Clinical Neurophysiology最新文献

Objective: Direct cortical responses (DCR) and axono-cortical evoked potentials (ACEP) are generated by electrically stimulating the cortex either directly or indirectly through white matter pathways, potentially leading to different electrogenic processes. For ACEP, the slow conduction velocity of axons (median ≈ 4 m.s^-1) is anticipated to induce a delay. For DCR, direct electrical stimulation (DES) of the cortex is expected to elicit additional cortical activity involving smaller and slower non-myelinated axons. We tried to validate these hypotheses.

Methods: DES was administered either directly on the cortex or to white matter fascicles within the resection cavity, while recording DCR or ACEP at the cortical level in nine patients.

Results: Short but significant delays (≈ 2 ms) were measurable for ACEP immediately following the initial component (≈ 7 ms). Subsequent activities (≈ 40 ms) exhibited notable differences between DCR and ACEP, suggesting the presence of additional cortical activities for DCR.

Conclusion: Distinctions between ACEPs and DCRs can be made based on a delay at the onset of early components and the dissimilarity in the shape of the later components (>40 ms after the DES artifact).

Significance: The comparison of different types of evoked potentials allows to better understand the effects of DES.

Objective: Motivated by previous inconsistent findings, this study aims to improve understanding of sensorimotor beta (β; 15-30 Hz) and alpha (α; 8-14 Hz) speech-related power differences between stuttering and non-stuttering adults.

Methods: Electroencephalography was recorded as adults who stutter (AWS) and matched fluent controls answered questions in Quiet and Informational Masked backgrounds. Bilateral sensorimotor β and α power during speech planning and execution were measured from mu (μ) rhythm components.

Results: Compared to controls, AWS exhibited reduced left hemisphere β and α power in both speaking conditions during speech planning and execution. AWS displayed reduced left α power in the Informational Masking compared to Quiet. Within AWS β and α power, which were tightly coupled, oppositely predicted stuttering severity and β-α dissociation (β minus α) was the strongest predictor.

Conclusion: Neither β nor α power are reliable markers of speech motor stability due to their sensitivity to speech task automaticity. However, relationships between these two sensorimotor rhythms warrant further investigation for understanding motor control.

Significance: Data help explain previous mixed findings in reference to extant models of speech motor control in stuttering and may have clinical implications for developing neurostimulation protocols targeting improved speech fluency.

Objective: This study aimed to optimally evaluate the effect of the long-interval intracortical inhibition (LICI) in the dorsolateral prefrontal cortex (DLPFC) through transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) by eliminating the volume conductance with signal source estimation and using a realistic sham coil as a control.

Methods: We compared the LICI effects from the DLPFC between the active and sham stimulation conditions in 27 healthy participants. Evoked responses between the two conditions were evaluated at the sensor and source levels.

Results: At the sensor level, a significant LICI effect was confirmed in the active condition in the global mean field power analysis; however, in the local mean field power analysis focused on the DLPFC, no LICI effect was observed in the active condition. However, in the signal source estimation analysis for the DLPFC, we could reconfirm a significant LICI effect (p = 0.023) in the interval 30-250 ms post-stimulus, compared to the sham condition.

Conclusions: Our results demonstrate that application of realistic sham stimulation condition and source estimation method allows for a robust and optimal identification of the LICI effect in the DLPFC.

Significance: The optimal DLPFC-LICI effect was identified by the use of the sophisticated sham coil.

On July 6th of 1924 Hans Berger -a German psychiatrist- first recorded electric signals from the human brainvia scalp electrodes. This date marks the beginning of Electroencephalography. In this review a representative panel of past and present Officers of the International Federation of Clinical Neurophysiology (IFCN) and of its Official Journal briefly summarizes the past, present and future of Electroencephalographic and related neurophysiological techniques' impact and the role of the IFCN in global collaboration, education, standardization, research innovation, and clinical practice.

Introduction/objective: Biallelic expansion of the pentanucleotide AAGGG in the RFC1- gene is associated with cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS). This study aimed to comprehensively characterise this condition by conducting an in-depth neurophysiological examination of afflicted patients.

Methods: A retrospective analysis was conducted in 31 RFC1-positive patients. Assessment included clinical examination and electrodiagnostic tests: nerve conduction studies, F waves, needle electromyography, H, blink and masseter reflexes; Autonomic Nervous System (ANS): Heart Rate Variability, Sympathetic Skin Response and Electrochemical Skin Conductance, and Quantitative Sensory Test (QST). Medullar tracts were assessed using Somatosensory Evoked Potentials (SEPs) and Transcranial Magnetic Stimulation.

Results: All patients exhibited moderate to severe sensory axonal neuropathy/neuronopathy, whereas motor nerve conduction parameters and the pyramidal pathway showed no abnormalities. Tibial nerve SEPs were absent or severely attenuated in all patients, and were moderately affected by the median nerve. H-reflexes were preserved in 85.7% and blink reflex in 60% of tested patients. ANS tests yielded predominantly normal results, although 74% demonstrated impaired QST.

Conclusions: Our findings highlight the characteristic features of sensory neuropathy/neuronopathy and severe somatosensory deficits, with predominantly preserved H-reflexes and motor sparing. Thermoalgesic fibres are frequently involved, whereas the ANS is relatively preserved.

Significance: Neurophysiological examinations can objectively characterize the spectrum of RFC1-related disease.

This article updates the prior 2018 consensus statement by the National Network of Depression Centers (NNDC) on the use of transcranial magnetic stimulation (TMS) in the treatment of depression, incorporating recent research and clinical developments. Publications on TMS and depression between September 2016 and April 2024 were identified using methods informed by PRISMA guidelines. The NNDC Neuromodulation Work Group met monthly between October 2022 and April 2024 to define important clinical topics and review pertinent literature. A modified Delphi method was used to achieve consensus. 2,396 abstracts and manuscripts met inclusion criteria for review. The work group generated consensus statements which include an updated narrative review of TMS safety, efficacy, and clinical features of use for depression. Considerations related to training, roles/responsibilities of providers, and documentation are also discussed. TMS continues to demonstrate broad evidence for safety and efficacy in treating depression. Newer forms of TMS are faster and potentially more effective than conventional repetitive TMS. Further exploration of targeting methods, use in special populations, and accelerated protocols is encouraged. This article provides an updated overview of topics relevant to the administration of TMS for depression and summarizes expert, consensus opinion on the practice of TMS in the United States.