Publications by authors named "Peter W Kaplan"

180 Publications

Neurophysiological and Neuroimaging Modalities in Acute and Subacute Disorders of Consciousness.

J Clin Neurophysiol 2021 Aug 30. Epub 2021 Aug 30.

Department of Pediatrics, United Arab Emirates University, Al Ain, United Arab Emirates Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A. State University of New York at Buffalo, Buffalo, New York, U.S.A. EEG and Epilepsy, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.

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http://dx.doi.org/10.1097/WNP.0000000000000816DOI Listing
August 2021

Prediction of Postictal Delirium Following Status Epilepticus in the ICU: First Insights of an Observational Cohort Study.

Crit Care Med 2021 Jul 13. Epub 2021 Jul 13.

Department of Intensive Care Medicine, University Hospital Basel, Basel, Switzerland. Department of Medical Communication and Psychosomatic Medicine, University Hospital Basel, Basel, Switzerland. Medical Faculty of the University of Basel, Basel, Switzerland. Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD. Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD. Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, MD. Department of Neurology, University Hospital Basel, Basel, Switzerland.

Objectives: To identify early predictors of postictal delirium in adult patients after termination of status epilepticus.

Design: Retrospective study.

Setting: ICUs at a Swiss tertiary academic medical center.

Patients: Status epilepticus patients treated on the ICUs for longer than 24 hours from 2012 to 2018.

Interventions: None.

Methods: Primary outcome was postictal delirium during post-status epilepticus treatment defined as an Intensive Care Delirium Screening Checklist greater than or equal to 4. Associations with postictal delirium were secondary outcomes. A time-dependent multivariable Cox proportional hazards model was used to identify risks of postictal delirium. It included variables that differed between patients with and without delirium and established risk factors for delirium (age, sex, number of inserted catheters, illness severity [quantified by the Sequential Organ Failure Assessment and Status Epilepticus Severity Score], neurodegenerative disease, dementia, alcohol/drug consumption, infections, coma during status epilepticus, dose of benzodiazepines, anesthetics, and mechanical ventilation).

Measurements And Main Results: Among 224 patients, post-status epilepticus Intensive Care Delirium Screening Checklist was increased in 83% with delirium emerging in 55% with a median duration of 2 days (interquartile range 1-3 d). Among all variables, only the history of alcohol and/or drug consumption was associated with increased hazards for delirium in multivariable analyses (hazard ratio = 3.35; 95% CI, 1.53-7.33).

Conclusions: Our study provides first exploratory insights into the risks of postictal delirium in adult status epilepticus patients treated in the ICU. Delirium following status epilepticus is frequent, lasting mostly 2-3 days. Our findings that with the exception of a history of alcohol and/or drug consumption, other risk factors of delirium were not found to be associated with a risk of postictal delirium may be related to the limited sample size and the exploratory nature of our study. Further investigations are needed to investigate the role of established risk factors in other status epilepticus cohorts. In the meantime, our results indicate that the risk of delirium should be especially considered in patients with a history of alcohol and/or drug consumption.
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http://dx.doi.org/10.1097/CCM.0000000000005212DOI Listing
July 2021

Atypical or Typical Triphasic Waves-Is There a Difference? A Review.

J Clin Neurophysiol 2021 Sep;38(5):384-398

Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.

Summary: The entity of triphasic waves (TWs) and TW encephalopathy has derived from the subjective art of EEG interpretation. Indeed, there are few if any guidelines regarding many different aspects of TWs. The authors seek to shed light on the nature and the diagnostic characteristics of various types of TWs, differentiating "typical" from "atypical" forms. The authors conclude that morphologies in the form of bursts of well-formed, smoothly contoured, negative-positive-negative, bilateral, symmetrical and synchronous, regular, reactive, periodic or rhythmic, 1.5 to 2.0 Hz, fronto-central, triphasic complexes with fronto-occipital lag meet the criteria for typical TWs and are highly suggestive of toxic-metabolic encephalopathies. These are most frequently hepatic, uremic, or sepsis-associated encephalopathies with multi-organ failure. In such cases, atypical TWs (frontopolar or parieto-occipital maximum, negative-positive or negative-positive-negative, asymmetric and asynchronous, unreactive, irregular, multifocal, continuous with spatiotemporal evolution, sharper and without fronto-occipital/occipito-frontal lag, or triphasic delta waves) are rarely seen. Atypical TWs are encountered in Angelman syndrome, toxic encephalopathies, hyperthyroidism/hypothyroidism, Hashimoto encephalopathy, nonconvulsive status epilepticus, dementia, sepsis-associated encephalopathy, cerebrovascular disorders, and certain boundary syndromes. Investigations describing TWs with uncommon etiologies revealed few with typical TWs, suggesting that the term "TWs" has been overused in the past. Triphasic waves arise from the interaction of multiple factors including toxic, metabolic, infectious, and structural disorders that affect circuits between thalamus and cortex. The patient's metabolic status, presence of potentially neurotoxic drugs, cerebral atrophy, white matter disease, dementia, or seizures help differentiate typical from typical TWs. Future studies will determine whether this dichotomy is heuristically and clinically helpful.
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http://dx.doi.org/10.1097/WNP.0000000000000731DOI Listing
September 2021

