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PURPOSE The spike-wave index (SWI) is a key feature in the diagnosis of electrical status epilepticus during slow-wave sleep. Estimating the SWI manually is time-consuming and is subject to interrater and intrarater variability. Use of automated detection software would save time. Thereby, this software will consistently detect a certain EEG phenomenon as epileptiform and is not influenced by human factors. To determine noninferiority in calculating the SWI, we compared the performance of a commercially available spike detection algorithm (P13 software, Persyst Development Corporation, San Diego, CA) with human expert consensus. METHODS The authors identified all prolonged EEG recordings for the diagnosis or follow-up of electrical status epilepticus during slow-wave sleep carried out from January to December 2018 at an epilepsy tertiary referral center. The SWI during the first 10 minutes of sleep was estimated by consensus of two human experts. This was compared with the SWI calculated by the automated spike detection algorithm using the three available sensitivity settings: "low," "medium," and "high." In the software, these sensitivity settings are denoted as perception values. RESULTS Forty-eight EEG recordings from 44 individuals were analyzed. The SWIs estimated by human experts did not differ from the SWIs calculated by the automated spike detection algorithm in the "low" perception mode (P = 0.67). The SWIs calculated in the "medium" and "high" perception settings were, however, significantly higher than the human expert estimated SWIs (both P < 0.001). CONCLUSIONS Automated spike detection (P13) is a useful tool in determining SWI, especially when using the "low" sensitivity setting. Using such automated detection tools may save time, especially when reviewing larger epochs.

Elderly people and people with epilepsy may need assistance after falling, but may be unable to summon help due to injuries or impairment of consciousness. Several wearable fall detection devices have been developed, but these are not used by all people at risk. We present an automated analysis algorithm for remote detection of high impact falls, based on a physical model of a fall, aiming at universality and robustness. Candidate events are automatically detected and event features are used as classifier input. The algorithm uses vertical velocity and acceleration features from optical flow outputs, corrected for distance from the camera using moving object size estimation. A sound amplitude feature is used to increase detector specificity. We tested the performance and robustness of our trained algorithm using acted data from a public database and real life data with falls resulting from epilepsy and with daily life activities. Applying the trained algorithm to the acted dataset resulted in 90% sensitivity for detection of falls, with 92% specificity. In the real life data, six/nine falls were detected with a specificity of 99.7%; there is a plausible explanation for not detecting each of the falls missed. These results reflect the algorithm's robustness and confirms the feasibility of detecting falls using this algorithm.

Background: The most common subtypes of Guillain-Barré syndrome (GBS) are acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). In the first days after the onset of weakness, standard nerve conduction studies (NCS) may not distinguish GBS subtypes. Reduced nerve excitability may be an early symptom of nerve dysfunction, which can be determined with the compound muscle action potential (CMAP) scan. The aim of this study was to explore whether early changes in motor nerve excitability in GBS patients are related to various subtypes. Methods: Prospective case–control study in 19 GBS patients from The Netherlands and 22 from Bangladesh. CMAP scans were performed within 2 days of hospital admission and NCS 7–14 days after onset of weakness. CMAP scans were also performed in age- and country-matched controls. Results: CMAP scan patterns of patients who were classified as AMAN were distinctly different compared to the CMAP scan patterns of the patients who were classified as AIDP. The most pronounced differences were found in the stimulus intensity parameters. Conclusions: CMAP scans made at hospital admission demonstrate several characteristics that can be used as an early indicator of GBS subtype.

Purpose Complete visual review of prolonged video-EEG recordings at an EMU (Epilepsy Monitoring Unit) is time consuming and can cause problems in times of paucity of educated personnel. In this study we aimed to show non inferiority for electroclinical diagnosis using sampled review in combination with EEG analysis softreferware (P13 software, Persyst Corporation), in comparison to complete visual review. Method Fifty prolonged video-EEG recordings in adults were prospectively evaluated using sampled visual EEG review in combination with automated detection software of the complete EEG record. Visually assessed samples consisted of one hour during wakefulness, one hour during sleep, half an hour of wakefulness after wake-up and all clinical events marked by the individual and/or nurses. The final electro-clinical diagnosis of this new review approach was compared with the electro-clinical diagnosis after complete visual review as presently used. Results The electro-clinical diagnosis based on sampled visual review combined with automated detection software did not differ from the diagnosis based on complete visual review. Furthermore, the detection software was able to detect all records containing epileptiform abnormalities and epileptic seizures. Conclusion Sampled visual review in combination with automated detection using Persyst 13 is non-inferior to complete visual review for electroclinical diagnosis of prolonged video-EEG at an EMU setting, which makes this approach promising.

Objective User safety and the quality of diagnostics on the epilepsy monitoring unit (EMU) depend on reaction to seizures. Online seizure detection might improve this. While good sensitivity and specificity is reported, the added value above staff response is unclear. We ascertained the added value of two electroencephalograph (EEG) seizure detection algorithms in terms of additional detected seizures or faster detection time. Methods EEG-video seizure recordings of people admitted to an EMU over one year were included, with a maximum of two seizures per subject. All recordings were retrospectively analyzed using Encevis EpiScan and BESA Epilepsy. Detection sensitivity and latency of the algorithms were compared to staff responses. False positive rates were estimated on 30 uninterrupted recordings (roughly 24 h per subject) of consecutive subjects admitted to the EMU. Results EEG-video recordings used included 188 seizures. The response rate of staff was 67%, of Encevis 67%, and of BESA Epilepsy 65%. Of the 62 seizures missed by staff, 66% were recognized by Encevis and 39% by BESA Epilepsy. The median latency was 31 s (staff), 10 s (Encevis), and 14 s (BESA Epilepsy). After correcting for walking time from the observation room to the subject, both algorithms detected faster than staff in 65% of detected seizures. The full recordings included 617 h of EEG. Encevis had a median false positive rate of 4.9 per 24 h and BESA Epilepsy of 2.1 per 24 h. Conclusions EEG-video seizure detection algorithms may improve reaction to seizures by improving the total number of seizures detected and the speed of detection. The false positive rate is feasible for use in a clinical situation. Implementation of these algorithms might result in faster diagnostic testing and better observation during seizures.

Aim. Epilepsy is difficult to diagnose using routine EEG recordings of short duration in patients who have low seizure frequency. Long-term EEG may be useful but is impractical in an out-of-hospital setting. We investigated whether single-channel scalp EEG placed behind the earlobe is suitable for seizure identification during prolonged EEG monitoring. Methods. Scalp EEG samples were selected from subjects over 15 years of age, and comprised two segments of either background followed by seizure or background followed by background. Bipolar EEG derivations in three directions (F8-T8, C4-T8 and T8-P8) were evaluated for the presence of a seizure by two experienced reviewers. For each EEG segment containing a seizure, one pair of electrodes was oriented towards the suspected region of seizure onset, while two pairs of electrodes were oriented elsewhere. Results. The EEG data contained five frontally localized seizures, five parietal, five temporal, two occipital, and four primary or secondary generalized seizures. The sensitivity and specificity for recognition of seizures was 86% and 95% for Reviewer 1, and 79% and 99% for Reviewer 2, respectively. When identifying a seizure with the lead orientation towards the region of seizure onset, both reviewers identified 20 out of 21 seizures (95%). When the lead was not oriented towards the region of seizure onset, the reviewers identified 34 and 30 out of 42 ictal records correctly, respectively. Conclusions. These results suggest that it is possible to identify epileptic seizures by bipolar EEG derivation using only two scalp electrodes. Lead orientation towards the suspected region of seizure onset is important for optimal detection sensitivity.

