共查询到20条相似文献，搜索用时 31 毫秒
1.
Alexia-Sabine Moldovan Christian Johannes Hartmann Carlos Trenado Nicola Meumertzheim Philipp Jörg Slotty Jan Vesper Alfons Schnitzler Stefan Jun Groiss 《Brain stimulation》2018,11(5):1132-1139
Background
Shorter pulse widths than conventional pulse width settings may lead to reduction of side effects and therefore be a valuable therapeutic option for deep brain stimulation (DBS) in patients with essential tremor (ET).Objective
To compare the DBS effect of shorter pulse width at 40?μs?(DBS-40?μs) to conventional pulse width at 60?μs?(DBS-60?μs) on the therapeutic window in ET patients.Methods
For this prospective, randomized, double-blind, crossover study 9?ET patients with chronic DBS of the ventral intermediate nucleus (VIM)/posterior subthalamic area (PSA) were recruited. Therapeutic window was calculated by determining efficacy and side effect thresholds for DBS-40?μs and DBS-60?μs. Tremor Rating Scales and Kinesia tremor analyses were used to compare clinical efficacy between the considered settings and deactivated DBS (DBS-OFF). Volume of neural activation (VNA) was calculated for both efficacy and side effect thresholds at each pulse width.Results
DBS-40?μs showed a significantly larger therapeutic window than DBS-60?μs mainly due to higher side-effect thresholds. Both conditions significantly improved tremor compared to DBS-OFF, while efficacy was comparable between DBS-40?μs and DBS-60?μs. Moreover, VNA at efficacy threshold was smaller and less energy was required for tremor suppression with DBS-40?μs compared to DBS-60?μs.Conclusions
VIM/PSA-DBS with short pulse width represents a promising programming option for DBS in ET as it reduces side effects while maintaining efficient tremor suppression. Furthermore, our data support the notion of pulse width dependent selective modulation of distinct fiber tracts leading to widening of the therapeutic window. 相似文献2.
Hongmei Cao Johanna Thompson-Westra Mark Hallett Dietrich Haubenberger 《Clinical neurophysiology》2018,129(7):1467-1471
Objective
To investigate the effect of octanoic acid (OA) on the peripheral component of tremor, as well as OA’s differential effects on the central and peripheral tremor component in essential tremor (ET) patients.Methods
We analyzed postural tremor accelerometry data from a double-blind placebo-controlled cross-over study evaluating the effect of 4?mg/kg OA in ET. The weighted condition was used to identify tremor power for both the central and peripheral tremor components. Exploratory non-parametric statistical analyses were used to describe the relation between the central and peripheral component of tremor power.Results
A peripheral tremor component was identified in 4 out of 18 subjects. Tremor power was reduced after OA administration in both the central and the peripheral tremor component. There was a positive correlation of tremor power between the central and peripheral component, both after placebo and OA.Conclusions
When present, the peripheral component was closely related to the central tremor component. We hypothesize that the magnitude of the peripheral mechanical component of tremor is determined by that of the central component.Significance
Both central and peripheral component of tremor are reduced after OA, with the central component providing the energy driving the peripheral component. 相似文献3.
Daniel R. Edgcumbe Volker Thoma Davide Rivolta Michael A. Nitsche Cynthia H.Y. Fu 《Brain stimulation》2019,12(3):652-658
Background
Accounts of cognitive processes in judgment and decision-making are frequently based on a dual-process framework, which reflects two qualitatively different types of processing: intuitive (Type 1) and analytical (Type 2) processes.Objective
The present study investigated the effects of bilateral transcranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex (DLPFC) on judgment and decision-making performance.Methods
Participants received anodal tDCS stimulation to the right DLPFC, left DLPFC or sham. There were 3 tasks: vignettes measuring heuristic thinking, belief bias syllogisms, and the cognitive reflection test (CRT), a measure of the ability to inhibit automatic responses to reach a correct solution. Fifty-four participants (mean age?=?24.63?±?4.46 years; 29 females) were recruited.Results
Results showed that anodal tDCS to the right DLPFC was associated with an increase in cognitive reflection performance (Type 2 processing) as compared to left DLPFC and to sham. Logic thinking was reduced following anodal tDCS to the left DLPFC.Conclusion
These findings are broadly consistent with a dual process framework, and cannot be explained by differences in cognitive ability and thinking style. The results demonstrate the involvement of the right DLPFC in cognitive reflection, and suggest the possibility of improving cognitive performance through tDCS. 相似文献4.