Editorial on Triphasic Waves.

Authors:
Peter W Kaplan

J Clin Neurophysiol 2021 Sep;38(5):347

Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.

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http://dx.doi.org/10.1097/WNP.0000000000000755DOI Listing
September 2021

Triphasic Waves: Historical Overview of an Unresolved Mystery.

J Clin Neurophysiol 2021 Sep;38(5):399-409

Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.

Summary: Triphasic waves are a fascinating and mysterious EEG feature. We now have to accept that, at times, epileptiform discharges may have a blunted "triphasic morphology," and that there may be great difficulty in distinguishing between these often similar forms. The aim of this review was to describe the evolution in our understanding of triphasic waves that has occurred regarding the pathophysiology of triphasic waves, their most frequent causes, and the diagnostic difficulties involved in interpretation and differentiation from nonconvulsive status epilepticus.
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http://dx.doi.org/10.1097/WNP.0000000000000809DOI Listing
September 2021

White Matter Disease-The True Source of Triphasic Waves?

J Clin Neurophysiol 2021 Sep;38(5):359-361

Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.; and.

Summary: Triphasic waves are EEG phenomena typically seen in patients with acute encephalopathy and have importance in diagnosis and prognosis in these cases. The underlying metabolic disturbances associated with their incidence have been described previously, but neuroimaging characteristics are not well delineated. There are a few small studies that define neuroimaging results in patients with triphasic waves. This review highlights the most common neuroimaging findings in these patients, including subcortical white matter disease, which itself may be a risk factor for triphasic waves.
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http://dx.doi.org/10.1097/WNP.0000000000000745DOI Listing
September 2021

An EEG Voyage in Search of Triphasic Waves-The Sirens and Corsairs on the Encephalopathy/EEG Horizon: A Survey of Triphasic Waves.

J Clin Neurophysiol 2021 Sep;38(5):348-358

Intensive Care Units and Department of Neurology, University Hospital Basel, Basel, Switzerland; and.

Summary: Generalized periodic discharges with triphasic wave (TW) morphology, long referred to as TWs, are typical of many toxic, metabolic, infectious, and cerebral structural problems, often in concert. Identifying TWs has been challenging for the electroencephalographer and clinician, as has been their cause, significance, prognosis, and treatment. This review highlights the many different patterns of TWs with commentary on their various causes and etiologies, characteristics, different morbidities, differentiation from nonconvulsive status epilepticus, and their prognosis. The articles in this Journal of Clinical Neurophysiology special issue on TWs will review the many challenges the clinician face when TWs are sighted.
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http://dx.doi.org/10.1097/WNP.0000000000000725DOI Listing
September 2021

Stimulus-Induced Rhythmic or Periodic Intermittent Discharges (SIRPIDs) in patients with triphasic waves and Creutzfeldt-Jakob disease.

Clin Neurophysiol 2021 Aug 20;132(8):1757-1769. Epub 2021 May 20.

Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

Since the term Stimulus-Induced Rhythmic, Periodic, or Ictal Discharges (SIRPIDs) was introduced into the vocabulary of electrophysiologists/neurologists, there has been an ongoing debate about its significance, as well as its correlation with outcomes. SIRPIDs are frequently seen in patients who are critically ill from various causes. The literature reflects the findings of triphasic morphology, with the generalized periodic discharge (GPD) classification in many patients with SIRPIDs: toxic/metabolic encephalopathies, septic, and hypoxemic/hypercapnic encephalopathies, but also sharp periodic complexes in Creutzfeldt-Jakob disease and advanced Alzheimer's disease. In these settings, GPDs disappear when patients fall asleep and reappear when patients spontaneously wake up, or are awoken by an external stimulus, or sometimes because of a respiratory event, with the possibility of the appearance of GPDs with a cyclic alternating pattern. SIRPIDs may be seen as a transitional pattern between sleep and waking states, corresponding to a postarousal/awakening phenomenon. As SIRPIDs are a transient phenomenon and can usually be recorded repeatedly with each stimulation, the word "Ictal" could be replaced by "Intermittent": Stimulus-Induced Rhythmic or Periodic Intermittent Discharges. However, considering that SIRPIDs may be "potentially ictal" or on an "ictal-interictal continuum" in some situations, the "plus" modifier may be added: SIRPIDs-plus.
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http://dx.doi.org/10.1016/j.clinph.2021.05.002DOI Listing
August 2021

Practice Guideline: Use of Quantitative EEG for the Diagnosis of Mild Traumatic Brain Injury: Report of the Guideline Committee of the American Clinical Neurophysiology Society.

J Clin Neurophysiol 2021 07;38(4):287-292

Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A.; and.

Summary: Despite many decades of research, controversy regarding the utility of quantitative EEG (qEEG) for the accurate diagnosis of mild traumatic brain injury (mTBI) remains. This guideline is meant to assist clinicians by providing an expert review of the clinical usefulness of qEEG techniques for the diagnosis of mTBI. This guideline addresses the following primary aim: For patients with or without posttraumatic symptoms (abnormal cognition or behavior), does qEEG either at the time of injury or remote from the injury, as compared with current clinical diagnostic criteria, accurately identify those patients with mTBI (i.e., concussion)? Secondary aims included differentiating between mTBI and other diagnoses, detecting mTBI in the presence of central nervous system medications, and pertinence of statistical methods for measurements of qEEG components. It was found that for patients with or without symptoms of abnormal cognition or behavior, current evidence does not support the clinical use of qEEG either at the time of the injury or remote from the injury to diagnose mTBI (level U). In addition, the evidence does not support the use of qEEG to differentiate mTBI from other diagnoses or detect mTBI in the presence of central nervous system medications, and suitable statistical methods do not exist when using qEEG to identify patients with mTBI. Based upon the current literature review, qEEG remains an investigational tool for mTBI diagnosis (class III evidence).
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http://dx.doi.org/10.1097/WNP.0000000000000853DOI Listing
July 2021

Lateralized Periodic Discharges: Which patterns are interictal, ictal, or peri-ictal?

Clin Neurophysiol 2021 07 27;132(7):1593-1603. Epub 2021 Apr 27.

Epilepsy and EEG Unit, Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.

There is an ongoing debate if Lateralized Periodic Discharges (LPDs) represent an interictal pattern reflecting non-specific but irritative brain injury, or conversely, is an ictal pattern. The challenge is: how to correctly manage these patients? Between this apparent dichotomous distinction, there is a pattern lying along the interictal-ictal continuum (IIC) that we may call "peri-ictal". Peri-ictal means that LPDs are temporally associated with epileptic seizures (although not necessarily in the same recording). Their recognition should lead to careful EEG monitoring and longer periods of video-EEG to detect seizure activity (clinical and/or subclinical seizures). In order to distinguish which kind of LPDs should be considered as representing interictal/irritative brain injury versus ictal/peri-ictal LPDs, a set of criteria, with both clinical/neuroimaging and EEG, is proposed. Among them, the dichotomy LPDs-proper versus LPDs-plus should be retained. Spiky or sharp LPDs followed by associated slow after-waves or periods of flattening giving rise to a triphasic morphology should be included in the definition of LPDs-plus. We propose defining a particular subtype of LPDs-plus that we call "LPDs-max". The LPDs-max pattern corresponds to an ictal pattern, and therefore, a focal non-convulsive status epilepticus, sometimes associated with subtle motor signs and epileptic seizures. LPDs-max include periodic polyspike-wave activity and/or focal burst-suppression-like patterns. LPDs-max have a posterior predominance over the temporo-parieto-occipital regions and are refractory to antiseizure drugs. Interpretations of EEGs in critically ill patients require a global clinical approach, not limited to the EEG patterns. The clinical context and results of neuroimaging play key roles.
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http://dx.doi.org/10.1016/j.clinph.2021.04.003DOI Listing
July 2021

Are Triphasic Waves Different From Generalized Spike-Wave Discharges?