Background Long-term video-EEG monitoring (LTM) aims to record the habitual event and is a useful diagnostic tool for neurological paroxysmal clinical events. In our epilepsy monitoring unit (EMU) setting, admissions are usually planned to last up to five days. We ascertained time taken for the recording of a first event and determined correlations between different clinical characteristics and timings. Methods We retrospectively reviewed diagnostic and classification LTM recording performed at a tertiary epilepsy centre. Results Sixty-three recordings were reviewed. Most subjects (89%) had events at least once a week prior to admission. In 40 (63%) a habitual event was recorded, mostly (93%) within the first two days. No events were recorded on day four or five. A few characteristics were associated with a trend for events occurring earlier (events more than once a week vs less than once a week, motor symptoms compared with aura or dyscognitive events, and reduction of antiepileptic drugs versus no reduction). Conclusions Our finding suggests that, for diagnostic event recording in people with epilepsy or PNEA, a maximum recording time of three days is sufficient in two thirds of them, if event frequency is at least once a week. In the remaining third, prolonged recording up to five days did not result in capturing a clinical event. For these individuals, shorter admission could be planned, for example for 2 days rather than 5 days.

Objective No international guideline is available for minimum safety measures at epilepsy monitoring units (EMUs), although recommendations for preferred practices exist. These are mostly based on expert opinion, without evidence of effectiveness. We do not apply all of these preferred practices at our EMU setting. We audited adverse events and diagnostic utility at our EMU over one year. Methods From May 2018 to May 2019, we prospectively collected data concerning adverse events and diagnostic utility of all EMU admissions (noninvasive video-electroencephalogram (EEG) recordings); during these admissions, individuals can be ambulant within their EMU room. Results There were 1062 admissions comprising 1518 EMU days. In 2% of the admissions, a complication occurred, mostly a fall without injury (n = 6). In almost half of the falls, this was from the bed. Complications occurred most often during admissions for presurgical evaluation. Antiseizure medication (ASM) was tapered in 86% of presurgical cases, but no serious injury occurred, and occurring seizures were effectively treated with intranasal midazolam if needed. Conclusions The overall adverse event rate was low. Falls are the most common adverse event comparable with previously published fall rates at other EMUs where people are restricted to their bed. We showed that restricted ambulation at a well-monitored EMU is not necessary and possibly unwanted. No serious injury due to tapering of ASM occurred, and intranasal midazolam was shown to be effective as acute seizure treatment.

Introduction: The effective cerebral perfusion pressure (CPPe), zero-flow pressure (ZFP), and resistance area product (RAP) are important determinants of cerebral blood flow. ZFP and RAP are usually estimated by linear regression analysis of pressurevelocity relationships of the middle cerebral artery. The aim of this study was to validate 4 other estimation methods against the standard linear regression method. Methods: In a previous study, electroencephalography, arterial blood pressure, and middle cerebral artery flow velocity were measured in patients during internal cardioverter defibrillator implantation procedures to determine the electroencephalography frequency ranges that represent ischemic changes during periods of circulatory arrest. In this secondary analysis, arterial blood pressure and middle cerebral artery flow velocity were used to estimate CPPe, ZFP, and RAP by 4 different methods—the 3-point intercept calculation (LR3, systolic/mean/diastolic) and methods described by Czosnyka (systolic/diastolic), Belford (mean/diastolic), and Schmidt (systolic/diastolic)—and compare them with the reference linear regression method. CPPe was calculated as the difference between mean arterial pressure and ZFP. The primary endpoint was the difference, correlation, and agreement of these differently estimated CPPe measurements. Results: In total, 174 measurements in 35 patients were collected under steady-state conditions before the first circulatory arrest phase during internal cardioverter defibrillator testing. CPPe, ZFP, and RAP measurements based on the 3-point intercept and Czosnyka calculation methods showed small mean differences, good agreement, low percentage errors, and excellent correlation when compared with the reference method. Agreement and correlation were moderate for the Belford method and unsatisfactory for the Schmidt method. Conclusions: CPPe, ZFP, and RAP measurements based on 2 alternative calculation methods are comparable to the linear regression reference method.

_Introduction:_ The aim of this study was to determine whether electrically evoked multiplet discharges (MDs) are related to severity of clinical deterioration in motor neuron disease (MND). _Methods:_ Stimulated high-density surface electromyographic (HDsEMG) recordings were performed in thenar muscles. Data were collected from 31 MND patients. MDs from the HDsEMG recordings were determined at baseline. ALSFRS-R scores were obtained at baseline and at a maximum of 16 weeks follow-up. _Results:_ The presence of MDs was associated with progressive deterioration of ALSFRS-R score (P = 0.02) and fine motor function (FMF) (P < 0.001). Patients who had a higher number of motor units that generated MDs (r = 0.61, P < 0.001) and patients who had a higher number of MDs (as percentage of applied stimuli) (r = 0.59, P = 0.001) had a more severe decline in FMF. _Conclusions:_ Electrically evoked MDs are associated with more marked clinical deterioration in patients with MND.

Objective Absence epilepsy (AE) is related to both cognitive and physical impairments. In this narrative review, we critically discuss the pathophysiology of AE and the impairment of attention in children and adolescents with AE. In particular, we contextualize the attentive dysfunctions of AE with the associated risks, such as accidental injuries. Data source An extensive literature search on attention deficits and the rate of accidental injuries in AE was run. The search was conducted on Scopus, Pubmed, and the online libraries of the University of Twente and Maastricht University. Relevant references of the included articles were added. Retrospective and prospective studies, case reports, meta-analysis, and narrative reviews were included. Only studies written in English were considered. Date of last search is February 2020. The keywords used were “absence epilepsy” AND “attention”/“awareness”, “absence epilepsy” AND “accidental injuries”/“accident*”/“injuries”. Results Ten retrospective and two prospective studies on cognition and AE were fully screened. Seventeen papers explicitly referring to attention in AE were reviewed. Just one paper was found to specifically focus on accidental injuries and AE, while twelve studies generally referring to epilepsy syndromes – among which AE – and related accidents were included. Conclusion Absence epilepsy and attention deficits show some patterns of pathophysiological association. This relation may account for dysfunctions in everyday activities in the pediatric population. Particular metrics, such as the risk related to biking in children with AE, should be used in future studies to address the problem in a novel way and to impact clinical indications.

