Showing papers in "Journal of Clinical Neurophysiology in 2016"
TL;DR: This revision to the EEG Guidelines is an update incorporating current electroencephalography technology and practice and was previously published as Guideline 5.
Abstract: This revision to the EEG Guidelines is an update incorporating current electroencephalography technology and practice and was previously published as Guideline 5. While the 10-10 system of electrode position nomenclature has been accepted internationally for almost two decades, it has not been used universally. The reasons for this and clinical scenarios when the 10-10 system provides additional localizing information are discussed in this revision. In addition, situations in which AF1/2, AF5/6, PO1/2 and PO5/6 electrode positions may be utilized for EEG recording are discussed.
178 citations
TL;DR: This paper presents a poster presented at the 2016 American Academy of Neurology Congress entitled “Advances in Neurosurgery and Epilepsy: Foundations of Clinical Neurophysiology, 2nd Ed.” (June 2016).
Abstract: Although no single best method exists for recording EEGs under all circumstances, the following standards are considered the minimum for the usual clinical recording of EEGs in all age groups excep...
131 citations
TL;DR: Rigorous SEEG, thanks to its basic principles and updated technologies, is a safe and accurate method to define the epileptogenic zone by means of stereotactically implanted intracerebral electrodes.
Abstract: Background:Stereoelectroencephalography (SEEG) was developed by Talairach and Bancaud in Paris in the late 1950s. Subsequently, the Talairach methodology was adopted at a number of additional centers in Europe and Canada. Technical aspects remained essentially unchanged for the following 30 years. O
99 citations
TL;DR: The techniques for recording and interpreting TES-MEPs have become sufficiently well established to warrant the formulation of these guidelines, and the recommendations herein for the recording of the MEPs that are eliciting by transcranial electrical brain stimulation would also apply to recording of MEPs elicited by direct cortical stimulation.
Abstract: Motor evoked potentials (MEPs) are electrical signals recorded from neural tissue or muscle after activation of central motor pathways. They complement other clinical neurophysiology techniques, such as somatosensory evoked potentials (SEPs), in the assessment of the nervous system, especially during intraoperative neurophysiologic monitoring (IONM). Somatosensory evoked potentials directly assess only a part of the spinal cord, the dorsal columns (Emerson, 1988), and also the medial lemniscus, the thalamocortical radiations, and somatosensory cortex. Because they provide indirect surveillance of the motor tracts, their use has been shown to improve neurologic outcomes during spinal surgery (Nuwer et al., 1995). However, SEPs can fail to detect damage to the spinal cord motor pathways when the dorsal columns are spared (Ben-David et al., 1987; Ginsburg et al., 1985; Jones et al., 2003; Krieger et al., 1992; Legatt et al., 2014; Zornow et al., 1990); this led to the development of techniques for directly monitoring the central motor pathways. Most often, this is accomplished using transcranial electrical stimulation (TES) of the brain and recording of evoked neural or myogenic activity caudal to the area that is at risk during surgery (Legatt, 2002). During TES, high-intensity stimuli must be delivered to the scalp to stimulate the brain through the intact skull, with stimulus voltage and current levels far above those used to elicit SEPs. If a craniotomy permits direct stimulation of motor cortex by electrodes placed on the brain surface, low-intensity direct cortical stimulation can also be used to elicit MEPs for IONM (Szelényi et al., 2007b; Taniguchi et al., 1993). Direct cortical stimulation is outside the scope of this guideline, but the recommendations herein for the recording of the MEPs that are elicited by transcranial electrical brain stimulation would also apply to recording of MEPs elicited by direct cortical stimulation. Transcranial magnetic stimulation has also been used to elicit MEPs by inducing electrical current flows within the brain tissue without passing large amounts of current through the scalp. This reduces stimulation of pain fibers in the scalp, skull, and meninges and makes it a practical technique for MEP studies in awake subjects (Chen et al., 2008). However, transcranial magnetic stimulation is not the optimal MEP technique for IONM because of the anesthetic suppression of transcranial magnetic stimulation– MEPs which are generated mainly by eliciting I-waves (see section on Definitions and Physiology, below) and difficulties in maintaining a constant position of the coil relative to the patient’s head (Legatt, 2004). Neither TES with single stimulus pulses nor transcranial magnetic stimulation consistently produces robust myogenic MEPs suitable for IONM. The commercial availability of stimulators that can deliver trains of high-intensity electrical pulses has made reliable MEP monitoring using TES possible in most patients. At this time, the techniques for recording and interpreting TES-MEPs have become sufficiently well established to warrant the formulation of these guidelines. Personnel performing TES-MEP monitoring must be cognizant of the technical challenges and risks of the technique.