J Clin Neurophysiol 2021 Sep;38(5):e20-e23

Department of Neurology, Johns Hopkins University; Baltimore, Maryland, U.S.A.; and.

Summary: Generalized periodic discharges with triphasic morphology were previously referred to as triphasic waves but have now been subsumed into the ACNS classification as generalized periodic discharges. Although triphasic waves and generalized spike-wave complexes may resemble each other and hence may be incorrectly identified in comatose critically ill patients, many authors believe that there are different entities, with definable morphologic and clinical differences attributable to each waveform. The occurrence of both patterns in the same patient is extremely rare with only a single prior case report. Here the authors report a patient with typical triphasic waves and generalized spike-wave complexes and highlight the morphologic and EEG differences between the two patterns. The occurrence of both waveforms in the same EEG recording supports the notion of different cerebral generators and pathways, further differentiating rather than merging these morphologies.
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http://dx.doi.org/10.1097/WNP.0000000000000845DOI Listing
September 2021

Source Imaging of Triphasic Waves and Other Encephalopathies.

J Clin Neurophysiol 2021 Sep;38(5):420-425

Department of Neurology, Johns Hopkins University, Baltimore, Maryland, U.S.A.

Purpose: Triphasic waves (TWs) are defined as high-amplitude positive waveforms with preceding and after-going negative waves, typically seen in medically ill patients. TWs manifest in similar clinical presentations as other EEG encephalopathies; however, electrographically, they appear different. To better understand the difference, the authors used two different source localization software programs to find a reproducible and unique signature for TW.

Methods: EEGs performed at Johns Hopkins Hospital and Duke University Hospital were retrospectively analyzed. EEG samples of TW, Delta, Theta-Delta, and Frontal Intermittent Rhythmic Delta Activity were selected. The authors did source localization via Commercial Curry 8 and open-source Brainstorm software. A minimum of 10 stereotypical waveforms per subject were selected. The authors used the Boundary Element Method for the head model, which was derived from the Montreal Neurological Institute averaged imaging data set. Dipole and current density analyses were performed.

Results: Twenty-eight patients were selected (10 TW, 4 Frontal Intermittent Rhythmic Delta Activity, 6 Theta-Delta, and 8 Delta). The findings suggest the activation of anterior frontal and midline structures for TW. Frontal Intermittent Rhythmic Delta Activity had a similar localization but without a moving dipole. In comparison, the Delta and Delta-Theta appeared to have a more diffuse origin.

Conclusions: Source analysis of TW via two different software suggests the anterior midline location of TW with anterior to posterior propagation. These findings correlate with the previous hypotheses of TW origin. Retrospective analysis, low number of recording electrodes, and difficult analysis of slow waves limit the interpretation of these results. Nonetheless, this article opens the prospect of future studies in this field.
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http://dx.doi.org/10.1097/WNP.0000000000000798DOI Listing
September 2021

Status Epilepticus: Definition, Classification, Pathophysiology, and Epidemiology.

Semin Neurol 2020 Dec 11;40(6):647-651. Epub 2020 Nov 11.

Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland.

Status epilepticus (SE) is the state of continuous or repetitive seizures, which can occur with or without convulsions. Evolving definitions of SE take into account the concept that neuronal injury may occur at different times in different types of SE.SE that does not respond to initial treatment may become refractory or even super-refractory. Nonconvulsive SE is increasingly recognized in comatose patients in critical care units, with the growing use of continuous electroencephalogram monitoring. SE is a neurologic emergency that carries a high risk of mortality and morbidity.
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http://dx.doi.org/10.1055/s-0040-1718722DOI Listing
December 2020

Deep active learning for Interictal Ictal Injury Continuum EEG patterns.

J Neurosci Methods 2021 03 22;351:108966. Epub 2020 Oct 22.