Central apneas occurring in the aftermath of epileptic seizures may lead to sudden death. Contact-sensors currently used to detect apneas are not always suitable or tolerated. We developed a robust automated non-contact algorithm for real-time detection of central apneas using video cameras. One video recording with simulated apneas and nine with real-life apneas associated with epileptic seizures, each recorded from 3 to 4 angles, were used to develop the algorithm. Videos were preprocessed using optical flow, from which translation, dilatation and shear rates were extracted. Presence of breathing motions was quantified in the time-frequency spectrum by calculating the relative power in the respiratory range (0.1–1 Hz). Sigmoid modulation was calculated over different scales to quantify sigmoid-like drops in respiratory range power. Each sigmoid modulation maximum constitutes a possible apnea event. Two event features were calculated to enable distinction between apnea events and movements: modulation maximum amplitude and total spectral power modulation at the time of the event. An ensemble support vector machine was trained to classify events using a bagging procedure and validated in a leave-one-subject-out cross validation procedure. All apnea episodes were detected in the signals from at least one camera angle. Integrating camera inputs capturing different angles increased overall detection sensitivity (>90%). Overall detection specificity of >99% was achieved with both individual cameras and integrated camera inputs. These results suggest that it is feasible to detect central apneas automatically in video, using this algorithm. When validated, the algorithm might be used as an online remote apnea detector for safety monitoring.

Background Epilepsy and migraine are paroxysmal neurological conditions associated with disturbances of cortical excitability. No useful biomarkers to monitor disease activity in these conditions are available. Phase clustering was previously described in electroencephalographic (EEG) responses to photic stimulation and may be a potential epilepsy biomarker. Objective The objective of this study was to investigate EEG phase clustering in response to transcranial magnetic stimulation (TMS), compare it with photic stimulation in controls, and explore its potential as a biomarker of genetic generalized epilepsy or migraine with aura. Methods People with (possible) juvenile myoclonic epilepsy (JME), migraine with aura, and healthy controls underwent single-pulse TMS with concomitant EEG recording during the interictal period. We compared phase clustering after TMS with photic stimulation across the groups using permutation-based testing. Results We included eight people with (possible) JME (five off medication, three on), 10 with migraine with aura, and 37 controls. The TMS and photic phase clustering spectra showed significant differences between those with epilepsy without medication and controls. Two phase clustering-based indices successfully captured these differences between groups. One participant was tested multiple times. In this case, the phase clustering-based indices were inversely correlated with the dose of antiepileptic medication. Phase clustering did not differ between people with migraine and controls. Conclusion We present methods to quantify phase clustering using TMS–EEG and show its potential value as a measure of brain network activity in genetic generalized epilepsy. Our results suggest that the higher propensity to phase clustering is not shared between genetic generalized epilepsy and migraine.

Purpose Caffeine is the most commonly used central nervous system (CNS) stimulant. The relationship between caffeine, seizures, epilepsy, and antiepileptic drugs (AEDs) is complex and not fully understood. Case reports suggest that caffeine triggers seizures in susceptible people. Our systematic review reports on the relationship between caffeine, seizures, and drugs in animal and human studies. Quantitative analyses were also done on animal studies regarding the effects of caffeine on AEDs. Methods PubMed was searched for studies assessing the effects of caffeine on seizure susceptibility, epilepsy, and drug interactions in people and in animal models. To quantify the interaction between AEDs and caffeine, the data of six animal studies were pooled and analyzed using a general linear model univariate analysis or One-way Analysis of Variance (ANOVA). Results In total, 442 items were identified from which we included 105 studies. Caffeine can increase seizure susceptibility and protect from seizures, depending on the dose, administration type (chronic or acute), and the developmental stage at which caffeine exposure started. In animal studies, caffeine decreased the antiepileptic potency of some drugs; this effect was strongest in topiramate. Conclusion Preclinical studies suggest that caffeine increases seizure susceptibility. In some cases, chronic use of caffeine may protect against seizures. Caffeine lowers the efficacy of several drugs, especially topiramate. It is unclear how these findings in models can be translated to the clinical condition. Until clinical studies suggest otherwise, caffeine intake should be considered as a factor in achieving and maintaining seizure control in epilepsy.

Cortical excitability, as measured by transcranial magnetic stimulation combined with electromyography, is a potential biomarker for the diagnosis and follow-up of epilepsy. We report on long-interval intracortical inhibition data measured in four different centres in healthy controls (n = 95), subjects with refractory genetic generalized epilepsy (n = 40) and with refractory focal epilepsy (n = 69). Long-interval intracortical inhibition was measured by applying two supra-threshold stimuli with an interstimulus interval of 50, 100, 150, 200 and 250 ms and calculating the ratio between the response to the second (test stimulus) and to the first (conditioning stimulus). In all subjects, the median response ratio showed inhibition at all interstimulus intervals. Using a mixed linear-effects model, we compared the long-interval intracortical inhibition response ratios between the different subject types. We conducted two analyses; one including data from the four centres and one excluding data from Centre 2, as the methods in this centre differed from the others. In the first analysis, we found no differences in long-interval intracortical inhibition between the different subject types. In all subjects, the response ratios at interstimulus intervals 100 and 150 ms showed significantly more inhibition than the response ratios at 50, 200 and 250 ms. Our second analysis showed a significant interaction between interstimulus interval and subject type (P = 0.0003). Post hoc testing showed significant differences between controls and refractory focal epilepsy at interstimulus intervals of 100 ms (P = 0.02) and 200 ms (P = 0.04). There were no significant differences between controls and refractory generalized epilepsy groups or between the refractory generalized and focal epilepsy groups. Our results do not support the body of previous work that suggests that long-interval intracortical inhibition is significantly reduced in refractory focal and genetic generalized epilepsy. Results from the second analysis are even in sharper contrast with previous work, showing inhibition in refractory focal epilepsy at 200 ms instead of facilitation previously reported. Methodological differences, especially shorter intervals between the pulse pairs, may have contributed to our inability to reproduce previous findings. Based on our results, we suggest that long-interval intracortical inhibition as measured by transcranial magnetic stimulation and electromyography is unlikely to have clinical use as a biomarker of epilepsy.

__Objective:__ Preeclampsia is a severe hypertensive disorder of pregnancy which may lead to brain complications such as eclampsia. Visual symptoms are present in ∼25% of preeclamptic women suggesting the visual cortex to be altered during preeclampsia. Visual evoked potentials (VEPs) measure the functional neuronal integrity of the visual pathway from retina to the occipital cortex of the brain. The objective of this study was to compare neurophysiological changes in women with preeclampsia and other hypertensive disorders of pregnancy, using VEPs. We hypothesized that women with preeclampsia and other hypertensive disorders of pregnancy develop abnormal latency and amplitude of VEPs as compared with normotensive pregnant women. __Methods:__ We performed a prospective observational study in 15 women with mild preeclampsia, 33 with severe preeclampsia (sPE), eight women with chronic hypertension, nine with pregnancy-induced hypertension, and 29 normotensive pregnant women. VEP measurements were made at four different time points of gestation (12-14 weeks, 26-28 weeks, 32-34 weeks, 36-40 weeks) and 6-8 weeks postpartum. __Results:__ We defined reference values for normotensive pregnant women. Normotensive pregnant women had a shorter latency during pregnancy compared to their postpartum value (P = 0.005). Women with sPE had a prolonged latency of VEPs compared with normotensive pregnant women (P = 0.006), a difference that disappeared postpartum. __Conclusion:__ Our study showed neurophysiological adaptation to pregnancy of the visual cortex in normotensive pregnant women, that seemed to be absent in women with sPE. The study groups of women with chronic hypertension and pregnancy-induced hypertension were to small to draw any conslusions from.