96 citations
TL;DR: Effective treatment for delayed cerebral ischemia will require improved detection of critical early pathophysiologic changes as well as therapeutic options that target multiple related pathways.
Abstract: Subarachnoid hemorrhage (SAH) affects 30,000 people in the Unites States alone each year. Delayed cerebral ischemia occurs days after subarachnoid hemorrhage and represents a potentially treatable cause of morbidity for approximately one-third of those who survive the initial hemorrhage. While vasospasm has been traditionally linked to the development of cerebral ischemia several days after subarachnoid hemorrhage, emerging evidence reveals that delayed cerebral ischemia is part of a much more complicated post-subarachnoid hemorrhage syndrome. The development of delayed cerebral ischemia involves early arteriolar vasospasm with microthrombosis, perfusion mismatch and neurovascular uncoupling, spreading depolarizations, and inflammatory responses that begin at the time of the hemorrhage and evolve over time, culminating in cortical infarction. Large-vessel vasospasm is likely a late contributor to ongoing injury, and effective treatment for delayed cerebral ischemia will require improved detection of critical early pathophysiologic changes as well as therapeutic options that target multiple related pathways.
95 citations
TL;DR: Some methodological aspects of the stimulation procedure influencing functional mapping are discussed because it pertains in particular to language mapping, which exemplifies the importance of anatomo-electro-clinical correlations in stereoelectroencephalography.
Abstract: The challenge in epilepsy surgery is to remove the epileptogenic zone without compromising postoperative function. Electrical stimulation (ES) was developed to identify with greater anatomical and physiological precision cortical structures essential to language and motor function. Because the language network is widely distributed in the left (dominant) hemisphere, and often varies among patients, brain mapping should delineate eloquent areas at the individual level. Although ES for language is commonly performed during a presurgical investigation, the procedure remains nonstandardized among centers, and differences between grids and intracerebral depth electrodes (stereoelectroencephalography) should be taken into account when comparing results from different series. Electrical simulation exerts a complex summation effect in a given volume of brain tissue; the net result may be difficult to predict because this depends on methodological and physiological factors as follows: stimulation parameters, type of electrodes used, tasks used, presence or not of an after-discharge. We discuss in the present article some methodological aspects of the stimulation procedure influencing functional mapping because it pertains in particular to language mapping. In stereoelectroencephalography, the other goal of ES is to trigger seizures. Because seizures develop in neural networks that are imperfectly sampled by intracerebral electrodes, spontaneous seizure recording is not always sufficient to properly localize the epileptogenic zone. The rationale for performing ES is based on the electrophysiological distinction between local/regional after-discharge and seizure networks. A different response to ES-induced seizures can be seen for supra- and infra-sylvian epilepsies. The procedures for triggering seizures and for functional mapping should be performed in conjunction to answer the fundamental question whether or not there is a spatio-temporal overlap between the epileptogenic and the functional network. The exploration of both networks through stimulation exemplifies the importance of anatomo-electro-clinical correlations in stereoelectroencephalography.
69 citations
TL;DR: This revision to the EEG Guidelines is an update incorporating current electroencephalography technology and practice and was previously published as Guideline 6.
Abstract: This revision to the EEG Guidelines is an update incorporating current electroencephalography technology and practice and was previously published as Guideline 6. A discussion of methodology for the appropriate selection of reference electrodes is added. In addition, montages are added to assist with localization of abnormal activity in mesial frontal and anterior temporal regions.
