all epilepsy patients several seconds after injection similar to patients in the control group.

Conclusion

General anesthesia with etomidate is a safe procedure. In contrast to epilepsy patients, patients in the control group did not show any clinical symptoms. However, in this study no epileptic activity could be recorded with surface EEG after administration of etomidate. These results were in contrast to prior invasive EEG and MEG studies. Future studies should evaluate the differences in recordings from surface EEG, MEG and invasive EEG using etomidate activation.     

Combination of Clinical Exam,MRI and EEG to Predict Outcome Following Cardiac Arrest and Targeted Temperature Management

Background

Despite the widespread adoption of targeted temperature management (TTM), coma after cardiac arrest remains a common problem with a high proportion of patients suffering substantial disability. Prognostication after cardiac arrest, particularly the identification of patients with likely good outcome, remains difficult.

Methods

We performed a retrospective study of 78 patients who underwent TTM after cardiac arrest and were evaluated with both electroencephalography (EEG) and magnetic resonance imaging (MRI). We hypothesized that combining malignant versus non-malignant EEG classification with clinical exam and quantitative analysis of apparent diffusion coefficient (ADC) and fluid-attenuated inversion recovery imaging would improve prognostic ability.

Results

Consistent with prior literature, presence of a malignant EEG pattern was 100% specific for poor outcome. We found that decreased whole brain ADC signal intensity was associated with poor outcome (853?±?14 vs. 950?±?17.5 mm²/s, p?<?0.0001). Less than 15% total brain volume with ADC signal intensity <?650 mm²/s was predictive of good outcome with 100% sensitivity, 51% specificity and an area under the curve of 0.787. A model combining this ADC marker with non-malignant EEG and flexor-or-better motor response was 100% sensitive and 91.1% specific for good outcome following cardiac arrest and targeted temperature management.

Conclusion

We conclude that in the absence of malignant EEG findings, combination of physical exam and MRI findings can be a useful to identify those patients who have potential for recovery. Variability in timing of imaging and findings in different modalities argue for the need for future prospective studies of multimodal outcome prediction after cardiac arrest.

     

Successful Wean Despite Emergence of Ictal–Interictal EEG Patterns During the Weaning of Prolonged Burst-Suppression Therapy for Super-Refractory Status Epilepticus

Background

Management of refractory status epilepticus (SE) commonly involves the induction of burst suppression using intravenous anesthetic agents. However, the endpoints of these therapies are not well defined. Weaning anesthetic agents are complicated by the emergence of electroencephalogram (EEG) patterns along the ictal–interictal continuum (IIC), which have uncertain significance given that IIC patterns may worsen cerebral metabolism and oxygenation, have a dissociation between scalp and depth EEG recordings, or may indicate a late stage of SE itself. Determining the significance of IIC patterns in the unique context of anesthetic weaning is important to prevent the potential for unnecessarily prolonging anesthetic coma.

Methods

Among 118 individuals with SE, we retrospectively identified a series of patients who underwent at least 24 h of burst-suppression therapy, experienced two or more weaning trials, and developed IIC patterns during anesthetic weaning. Anesthetic titration strategies during the emergence of these patterns were examined.

Results

Each of the six individuals who met inclusion criteria experienced aggressive weaning despite the emergence of IIC patterns. The IIC patterns that were encountered during anesthetic weaning (including generalized and lateralized periodic discharges) are described in detail. Favorable outcomes were reported in each subject.

Conclusion

IIC patterns encountered during anesthetic weaning may be transitional and warrant observation, allowing for the emergence of more definitive clinical or electrographic results. The metabolic impact of these IIC patterns on brain activity is uncertain, but weaning strategies that treat IIC as a surrogate of recurrent SE risk further prolonging anesthetic management and its known toxicity. We speculate that these patterns may have a context-specific association with SE relapse, with less-risk conferred when these patterns are observed during the weaning of anesthetic agents after prolonged burst-suppression therapy. Other electrographic features aside from this clinical context may discriminate the risk of SE relapse, such as EEG background activity.

