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Ambulatory EEG (AEEG) devices offer portable, multichannel, digital EEG recording with or without video in the patient's natural environment. The technology applied for AEEG recording is like the technology for routine EEG and inpatient long-term video-EEG monitoring but designed to be compact and wearable. Computer-based AEEG technology is well-suited to digital recording, signal processing, and visual display. However, acquiring interpretable EEG outside of the hospital setting presents its own technical challenges. Published guidelines have established technical standards for performing routine EEG and inpatient video-EEG monitoring, but technical standards for AEEG are lacking. Therefore, this guideline provides minimal technical standards for the performance of AEEG which are essential to ensure the quality of studies for clinical and research practice. We expect these minimum standards to evolve over time with improved performance and advances in the technology.

ObjectivePatients with acute lung or heart failure can experience hypoxic ischemic brain injury resulting in neurovascular unit (NVU) dysfunction. The NVU couples brain activity and perfusion. Extracorporeal membrane oxygenation (ECMO) is used for refractory lung and/or heart failure and often necessitates sedation, obfuscating neurological assessments. We hypothesized that combining cerebral electrographic activity and perfusion monitoring can detect brain injury in adults undergoing ECMO.MethodsFast Fourier transformation was used to identify fast (α+β) and slow (δ) power bands from cEEG. Diffuse correlation spectroscopy (DCS) measured blood flow index (BFI), a surrogate of perfusion, daily in adults undergoing ECMO. Correlations between α+β/δ ratio (ABDR) and BFI were compared between patients who were grouped into brain-injured and uninjured groups by neurologic exam and neuroimaging findings.ResultsTen patients (21-78 years old, five females, five brain-injured) underwent cEEG and DCS monitoring. Sixty-eight monitoring sessions (average 127 minutes/session) were analyzed. ABDR-BFI correlation was significantly higher in uninjured patients than brain-injured ones. Sedation did not significantly impact CBF-power band correlation.ConclusionsBrain-injured patients exhibited significantly less correlation between brain activity and perfusion, possibly as a result of NVU dysfunction.SignificanceABDR-BFI correlation can be measured continuously and noninvasively at the bedside and may represent a marker of NVU dysfunction.HighlightsQuantitative EEG and diffuse correlative spectroscopy can be used to measure markers of brain injury noninvasively, continuously, and at the bedside.Decreased ABDR-BFI correlation may be a marker of neurovascular decoupling in patients with hypoxic ischemic brain injury.ABDR-BFI correlation may be independent of analgosedation, which is used heavily in patients undergoing ECMO.

The Critical Care EEG Monitoring Research Consortium (CCEMRC) is an international research group focusing on critical care EEG and epilepsy. As CCEMRC grew to include 50+ institutions over the past decade, members met to establish research priorities.The authors used an analytical hierarchy process-based research prioritization method, adapted from an approach previously applied to a Department of Defense health-related research program. Forty-six CCEMRC members identified and scored a set of eight clinical problems (CPs) and 15 research topic areas (RTAs) at an annual CCEMRC meeting. Members scored CPs on three criteria using a five-point ordinal scale: Incidence, Impact, and Gap Size; and RTAs on four additional criteria: Niche, Feasibility, Scientific Importance, and Medical Importance, each of which was assigned a weight. The first three RTA criteria were scored using a five-point scale, and CPs were mapped to RTAs using a four-point scale. The Medical Importance score was a weighted average of its mapping scores and the CP score. Finally, a Priority score was calculated for each RTA as a product of the four RTA criteria scores.The CPs with the highest scores were "Altered mental status" and "Long-term neurologic disability after hospital discharge." The RTAs with the highest priority scores were "Development of risk prediction tools," "Multicenter observational studies," and "Outcome prediction."Research prioritization helped CCEMRC evaluate its current research trajectory, identify high-priority near-term research pursuits, and create a roadmap for future research plans aligned with its mission. This approach may be helpful to other academic consortia and research programs.