62 citations
TL;DR: Neuromuscular ultrasound (US) augments a careful physical examination and electrodiagnostic evaluation in the evaluation of suspected myopathy with sensitivities and specificities similar to electromyogram for detection of myopathy.
Abstract: Neuromuscular ultrasound (US) augments a careful physical examination and electrodiagnostic evaluation in the evaluation of suspected myopathy. Ultrasound evaluation of muscle can identify abnormal echo intensity, size, and movement. Because it is painless and noninvasive, US can be used to evaluate multiple muscles to direct the electrodiagnostic examination or muscle biopsy. Some patterns of muscle involvement can suggest specific etiologies. Most muscular dystrophies show homogenously increased muscle echo intensity with attenuation of the US signal, likely resultant from increased intramuscular fat and fibrosis. Inflammatory myopathies can also show homogenously increased echogenicity but lack the signal attenuation seen in muscular dystrophies. In contrast, denervation can show "moth-eaten," atrophic muscles with fasciculations. Advanced age and obesity also impacts muscle size and echo intensity and can hamper efforts to detect mild pathologies. The sensitivity and specificity of US for detecting neuromuscular disease have been best studied in children and depend on the type and severity of the disorder. In general, muscle US yields sensitivities and specificities of 67% to 100% for detecting neuromuscular disorders in children and is similar to electromyogram for detection of myopathy. Ultrasound is most sensitive for detecting muscular dystrophies and is less sensitive in metabolic myopathies and very young children.
62 citations
TL;DR: There is expanded documentation of the patient history to include more relevant clinical information that can affect the EEG recording and interpretation and recommendations for the technical conditions of the recording are enhanced to include post hoc review parameters and type of EEG recording.
Abstract: This EEG Guideline incorporates the practice of structuring a report of results obtained during routine adult electroencephalography. It is intended to reflect one of the current practices in reporting an EEG and serves as a revision of the previous guideline entitled "Writing an EEG Report." The goal of this guideline is not only to convey clinically relevant information, but also to improve interrater reliability for clinical and research use by standardizing the format of EEG reports. With this in mind, there is expanded documentation of the patient history to include more relevant clinical information that can affect the EEG recording and interpretation. Recommendations for the technical conditions of the recording are also enhanced to include post hoc review parameters and type of EEG recording. Sleep feature documentation is also expanded upon. More descriptive terms are included for background features and interictal discharges that are concordant with efforts to standardize terminology. In the clinical correlation section, examples of common clinical scenarios are now provided that encourages uniformity in reporting. Including digital samples of abnormal waveforms is now readily available with current EEG recording systems and may be beneficial in augmenting reports when controversial waveforms or important features are encountered.
49 citations
TL;DR: In this article, the authors briefly review essentials of EEG generation and the effects of ischemia on the underlying neuronal processes and discuss the differential sensitivity of various neuronal processes to energy limitations, including synaptic disturbances.
Abstract: EEG is very sensitive to changes in neuronal function resulting from ischemia. The authors briefly review essentials of EEG generation and the effects of ischemia on the underlying neuronal processes. They discuss the differential sensitivity of various neuronal processes to energy limitations, including synaptic disturbances. The clinical applications reviewed include continuous EEG monitoring during carotid surgery and acute ischemic stroke, and EEG monitoring for prognostication after cardiac arrest.
46 citations
TL;DR: This revision to the EEG Guidelines is an update incorporating current EEG technology and practice and suggested technical criteria for making the diagnosis of electrocerebral inactivity are suggested.
Abstract: This revision to the EEG Guidelines is an update incorporating current EEG technology and practice. The role of the EEG in making the determination of brain death is discussed as are suggested technical criteria for making the diagnosis of electrocerebral inactivity.