     

Periodic complexes and alternating rotatory nystagmus with cyclic pupillary changes

A 69-year-old male, with a history of a previous subdural hematoma, multistroke dementia and ventricular shunting for hydrocephalus, exhibited while comatose isolated periodic alternating rotatory nystagmus with cyclic pupillary changes and periodic alternating gaze. His simultaneous EEG showed PLEDs and subsequently burst-suppression pattern. The latter abnormality was associated, in addition, to transient eyelid opening, synchronized with the EEG bursts. Complex neuro-ophthalmologic clinical signs, sometimes subtle, may be the sole manifestation of EEG periodic complexes that have potential prognostic and therapeutic implications.     

Prevalence of resistant occipital lobe epilepsy associated with celiac disease in children

Purpose

Celiac disease (CD) is a chronic, inflammatory autoimmune disorder caused by intolerance to ingested gluten. Increased frequency of CD has been reported in occipital lobe epilepsy. The aim of the present study is to investigate the frequency of CD among children followed up due to epilepsy and diagnosed with epileptic activity in the occipital lobe in at least one electroencephalography (EEG) test.

Methods

For this research, 90 pediatric epilepsy patients with epileptic activity in the occipital lobe were enrolled in the study group, while the control group comprised of 100 healthy children. In addition to the EEG examination, tissue transglutaminase (tTG) antibody was determined on duodenal biopsy.

Results

None of the healthy children in the control group was positive in terms of the tTG antibody test used to scan CD. In the group with epileptic activity in the occipital lobe, two patients out of 90 were tTG antibody positive. The seroprevalence was 1/45 (2.22 %) in this group. These two patients were diagnosed with CD based on the endoscopic duodenal biopsy. In these patients, the seizures were uncontrollable through monotherapy.

Conclusions

Our results showed that the prevalence of CD is observed to be higher than the normal population among the patients with occipital lobe epilepsy. This type of seizure disorder seems to be more resistant to monotherapy, compared with other types of occipital epilepsy. Therefore, screening for CD is recommended in children with resistant epileptic activity in the occipital lobe.     

Electrooculogram and submandibular montage to distinguish different eye,eyelid, and tongue movements in electroencephalographic studies

Objective

We propose an electrooculogram and submandibular montage that helps to discriminate eye/eyelid/tongue movements and to differentiate them from epileptiform activity or slowing on electroencephalography (EEG).

Comparative role of neuropsychological testing in the presurgical evaluation of children with medically intractable epilepsies

Purpose

In the present study, we evaluated the preoperative demographic, clinical, and neuropsychological variables that could predict postoperative seizure outcome in a group of pediatric epileptic patients.

Materials and methods

We studied 40 consecutive pediatric patients, ages ranging from 6 to 16 years, that underwent resective surgery for the treatment of medically intractable epilepsy at the Clinical Hospital of Ribeirão Preto School of Medicine. We performed ictal electroencephalography (EEG), interictal EEG, magnetic resonance imaging (MRI), and a preoperative neuropsychological assessment in the presurgical workup.

Results

The following factors were correlated with seizure outcome: (1) duration of epilepsy, (2) surgery localization, (3) localized Neuropsychological (NPS) Evaluation, (4) ictal EEG, (5) interictal EEG, and (6) MRI. Mental retardation, NPS tests, and the other demographic variables failed to correlate with seizure reduction.

Conclusions

The identification of predictor variables of epilepsy surgery outcome could improve the epileptic prognosis and guarantee the children's full potential development.

     

Delayed Deterioration of EEG Background Rhythm Post-cardiac Arrest

Background

Electroencephalogram (EEG) background continuity is associated with a favorable prognosis in cardiac arrest patients post-therapeutic hypothermia. However, the continuous EEG in a subset of patients will undergo ‘delayed EEG deterioration’; they will invariably have poor outcome. The aim of this study was to characterize this phenomenon.

