Journal of Clinical Neurophysiology最新文献

Purpose: Carotid endarterectomy (CEA) is a common surgical intervention, but the perioperative stroke risk may be as high as 12%, with an average reported rate approximately 3%. Intraoperative neurophysiologic monitoring (IONM) can provide real-time feedback to guide the surgical team on whether or not to place a temporary shunt to reduce the length of time that cerebral blood flow is interrupted. In this study, the authors assessed the utility of adding transcranial motor evoked potentials (tcMEPs) to other IONM modalities in early detection of cerebral ischemia during CEAs.

Methods: The authors conducted a retrospective review of CEA cases from 2010 to 2020 at this center and included all CEA cases with electroencephalogram (EEG), somatosensory evoked potentials (SSEPs) and tcMEPs. The authors analyzed the IONM reports for case details. The primary study end points were types of IONM changes and their relative onsets to carotid occlusion.

Results: The authors identified 254 patients who underwent 274 CEAs using multimodal IONM. In 35 (12.7%) cases, there were critical IONM changes with 33 (12.0%) demonstrating changes during clamping of the carotid artery. Of these 35 cases, changes in both SSEPs and tcMEPs were observed in 20 (57.1%), only SSEP changes in 8 (22.9%), and only tcMEP changes in 2 (5.7%). In 5 cases, tcMEP loss was noted to precede other IONM changes. In total, 82% of significant changes were observed within the first 10 minutes of carotid clamping.

Conclusions: This large cohort study shows that multimodal IONM with tcMEPs can contribute to the early detection of cerebral ischemia during CEA.

Purpose: Charcot-Marie-Tooth disease (CMT), the most common form of hereditary neuropathy causes varying disability. Valid and accessible tools are needed for clinical and research evaluation. Previous studies have shown sonographic muscle thickness correlates with clinical and electrophysiological findings in many neuromuscular disorders. This study examines the correlation between muscle thickness in CMT1A patients with disease progression and clinical parameters, including the CMT neuropathy scale.

Methods: Prospective study evaluating CMT1A patients between January and December 2023 at the neuromuscular unit in Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. Patients underwent comprehensive clinical evaluation including the CMT neuropathy scale, and quantitative sonographic evaluation of muscle thickness in eight limb muscles.

Results: Eight CMT1A patients were examined, five on two occasions. Sum muscle thickness measured by ultrasound strongly correlated with most clinical parameters, including the CMT neuropathy scale. However, disease progression showed strong correlation with CMT neuropathy scale only.

Conclusions: In CMT1A patients, standardized quantitative sonographic muscle thickness assessment is a valid and promising tool for evaluating disease burden and, to a lesser extent, progression, showing strong correlations with key clinical parameters. Consistent with prior studies of other neuromuscular disorders.

Purpose: This systematic review and meta-analysis aimed to evaluate the effectiveness of automatic detection systems for tonic seizures, focusing on different noninvasive modalities, algorithms, and performance metrics.

Methods: Following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, a comprehensive search was conducted across PubMed, Scopus, and Wiley databases for studies published between 2014 and 2024. Inclusion criteria targeted studies assessing automatic detection systems for tonic seizures using various modalities. Performance metrics such as sensitivity, specificity, accuracy, and false alarm rates per hour (False-Positive Alarm Rate per hour) were analyzed and recalculated where necessary to ensure comparability.

Results: A total of 19 studies met the inclusion criteria. Multimodal systems integrating signals from accelerometry, gyroscopes, and other sensors demonstrated the highest sensitivities (up to 1.0) and accuracies (up to 0.97), significantly outperforming single-modality approaches. False alarm rates were lowest in controlled settings, particularly for ECG-based systems, but real-world applications highlighted variability and challenges with noise and signal acquisition. The findings underscore the potential of combining physiologic and neural signals with machine learning techniques to improve detection accuracy.

Conclusions: Although recent advances in neurotechnology have enabled substantial progress in tonic seizure detection, significant challenges remain, including variability in performance metrics, generalizability to diverse populations, and scalability for real-world applications. Future research should focus on standardizing evaluation frameworks, diversifying training data sets, and validating systems in clinical and outpatient settings.

Purpose: These consensus guidelines by the American Clinical Neurophysiology Society (ACNS) describe best practices for performing intraoperative Electrocorticography (ioECoG) using subdural or depth electrodes for adult and pediatric population.

Methods: A group of ACNS members was convened to develop technical standards for performing ioECoG. PubMed searches were performed to identify pertinent peer-reviewed literature. Sections were assigned to individual authors based on expertise. Consensus was achieved during subsequent group discussions to develop evidence-based recommendations to the extent possible.

Recommendations: Communication between the neurosurgical and the neurophysiology teams is essential in verifying and documenting the location of the contacts. Most authors recommend ioECoG recordings of at least 5 and up to 30 minutes in duration to allow for sufficient observation of interictal activity. The anesthesia should be adjusted to allow continuous EEG activity and to minimize the effect on the ioECoG recording during general anesthesia or awake surgery. The surgical procedure and technical report should separate ioECoG recordings to define the irritative zone from ioECoG findings during functional mapping. The neurophysiology physician's physical presence in the operating room is required in the definition of the services.

Conclusion: These consensus guidelines by the ACNS describe best practices for performing intraoperative ECoG based on published literature and expert consensus.

Introduction: In neuromuscular diseases, respiratory failure is a major complication. Pulmonary function tests are generally used to assess respiratory function but can be influenced by a number of factors. Nerve conduction studies of the phrenic nerve (PN) is a simple, noninvasive, and safe method to assess diaphragm compromise in neuromuscular diseases.