Zhen Ni Robin F.H. Cash Carolyn Gunraj Eduard Bercovici Mark Hallett Robert Chen 《Brain stimulation》2019,12(1):84-86
Background
Paired associative stimulation (PAS), with stimulus interval of 21.5 or 25?ms, using transcranial magnetic stimulation in the posterior-anterior (PA) current direction, produces a long-term-potentiation-like effect. Stimulation with PA directed current generates both early and late indirect (I)-waves while that in anterior-posterior (AP) current predominantly elicits late I-waves. Short interval intracortical inhibition (SICI) inhibits late I-waves but not early I-waves.Objective
To investigate how cortical inhibition modulates the effects of PAS.Methods
PAS at stimulus interval of 21.5?ms conditioned by SICI (SICI-PAS) was compared to PAS alone with both PA and AP directed currents.Results
PAS with both current directions increased cortical excitability. SICI-PAS increased cortical excitability in the PA but not the AP current direction.Conclusions
Both early and late I-waves circuits can mediate cortical PAS plasticity under different conditions. Plasticity induction with the late but not the early I-wave circuits is blocked by SICI. 相似文献5.
Shinichi Iwasaki Chisato Fujimoto Naoya Egami Makoto Kinoshita Fumiharu Togo Yoshiharu Yamamoto Tatsuya Yamasoba 《Brain stimulation》2018,11(4):709-715
Background
Galvanic vestibular stimulation delivered as zero-mean current noise (noisy GVS) has been shown to improve static and dynamic postural stability probably by enhancing vestibular information.Objective
/Hypothesis: To examine the effect of an imperceptible level of noisy GVS on dynamic locomotion in normal subjects as well as in patients with bilateral vestibulopathy.Methods
Walking performance of 19 healthy subjects and 12 patients with bilateral vestibulopathy at their preferred speed was examined during application of noisy GVS with an amplitude ranging from 0 to 1000?μA. The gait velocity, stride length and stride time were analyzed.Results
Noisy GVS had significant effects on gait velocity, stride length and stride time in healthy subjects as well as in patients with bilateral vestibulopathy (p?<?0.05). The optimal amplitude of noisy GVS improved gait velocity by 10.9?±?1.2%, stride length by 5.7?±?1.2% and stride time by 4.6?±?7% (p?<?0.0001) compared to the control session in healthy subjects. The optimal stimulus improved gait velocity by 12.8?±?1.3%, stride length by 8.3?±?1.1% and stride time by 3.7?±?7% (p?<?0.0001) in patients with bilateral vestibulopathy. The improved values of these parameters of locomotion by noisy GVS in the patients were not significantly different from those in healthy subjects in the control condition (p?>?0.4).Conclusion
Noisy GVS is effective in improving gait performance in healthy subjects as well as in patients with bilateral vestibulopathy. 相似文献6.
Anton Fomenko Clemens Neudorfer Robert F. Dallapiazza Suneil K. Kalia Andres M. Lozano 《Brain stimulation》2018,11(6):1209-1217
Background
There is an emerging need for noninvasive neuromodulation techniques to improve patient outcomes while minimizing adverse events and morbidity. Low-intensity focused ultrasound (LIFUS) is gaining traction as a non-surgical experimental approach of modulating brain activity. Several LIFUS sonication parameters have been found to potentiate neural firing, suppress cortical and epileptic discharges, and alter behavior when delivered to cortical and subcortical mammalian brain regions.Objective
This review introduces the elements of an effective sonication protocol and summarizes key preclinical studies on LIFUS as a neuromodulation modality. The state of the art in human ultrasound neuromodulation is then comprehensively summarized, and current hypotheses regarding the underlying mechanism of action on neural activity are presented.Methods
Peer-reviewed literature on human ultrasound neuromodulation was obtained by searching several electronic databases. The abstracts of all reports were read and publications which examined low-intensity transcranial ultrasound applied to human subjects were selected for review.Results
LIFUS can noninvasively influence human brain activity by suppressing cortical evoked potentials, influencing cortical oscillatory dynamics, and altering outcomes of sensory/motor tasks compared to sham sonication. Proposed mechanisms include cavitation, direct effects on neural ion channels, and plasma membrane deformation.Conclusions
Though optimal sonication paradigms and transcranial delivery methods are still being established, future applications may include non-invasive human brain mapping experiments, and nonsurgical treatments for functional neurological disorders. 相似文献7.