Massachusetts General Hospital, Department of Neurology, Boston, MA, United States; Harvard Medical School, Boston, MA, United States. Electronic address:

Objectives: Seizures and seizure-like electroencephalography (EEG) patterns, collectively referred to as "ictal interictal injury continuum" (IIIC) patterns, are commonly encountered in critically ill patients. Automated detection is important for patient care and to enable research. However, training accurate detectors requires a large labeled dataset. Active Learning (AL) may help select informative examples to label, but the optimal AL approach remains unclear.

Methods: We assembled >200,000 h of EEG from 1,454 hospitalized patients. From these, we collected 9,808 labeled and 120,000 unlabeled 10-second EEG segments. Labels included 6 IIIC patterns. In each AL iteration, a Dense-Net Convolutional Neural Network (CNN) learned vector representations for EEG segments using available labels, which were used to create a 2D embedding map. Nearest-neighbor label spreading within the embedding map was used to create additional pseudo-labeled data. A second Dense-Net was trained using real- and pseudo-labels. We evaluated several strategies for selecting candidate points for experts to label next. Finally, we compared two methods for class balancing within queries: standard balanced-based querying (SBBQ), and high confidence spread-based balanced querying (HCSBBQ).

Results: Our results show: 1) Label spreading increased convergence speed for AL. 2) All query criteria produced similar results to random sampling. 3) HCSBBQ query balancing performed best. Using label spreading and HCSBBQ query balancing, we were able to train models approaching expert-level performance across all pattern categories after obtaining ∼7000 expert labels.

Conclusion: Our results provide guidance regarding the use of AL to efficiently label large EEG datasets in critically ill patients.
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http://dx.doi.org/10.1016/j.jneumeth.2020.108966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8135050PMC
March 2021

Acute Toxicity and Triphasic Waves-The Example of Cefepime.

J Clin Neurophysiol 2020 Oct 20. Epub 2020 Oct 20.

Department of Neurology, Johns Hopkins University, Baltimore, Maryland, U.S.A.

Purpose: Triphasic waves (TWs) have been associated with a host of medication toxicities, and cefepime has emerged recently as a frequently encountered offending agent. This investigation aims to evaluate cefepime-induced encephalopathy and to report the associated clinical, EEG expression with TWs, and the radiologic findings.

Methods: A retrospective multicenter observational study examining adult patients with cefepime-induced encephalopathy with generalized periodic discharges on either routine or continuous EEG between January 2014 and January 2020. Clinical, electrographic, and radiologic data were collected. Patients in whom cefepime was not the sole causative factor for their encephalopathy were excluded.

Results: Twenty-seven patients with cefepime-induced encephalopathy marked by generalized periodic discharges with triphasic morphology were identified at both centers, whereas no patients were presenting with generalized periodic discharges without TWs. Patients had a median age of 63 years (interquartile range, 56-73). Fifty-six percent of the cohort (15 patients) were <65 years of age. Eighteen patients (67%) had either acute or chronic kidney impairment (either acute kidney injury or chronic kidney disease or both), whereas 81% had preexisting white matter disease on brain imaging. Of these, 14 patients (51%) were classified as either moderate or severe. In the majority of the patients, TWs were either state-dependent or stimulus-sensitive, and in one third of them presented only as stimulus-induced pattern. All patients improved with discontinuation of cefepime.

Conclusions: Cefepime toxicity should be considered in the differential diagnosis in encephalopathic patients with TWs. The presence of preexisting white matter disease in these patients should heighten the degree of suspicion, especially in younger patients and patients without renal dysfunction.
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http://dx.doi.org/10.1097/WNP.0000000000000791DOI Listing
October 2020

In the Kingdom of Triphasic Waves, White Matter Is the Eminence Grise.

J Clin Neurophysiol 2020 Sep 14. Epub 2020 Sep 14.

Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A. Dr. Kotchetkov is now with the Department of Neurology, Memorial Sloan Kettering Cancer Center, New York, New York, U.S.A.

Purpose: Triphasic waves (TWs) have been associated with multiple conditions and adverse outcomes. This study explores the role of white matter disease (WMD) in the generation of TWs when other common causes associated with these discharges are absent.