Harvard University1, Emory University2, Columbia University3, University of Colorado Denver4, University of Pennsylvania5, Northwestern University6, Duke University7, Johns Hopkins University8, University of Alabama at Birmingham9, University of Texas Southwestern Medical Center10, Vanderbilt University11, Yale University12, Stanford University13, University of Maryland, Baltimore14, University of Toronto15
TL;DR: The authors describe the development of a research database incorporating the American Clinical Neurophysiology Society standardized terminology for critical care EEG monitoring that has been successfully developed and implemented with a dual role as a collaborative research platform and a clinical reporting tool.
Abstract: Purpose:The rapid expansion of the use of continuous critical care electroencephalogram (cEEG) monitoring and resulting multicenter research studies through the Critical Care EEG Monitoring Research Consortium has created the need for a collaborative data sharing mechanism and repository. The author
TL;DR: The electromyographer's approach to patients presenting with respiratory symptoms, with a focus on neuromuscular ultrasound is reviewed, including brightness-mode ultrasound imaging of the diaphragm, which is a very sensitive and specific diagnostic test in this setting.
Abstract: Electromyographers are often asked to evaluate patients presenting with dyspnea or respiratory failure, to rule out an underlying neuromuscular cause for those symptoms. Available tools for diagnosing such patients include pulmonary function tests, transdiaphragmatic pressure testing, various imaging modalities, phrenic nerve conduction studies, and diaphragm electromyography. Phrenic nerve conduction studies and diaphragm electromyography are technically challenging and can be limited by both false positive and false negative results. Integration of diagnostic ultrasound can enhance the accuracy and safety of diaphragm electromyography, and improve sensitivity and specificity of phrenic nerve conduction studies. In addition, brightness-mode ultrasound imaging of the diaphragm allows for measurement of muscle thickness and contractility, and is a very sensitive and specific diagnostic test in this setting. This article will review the electromyographer's approach to patients presenting with respiratory symptoms, with a focus on neuromuscular ultrasound.
TL;DR: The hope is that a better fundamental understanding of SDs will lead to novel therapeutic interventions to prevent SD occurrence and its adverse consequences contributing to injury progression in subarachnoid hemorrhage and other forms of acute brain injury.
Abstract: Delayed cerebral ischemia is the most feared cause of secondary injury progression after subarachnoid hemorrhage. Initially thought to be a direct consequence of large artery spasm and territorial ischemia, recent data suggests that delayed cerebral ischemia represents multiple concurrent and synergistic mechanisms, including microcirculatory dysfunction, inflammation, and microthrombosis. Among these mechanisms, spreading depolarizations (SDs) are arguably the most elusive and underappreciated in the clinical setting. Although SDs have been experimentally detected and examined since the late 1970s, their widespread occurrence in human brain was not unequivocally demonstrated until relatively recently. We now know that SDs occur with very high incidence in human brain after ischemic or hemorrhagic stroke and trauma, and worsen outcomes by increasing metabolic demand, decreasing blood supply, predisposing to seizure activity, and possibly worsening brain edema. In this review, we discuss the causes and consequences of SDs in injured brain. Although much of our mechanistic knowledge comes from experimental models of focal cerebral ischemia, clinical data suggest that the same principles apply regardless of the mode of injury (i.e., ischemia, hemorrhage, or trauma). The hope is that a better fundamental understanding of SDs will lead to novel therapeutic interventions to prevent SD occurrence and its adverse consequences contributing to injury progression in subarachnoid hemorrhage and other forms of acute brain injury.
TL;DR: This revision to the EEG Guidelines is an update incorporating the current electroencephalography technology and practice and delineates the aspects of Guideline 1 that should be modified for neonates and young children.
Abstract: 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.
TL;DR: The technical and methodological aspects of the SEEG will be discussed focusing on the planning of SEEg implantations, technical nuances, conceptualization of the epileptogenic zone, and the different methods of SEEG-guided surgical resections and ablations.
