重复频率电刺激对儿童重症肌无力的诊断价值

目的：研究重复频率电刺激（RNS）在儿童重症肌无力（MG）诊断中的价值。方法：对67例儿童MG患儿分别进行面、腋、尺神经的低频RNS，并对结果进行分析。结果：67例MG患儿中属眼肌型（Ⅰ型，最轻型）50例RNS检测结果阳性率为58％～75％；属于全身型（Ⅱ型）17例RNS检测结果阳性率达100％。结论：MG患儿RNS检测结果与临床病情的严重程度呈正相关。     

Repetitive thought is associated with both subjectively and objectively recorded polysomnographic indices of disrupted sleep in insomnia disorder

BackgroundRepetitive thought is a hallmark of several psychopathological conditions and in particular a perpetuating and maintaining factor in Insomnia Disorder. Accordingly, one of the primary complaints reported by Insomnia patients is the inability to shut-off or control thoughts. Worry and rumination are the two best-known styles of repetitive thought leading to sleep disturbances. The aim of this study was to investigate the relationship of these two cognitive processes on nocturnal sleep indices objectively recorded by polysomnography.Methods27 Insomnia patients and 20 healthy controls matched for sex and age were recruited and completed a comprehensive assessment aimed to evaluate sleep quality, excessive daytime sleepiness, insomnia severity, worry, rumination, depressive and anxious symptomatology, and the ability to produce reasonable cognitive estimates. Sleep diaries indices and polysomnographic recordings were evaluated.ResultsInsomnia patients showed increased levels of worry and rumination in comparison to controls. Our polysomnographic study revealed that these two different types of repetitive thoughts were significantly associated with objective sleep variables. In particular, heightened worry levels were related to an augmented wake after sleep onset and diminished total sleep time, sleep efficiency and percentage of REM sleep, whereas rumination was associated with an increase of sleep latency and a decrement of sleep efficiency. However, after controlling for anxiety and depressive symptoms only worry maintained a significant relationship with polysomnographic variables. Remarkably, repetitive thoughts did not correlate with microstructural REM sleep features and quantitative EEG analysis.ConclusionOur study indicates the existence of a significant relationship between daytime levels of repetitive thought and sleep, thus corroborating the hypothesis of an interplay between cognitive and nocturnal electrophysiological activity in insomniacs.     

Finger tapping analysis in patients with Parkinson’s disease and atypical parkinsonism

The goal of this study was to investigate repetitive finger tapping patterns in patients with Parkinson’s disease (PD), progressive supranuclear palsy–Richardson syndrome (PSP-R), or multiple system atrophy of parkinsonian type (MSA-P). The finger tapping performance was objectively assessed in PD (n = 13), PSP-R (n = 15), and MSA-P (n = 14) patients and matched healthy controls (HC; n = 14), using miniature inertial sensors positioned on the thumb and index finger, providing spatio-temporal kinematic parameters. The main finding was the lack or only minimal progressive reduction in amplitude during the finger tapping in PSP-R patients, similar to HC, but significantly different from the sequence effect (progressive decrement) in both PD and MSA-P patients. The mean negative amplitude slope of −0.12°/cycle revealed less progression of amplitude decrement even in comparison to HC (−0.21°/cycle, p = 0.032), and particularly from PD (−0.56°/cycle, p = 0.001), and MSA-P patients (−1.48°/cycle, p = 0.003). No significant differences were found in the average finger separation amplitudes between PD, PSP-R and MSA-P patients (p_msa-pd = 0.726, p_msa-psp = 0.363, p_psp-pd = 0.726). The lack of clinically significant sequence effect during finger tapping differentiated PSP-R from both PD and MSA-P patients, and might be specific for PSP-R. The finger tapping kinematic parameter of amplitude slope may be a neurophysiological marker able to differentiate particular forms of parkinsonism.     