Methods: This is a retrospective case series performed at Johns Hopkins Bayview Medical Center from January 2016 to May 2018, which screened for patients with severe WMD, who had TWs on EEG without the presence of commonly cited provoking factors, including (1) hepatic disease; (2) severe uremia over baseline; (3) the drugs cefepime, ifosfamide, lithium, and baclofen; or (4) global hypoxic-ischemic injury. A control population with no WMD or abnormal electrographic findings outside of theta-delta slowing was also identified.

Results: Eleven patients were identified. The most common comorbid condition was infection, occurring in 82% of patients. Infections were urinary tract infection (36%), respiratory (27%), and central nervous system (18%). Metabolic abnormalities included glucose aberrations (36%), calcium derangements (18%), and hypernatremia (9%). Structural abnormalities included acute stroke (9%) and chronic central nervous system abscess (9%). All except one patient had one or more structural, metabolic, or infectious abnormalities in addition to WMD. Comorbidities were not statistically different in the control population.

Conclusions: This is the first series to demonstrate convincingly the presence of TWs in patients with WMD in the absence of commonly cited risk factors. The authors hypothesize that less recognized risk factors of WMD and mild metabolic or infectious abnormalities may be drivers of TWs. With a growing elderly population, the presence of WMD will increase, and treating physicians need to look beyond the common causes of TWs.
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http://dx.doi.org/10.1097/WNP.0000000000000721DOI Listing
September 2020

Current Knowledge and Challenges in Status Epilepticus.

J Clin Neurophysiol 2020 09;37(5):373-374

Department of Neurology, Harvard Medical School, Boston, Massachusetts, U.S.A.

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http://dx.doi.org/10.1097/WNP.0000000000000733DOI Listing
September 2020

Triphasic Waves Are Generated by Widespread Bilateral Cortical Networks.

J Clin Neurophysiol 2021 Sep;38(5):415-419

Departments of Clinical Neurophysiology and.

Purpose: Triphasic waves (TWs) have been observed in the EEG recorded in patients with various types of encephalopathy, yet their genesis and significance is still debated. The aim of this study was to elucidate the localization of the cortical generators of TWs using EEG source imaging.

Methods: In 20 consecutive patients who had encephalopathy with TWs, EEG source imaging of the first negative and the positive phases of the TW was performed. Three different approaches were used: equivalent current dipoles, a distributed source model, and a recently described spatial filtration method for visualizing EEG in source space.

Results: Equivalent current dipole models failed to provide valid solutions. The distributed source model and the spatial filtration method suggested that TWs were generated by large, bilateral cortical networks, invariably involving the anterior frontal and the temporo-polar areas.

Conclusions: Source imaging localized TWs to anterior frontal and temporo-frontal structures. Involvement of these regions is consistent with the typical pathophysiological changes of altered consciousness and cognitive changes observed in patients with TW encephalopathy.
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http://dx.doi.org/10.1097/WNP.0000000000000770DOI Listing
September 2021

New-onset epilepsy in women with first time seizures during pregnancy.

Seizure 2020 Aug 2;80:42-45. Epub 2020 Jun 2.

Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, United States.

Introduction: In women with epilepsy, seizure frequency and severity can be affected during pregnancy by factors such as changes in ASD (anti-seizure drug) metabolism, changes in hormone levels, and medication compliance. Some women with epilepsy experience seizure worsening during pregnancy, while others have an improvement. Most epileptic seizures during pregnancy occur in women with pre-existing epilepsy. Rarely, women develop new-onset seizure-like episodes concerning for epileptic seizures during pregnancy, posing a diagnostic and therapeutic challenge for the physician.

Methods: To determine the frequency of new-onset seizures during pregnancy and the clinical course of those with new seizures, we performed a retrospective study of all women with concomitant diagnoses of pregnancy and seizures (excluding eclampsia) at the Johns Hopkins Medical Institutions over a five-year period. We calculated the frequency of events concerning for seizures during pregnancy, including first-lifetime events, and classified these events as epileptic seizures or as seizure mimics. For those with epileptic seizures, we followed up with the patient to determine whether seizures recurred in or after pregnancy, and whether treatment with anti-seizure medication was initiated.

Results: Over a five-year period, 41,869 women received care at Johns Hopkins Medical Institutions during pregnancy. 84 women had at least one event concerning for seizure during their pregnancies. Of these, 11 had no prior history of seizures; 5 of these women were found to have first-time unprovoked epileptic seizures supported by epileptiform abnormalities on EEG. All women delivered at term with no major complications. Four of these women continued to have epileptic seizures after delivery.