Methods

We studied a prospectively collected cohort of consecutive cardiac arrest patients who underwent therapeutic hypothermia between July 2012 and May 2015. We identified patients with an initially favorable EEG rhythm post-cooling and characterized a subset of patients with delayed EEG deterioration.

Results

A total of 133 patients were included in the analysis. Of these, 69/133 (51.9%) had an initially favorable EEG. Of those patients with initially favorable EEG, 7/69 (10.1%) had a subsequent deterioration. Delayed EEG deterioration was associated with poor outcome. The median time to deterioration was 55 h.

Conclusions

Delayed EEG deterioration is associated with poor clinical outcomes. We hypothesize that this is the result of delayed neuronal degeneration, the exact mechanism requiring further exploration. Identifying patients with delayed EEG deterioration post-therapeutic hypothermia is paramount as further interventions may yet salvage their outcomes, though further study is needed.

     

Frequency of Non-convulsive Seizures and Non-convulsive Status Epilepticus in Subarachnoid Hemorrhage Patients in Need of Controlled Ventilation and Sedation

Background

Non-convulsive seizures (NCSZ) can be more prevalent than previously recognized among comatose neuro-intensive care patients. The aim of this study was to evaluate the frequency of NCSZ and non-convulsive status epilepticus (NCSE) in sedated and ventilated subarachnoid hemorrhage (SAH) patients.

Methods

Retrospective study at a university hospital neuro-intensive care unit, from January 2008 until June 2010. Patients were treated according to a local protocol, and were initially sedated with midazolam or propofol or combinations of these sedative agents. Thiopental was added for treatment of intracranial hypertension. No wake-up tests were performed. Using NicoletOne^? equipment (VIASYS Healthcare Inc., USA), continuous EEG recordings based on four electrodes and a reference electrode was inspected at full length both in a two electrode bipolar and a four-channel referential montage.

Results

Approximately 5,500?h of continuous EEG were registered in 28 SAH patients (33?% of the patients eligible for inclusion). The median Glasgow Coma scale was 8 (range 3?C14) and the median Hunt and Hess score was 4 (range 1?C4). During EEG registration, no clinical seizures were observed. In none of the patients inter ictal epileptiform activity was seen. EEG seizures were recorded only in 2/28 (7?%) patients. One of the patients experienced 4?min of an NCSZ and one had a 5?h episode of an NCSE.

Conclusion

Continuous EEG monitoring is important in detecting NCSZ in sedated patients. Continuous sedation, without wake-up tests, was associated with a low frequency of subclinical seizures in SAH patients in need of controlled ventilation.     

Pediatric temporal low-grade glial tumors: epilepsy outcome following resection in 48 children

Purpose

This paper summarizes our experience with surgical treatment of pediatric low-grade glial temporal lobe tumors focusing on the long-term outcome of seizures and identifying factors associated with seizure control and failure.

Methods

We reviewed all medical records of pediatric patients that underwent temporal lobe surgery due to seizures at our institution between 1997 and 2009. Only patients with temporal lobe tumors were included in this series. The files were retrospectively reviewed for seizure history. All children had undergone pre- and postoperative evaluation, neurological examination, EEG, and MRI.

Results

The cohort includes 48 children with mean follow-up time of 5.15?years (1?C12?years). The mean age at surgery was 8.2?years (1?C18.1) and the mean seizure duration until surgery was 2.6?years. All lesions in the cohort were low-grade tumors; pilocytic astrocytoma was the most common (41%). Eighty-three percent of the patients were classified as Engel class I following surgery. There was no correlation between Engel score and the preoperative epilepsy duration, age of seizure onset or type of seizures, and pathology. The surgical complication rate was 4.1% (2/48).

Conclusions

Surgical treatment for seizure control in children and adolescents with low-grade temporal tumors provides excellent long-term results.     

Electro-Radiological Observations of Grade III/IV Hepatic Encephalopathy Patients with Seizures

Background

Neurological complications in liver failure are common. Often under-recognized neurological complications are seizures and status epilepticus. These may go unrecognized without continuous electroencephalography (CEEG). We highlight the observed electro-radiological changes in patients with grade III/IV hepatic encephalopathy (HE) found to have seizures and/or status epilepticus on CEEG and the associated neuroimaging.