Asymmetric cerebral perfusion can occur when extracorporeal membrane oxygenation (ECMO) flow competes with native cardiac circulation. It is unclear whether this phenomenon associates with brain injury. Diffuse correlation spectroscopy (DCS) provides continuous, laser-based, non-invasive, bedside monitoring of relative cerebral blood flow (rCBF). This study measured rCBF in ECMO patients via DCS to determine whether comatose patients experience asymmetric cerebral perfusion. Adults receiving ECMO for any indication were prospectively recruited from 12/2019-3/2021. Patients with prior neurologic injury, scalp/facial lacerations, and SARS-CoV-2 infection were excluded. DCS monitoring was performed daily during ECMO support with sensors placed on bilateral foreheads. Mean arterial pressure (MAP) was continuously recorded from the bedside monitor. The Glasgow Coma Scale (GCS) was assessed by clinical staff multiple times daily with sedation pauses, if possible, per standard of care. rCBF was calculated by comparing continuous cerebral blood flow (CBF) measurements to the daily median CBF, then averaged at each MAP value. Daily rCBF asymmetry was calculated by summing the absolute difference of rCBF between the two hemispheres at each MAP value, normalized for the total MAP range experienced by the patient that day. Twelve subjects were enrolled in this study (ages 21-78, 6 with cardiac arrest, 4 with acute heart failure, 2 with ARDS) and grouped by maximum GCS motor (GCS-M) score during ECMO, with 3 “comatose” subjects (GCS-M ≤ 4), and 9 “awake” subjects (GCS-M > 4). DCS was performed over 66 sessions with a mean duration of 131.83 ± 1.13 minutes. Comatose subjects exhibited more rCBF asymmetry than awake subjects (0.28 ± 0.06 mmHg-1 vs. 0.10 ± 0.001 mmHg-1, p=0.045). No difference in asymmetry was noted between patients with or without cardiac arrest. We found that comatose ECMO subjects exhibited higher inter-hemispheric rCBF asymmetry over a range of blood pressures than awake subjects. Though our comatose sample is small, further validation of this finding and its causes, such as cerebrovascular dysregulation, is warranted.

Extracorporeal membrane oxygenation (ECMO) is a mechanical circulatory support method that is associated with a high burden of neurologic injury, but neurologic examination and imaging of this population presents prohibitive medical and logistical challenges. Diffuse correlation spectroscopy (DCS) can measure relative cerebral blood flow (rBF) non-invasively at the bedside. In this study we observed interhemispheric differences in rBF in response to mean arterial pressure (MAP) changes in adult ECMO recipients. Thirteen patients were recruited (ages 21-78, 7 with cardiac arrest, 4 with acute heart failure, 2 with acute respiratory distress syndrome). They were dichotomized via Glasgow Coma Scale Motor score (GCS-M) into comatose (GCS-M ≤ 4; n=4) and non-comatose (GCS-M > 4; n=9) groups. Comatose patients had more interhemispheric rBF asymmetry (ASYMrBF) vs. non-comatose patients over a range of MAP values (29% [IQR 23-34%] vs. 11% [IQR 8-13%], p=0.009). ASYMrBF in comatose patients resolved near a MAP range of 70-80 mm Hg, while rBF remained symmetric through a wider MAP range in non-comatose patients. Associations between post-oxygenator pCO2 or pH vs. ASYMrBF individually did not meet significance, though the linear model slopes were different between comatose and non-comatose subgroups. Here we have demonstrated asymmetric cerebral autoregulation in comatose ECMO patients.

Background and ObjectivesThe utility of the Glasgow Coma Scale (GCS) in intubated patients is limited due to reliance on language function evaluation. The Full Outline of Unresponsiveness (FOUR) Score was designed to circumvent this shortcoming, instead adding evaluations of brainstem reflexes (FOUR B) and specific respiratory patterns (FOUR R). We aimed to determine whether the verbal component of the GCS (GCS V) among nonintubated patients with encephalopathy significantly contributes to mortality prediction and to assess GCS vs FOUR Score performance.MethodsAll prospectively consented patients ≥18 years of age admitted to the Internal Medicine service at Zambia's University Teaching Hospital from October 3, 2017, to May 21, 2018, with a GCS score ≤10 have undergone simultaneous GCS and FOUR Score assessments. The patients were not eligible for mechanical ventilatory support per local standards. Patients' demographics and clinical characteristics were presented as either percentage frequencies or numerical summaries of spread. The predictive power of the GCS without the Verbal component vs total GCS vs FOUR Score on mortality was estimated with the area under the receiver operating characteristic curve (AU ROC).ResultsTwo hundred thirty-five patients (50% women, mean age 47.5 years) were enrolled. All patients were Black. Presumed etiology was CNS infection (64, 27%), stroke (63, 27%), systemic infection (39, 16.6%), and metabolic encephalopathy (3, 14.5%); 14.9% had unknown etiology. In-hospital mortality was 83%. AU ROC for GCS Eye + Motor score (0.662) vs total GCS score (0.641) vs total FOUR Score (0.657) did not differ. Odds ratio mortality for GCS score >6 vs ≤6 was 0.32 (95% confidence interval [CI] 0.14–0.72, p = 0.01); for FOUR Score >10 vs ≤10, it was 0.41 (95% CI 0.19–0.86, p = 0.02).DiscussionAbsence of a verbal component of GCS had no significant impact on the performance of the total GCS, and either GCS or FOUR Score is an acceptable scoring tool for mortality prediction in the resource-limited setting. These findings need further validation in the countries with readily available mechanical ventilatory support.Classification of EvidenceThis study provides Class I evidence that the verbal component of the GCS does not significantly contribute to a total GCS score in mortality prediction among patients with encephalopathy who are not intubated.