Introduction: Fasciculations, the spontaneous activity of single motor units (MUs) are characteristic, but nonspecific for motor neuron disease (MND). We aimed to identify MU discharge properties to optimally differentiate MND patients from healthy controls. Methods: High-density surface electromyography recordings were performed in the thenar muscles during 10 min of rest. MU discharges were classified as “isolated” when the interspike intervals (ISIs) before and after were > 250 ms, “continual” when both ISIs were ≤ 250 ms, or as “other”. Results: In patients (n = 30) compared with controls (n = 14), more MUs were active (9 vs. 3, P < 0.001) and generated relatively more isolated discharges (35% vs. 10%, P = 0.01). Two or more MUs with isolated discharges occurred more frequently in patients compared with controls (24% vs.

Objective. To define reference values of the patellar reflex in normotensive pregnant and postpartum women and to compare these with values in women with preeclampsia. Design. Observational study. Setting. University teaching hospital in the Netherlands. Population. Normotensive non-pregnant women, pregnant women and preeclamptic women. Methods. In normotensive pregnant women the patellar reflex was cross-sectionally recorded using surface electromyography at four time points during pregnancy and six to eight weeks postpartum. In non-pregnant normotensive women this was recorded once. Preeclamptic women were recorded during pregnancy and postpartum. Main outcome measures. Latency and amplitude of the compound muscle action potential of the patellar reflex. Results. Latency and amplitude of the compound muscle action potential during normotensive pregnancies showed no changes compared with the non-pregnant state during reproductive age. Latency of the compound muscle action potential was increased in pregnancies with severe preeclampsia compared with normotensive pregnancies. These differences disappeared postpartum. Conclusions. During pregnancy, the patellar reflex can be assessed using surface electromyography. Latency and amplitude show no changes during normotensive pregnancies and are no different from the postpartum or non-pregnant values. In severely preeclamptic women, latency is increased. The clinical value of this is limited.

Objective: To determine whether there is a relation between electrically evoked multiplet discharges (MDs) and motor axonal excitability properties. We hypothesized that electrically evoked MDs share their underlying pathophysiological mechanism with fasciculations. Methods: High-density surface EMG and motor nerve excitability recordings of the thenar muscles were performed in 22 patients with motor neuron disease (MND) in their differential diagnosis and who were referred for EMG examination. Results: Supernormality (hyperexcitable phase following the refractory period) was significantly increased in patients with MDs (n = 10) compared to patients without MDs (n = 12) (25.5% vs 17.0%; p = 0.02). Depolarizing threshold electrotonus differed significantly between both groups as well (TEd-peak, 76.6% vs 66.6%, p < 0.01; TEd90-100 ms, 51.7% vs 44.3%, p < 0.01) Conclusions: Our findings imply that the same pathophysiological excitability changes are involved in generating MDs and fasciculations. Yet, MDs may be quantified more easily, and may be more specific for abnormal distal excitability than fasciculations, because fasciculations may originate along the motor axon as well as in the neuron cell body. Significance: MDs are potentially useful as objective measure of increased distal axonal excitability at individual motor unit level and might complement clinical studies in MND. (C) 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

ObjectiveTo determine and compare the diagnostic accuracy of electrically elicited multiplet discharges (MDs) and fasciculation potentials (FPs) in motor neuron disease (MND).MethodsPatients were eligible when they had MND in their differential diagnosis and were referred for electromyogram (EMG). Stimulated high-density surface EMG of the thenar muscles was performed on the same day as standard EMG examination. High-density recordings were analysed for presence of MDs and needle EMG of any muscle investigated in the cervical region for presence of FPs.ResultsOf the 61 patients enrolled in this diagnostic study, 24 patients were clinically diagnosed with amyotrophic lateral sclerosis (ALS) and 11 patients with progressive muscular atrophy (PMA). Another diagnosis was made in 26 patients. Sixteen patients in whom MDs were detected were diagnosed with either ALS (n=11) or PMA (n=5; sensitivity=47.1%, PPV=94.1%). MDs were detected in only one patient initially diagnosed with PMA, but in whom later on, multifocal motor neuropathy could not be excluded (specificity=96.2%). Electrically elicited MDs had a higher specificity than FPs (96.2% vs 53.9%, pConclusionsElectrically evoked MDs are highly specific for ALS and PMA and are an early sign of lower motor neuron dysfunction.

People with epilepsy need assistance and are at risk of sudden death when having convulsive seizures (CS). Automated real-time seizure detection systems can help alert caregivers, but wearable sensors are not always tolerated. We determined algorithm settings and investigated detection performance of a video algorithm to detect CS in a residential care setting. The algorithm calculates power in the 2-6 Hz range relative to 0.5-12.5 Hz range in group velocity signals derived from video-sequence optical flow. A detection threshold was found using a training set consisting of video-electroencephalogaphy (EEG) recordings of 72 CS. A test set consisting of 24 full nights of 12 new subjects in residential care and additional recordings of 50 CS selected randomly was used to estimate performance. All data were analyzed retrospectively. The start and end of CS (generalized clonic and tonic-clonic seizures) and other seizures considered desirable to detect (long generalized tonic, hyperkinetic, and other major seizures) were annotated. The detection threshold was set to the value that obtained 97% sensitivity in the training set. Sensitivity, latency, and false detection rate (FDR) per night were calculated in the test set. A seizure was detected when the algorithm output exceeded the threshold continuously for 2 seconds. With the detection threshold determined in the training set, all CS were detected in the test set (100% sensitivity). Latency was ≤10 seconds in 78% of detections. Three/five hyperkinetic and 6/9 other major seizures were detected. Median FDR was 0.78 per night and no false detections occurred in 9/24 nights. Our algorithm could improve safety unobtrusively by automated real-time detection of CS in video registrations, with an acceptable latency and FDR. The algorithm can also detect some other motor seizures requiring assistance.

Standardized terminology for computer-based assessment and reporting of EEG has been previously developed in Europe. The International Federation of Clinical Neurophysiology established a taskforce in 2013 to develop this further, and to reach international consensus. This work resulted in the second, revised version of SCORE (Standardized Computer-based Organized Reporting of EEG), which is presented in this paper. The revised terminology was implemented in a software package (SCORE EEG), which was tested in clinical practice on 12,160 EEG recordings. Standardized terms implemented in SCORE are used to report the features of clinical relevance, extracted while assessing the EEGs. Selection of the terms is context sensitive: initial choices determine the subsequently presented sets of additional choices. This process automatically generates a report and feeds these features into a database. In the end, the diagnostic significance is scored, using a standardized list of terms. SCORE has specific modules for scoring seizures (including seizure semiology and ictal EEG patterns), neonatal recordings (including features specific for this age group), and for Critical Care EEG Terminology. SCORE is a useful clinical tool, with potential impact on clinical care, quality assurance, data-sharing, research and education.