Methods

This study was a retrospective review of patients with West Haven grade III/IV HE and seizures/status epilepticus on CEEG.

Results

Eleven patients were included. Alcohol was the most common cause of HE (54.5%). All patients were either stuporous/comatose. The most common CEEG pattern was diffuse slowing (100%) followed by generalized periodic discharges (GPDs; 36.4%) and lateralized periodic discharges (LPDs, 36.4%). The subtype of GPDs with triphasic morphology was only seen in 27.3%. All seizures and/or status epilepticus were without clinical signs. Magnetic resonance imaging (MRI) was available in six patients. Cortical hyperintensities on diffusion weighted imaging sequence were seen in all six patients. One patient had CEEG seizure concomitantly with the MRI. Seven patients died prior to discharge.

Conclusion

Seizures or status epilepticus in the setting of HE were without clinical findings and could go unrecognized without CEEG. The finding of cortical hyperintensity on MRI should lead to further evaluation for unrecognized seizure or status epilepticus.

     

Redefining periodic patterns on electroencephalograms of patients with sporadic Creutzfeldt–Jakob disease

Objective

We aimed to redefine various periodic patterns (PPs) observed on electroencephalography (EEG) in patients with sporadic Creutzfeldt–Jakob disease (sCJD) using the American Clinical Neurophysiology Society’s (ACNS) Criteria.

Different seizure-onset patterns in mesiotemporal lobe epilepsy have a distinct interictal signature

Objective

Experimental research demonstrated that distinct underlying mechanisms go along with different seizure-onset patterns on EEG. These different mechanisms may reflect different tissue abnormalities which, we hypothesize, could also be reflected in morphological differences in the interictal epileptic and background EEG activity.

Rapid Bedside Evaluation of Seizures in the ICU by Listening to the Sound of Brainwaves: A Prospective Observational Clinical Trial of Ceribell’s Brain Stethoscope Function

Background

Patients suffering from non-convulsive seizures experience delays in diagnosis and treatment due to limitations in acquiring and interpreting electroencephalography (EEG) data. The Ceribell EEG System offers rapid EEG acquisition and conversion of EEG signals to sound (sonification) using a proprietary algorithm. This study was designed to test the performance of this EEG system in an intensive care unit (ICU) setting and measure its impact on clinician treatment decision.

Methods

Encephalopathic ICU patients at Stanford University Hospital were enrolled if clinical suspicion for seizures warranted EEG monitoring. Treating physicians rated suspicion for seizure and decided if the patient needed antiepileptic drug (AED) treatment at the time of bedside evaluation. After listening to 30 s of EEG from each hemisphere in each patient, they reevaluated their suspicion for seizure and decision for additional treatment. The EEG waveforms recorded with Ceribell EEG were subsequently analyzed by three blinded epileptologists to assess the presence or absence of seizures within and outside the sonification window. Study outcomes were EEG set up time, ease of use of the device, change in clinician seizure suspicion, and change in decision to treat with AED before and after sonification.

Results

Thirty-five cases of EEG sonification were performed. Mean EEG setup time was 6?±?3 min, and time to obtain sonified EEG was significantly faster than conventional EEG (p?<?0.001). One patient had non-convulsive seizure during sonification and another had rhythmic activity that was followed by seizure shortly after sonification. Change in treatment decision after sonification occurred in approximately 40% of patients and resulted in a significant net reduction in unnecessary additional treatments (p?=?0.01). Ceribell EEG System was consistently rated easy to use.

Conclusion

The Ceribell EEG System enabled rapid acquisition of EEG in patients at risk for non-convulsive seizures and aided clinicians in their evaluation of encephalopathic ICU patients. The ease of use and speed of EEG acquisition and interpretation by EEG-untrained individuals has the potential to improve emergent clinical decision making by quickly detecting non-convulsive seizures in the ICU.