Clinical Neurophysiology最新文献

Objective

Temporally extended signal space separation (tSSS) is a powerful method for artifact suppression in magnetoencephalography (MEG). Because tSSS first separates MEG signals coming from inside and outside a certain sphere, definition of the sphere origin is important. For this study, we explored the influence of origin choice on tSSS performance in spontaneous and evoked activity from epilepsy patients.

Methods

Interictal epileptiform discharges (IEDs) and somatosensory evoked fields (SEFs) were processed with two tSSSs: one with the default origin of (0, 0, 40 mm) in the head coordinate, and the other with an individual origin estimated using each patient’s anatomical magnetic resonance imaging (MRI). Equivalent current dipoles (ECDs) were calculated for the data. The ECD location and quality of estimation were compared across conditions.

Results

MEG data from 21 patients revealed marginal differences in ECD location, but the estimation quality inferred from goodness of fit (GOF) and confidence volume (CV) was better for the tSSS with individual origins. This choice affected IEDs more than it affected SEFs.

Conclusions

Individual sphere model resulted in better GOF and CV.

Significance

Application of tSSS using an individual origin would be more desirable when available. This parameter might influence spontaneous activity more strongly.

One hundred years ago, Erlanger and Gasser demonstrated that conduction velocity is correlated with the diameter of a peripheral nerve axon. Later, they also demonstrated that the functional role of the axon is related to its diameter: touch is signalled by large-diameter axons, whereas pain and temperature are signalled by small-diameter axons. Certain discoveries in recent decades prompt a modification of this canonical classification. Here, we review the evidence for unmyelinated (C) fibres signalling touch at a slow conduction velocity and likely contributing to affective aspects of tactile information. We also review the evidence for large-diameter Aβ afferents signalling pain at ultrafast conduction velocity and likely contributing to the rapid nociceptive withdrawal reflex. These discoveries imply that conduction velocity is not as clear-cut an indication of the functional role of the axon as previously thought. We finally suggest that a future taxonomy of the peripheral afferent nervous system might be based on the combination of the axońs molecular expression and electrophysiological response properties.

Objective

We investigated the role of transverse temporal gyrus and adjacent cortex (TTG+) in facial expressions and perioral movements.

Methods

In 31 patients undergoing stereo-electroencephalography monitoring, we describe behavioral responses elicited by electrical stimulation within the TTG+. Task-induced high-gamma modulation (HGM), auditory evoked responses, and resting-state connectivity were used to investigate the cortical sites having different types of responses on electrical stimulation.

Results

Changes in facial expressions and perioral movements were elicited on electrical stimulation within TTG+ in 9 (29%) and 10 (32%) patients, respectively, in addition to the more common language responses (naming interruptions, auditory hallucinations, paraphasic errors). All functional sites showed auditory task induced HGM and evoked responses validating their location within the auditory cortex, however, motor sites showed lower peak amplitudes and longer peak latencies compared to language sites. Significant first-degree connections for motor sites included precentral, anterior cingulate, parahippocampal, and anterior insular gyri, whereas those for language sites included posterior superior temporal, posterior middle temporal, inferior frontal, supramarginal, and angular gyri.

Conclusions

Multimodal data suggests that TTG+ may participate in auditory-motor integration.

Significance

TTG+ likely participates in facial expressions in response to emotional cues during an auditory discourse.

Background

Immune effector cell-associated neurotoxicity syndrome (ICANS) is common after chimeric antigen receptor T-cell (CAR-T) therapy.

Objective

This study aimed to assess the impact of preinfusion electroencephalography (EEG) abnormalities and EEG findings at ICANS onset for predicting ICANS risk and severity in 56 adult patients with refractory lymphoma undergoing CAR-T therapy.

Study design

EEGs were conducted at the time of lymphodepleting chemotherapy and shortly after onset of ICANS.

Results

Twenty-eight (50%) patients developed ICANS at a median time of 6 days after CAR-T infusion. Abnormal preinfusion EEG was identified as a risk factor for severe ICANS (50% vs. 17%, P = 0.036). Following ICANS onset, EEG abnormalities were detected in 89% of patients [encephalopathy (n = 19, 70%) and/or interictal epileptiform discharges (IEDs) (n = 14, 52%)]. Importantly, IEDs seemed to be associated with rapid progression to higher grades of ICANS within 24 h.

Conclusions

If confirmed in a large cohort of patients, these findings could establish the basis for modifying current management guidelines, enabling the identification of patients at risk of neurotoxicity, and providing support for preemptive corticosteroid use in patients with both initial grade 1 ICANS and IEDs at neurotoxicity onset, who are at risk of neurological impairment.

Objective

Increasing evidence suggests that the seizure-onset pattern (SOP) in stereo-electroencephalography (SEEG) is important for localizing the “true” seizure onset. Specifically, SOPs with low-voltage fast activity (LVFA) are associated with seizure-free outcome (Engel I). However, several classifications and various terms corresponding to the same pattern have been reported, challenging its use in clinical practice.

Method

Following the Preferred Reporting Items of Systematic reviews and Meta-Analyses (PRISMA) guideline, we performed a systematic review of studies describing SOPs along with accompanying figures depicting the reported SOP in SEEG.

Results

Of 1799 studies, 22 met the selection criteria. Among the various SOPs, we observed that the terminology for low frequency periodic spikes exhibited the most variability, whereas LVFA is the most frequently used term of this pattern. Some SOP terms were inconsistent with standard EEG terminology. Finally, there was a significant but weak association between presence of LVFA and seizure-free outcome.