Objective: To evaluate an automated method that extracts motor unit (MU) information from the CMAP scan, a high-detail stimulus-response curve recorded with surface EMG. Discontinuities in the CMAP scan are hypothesized to result from MU loss and reinnervation. Methods: We introduce the parameter D50 to quantify CMAP scan discontinuities. D50 was compared with a previously developed manual score in 253 CMAP scans and with a simultaneously obtained motor unit number estimate (MUNE) in 173 CMAP scans. The effect of MU loss on D50 was determined with a simulation model. Results: We found a high agreement (sensitivity = 86.8%, specificity = 96.6%) between D50 and the manual score. D50 and MUNE were significantly correlated below 80 MUs (r = 0.65, n = 68, p < 0.001), but not when MUNE was larger than 120 MUs (r = 0.23, n = 59, p = 0.08). Conclusions: Discontinuities in the CMAP scan as expressed by a decreased D50 are related to significant MU loss. The determination of D50 is objective, quantitative, and less time-consuming than both manual scoring and many existing MUNE methods. Significance: D50 is potentially useful to monitor neurogenic disorders and moderate to severe MU loss. (C) 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Typical Miller Fisher syndrome (MFS) lacks limb muscle weakness, but some patients may unpredictably progress to severe Guillain-Barre syndrome. The compound muscle action potential (CMAP) scan is a recently developed non-invasive, painless, and reproducible method for detecting early changes in motor nerve excitability. This technique was used to monitor subclinical limb motor nerve dysfunction during disease course in typical MFS. Three Miller Fisher patients with preserved limb muscle strength and normal routine nerve conduction studies were included. Frequent serial CMAP scanning of the median nerve was performed during acute phase and follow-up and was related to clinical course and outcome. All patients showed an abnormal increase in the range of stimulus intensities at the day of hospital admission, indicating reduced motor nerve excitability already at the earliest stage of disease. Median nerve dysfunction progressed in parallel or even before clinical deterioration, and improved with clinical recovery. Our study shows that typical MFS is a more general neuropathy, affecting peripheral motor nerves even in patients with preserved limb strength and conduction velocity. CMAP scanning is a sensitive technique for early detection of subclinical motor nerve dysfunction and for monitoring disease activity in immune-mediated neuropathies.

Amyotrophic lateral sclerosis (ALS) and progressive muscular atrophy (PMA) are characterized by a loss of motor units (MUs), reinnervation and, eventually, muscle fibre loss. These three aspects are all reflected in the compound muscle action potential scan (CMAP scan, a high-detail stimulus response curve), which visualizes large MU potentials as 'steps'. We explored changes in the CMAP scan over time, combined the information on steps and CMAP amplitude into a CMAP scan-based progression score (CSPS), and correlated this score with motor unit number estimates (MUNE). Ten patients (three PMA, seven ALS; age 37-77 years) were included. CMAP scan and MUNE measurements were performed five times during a three-month period. Nine patients had additional measurements. The follow-up period was 3-24 months. Results demonstrated that abnormalities in steps preceded a decline in maximum CMAP amplitude during follow-up. Usually, both steps and maximum CMAP amplitude changed between recordings. The correlation between the CSPS and MUNE was -0.80 (p < 0.01). In conclusion, the CMAP scan can be used to visualize and quantify disease progression in a muscle affected by MND. The CSPS is a measure of MU loss that is quick and easy to obtain and that, in contrast to MUNE, has no sample bias.

SummaryObjective Following a sudden death at a residential care unit, the Dutch Health and Care Inspectorate advised intensification of the use of video monitoring (VM) at the unit. We assessed whether VM resulted in increased identification of seizures that required clinical intervention. Methods The unit provides care for 340 individuals with refractory epilepsy and severe learning disabilities. Acoustic detection systems (ADSs) cover all individuals; 37 people also have a bed motion sensor (BMS) and 46 people with possible nocturnal seizures are now monitored by VM. During a 6-month period, in all cases of a suspected seizure we asked the caregivers to specify which device alerted them and to indicate whether this led to an intervention. Staff costs of VM were estimated using payroll information. Results We identified 1,208 seizures in 37 individuals: 4 had no nocturnal seizures and 393 (33%) seizures were seen only on video. In 169 (14%) of 1,208 seizures an intervention was made and this included 39 (10%) of 393 seizures seen only on video. When compared to seizures observed with an ADS or BMS, seizures seen only on video were more often tonic seizures (71% vs. 22%, p < 0.001) and occurred mostly in the beginning or at the end of the night (40% vs. 26%, p < 0.001). The extra staff costs of monitoring was 7,035 euro per seizure seen only on video and leading to an intervention. Significance VM facilitates nocturnal surveillance, but the costs are high. This underscores the need for development of reliable seizure detection devices.

textabstractObjectives: To compare electroencephalography (EEG) findings during pregnancy and postpartum in women with normotensive pregnancies and pregnancies complicated by hypertensive disorders. Also the health related quality of life postpartum was related to these EEG findings. Materials and Methods: An observational case-control study in a university hospital in the Netherlands. Twenty-nine normotensive and 58 hypertensive pregnant women were included. EEG's were recorded on several occasions during pregnancy and 6-8 weeks postpartum. Postpartum, the women filled out health related quality of life questionnaires. Main outcome measures were qualitative and quantitative assessments on EEG, multidimensional fatigue inventory, Short Form (36) Health Survey and EuroQol visual analogue scale. Results: In women with severe preeclampsia significantly lower alpha peak frequency, more delta and theta activity bilaterally and a higher EEG Sum Score were seen. Postpartum, these women showed impaired mental health, mental fatigue and social functioning, which could not be related to the EEG findings. Conclusions: Severe preeclamptic patients show more EEG abnormalities and have impaired mental wellbeing postpartum, but these findings are not correlated.

Even though it is known that neonatal seizures are associated with acute brain lesions, the relationship of electroencephalographic (EEG) seizures to acute perinatal brain lesions visible on magnetic resonance imaging (MRI) has not been objectively studied. EEG source localization is successfully used for this purpose in adults, but it has not been sufficiently explored in neonates. Therefore, we developed an integrated method for ictal EEG dipole source localization based on a realistic head model to investigate the utility of EEG source imaging in neonates with postasphyxial seizures. We describe here our method and compare the dipole seizure localization results with acute perinatal lesions seen on brain MRI in 10 full-term infants with neonatal encephalopathy. Through experimental studies, we also explore the sensitivity of our method to the electrode positioning errors and the variations in neonatal skull geometry and conductivity. The localization results of 45 focal seizures from 10 neonates are compared with the visual analysis of EEG and MRI data, scored by expert physicians. In 9 of 10 neonates, dipole locations showed good relationship with MRI lesions and clinical data. Our experimental results also suggest that the variations in the used values for skull conductivity or thickness have little effect on the dipole localization, whereas inaccurate electrode positioning can reduce the accuracy of source estimates. The performance of our fused method indicates that ictal EEG source imaging is feasible in neonates and with further validation studies, this technique can become a useful diagnostic tool.