Abstract: The stereo-electroencephalography (SEEG) methodology and technique was developed almost 60 years ago in Europe and it has proven its efficacy and safety over the last 55 years. The main advantage of the SEEG method is the possibility to study the epileptogenic neuronal network in its dynamic and tri-dimensional aspect, with an optimal time and space correlation with the clinical semiology. In this manuscript, the technical and methodological aspects of the SEEG will be discussed focusing on the planning of SEEG implantations, technical nuances, conceptualization of the epileptogenic zone, and the different methods of SEEG-guided surgical resections and ablations.
TL;DR: The evidence demonstrates that nerve ultrasound has an essential, complementary role with electrodiagnostic testing, and supports the use of neuromuscular ultrasound as a standard component for evaluating focal neuropathies.
Abstract: Focal neuropathies represent the most common indication for referral to electrodiagnostic laboratories. The etiologies range from chronic compression, as might be seen in carpal tunnel syndrome, to acute traumatic nerve injuries that require rapid intervention. The gold standard for diagnosis, electrodiagnostic testing, cannot provide the complementary anatomical information necessary to guide accurate diagnosis and treatment. An expanding body of literature supports the use of neuromuscular ultrasound as a standard component for evaluating focal neuropathies. In the current review, the role of ultrasound in both common and unusual compression neuropathies is reviewed, along with the use of ultrasound in traumatic nerve injury. The evidence demonstrates that nerve ultrasound has an essential, complementary role with electrodiagnostic testing.
TL;DR: This review compiles current data of the impact of continuous electroencephalography on the detection of subtle and nonconvulsive status epilepticus in different clinical scenarios and its contribution to treatment and monitoring in intensive care units.
Abstract: Continuous electroencephalography uncovers a clinically underappreciated burden of subtle and nonconvulsive status epilepticus in critically ill patients. Prolonged recordings over days are labor intensive and patient or medical equipment related electrographic artifacts are challenging, calling for a targeted use of electroencephalography in patients with defined seizure risk profiles. This review compiles current data of the impact of continuous electroencephalography on the detection of subtle and nonconvulsive status epilepticus in different clinical scenarios and its contribution to treatment and monitoring in intensive care units. Current recommendations on the use of continuous electroencephalography in the critically ill are outlined.
TL;DR: QEEG is being used by neurophysiologists and nonneuroPhysiologists for applications beyond seizure detection, but practice patterns vary widely, and there is a need for standardization of QEEG methods and practices.
Abstract: Purpose Quantitative EEG (QEEG) can be used to assist with review of large amounts of data generated by critical care continuous EEG monitoring. This study aimed to identify current practices regarding the use of QEEG in critical care continuous EEG monitoring of critical care patients. Methods An online survey was sent to 796 members of the American Clinical Neurophysiology Society (ACNS), instructing only neurophysiologists to participate. Results The survey was completed by 75 neurophysiologists that use QEEG in their practice. Survey respondents reported that neurophysiologists and neurophysiology fellows are most likely to serve as QEEG readers (97% and 52%, respectively). However, 21% of respondents reported nonneurophysiologists are also involved with QEEG interpretation. The majority of nonneurophysiologist QEEG data review is aimed to alert neurophysiologists to periods of concern, but 22% reported that nonneurophysiologists use QEEG to directly guide clinical care. Quantitative EEG was used most frequently for seizure detection (92%) and burst suppression monitoring (59%). A smaller number of respondents use QEEG for monitoring the depth of sedation (29%), ischemia detection (28%), vasospasm detection (28%) and prognosis after cardiac arrest (21%). About half of the respondents do not review every page of the raw critical care continuous EEG record when using QEEG. Respondents prefer a panel of QEEG trends displayed as hemispheric data, when applicable. There is substantial variability regarding QEEG trend preferences for seizure detection and ischemia detection. Conclusions QEEG is being used by neurophysiologists and nonneurophysiologists for applications beyond seizure detection, but practice patterns vary widely. There is a need for standardization of QEEG methods and practices.
TL;DR: Previously used methods to extract signatures from seizure signals that range from those that mimic the clinical neurophysiologist to those that exploit mathematical models of neonatal EEG generation are reviewed.