Conclusions: New onset seizures during pregnancy were rare. Most women with first-time epileptic seizures during pregnancy also had epileptic seizures after pregnancy, indicating a first presentation of epilepsy.
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http://dx.doi.org/10.1016/j.seizure.2020.05.022DOI Listing
August 2020

How to carry out and interpret EEG recordings in COVID-19 patients in ICU?

Clin Neurophysiol 2020 08 13;131(8):2023-2031. Epub 2020 May 13.

Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

There are questions and challenges regarding neurologic complications in COVID-19 patients. EEG is a safe and efficient tool for the evaluation of brain function, even in the context of COVID-19. However, EEG technologists should not be put in danger if obtaining an EEG does not significantly advance diagnosis or change management in the patient. Not every neurologic problem stems from a primary brain injury: confusion, impaired consciousness that evolves to stupor and coma, and headaches are frequent in hypercapnic/hypoxic encephalopathies. In patients with chronic pulmonary disorders, acute symptomatic seizures have been reported in acute respiratory failure in 6%. The clinician should be aware of the various EEG patterns in hypercapnic/hypoxic and anoxic (post-cardiac arrest syndrome) encephalopathies as well as encephalitides. In this emerging pandemic of infectious disease, reduced EEG montages using single-use subdermal EEG needle electrodes may be used in comatose patients. A full 10-20 EEG complement of electrodes with an ECG derivation remains the standard. Under COVID-19 conditions, an expedited study that adequately screens for generalized status epilepticus, most types of regional status epilepticus, encephalopathy or sleep may serve for most clinical questions, using simplified montages may limit the risk of infection to EEG technologists. We recommend noting whether the patient is undergoing or has been placed prone, as well as noting the body and head position during the EEG recording (supine versus prone) to avoid overinterpretation of respiratory, head movement, electrode, muscle or other artifacts. There is slight elevation of intracranial pressure in the prone position. In non-comatose patients, the hyperventilation procedure should be avoided. At present, non-specific EEG findings and abnormalities should not be considered as being specific for COVID-19 related encephalopathy.
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http://dx.doi.org/10.1016/j.clinph.2020.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7217782PMC
August 2020

Generalized Periodic Discharges With Triphasic Morphology in the Setting of Aztreonam Neurotoxicity.

Clin EEG Neurosci 2021 Jan 13;52(1):66-68. Epub 2020 May 13.

Johns Hopkins Bayview Medical Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Generalized periodic discharges with triphasic morphology (GPDs + TWm) have been reported with multiple metabolic and drug toxicities. Beta-lactam antibiotics in some cases can cause neurotoxicity with GPDs + TWm on EEG. There are no reports in the literature of aztreonam causing neurotoxicity and GPDs + TWm. Here we describe GPDs + TWm and encephalopathy developing in a patient with underlying dementia and acute kidney injury who was started on aztreonam for cystitis. Neurotoxic effects of beta-lactam antibiotics have been well studied at this point, likely related to GABA receptor antagonism by the beta lactam ring. Risk factors for toxicity include, advanced age, prior neurological injury and decreased renal clearance. This patient carried multiple risk factors for beta-lactam neurotoxicity. Discontinuation of aztreonam led to a resolution of GPDs + TWm on EEG, and regression of encephalopathy.
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http://dx.doi.org/10.1177/1550059420917842DOI Listing
January 2021

Optimizing status epilepticus care during the COVID-19 pandemic.

Epilepsy Behav 2020 08 21;109:107124. Epub 2020 Apr 21.

Department of Neurology, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224, USA.

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http://dx.doi.org/10.1016/j.yebeh.2020.107124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7172759PMC
August 2020

Transnasal Revolution? The Promise of Midazolam Spray to Prevent Seizure Clusters.

CNS Drugs 2020 05;34(5):555-557

Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.

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http://dx.doi.org/10.1007/s40263-020-00724-6DOI Listing
May 2020

A multimodal approach using somatosensory evoked potentials for prognostication in hypoglycemic encephalopathy.

Clin Neurophysiol Pract 2019 17;4:194-197. Epub 2019 Oct 17.