Introduction: The CMAP scan is a surface EMG method based on the successive activation of motor units. It provides information about reinnervation processes, the number of functional motor units and nerve excitability. The CMAP scan has potential value as a follow-up tool in monitoring disease progression, recovery or aging of the peripheral nerves. In this study, we assessed its interobserver and different day reproducibility. Methods: Two investigators recorded CMAP scans in ten healthy subjects, each on two different days. Intraclass correlation coefficients (ICCs) and coefficients of variation (CoVs) were calculated for the parameters extracted from the CMAP scan. Results: All CMAP scan parameters had a good different day (ICCs > 0.8 and CoVs < 15%) and interobserver reproducibility (ICCs > 0.7 and CoVs

Ultrasound-guided near-nerve neurography is a new tool that can be used to assess nerve regeneration before reinnervation occurs. In this study, ultrasound-guided near-nerve measurements were validated against axon diameter counts in rabbits during a 15-week regeneration period after a crush lesion of their peroneal nerve. The course of the nerve was determined ultrasonically, and the active near-nerve needle electrode was maneuvered just next to the nerve under ultrasound guidance. Measured action potentials were compared with axon diameter counts from histological sections of these same nerves. A moderate to good positive correlation was found, which reached a maximum of 0.7 at a cut-off of 3 μm, corresponding to the minimal size of the myelinated axons. Our results suggest that, following a similar validation study in humans, ultrasound-guided near-nerve neurography may be clinically useful when early evaluation of nerve activity is needed.

Electrodiagnostic assessments of the peripheral nervous system often require limb warming. The traditional warming method, the hot water bath, has several disadvantages. We present an alternative: hot water blankets containing circulating water of a constant temperature. In addition to having practical advantages, these blankets allow for accurate and continuous monitoring of limb temperature and nerve conduction velocity (NCV) during warming. We therefore aimed to determine (1) the temperature dependence of the NCV of the median motor and sensory nerve, deep peroneal nerve, and sural nerve during warming with blankets, and (2) the optimal warming strategy for clinical purposes. We warmed the limbs of 10 subjects for 90 minutes with blankets set at a temperature of 41 degrees C. During warming, the NCV of the three nerves and distal motor latency of the two motor nerves were measured every 2(1/2) minutes. After 25 minutes of warming from an initial temperature of 28 degrees C, the NCV and distal motor latency of all nerves were within the normal range. However, after median nerve warming until a predefined temperature of 34 degrees C (i.e., for 17 minutes on average), two of nine subjects showed abnormal NCVs. We therefore conclude that for limb warming with hot water blankets, a fixed 25-minute warming period is optimal.

A novel automated algorithm is proposed to approximate the seizure onset zone (SOZ), while providing reproducible output. The SOZ, a surrogate marker for the epileptogenic zone (EZ), was approximated from intracranial electroencephalograms (iEEG) of nine people with temporal lobe epilepsy (TLE), using three methods: (1) Total ripple length (TRL): Manually segmented high-frequency oscillations, (2) Rippleness (R): Area under the curve (AUC) of the autocorrelation functions envelope, and (3) Autoregressive model residual variation (ARR, novel algorithm): Time-variation of residuals from autoregressive models of iEEG windows. TRL, R, and ARR results were compared in terms of separability, using Kolmogorov–Smirnov tests, and performance, using receiver operating characteristic (ROC) curves, to the gold standard for SOZ delineation: visual observation of ictal video-iEEGs. TRL, R, and ARR can distinguish signals from iEEG channels located within the SOZ from those outside it (p < 0.01). The ROC AUC was 0.82 for ARR, while it was 0.79 for TRL, and 0.64 for R. ARR outperforms TRL and R, and may be applied to identify channels in the SOZ automatically in interictal iEEGs of people with TLE. ARR, interpreted as evidence for nonharmonicity of high-frequency EEG components, could provide a new way to delineate the EZ, thus contributing to presurgical workup.

In addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2 -induced changes in CBF, CVR, CPPe, ZFP, and RAP is not fully understood. In a controlled crossover trial, we investigated 10 anesthetized patients aiming at PaCO2 levels of 30, 37, 43, and 50 mm Hg. Cerebral blood flow was measured with a modified Kety-Schmidt-technique. Zero flow pressure and RAP was estimated by linear regression analysis of pressure–flow velocity relationships of the middle cerebral artery. Effective cerebral perfusion pressure was calculated as the difference between mean arterial pressure and ZFP, CVR as the ratio CPPe/CBF. Statistical analysis was performed by one-way RM-ANOVA. When comparing hypocapnia with hypercapnia, CBF showed a significant exponential reduction by 55% and mean VMCA by 41%. Effective cerebral perfusion pressure linearly decreased by 17% while ZFP increased from 14 to 29 mm Hg. Cerebrovascular resistance increased by 96% and RAP by 39%; despite these concordant changes in mean CVR and Doppler-derived RAP correlation between these variables was weak ( r = 0.43). In conclusion, under general anesthesia hypocapnia-induced reduction in CBF is caused by both an increase in CVR and a decrease in CPPe, as a consequence of an increase in ZFP.

Many Guillain-Barré syndrome (GBS) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) patients recover well, but suffer from excessive fatigue, which may persist for years and reduce the quality of life considerably. In order to determine whether residual subclinical peripheral nerve dysfunction is a possible underlying mechanism of fatigue, we performed standardized nerve conduction (NC) studies in 16 fatigued patients, mean 6.5 years after diagnosis. Thirteen were relatively well recovered from GBS and 3 had stable CIDP. In contrast to CIDP, most NC values in GBS patients were remarkably restored and within normal values. No correlations were found between the electrophysiological findings and the fatigue scores,muscle strength, or functional scores. This study demonstrates that fatigue in GBS is not explained by residual nerve dysfunction, using conventional NC measurements.

Many patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) suffer from excessive fatigue. To assess whether this fatigue might be related to changes in slow-conducting nerve fibers, we determined the conduction velocity distribution (CVD) in the median nerve. Thirteen fatigued but neurologically well-recovered GBS patients, 2 fatigued and stable CIDP patients, and 19 healthy controls participated in this study. Conventional maximal nerve conduction velocities (NCVs) did not show differences between GBS patients and healthy controls. However, in both GBS and CIDP patients the CVD was altered, showing significant narrowing of the velocity distribution with loss of the fastest- and slowest-conducting fibers. These changes were most pronounced in the subgroup of patients with the lowest fatigue scores. We therefore conclude that the observed CVD changes in patients are not likely to contribute to persisting complaints of fatigue after GBS.

textabstractUltrasound imaging of peripheral nerves is increasingly used in the clinic for a wide range of applications. Although yet unapplied for experimental neuroscience, it also has potential value in this research area. This study explores the feasibility, possibilities and limitations of this technique in rabbits, with special focus on peripheral nerve regeneration after trauma. The peroneal nerve of 25 New Zealand White rabbits was imaged at varying time intervals after a crush lesion. The ultrasonic appearance of the nerve was determined, and recordings were validated with in vivo anatomy. Nerve swelling at the lesion site was estimated from ultrasound images and compared with anatomical parameters. The peroneal nerve could reliably be identified in all animals, and its course and anatomical variations agreed perfectly with anatomy. Nerve diameters from ultrasound were related to in vivo diameters (p < 0.001, R2 = 77%), although the prediction interval was rather wide. Nerve thickenings could be visualized and preliminary results indicate that ultrasound can differentiate between neuroma formation and external nerve thickening. The value of the technique for experimental neuroscience is discussed. We conclude that ultrasound imaging of the rabbit peroneal nerve is feasible and that it is a promising tool for different research areas within the field of experimental neuroscience.