Objective During the Covid-19 pandemic, government restrictions limited health care to urgent needs. Neurophysiology centers had to suddenly reschedule their activities, with a lack of specific recommendations about electroencephalography (EEG) execution. During the pandemic phase 1, we launched an online survey to understand the flaws and strengths of the EEG management in Italy at the time of Covid-19 pandemic. Methods A 45-item online survey (published from April 16 to 30, 2020), endorsed by the Italian Society of Clinical Neurophysiology (SINC), the Italian League Against epilepsy (LICE), and the Italian Association of Neurophysiology technologists (AITN), collected EEG management data (EEG’s number and type, indications, personnel and patients safety, devices’ sanification) during the Covid-19 pandemic. Results We received responses from 206 centers. The number of EEGs performed was reduced by 76 ± 20%, and several types of specific EEG (video-EEG, ambulatory-EEG, LTM, polysomnography) were reduced at a minimum. Half of the centers performed inpatient EEGs only for urgencies. Repetitive seizures, encephalitis, and non-convulsive status epilepticus were the most common indications. Covid-19-positive patients received less EEG than negative ones (p

Effects of extracorporeal membrane oxygenation (ECMO) treatment on brain health are currently unknown. For this study, we will noninvasively monitor these patients with diffuse correlation spectroscopy and transcranial doppler ultrasound during ECMO treatment.

Continuous EEG (cEEG) monitoring is primarily used for diagnosing seizures and status epilepticus, and for prognostication after cardiorespiratory arrest. The purpose of this study was to investigate whether cEEG could predict survival and meaningful recovery.The authors reviewed inpatient cEEG reports obtained between January 2013 and November 2015 and recorded demographics, preadmission modified Rankin Scale, history of preexisting epilepsy, Glasgow Coma Scale for those admitted to the intensive care unit, and EEG data (posterior dominant rhythm, reactivity, epileptiform discharges, seizures, and status epilepticus). Associations between clinical outcomes (death vs. survival or clinically meaningful recovery [inpatient rehabilitation, home-based rehabilitation, or home] vs. other [death, skilled nursing facility]) and cEEG findings were assessed with logistic regression models. P0.05 was considered significant.For 218 cEEG reports (197 intensive care unit admits), the presence of at least a unilateral posterior dominant rhythm was associated with survival (odds ratio for death, 0.38; 95% confidence interval, 0.19-0.77; P = 0.01) and with a clinically meaningful outcome (odds ratio, 3.26; 95% confidence interval, 1.79-5.93; P0.001); posterior dominant rhythm remained significant after adjusting for preadmission disability. Those with preexisting epilepsy had better odds of a meaningful recovery (odds ratio, 3.31; 95% CI, 1.34-8.17; P = 0.001). Treated seizures and status epilepticus were not associated with a worse mortality (P = 0.6) or disposition (P = 0.6). High Glasgow Coma Scale (≥12) at intensive care unit admission was associated with a clinically meaningful recovery (odds ratio, 16.40; 95% confidence interval, 1.58-170.19; P = 0.02).Continuous EEG findings can be used to prognosticate survival and functional recovery, and provide guidance in establishing goals of care.

Objective In Western settings, non‐convulsive status epilepticus (NCSE) and non‐convulsive seizures (NCSz) are associated with high mortality. In comatose patients, interictal epileptiform discharges (IEDs) identified on routine electroencephalogram (EEG) are predictive of NCSE/NCS. Little is known regarding the prevalence, causes, or outcomes of NCSE/NCSz in sub‐Saharan Africa (SSA). We sought to investigate the prevalence of IEDs and NCSE/NCSz at a single teaching institution in SSA. Methods From October 3, 2017, to May 21, 2018, adult inpatients on the internal medicine service at Zambia's University Teaching Hospital (UTH) with a Glasgow Coma Score (GCS) of ≤10 were identified, excluding patients with mechanical ventilation or open head wounds. Signed consent by a proxy was required for enrollment and 30‐minute EEG. Chart abstractions provided coma duration, presence/absence of clinical seizures during/prior to admission, history of epilepsy, and presumed coma etiology. A structured neurological examination was completed. Patients were followed to discharge or death. Risk factors for IEDs were evaluated. Results Of 392 eligible patients, 250 had EEGs. EEGs were not completed on eligible patients due to death (74), improved GCS (37), transfer within UTH (25), or lack of proxy (6). NCSE occurred in 22 of 250 (8.8%), NCSz in 3 of 250 (1.2%), and IEDs in 46 of 250 (18.4%) patients. Of the 250, 197 (78.8%) died. No specific risk factors for IEDs were identified. Significance If the association between IEDs and NCSE among monitored populations in developed settings holds true for SSA, a projected 17%‐21% of comatose African adults have NCSE. No clinical characteristics identified those at risk.