Methods: A group of 132 (78 males) healthy subjects, aged between 23 and 90 years, was studied, with bilateral stimulation of the PN, with recording of diaphragm motor responses. Anthropometric variables (sex, age, height, and weight) were collected, and their influence on diaphragm motor response was assessed. Side-to-side differences were also analyzed.

Results: PN compound muscle action potential (CMAP) had significantly higher amplitude and area on the left side. Men had longer latency, and higher amplitude and area when compared with women, on both sides. Age was a significant factor influencing CMAP latency, with an average increase of 0.25 ms per decade of life. In men, a latency longer than 9.5 ms and a CMAP amplitude lower than 0.62 mV should be considered abnormal, while in women, the values are 8.5 ms and 0.48 mV, respectively.

Conclusions: PN conduction studies offer a simple and reliable technique readily applicable in clinical settings. Diaphragm CMAP parameters are significantly influenced by the anthropometric variables of sex and age. Notably, CMAP amplitude and area are greater for the left PN.

Purpose: Single-fiber electromyography is the most sensitive tool for diagnosing neuromuscular diseases but is limited in differentiating between presynaptic and postsynaptic neuromuscular junction involvement with increased jitter. With rising botulinum toxin (BoNT) use for therapeutic and cosmetic applications, referrals for electromyography because of myasthenia-like symptoms have increased, complicating differential diagnosis. This study examines whether spike count measurements from single-use concentric needle electrodes can distinguish BoNT effects from neuromuscular junction diseases such as myasthenia gravis.

Methods: We analyzed 49 patients and 26 controls, assessing jitter and spike count with concentric needle electrodes in the frontalis muscle. Groups included those exposed to BoNT (>1 month and <1 month prior) and patients with myasthenia gravis, with normal jitter controls for comparison. Data were analyzed for jitter, spike count, and additional electrophysiologic parameters using standard statistical tests ( P < 0.05).

Results: Results showed that spike counts were significantly different across the groups. Higher spike counts with lower single spike frequency were found in patients with BoNT exposure >1 month, suggesting a differentiation point from primary neuromuscular involvement. In contrast, patients with myasthenia gravis exhibited increased jitter without increased spike counts.

Conclusions: These findings indicate that spike count analysis with concentric needle electrodes may aid in differentiating iatrogenic BoNT effects from primary neuromuscular junction disorders, such as myasthenia gravis. However, further studies with larger sample sizes are necessary to validate these results.

Purpose: To improve EEG source localization results of interictal epileptic discharges (IED) by applying postprocessing step to electrical source imaging (ESI).

Methods: Localization error of ESI was evaluated in comparison to known sources of stimulation potentials (ESP) by recording simultaneous stereo-EEG/scalp EEG. Error vectors were defined as the offset of the ESI-dipole of ESP to the stereo-EEG contacts used for stimulation. The inverted error vector was applied to the ESI-dipole of IED (IED-dipole).

Results: Seven IED clusters were evaluated. Corrected IED-dipoles were located closer to IED-onset contacts on stereo-EEG than uncorrected IED-dipoles ( median [ IQR ]: 7.8 [2.5] versus 18.7 [10.7] mm, P = 0.02). Anatomically, for high skull conductivities, all corrected IED-dipoles were located in cortical structures or adjacent to epileptogenic lesion, whereas uncorrected IED-dipoles were located in white matter or CSF ( P = 0.02). Physiologically, cortical extent of IED generators estimated from corrected IED-dipoles was 16.5 cm 2 ( IQR = 10.4 cm 2 ) and 7.4 cm 2 (range 5.8-9.2 cm 2 ) in the group of anterior temporal IED and prefrontal IED, respectively; the former was concordant with the extent estimated by subdural electrodes. In addition, the relationship of stereo-EEG IED amplitude (a) drop with increasing distance (d) from corrected IED-dipole could be modeled as a negative power equation a(d)∝1/d b ( R2 = 0.87, P < 0.01), with b ranging from 0.79 to 2.3, median: 1.57, consistent with a simulation model of the sensitivity of intracerebral electrode.

Conclusions: Application of inverted error vector reduces localization error and shifts IED-dipole to an anatomically and physiologically plausible location.

Abstract: Peripheral nerve hyperexcitability syndromes are characterized by spontaneous motor discharges, fasciculations, and cramps. Morvan syndrome differs from Isaacs syndrome by its central nervous system involvement, autonomic dysfunction, and profound sleep disruption, often presenting as agrypnia excitata. We report two seropositive patients with cramps, fasciculations, insomnia, and autonomic dysfunction but without neuropsychiatric features. Case 1, a 49-year-old man, had LGI1 antibodies and presented with insomnia and autonomic symptoms. Video-polysomnography revealed severe insomnia with absent N3/REM sleep, reduced spindles and K-complexes, and oneiric stupor behaviors. Case 2, a 25-year-old woman, had LGI1 and CASPR2 antibodies, neuropathic pain, and fasciculations. Video-polysomnography demonstrated REM sleep without atonia, rapid N1-to-REM transitions, and microstructural abnormalities of N2 sleep. Tumor screening was negative in both; both improved with immunotherapy. A literature review confirms that video-polysomnography consistently reveals central involvement in Morvan syndrome, characterized by loss of sleep spindles, K-complexes, and pathological REM features, while Isaacs syndrome preserves normal sleep structure. Video-polysomnography is therefore an essential tool to detect subclinical central nervous system dysfunction in Morvan syndrome, especially when neuropsychiatric symptoms are absent, and helps distinguish it from Isaacs syndrome.