Abstract: It is now generally accepted that EEG is the only reliable way to accurately detect newborn seizures and, as such, prolonged EEG monitoring is increasingly being adopted in neonatal intensive care units. Long EEG recordings may last from several hours to a few days. With neurophysiologists not always available to review the EEG during unsociable hours, there is a pressing need to develop a reliable and robust automatic seizure detection method-a computer algorithm that can take the EEG signal, process it, and output information that supports clinical decision making. In this study, we review existing algorithms based on how the relevant seizure information is exploited. We start with commonly used methods to extract signatures from seizure signals that range from those that mimic the clinical neurophysiologist to those that exploit mathematical models of neonatal EEG generation. Commonly used classification methods are reviewed that are based on a set of rules and thresholds that are either heuristically tuned or automatically derived from the data. These are followed by techniques to use information about spatiotemporal seizure context. The usual errors in system design and validation are discussed. Current clinical decision support tools that have met regulatory requirements and are available to detect neonatal seizures are reviewed with progress and the outstanding challenges are outlined. This review discusses the current state of the art regarding automatic detection of neonatal seizures.
TL;DR: An institutional guideline implementing cEEG for SAH ischemia monitoring and reporting is feasible to implement and efficiently identify patients at high baseline risk of DCI during the period of monitoring.
Abstract: Delayed cerebral ischemia (DCI) is the most common and disabling complication among patients admitted to the hospital for subarachnoid hemorrhage (SAH). Clinical and radiographic methods often fail to detect DCI early enough to avert irreversible injury. We assessed the clinical feasibility of implementing a continuous EEG (cEEG) ischemia monitoring service for early DCI detection as part of an institutional guideline. An institutional neuromonitoring guideline was designed by an interdisciplinary team of neurocritical care, clinical neurophysiology, and neurosurgery physicians and nursing staff and cEEG technologists. The interdisciplinary team focused on (1) selection criteria of high-risk patients, (2) minimization of safety concerns related to prolonged monitoring, (3) technical selection of quantitative and qualitative neurophysiologic parameters based on expert consensus and review of the literature, (4) a structured interpretation and reporting methodology, prompting direct patient evaluation and iterative neurocritical care, and (5) a two-layered quality assurance process including structured clinician interviews assessing events of neurologic worsening and an adjudicated consensus review of neuroimaging and medical records. The resulting guideline's clinical feasibility was then prospectively evaluated. The institutional SAH monitoring guideline used transcranial Doppler ultrasound and cEEG monitoring for vasospasm and ischemia monitoring in patients with either Fisher group 3 or Hunt-Hess grade IV or V SAH. Safety criteria focused on prevention of skin breakdown and agitation. Technical components included monitoring of transcranial Doppler ultrasound velocities and cEEG features, including quantitative alpha:delta ratio and percent alpha variability, qualitative evidence of new focal slowing, late-onset epileptiform activity, or overall worsening of background. Structured cEEG reports were introduced including verbal communication for findings concerning neurologic decline. The guideline was successfully implemented over 27 months, during which neurocritical care physicians referred 71 SAH patients for combined transcranial Doppler ultrasound and cEEG monitoring. The quality assurance process determined a DCI rate of 48% among the monitored population, more than 90% of which occurred during the duration of cEEG monitoring (mean 6.9 days) beginning 2.7 days after symptom onset. An institutional guideline implementing cEEG for SAH ischemia monitoring and reporting is feasible to implement and efficiently identify patients at high baseline risk of DCI during the period of monitoring.
TL;DR: Whether or not HEBs are indeed predictive of recurrent seizure or may be used to direct the therapy for status epilepticus, specifically the weaning of anesthetic medications, requires further prospective study in a larger cohort of patients.