This revision to the EEG Guidelines is an update incorporating the current electroencephalography technology and practice. It was previously published as Guideline 2. Similar to the prior guideline, it delineates the aspects of Guideline 1 that should be modified for neonates and young children. Recording conditions for photic stimulation and hyperventilation are revised to enhance the provocation of epileptiform discharges. Revisions recognize the difficulties involved in performing an EEG under sedation in young children. Recommended neonatal EEG montages are displayed for the reduced set of electrodes only since the montages in Guideline 3 should be used for a 21-electrode 10-20 system array. Neonatal documentation is updated to use current American Academy of Pediatrics term "postmenstrual age" rather than "conceptional age." Finally, because therapeutic hypothermia alters the prognostic value of neonatal EEG, the necessity of documenting the patient's temperature at the time of recording is emphasized.

Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary bypass that provides life-saving support to critically ill patients whose illness is progressing despite maximal conventional support. Use in adults is expanding, however neurological injuries are common. Currently, the existing brain imaging tools are a snapshot in time and require high-risk patient transport. Here we assess the feasibility of measuring diffuse correlation spectroscopy, transcranial Doppler ultrasound, electroencephalography, and auditory brainstem responses at the bedside, and developing a cerebral autoregulation metric. We report preliminary results from two patients, demonstrating feasibility and laying the foundation for future studies monitoring neurological health during ECMO.

To describe chronological electrographic features of the interictal EEG background observed in two patients with malignant migrating partial epilepsy in infancy from neonatal to early infantile period.EEGs of two patients who fulfilled diagnostic criteria for malignant migrating partial epilepsy in infancy were acquired over the period of 6 months to monitor treatment efficacy and characterize seizures and other paroxysmal events.Both patients followed a similar sequential pattern. A distinctive evolution from a dysmature term neonatal EEG pattern to an asynchronous suppression burst pattern was observed before the interictal background becoming continuous.Physicians providing care to infants with intractable epilepsy and burst suppression EEG pattern should be alert to the possibility of malignant migrating partial epilepsy in infancy. An earlier diagnosis of malignant migrating partial epilepsy in infancy would help to guide diagnostic workup including genetic testing.

Due to the complex pharmacokinetic profiles of phenytoin (PHT) and fosphenytoin (FOS), achieving sustained, targeted serum PHT levels in the first day of use is challenging.A population based approach was used to analyze total serum PHT (tPHT) level within 2-24h of PHT/FOS loading with or without supplementary maintenance or additional loading doses among PHT-naïve patients in the acute hospital setting. Adequate tPHT serum level was defined as ≥20μg/mL.Among 494 patients with 545 tPHT serum levels obtained in the first 2-24h after the loading dose (LD), tPHT serum levels of eitheror≥20μg/mL were observed along wide and overlapping cumulative dose ranges. Among those receiving 15-20mg/kg and 20-55mg/kg weight-based loading dose, 63% and 51% respectively did not attain tPHT serum level of ≥20μg/mL even within the first 6h of treatment. For the 393 available concomitant free and total serum PHT levels, correlation was weak, r=0.36.Close laboratory surveillance and PHT/FOS dose adjustments are recommended to ensure adequate and sustained tPHT serum levels early in treatment. Free serum PHT level is the preferred method of drug monitoring.

Diphenhydramine (DPH) acts on peripheral and central histamine H1 receptors, causing reduction of allergic symptoms and sedation, respectively.1 It is also a potent competitive antagonist of muscarinic acetylcholine receptors and can cause sinus tachycardia, xerostomia, mydriasis, blurred vision, ileus, urinary retention, CNS depression, agitation, hyperactivity, or psychosis. Given multiple potential mechanisms of action and its use for a variety of conditions, cases of medication misuse and abuse have been reported,2–5 primarily due to behavioral effects such as elevated mood, increased energy levels, and mild euphoria.6

A 77-year-old neurologically intact woman presented in hypertensive crisis (blood pressure [BP] 220/110 mm Hg) resulting in pulmonary edema. The patient had a history of remote (over 40 years) repaired aortic coarctation, breast cancer in remission, hypertension managed with 6 antihypertensive medications, and allergy to iodinated contrast. Her BP was reduced to as low as 134/26 mm Hg. Subsequently she developed acute paraplegia. Examination revealed nonlocalizing lower back and abdominal pain. Tibial pulses were absent, but extremities remained warm to touch. On neurologic examination, the abnormal findings were present only in the lower extremities, which were both flaccid with 0/5 strength and 0/4 deep tendon reflexes. Plantar responses were mute. Sensory perception to all primary sensory modalities was absent with a sensory level to pinprick at L1 dermatome. She was unable to generate rectal sphincter tone. Bladder dysfunction could not be assessed due to Foley catheter in place.