Conclusion

Divergent terms were used to describe the same SOPs and some of these terms showed inconsistencies with the standard EEG terminology. Additionally, our results confirmed the link between patterns with LVFA and seizure-free outcomes. However, this association was not strong.

Significance

These results underline the need for standardization of SEEG terminology.

Objective

Infant hypersensitivity affects daily challenges and parental stress. Although the crucial role of tactile sensation in infants' brain function has been highlighted, hypersensitive infants and their families lack support. Electroencephalography may be useful for understanding hypersensitivity traits. We investigated the relationship between infant perceptual hypersensitivity and parental stress, somatosensory-evoked potential (SEP), and magnitude-squared coherence (MSC) in the general population.

Methods

Infants aged 8 months (n = 63) were evaluated for hypersensitivity and parental stress using a questionnaire and for cortical activity using electroencephalography. Vibration stimuli were applied to the infant’s left foot. SEP components that peaked around 150 ms (N2) and at 200 ms (P2) after stimulus onset were evaluated by amplitude and latency at the midline electrode (Cz) and MSC between the midline electrodes (C3–C4).

Results

Parental stress was associated with infant hypersensitivity. The latency of Cz was delayed, and C3–C4 delta MSC was high in infants with hypersensitivity.

Conclusions

Increasing inter-hemispheric MSC synchrony in the stimulated condition in infants with hypersensitivity suggested atypical somatosensory cortical function.

Significance

These findings contribute to identifying, understanding the mechanisms of, and developing effective coping strategies for early-stage hypersensitivity.

Objective

To evaluate the associations between motor unit number index (MUNIX) and disease progression and prognosis in amyotrophic lateral sclerosis (ALS) in a large-scale longitudinal study.

Methods

MUNIX was performed at the patient's first visit, at 3, 6, and 12 months in 4 muscles. MUNIX data from the patients were compared with those from 38 age-matched healthy controls. Clinical data included the revised ALS functional rating scale (ALSFRS-R), the forced vital capacity (FVC), and the survival of the patients.

Results

Eighty-two patients were included at baseline, 62 were evaluated at three months, 48 at six months, and 33 at twelve months. MUNIX score was lower in ALS patients compared to controls. At baseline, MUNIX was correlated with ALSFRS-R and FVC. Motor unit size index (MUSIX) was correlated with patient survival. Longitudinal analyses showed that MUNIX decline was greater than ALSFRS-R decline at each evaluation. A baseline MUNIX score greater than 378 predicted survival over the 12-month period with a sensitivity of 82% and a specificity of 56%.

Conclusions

This longitudinal study suggests that MUNIX could be an early quantitative marker of disease progression and prognosis in ALS.

Significance

MUNIX might be considered as potential indicator for monitoring disease progression.

Objective

To investigate cortical oscillations during a sentence completion task (SC) using magnetoencephalography (MEG), focusing on the semantic control network (SCN), its leftward asymmetry, and the effects of semantic control load.

Methods

Twenty right-handed adults underwent MEG while performing SC, consisting of low cloze (LC: multiple responses) and high cloze (HC: single response) stimuli. Spectrotemporal power modulations as event-related synchronizations (ERS) and desynchronizations (ERD) were analyzed: first, at the whole-brain level; second, in key SCN regions, posterior middle/inferior temporal gyri (pMTG/ITG) and inferior frontal gyri (IFG), under different semantic control loads.

Results

Three cortical response patterns emerged: early (0–200 ms) theta-band occipital ERS; intermediate (200–700 ms) semantic network alpha/beta-band ERD; late (700–3000 ms) dorsal language stream alpha/beta/gamma-band ERD. Under high semantic control load (LC), pMTG/ITG showed prolonged left-sided engagement (ERD) and right-sided inhibition (ERS). Left IFG exhibited heightened late (2500–2550 ms) beta-band ERD with increased semantic control load (LC vs. HC).

Conclusions

SC involves distinct cortical responses and depends on the left IFG and asymmetric engagement of the pMTG/ITG for semantic control.

Significance

Future use of SC in neuromagnetic preoperative language mapping and for understanding the pathophysiology of language disorders in neurological conditions.

Background and purpose

To test the hypothesis that myoclonic seizures can evolve to tonic seizures, we documented the electroclinical features of this under-recognized seizure type.

Methods

We observed a distinct seizure pattern starting with myoclonus without returning to an interictal state, which subsequently evolved into generalized tonic seizures. The detailed symptomatic and electroencephalographic characteristics of this seizure were extracted, and the clinical manifestations, drug curative responses in patients with this seizure were reviewed and analyzed.

Results

The onset of all seizures was characterized by a preceding period of myoclonus and bursts of generalized spike or poly-spike slow wave discharges with high amplitude. This was closely followed by the occurrence of tonic seizures, which were distinguished by bursts of generalized fast activity at 10 Hz or higher frequency. This under-recognized seizure type has been designated as myoclonic-to-tonic (MT) seizure. The number of patients identified with MT seizures in this study was 34. The prevalence rate of MT seizures was found to be higher in males. While MT seizures typically included a tonic component, it should be noted that some patients experiencing this seizure type never presented with isolated tonic seizures. Generalized Epilepsy not further defined (GE) accounted for approximately one-third of the diagnosed cases, followed by Lennox-Gastaut syndrome and Epilepsy with Myoclonic-Atonic seizures. In comparison to other types of epilepsy, GE with MT seizures demonstrated a more favorable prognosis.

Conclusions

The classification of myoclonic-to-tonic seizure represents a novel approach in comprehending the ictogenesis of generalized seizures and can provide valuable assistance to clinicians in epilepsy diagnosis.