Abstract: Purpose Pharmacologic sedation is often used to induce burst suppression in cases of refractory status epilepticus, but there is little evidence to guide the weaning of sedation. Similarly, the morphologic feature of bursts is of unknown clinical relevance. Recently, the standardized American Clinical Neurophysiology Society terminology of critical care EEG introduced the term highly epileptiform bursts (HEBs). Knowing the association of HEBs with seizure may direct the therapy for refractory status epilepticus. Methods Consecutive adult patients classified as having burst suppression were identified in our EEG database. Those of an anoxic etiology were excluded. Available EEG records were reviewed, both visually and quantitatively, for the presence of burst suppression. Using the American Clinical Neurophysiology Society terminology, burst suppression was dichotomized into HEBs or nonepileptiform bursts. Periods of transition out of burst suppression were identified, and whether burst suppression was followed by seizure or a continuous slow EEG within 24 hours was determined. Results Twenty-four patients were identified with a burst suppression pattern followed by either seizure or a continuous slow EEG within 24 hours, with some patients having multiple (maximal 5) transitions out of burst suppression, for a total of 33 examples of burst suppression. HEBs were associated with subsequent seizure (P = 0.0001), independent of medication exposure. Conclusions Whether or not HEBs are indeed predictive of recurrent seizure or may be used to direct the therapy for status epilepticus, specifically the weaning of anesthetic medications, requires further prospective study in a larger cohort of patients.
TL;DR: MUNIX could serve as a sensitive technique to detect denervation of clinically intact muscles of ALS patients and among 9 intact first dorsal interosseous muscles of the ALS patients, 8 showed MUNIX values below the cutoff point, whereas only 2 first dorsal Interosseus muscles showed denervation on needle electromyography.
Abstract: Purpose: Diagnosis of amyotrophic lateral sclerosis (ALS) at an early stage is challenging, thus making the enrollment of these patients in clinical trials infeasible. In this study, we investigated the potential usability of motor unit number index (MUNIX) to detect denervation of clinically intact muscles of ALS patients. Methods: Thirty-two first dorsal interosseous muscles of 26 ALS patients were evaluated with both MUNIX and needle electromyography. Results: The mean MUNIX value of first dorsal interosseous muscles was 131 in the control group, whereas it was 48, 34, 15, and 8 for Medical Research Council scales of 5, 4, 3, and 2, respectively, in the ALS patients. The optimal cutoff point gave a sensitivity of 0.89 and a specificity of 1.0. Among 9 intact first dorsal interosseous muscles of the ALS patients, 8 showed MUNIX values below the cutoff point, whereas only 2 first dorsal interosseous muscles showed denervation on needle electromyography. Conclusions: MUNIX could serve as a sensitive technique to detect denervation of clinically intact muscles of ALS patients.
TL;DR: Several small studies in patients with aneurysmal subarachnoid hemorrhage now provide preliminary evidence that EEG monitoring can be successfully applied to detection of delayed cerebral ischemia with a good sensitivity.
Abstract: The EEG signal is the closest available measure of brain function and is exquisitely sensitive to ischemia. Data from animal models and from intraoperative monitoring suggest that continuous EEG monitoring is able disclose changes suggestive of impeding ischemia before infarction occurs. Several small studies in patients with aneurysmal subarachnoid hemorrhage now provide preliminary evidence that it can also be successfully applied to detection of delayed cerebral ischemia with a good sensitivity. These studies relied on quantitative analysis, underscoring the necessity to introduce such methods in clinical practice. Further improvements in quantitative EEG analysis, integration in a multimodality monitoring framework, and prospective validation studies are now required to confirm the utility of EEG monitoring for delayed cerebral ischemia detection.
TL;DR: The study suggests that neuromonitoring with a subdural recording strip for up to 15 days can be safely performed in patients with aSAH and did not lead to local damage of brain tissue or any increased rate of meningitis/ventriculitis.
Abstract: Purpose:Patients with aneurysmal subarachnoid hemorrhage (aSAH) frequently develop secondary noninfectious and infectious complications with an important impact on clinical course and outcome. In this study, we report on the rate of typical extracranial and intracranial complications in 30 prospecti
TL;DR: This document provides guidance for the creation of digital EEG recordings including documentation of patient information, notation of information during the recording, digital signal acquisition parameters during the recordings, storage of digital information, and display of digitalEEG signals.