The purpose of this study was to evaluate the contribution of quantitative EEG (qEEG) to an animal model of cerebral air embolism (CAE). In 12 anesthetized pigs, air was injected into the internal carotid artery, and hyperbaric oxygen (HBO) treatment was started either after 3 minutes or after 60 minutes (United States Navy Treatment Table 6). Off-line spectral analysis was used to determine the frequency content of the EEG signal, and factor analysis was performed to determine the frequency ranges that optimally showed the changes in the power spectrum. Factor analysis revealed two factors that represented different and independent spectral changes during embolization: 0.5 to 7.3 Hz (band 1) and 26.4 to 30.3 Hz (band 2). Shortly after embolization, the power in both bands decreased to a minimum, representing an isoelectric EEG in 11 out of the 12 animals. EEG differences between animals were considerable, despite standardized doses of injected air, and qEEG can objectively assess and quantify these differences in immediate impact of air embolism on brain function. Also, qEEG enabled monitoring of the recovery from the initial embolic event and of the response on treatment. The initial recovery was much more protracted in band 2 than in band 1, but even after completing HBO treatment, qEEG values did not return to baseline values in all animals. In addition, two animals did not survive until the end of the HBO treatment, and qEEG proved to be superior to the other measured hemodynamic variables to detect and ensure a deterioration of brain function. This study showed that qEEG monitoring has significant additional value to monitoring HBO treatment.

Editors' Note: Cuetter describes his experience with residual fatigue in Guillain-Barre syndrome, supporting the findings of Drenthen et al. This subclinical fatigue is related to axonal loss. Friedman critiques some of the deductions by the authors who studied the effect of amantadine withdrawal in the AMANDYSK trial. He believes that some of their observations in regard to fatigue and apathy may be related to the placebo effect. The authors respond. —Chafic Karam, MD, and Robert C. Griggs, MD Drenthen et …

Introduction Visual symptoms are present in about 25% of women with pre-eclampsia (PE). The origin of these visual disturbances is localized in either the neurological or ophthalmic pathway. The exact causative factors of these disturbances have not been elucidated yet. Cerebral edema may affect the visual cortex, which can even lead to cortical blindness. The occipital cortex seems to be more susceptible for preeclampsia related breakthrough of the cerebral autoregulation. Because the vertebrobasilar system is less innervated with sympathetic nerves, this part of the brain is less capable to regulate cerebral blood flow with rising blood pressure. Objectives The objective of the study was to describe the neurophysiological changes by means of visual evoked potentials (VEPs) in patients with PE. A VEP measures the functional integrity of the visual pathway from retina to the occipital cortex of the brain. Our hypothesis is that women with PE have a longer VEP latency and lower amplitude compared to normotensive pregnant women. Methods From October 2005 till July 2008 a prospective study was performed. Normotensive pregnant women were recruited at the outpatient clinic from a gestational age of 12 weeks. They underwent clinical and neurophysiological measurements at 5 different time points: at a gestational age of 12–14 weeks, 26–28 weeks, 32–34 weeks, 36–40 weeks and 6–8 weeks postpartum. Women PE were recruited at the moment of diagnosis and investigated during pregnancy and 6-8 weeks postpartum. The visual evoked potentials were measured using a checkerboard pattern (Viking 4 device). Results VEP measurements of 29 normotensive controls, 15 mild PE and 34 severe PE were performed. The absolute values of the mean latency and amplitude were not significantly different between the groups. When compared to normative values of a group of women in the age of 20–59 year in the normotensive controls a higher proportion of women in the severe PE group had a latency time >107 (left eye: controls 31.0%, mild PE 41.7%, severe PE 52.9%, p = 0.215; right eye: controls 10.3% , mild PE 26.7%, severe PE 38.2%, p = 0.041). Conclusion This study showed that a higher percentage of women with PE had a longer latency. We are now studying the association between the VEP results and the cerebral blood flow measured with transcranial Doppler in these women.

We studied heart rate (HR) changes during 169 seizures (mean 12 per patient, range 8 to 18) in 14 neonates with severe birth asphyxia. HR changes were found in 21 seizures (12.4%) in eight patients (HR increases in four, decreases in one, and both patterns in three patients), suggesting the existence of neonatal cerebral hemispheric connections with brainstem autonomic regulatory centers. HR monitoring appears to be insensitive for detecting postasphyxial neonatal seizures.

Headache and epilepsy often co-occur. Epidemiologic studies conducted in the past few years reinforce the notion of a bi-directional association between migraine and epilepsy. Data on an association between headache (in general) and epilepsy, however, are less clear. Peri-ictal headache often presents with migraine-like symptoms and can be severe. A correct diagnosis and management are paramount. It was demonstrated that cortical hyperexcitability may underlie both epilepsy and migraine. A recent study linked spreading depolarisation, the supposed underlying pathophysiological mechanism of migraine with aura, to epilepsy. Although this study was carried out in patients who had suffered a subarachnoid haemorrhage, the finding may shed light on pathophysiological mechanisms common to epilepsy and migraine.

The electroencephalography (EEG) signal has a high complexity, and the process of extracting clinically relevant features is achieved by visual analysis of the recordings. The interobserver agreement in EEG interpretation is only moderate. This is partly due to the method of reporting the findings in free-text format. The purpose of our endeavor was to create a computer-based system for EEG assessment and reporting, where the physicians would construct the reports by choosing from predefined elements for each relevant EEG feature, as well as the clinical phenomena (for video-EEG recordings). A working group of EEG experts took part in consensus workshops in Dianalund, Denmark, in 2010 and 2011. The faculty was approved by the Commission on European Affairs of the International League Against Epilepsy (ILAE). The working group produced a consensus proposal that went through a pan-European review process, organized by the European Chapter of the International Federation of Clinical Neurophysiology. The Standardised Computer-based Organised Reporting of EEG (SCORE) software was constructed based on the terms and features of the consensus statement and it was tested in the clinical practice. The main elements of SCORE are the following: personal data of the patient, referral data, recording conditions, modulators, background activity, drowsiness and sleep, interictal findings, "episodes" (clinical or subclinical events), physiologic patterns, patterns of uncertain significance, artifacts, polygraphic channels, and diagnostic significance. The following specific aspects of the neonatal EEGs are scored: alertness, temporal organization, and spatial organization. For each EEG finding, relevant features are scored using predefined terms. Definitions are provided for all EEG terms and features. SCORE can potentially improve the quality of EEG assessment and reporting; it will help incorporate the results of computer-assisted analysis into the report, it will make possible the build-up of a multinational database, and it will help in training young neurophysiologists.

Background The CMAP (Compound Muscle Action Potential) scan is a non-invasive electrodiagnostic tool, which provides a quick and visual assessment of motor unit potentials as electrophysiological components that together constitute the CMAP. The CMAP scan records the electrical activity of the muscle (CMAP) in response to transcutaneous stimulation of the motor nerve with gradual changes in stimulus intensity. Large MUs, including those that result from collateral reinnervation, appear in the CMAP scan as so-called steps, i.e., clearly visible jumps in CMAP amplitude. The CMAP scan also provides information on nerve excitability. This study aims to evaluate the influence of the stimulation protocol used on the CMAP scan and its quantification. Methods The stimulus frequency (1, 2 and 3 Hz), duration (0.05, 0.1 and 0.3 ms), or number (300, 500 and 1000 stimuli) in CMAP scans of 23 subjects was systematically varied while the other two parameters were kept constant. Pain was measured by means of a visual analogue scale (VAS). Non-parametric paired tests were used to assess significant differences in excitability and step variables and VAS scores between the different stimulus parameter settings. Results We found no effect of stimulus frequency on CMAP scan variables or VAS scores. Stimulus duration affected excitability variables significantly, with higher stimulus intensity values for shorter stimulus durations. Step variables showed a clear trend towards increasing values with decreasing stimulus number. Conclusions A protocol delivering 500 stimuli at a frequency of 2 Hz with a 0.1 ms pulse duration optimized CMAP scan quantification with a minimum of subject discomfort, artefact and duration of the recording. CMAP scan variables were influenced by stimulus duration and number; hence, these need to be standardized in future studies.