Cortical control of Inhibition of Return: Exploring the causal contributions of the left parietal cortex

Inhibition of Return (IOR) refers to longer response times (RTs) when processing information from an already inspected spatial location. This effect encourages orienting towards novel locations and may be hence adaptive to efficiently explore our environment. In a previous study (Bourgeois, Chica, Valero-Cabre, & Bartolomeo, 2013), we demonstrated that repetitive Transcranial Magnetic Stimulation (rTMS) over right hemisphere parietal sites, such as the intra-parietal sulcus (IPS), or the temporo-parietal junction (TPJ), lastingly interfered with manual but not saccadic IOR, for ipsilateral right-sided targets. For contralateral left-sided targets, rTMS over the right IPS, but not over the right TPJ, impaired both manual and saccadic IOR. In the present study, we investigated hemispheric differences in the cortical control of IOR by stimulating left parietal sites with the same design. Contrary to the stimulation of the right hemisphere, rTMS over the left IPS or TPJ did not produce significant modulations of either manual or saccadic IOR. This evidence extends to IOR the validity of current models of hemispheric asymmetries in the control of visuospatial attention.     

Does pericentral mu-rhythm “power” corticomotor excitability? – A matter of EEG perspective

BackgroundElectroencephalography (EEG) and single-pulse transcranial magnetic stimulation (spTMS) of the primary motor hand area (M1-HAND) have been combined to explore whether the instantaneous expression of pericentral mu-rhythm drives fluctuations in corticomotor excitability, but this line of research has yielded diverging results.ObjectivesTo re-assess the relationship between the mu-rhythm power expressed in left pericentral cortex and the amplitude of motor potentials (MEP) evoked with spTMS in left M1-HAND.Methods15 non-preselected healthy young participants received spTMS to the motor hot spot of left M1-HAND. Regional expression of mu-rhythm was estimated online based on a radial source at motor hotspot and informed the timing of spTMS which was applied either during epochs belonging to the highest or lowest quartile of regionally expressed mu-power. Using MEP amplitude as dependent variable, we computed a linear mixed-effects model, which included mu-power and mu-phase at the time of stimulation and the inter-stimulus interval (ISI) as fixed effects and subject as a random effect. Mu-phase was estimated by post-hoc sorting of trials into four discrete phase bins. We performed a follow-up analysis on the same EEG-triggered MEP data set in which we isolated mu-power at the sensor level using a Laplacian montage centered on the electrode above the M1-HAND.ResultsPericentral mu-power traced as radial source at motor hot spot did not significantly modulate the MEP, but mu-power determined by the surface Laplacian did, showing a positive relation between mu-power and MEP amplitude. In neither case, there was an effect of mu-phase on MEP amplitude.ConclusionThe relationship between cortical oscillatory activity and cortical excitability is complex and minor differences in the methodological choices may critically affect sensitivity.     

Repetitive Transcranial Magnetic Stimulation (rTMS) improves symptoms and reduces clinical illness in patients suffering from OCD – Results from a single-blind,randomized clinical trial with sham cross-over condition

ObjectivesBoth psychotherapeutic and psychopharmacological methods are used in the treatment of patients suffering from obsessive-compulsive disorders (OCD), and both with encouraging but also mixed results. Here, we tested the hypothesis that repetitive Transcranial Magnetic Stimulation (rTMS) improves symptoms and reduces illness severity in patients suffering from treatment-resistant OCD.MethodsA total of 21 patients (57% females; mean age: M = 35.8 years) suffering from treatment-resistant OCD were randomly assigned either to an rTMS-first-sham-second, or a sham-first-rTMS-second condition. Treatment sessions lasted for 4 weeks with five sessions per week, each of about 50 min duration. Symptoms were assessed via both self- and expert-ratings.ResultsBoth self- and expert-reported symptom severity reduced in the rTMS condition as compared to the sham condition. Full- and partial responses were observed in the rTMS-condition, but not in the sham-condition.ConclusionsThe pattern of results from this single-blind, sham- and cross-over design suggests that rTMS is a successful intervention for patients suffering from treatment-resistant OCD.