Abstract: Digital EEG recording systems are now widely available and relatively inexpensive. They offer multiple advantages over previous analog/paper systems, such as higher fidelity recording, signal postprocessing, automated detection, and efficient data storage. This document provides guidance for the creation of digital EEG recordings including (1) documentation of patient information, (2) notation of information during the recording, (3) digital signal acquisition parameters during the recording, (4) storage of digital information, and (5) display of digital EEG signals.
TL;DR: This revision to the EEG Guidelines is an update incorporating current EEG technology and practice, and “Standards of practice in clinical electroencephalography” has been removed.
Abstract: This revision to the EEG Guidelines is an update incorporating current EEG technology and practice. "Standards of practice in clinical electroencephalography" (previously Guideline 4) has been removed. It is currently undergoing revision through collaboration among multiple medical societies and will become part of "Qualifications and Responsibilities of Personnel Performing and Interpreting Clinical Neurophysiology Procedures." The remaining guidelines are reordered and renumbered.
TL;DR: It is demonstrated that good functional outcome is possible even after several days of SE and coma induction, and treatment of refractory SE should not be withdrawn from younger patients without structural brain damage at presentation solely because of the duration of SE.
Abstract: When status epilepticus (SE) remains refractory to appropriate therapy, it is associated with high mortality and with substantial morbidity in survivors. Many outcome predictors such as age, seizure type, level of consciousness before treatment, and mostly, etiology, are well-established. A longer duration of SE is often associated with worse outcome, but duration may lose its prognostic value after several hours. Several terms and definitions have been used to describe prolonged, refractory SE, including "malignant SE," "prolonged" SE, and more recently, "super refractory" SE, defined as "SE that has continued or recurred despite 24 hours of general anesthesia (or coma-inducing anticonvulsants)." There are few data available regarding the outcome of prolonged refractory SE, and even fewer for SE remaining refractory to anesthetic drugs. This article reviews reports of outcome after prolonged, refractory, and "super refractory" SE. Most information detailing the clinical outcome of patients surviving these severe illnesses, in which seizures can persist for days or weeks (and especially those concerning "super-refractory" SE) come from case reports and retrospective cohort studies. In many series, prolonged, refractory SE has a mortality of 30% to 50%, and several studies indicate that most survivors have a substantial decline in functional status. Nevertheless, several reports demonstrate that good functional outcome is possible even after several days of SE and coma induction. Treatment of refractory SE should not be withdrawn from younger patients without structural brain damage at presentation solely because of the duration of SE.
TL;DR: The ultrasonographic changes that occur in the nerves and muscles of those with more diffuse polyneuropathies and motor neuron diseases are investigated, and a review will detail the findings in these conditions.
Abstract: Neuromuscular ultrasound is an emerging technology for the evaluation of conditions affecting nerve and muscle, with most of the research focusing on focal neuropathies. Despite this focus, researchers have also investigated the ultrasonographic changes that occur in the nerves and muscles of those with more diffuse polyneuropathies and motor neuron diseases, and this review will detail the findings in these conditions. Specific findings are discussed in this article, but general themes will also be presented and include the following: hereditary polyneuropathies show diffuse nerve enlargement, whereas immune-mediated polyneuropathies show more patchy involvement; nerve enlargement is more profound in demyelinating than axonal polyneuropathies; and muscle changes in motor neuron diseases include heterogeneous increases in echogenicity, atrophy, readily detectable fasciculations, and increased subcutaneous tissue thickness.
TL;DR: These cases confirm that the site of nerve inflammation may lie outside the brachial plexus, keeping with previous reports, and suggests that peripheral nerve ultrasound imaging might aid in the diagnosis of neuralgic amyotrophy and exclude mimicking conditions.
Abstract: Purpose:Neuralgic amyotrophy is characterized by acute or subacute onset of shoulder and arm pain, followed by muscle atrophy and weakness, and variable sensory abnormalities. Historically, the site of inflammation has been localized to the brachial plexus, although the involvement of individual ner