OBJECTIVES: The case history is the cornerstone for the diagnosis of carpal tunnel syndrome (CTS). The value of neurological examination in CTS seems limited. In this study, we investigated the interobserver agreement in case history of CTS and the potential additional value of neurological examination. METHODS: Case history was taken and neurological examination was done in all patients referred for a possible CTS during a 6-month period. This was done independently by 2 senior neurologists. RESULTS: We studied 119 patients. The interobserver agreement for the conclusion of CTS after history was high (k = 0.79). Neurological examination rarely changed the diagnosis based on the case history. CONCLUSIONS: This study shows a high interobserver agreement in the diagnosis of CTS based on patient history alone. Neurological examination rarely changed this diagnosis, suggesting a prominent role for the case history and a limited role for neurological examination. This may have practical implications. Copyright

We hypothesized that action potentials evoked by distal stimulation might trigger ectopic activity (multiplet discharges, MDs). By studying MDs, we investigated the involvement of the axonal part of the peripheral motor neuron in amyotrophic lateral sclerosis (ALS) and progressive muscular atrophy (PMA). We performed stimulated high-density surface EMG recordings of the thenar muscles in 10 ALS/PMA patients, five recordings per patient over a three-month period. Furthermore, motor unit number estimates (MUNE) and ALSFRS-R scores were obtained in sessions 1 and 5. MDs were found in all patients, in 21% of the sampled motor units, and in response to 2.4% of the stimulations. The interspike interval range of the MD components was 2.9-6.5 ms, which is compatible only with a distal MD origin. The number of MDs, as percentage of the number of applied stimuli, was correlated with a decline in ALSFRS-R (r = 0.80, p = 0.006) and MUNE (r = 0.72, p = 0.02). In conclusion, MDs can be elicited with electrical stimulation in ALS and PMA patients. Analysis of MD characteristics provides further indications for pathophysiological excitability changes in the most distal part of the motor neuron. MDs are associated with clinical deterioration.

EEG inter-burst interval (IBI) and its evolution is a robust parameter for grading hypoxic encephalopathy and prognostication in newborns with perinatal asphyxia. We present a reliable algorithm for the automatic detection of IBIs. This automated approach is based on adaptive segmentation of EEG, classification of segments and use of temporal profiles to describe the global distribution of EEG activity. A pediatric neurologist has blindly scored data from 8 newborns with perinatal postasphyxial encephalopathy varying from mild to severe. 15 minutes of EEG have been scored per patient, thus totaling 2 hours of EEG that was used for validation. The algorithm shows good detection accuracy and provides insight into challenging cases that are difficult to detect.

Monitoring the electroencephalogram (EEG) in sick newborn babies in the neonatal intensive care units (NICU) gives important information about brain function. Seizures are frequently seen in the EEG of the sick neonate, and usually denote serious underlying brain dysfunction. Current clinical practice assumes that neonatal seizures have to be treated to prevent further injury to the brain. Recording of amplitude integrated EEG (aEEG) or the full EEG supports treatment decisions as well as prognostication has become standard practice in many NICUs. aEEG has become popular in recent years due to its user friendliness. A full EEG offers a more reliable window to study the ongoing activity in the newborn brain with high temporal and relatively good spatial resolution. However, the expertise required to register and interpret EEG is not available around the clock in the NICUs. For this purpose, automated monitoring devices have been developed, to assist neonatologists at the bedside and neurophysiologists in reviewing large amounts of monitoring data. The main topic of this chapter is automated detection of neonatal seizures and its possible impact in clinical practice. Three different detection approaches are reviewed: model-based, heuristic and classifier-based. Also a futuristic view on automated EEG analysis systems will be given.

The objective of this review was to evaluate the available medical literature concerning the electroencephalogram (EEG) during hypertensive disorders of pregnancy. All articles found during a MEDLINE and Embase database search on the subject of EEG differences associated with hypertensive disorders in pregnancy were screened for eligibility. In all, 22 articles which describe the EEG during preeclampsia (PE)/eclampsia were retrieved. Abnormal EEG findings were observed in the majority of the preeclamptic/eclamptic patients, consisting of slow waves most frequently localized in the occipital lobe, as well as spike discharges. The EEG abnormalities in PE/eclampsia were reversible in the majority of the cases. We conclude that these described abnormalities may be interpreted as a warning sign of deterioration of brain function in PE/eclampsia. However, some caution regarding this conclusion is advised because most of the retrieved articles were published in the 1950s and 1960s, and were not consistent with current clinical guidelines or medical terminology. Further research is needed to establish the clinical value of implementing EEGs in the assessment of the preeclamptic/eclamptic patient. Target Audience: Obstetricians & Gynecologists, Neurologists, Family Physicians Learning Objectives: After completion of this educational activity, the obstetrician, gynecologist and neurologist should be better able to evaluate whether the EEG is normal for pregnancy; distinguish EEG abnormalities in hypertensive disorders in pregnancy, and assess the value of EEG abnormalities in preeclampsia (PE)/eclampsia for the detection of early signs of ischemia. Copyright

Background In Guillain–Barre syndrome (GBS), the diversity in electrophysiological subtypes is unexplained but may be determined by geographical factors and preceding infections. Acute motor axonal neuropathy (AMAN) is a frequent GBS variant in Japan and one study proposed that in Japan, Campylobacter jejuni infections exclusively elicit AMAN. In The Netherlands C jejuni is the predominant type of preceding infection yet AMAN is rare. This may indicate that not all Dutch GBS patients with C jejuni infections have AMAN. Objective To determine if GBS patients with a preceding C jejuni infection in The Netherlands exclusively have AMAN. Methods Retrospective analysis of preceding infections in relation to serial electrophysiology and clinical data from 123 GBS patients. C jejuni related cases were defined as having preceding diarrhoea and positive C jejuni serology. Electrophysiological characteristics in C jejuni related cases were compared with those in viral related GBS patients. In addition, eight GBS patients from another cohort with positive stool cultures for C jejuni were analysed. Results 17 (14%) of 123 patients had C jejuni related GBS. C jejuni patients had lower motor and higher sensory action potentials compared with viral related cases. Nine (53%) C jejuni patients had either AMAN or inexcitable nerves. However, three (18%) patients fulfilled the criteria for acute inflammatory demyelinating polyneuropathy (AIDP). Also, two (25%) of eight additional patients with a C jejuni positive stool sample had AIDP. Conclusion In The Netherlands, C jejuni infections are strongly, but not exclusively, associated with axonal GBS. Some patients with these infections fulfil current criteria for demyelination.