Johns Hopkins Bayview Medical Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Objectives: We present a case of a patient with hypoglycemic encephalopathy with loss of median nerve N20 somatosensory evoked potentials (SSEPs) and describe our multimodal approach to prognostication in hypoglycemic encephalopathy.

Case: The patient was a 67-year-old woman with type 2 diabetes and stage 5 chronic kidney disease hospitalized for hypoglycemic encephalopathy. SSEPs showed bilateral absence of the median nerve N20 response. She ultimately suffered a poor outcome.

Discussion: There are no high-quality evidence-based clinical, neurophysiologic, or imaging studies available to aid in neurologic outcome prediction in hypoglycemic encephalopathy. In our practice we use a multimodal approach to neurologic prognostication, similar to that used in coma after cardiac arrest that includes SSEPs, EEG, and brain MRI, which enables an estimate of the severity of brain injury. As the literature is largely based on small studies or case reports, and is extrapolated from the cardiac arrest literature, we caution against early prognostication and disposition including the withdrawal of care, to avoid a self-fulfilling prophecy.
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http://dx.doi.org/10.1016/j.cnp.2019.09.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6921239PMC
October 2019

The role of CT perfusion in the evaluation of seizures, the post-ictal state, and status epilepticus.

Epilepsy Res 2020 01 12;159:106256. Epub 2019 Dec 12.

Department of Neurology: Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Rapid identification of stroke mimics, such as seizures, is a critical part of the evaluation of patients presenting with acute focal neurological deficits. The primary role of CT perfusion is in identification of patients with acute ischemic stroke who may be candidates for reperfusion therapy, but also holds promise as a modality for identifying a seizure etiology. We review the literature on this topic and attempt to define characteristic CT perfusion findings at various points along the ictal-interictal (epileptic) continuum. We suggest an approach for using CT perfusion to differentiate stroke from seizure in patients with acute onset focal neurological deficits.
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http://dx.doi.org/10.1016/j.eplepsyres.2019.106256DOI Listing
January 2020

Repetitive miniature spikes - An underreported EEG pattern.

Clin Neurophysiol 2020 01 14;131(1):40-45. Epub 2019 Oct 14.

Department of Neurology, Innsbruck, Medical University, Innsbruck, Austria.

Objectives: Low-voltage repetitive spikes are mainly described with invasive recordings and considered highly suggestive for focal cortical dysplasia (FCD). This EEG pattern has received less attention in routine scalp EEG.

Methods: Prospective collection of EEGs with low-voltage (<50 µV) repetitive spikes (repetitive miniature spikes - RMS) between July 1982 and July 2017 at the EEG laboratory of the Medical University of Innsbruck. We analyzed patterns of RMS on routine scalp EEG recordings and examined the relationship to clinical and brain imaging data.

Results: Overall, RMS were seen in 38 patients representing zero to four observations out of 5000 records per year. RMS occurred rhythmically in 14, periodically in 17 and irregularly in seven patients. The EEG pattern appeared with a frontal and central predominance. All but five patients had epilepsies; eleven patients had non-convulsive status epilepticus. Cerebral magnetic resonance imaging (cMRI) detected malformations of cortical development in eleven patients, including six patients with focal cortical dysplasias.

Conclusions: RMS are rare EEG patterns indicating focal epilepsy. Their observation on routine scalp EEGs should prompt further clinic-radiologic investigation.

Significance: RMS resemble a clearly recognizable pattern in routine EEG, which is highly associated with focal epilepsy. The term is descriptive and can be added to the red flags, which can be found on routine EEG indicating underlying structural brain pathology, often in form of focal cortical dysplasia.
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http://dx.doi.org/10.1016/j.clinph.2019.08.028DOI Listing
January 2020

Continuous EEG Monitoring Predicts a Clinically Meaningful Recovery Among Adult Inpatients.

J Clin Neurophysiol 2019 Sep;36(5):358-364

Epilepsy Division, Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York, U.S.A.

Purpose: 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.

Methods: 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. P < 0.05 was considered significant.

Results: 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; P < 0.001); 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).

Conclusions: Continuous EEG findings can be used to prognosticate survival and functional recovery, and provide guidance in establishing goals of care.
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http://dx.doi.org/10.1097/WNP.0000000000000594DOI Listing
September 2019
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