Soma Chakraborty Jana Kopecká Otakar Šprdlík Martina Hoskovcová Olga Ulmanová Evžen Růžička Martin Zapotocky 《Clinical neurophysiology》2017,128(4):622-634
Objective
To investigate the prevalence and the temporal structure of bilateral coherence in physiological (PT) and essential (ET) hand tremor.Methods
Triaxial accelerometric recordings from both hands in 30 healthy subjects and 34 ET patients were analyzed using spectral coherence and wavelet coherence methods. In 12 additional healthy subjects, the relation between the hand tremor and the chest wall acceleration was evaluated using partial coherence analysis.Results
The majority of both PT and ET subjects displayed significant bilateral coherence. While in PT, bilateral coherence was most frequently found in resting hand position (97% of subjects), in ET the prevalence was comparable for resting (54%) and postural (49%–57%) positions. In both PT and ET, epochs of strong coherence lasting several to a dozen seconds were separated by intervals of insignificant coherence. In PT, bilateral coherence at the main tremor frequency (8–12 Hz) was coupled with the ballistocardiac rhythm.Conclusion
The oscillations of the two hands are intermittently synchronized in both PT and ET. We propose that in postural PT, bilateral coherence at the main tremor frequency arises from transient simultaneous entrainment of the left and right hand oscillations to ballistocardiac forcing.Significance
Bilateral coherence of hand kinematics provides a sensitive measure of synchronizing influences on the left and right tremor oscillators. 相似文献8.
Ali Izadi Aleksandr Pevzner Darrin J. Lee Arne D. Ekstrom Kiarash Shahlaie Gene G. Gurkoff 《Brain stimulation》2019,12(3):735-742
Background
Temporal lobe epilepsy is most prevalent among focal epilepsies, and nearly one-third of patients are refractory to pharmacological intervention. Persistent cognitive and neurobehavioral comorbidities also occur due to the recurrent nature of seizures and medication-related side effects.Hypothesis
Electrical neuromodulation is an effective strategy to reduce seizures both in animal models and clinically, but its efficacy to modulate cognition remains unclear. We hypothesized that theta frequency stimulation of the medial septum would increase septohippocampal oscillations, increase seizure threshold, and improve spatial learning in a rat model of pilocarpine-induced epilepsy.Methods
Sham and pilocarpine rats were implanted with electrodes in the medial septum, hippocampus and prefrontal cortex. EEG was assessed days prior to and following stimulation. Sham and pilocarpine-treated rats received either no stimulation, continuous (throughout each behavior), or pre-task (one minute prior to each behavior) 7.7?Hz septal stimulation during the Barnes maze spatial navigation test and also during assessment of flurothyl-induced seizures.Results
Both continuous and pre-task stimulation prevented epilepsy-associated reductions in theta oscillations over time. Additionally, both stimulation paradigms significantly improved spatial navigation in the Barnes maze, reducing latency and improving search strategy. Moreover, stimulation led to significant increases in seizure threshold in pilocarpine-treated rats. There was no evidence of cognitive enhancement or increased seizure threshold in stimulated sham rats.Conclusion
These findings have profound implications as theta stimulation of the septum represents a single frequency and target that has the potential to both improve cognition and reduce seizures for patients with refractory epilepsy. 相似文献9.
Silvia Casarotto Francesco Turco Angela Comanducci Alessio Perretti Giorgio Marotta Gianni Pezzoli Mario Rosanova Ioannis U. Isaias 《Brain stimulation》2019,12(1):152-160
Background
Cortical dysfunctioning significantly contributes to the pathogenesis of motor symptoms in Parkinson's disease (PD).Objective
We aimed at testing whether an acute levodopa administration has measurable and specific cortical effects possibly related to striatal dopaminergic deficit.Methods
In thirteen PD patients, we measured the electroencephalographic responses to transcranial magnetic stimulation (TMS/EEG) of the supplementary motor area and superior parietal lobule (n?=?8) before and after an acute intake of levodopa. We also performed a single-photon emission computed tomography and [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane to identify the more affected and the less affected brain side in each patient, according to the dopaminergic innervation loss of the putamen. Cortical excitability changes before and after an acute intake of levodopa were computed and compared between the more and the less affected brain side at the single-patient as well as at the group level.Results
We found that levodopa intake induces a significant increase (P?<?0.01) of cortical excitability nearby the supplementary motor area in the more affected brain side, greater (P?<?0.025) than in the less affected brain side. Notably, cortical excitability changes nearby the superior parietal lobule were not statistically significant.Conclusions
These results strengthen the idea that dysfunction of specific cortico-subcortical circuits may contribute to pathophysiology of PD symptoms. Most important, they support the use of navigated TMS/EEG as a non-invasive tool to better understand the pathophysiology of PD. 相似文献10.
John Cirillo John G. Semmler Ronan A. Mooney Winston D. Byblow 《Brain stimulation》2018,11(6):1296-1305
Background
In human primary motor cortex (M1), the paired-pulse transcranial magnetic stimulation (TMS) paradigm of short-interval intracortical inhibition (SICI) can be expressed conventionally as a percent change in the relative amplitude of a conditioned motor evoked potential to non-conditioned; or adaptive threshold-hunting a target motor evoked potential amplitude in the absence or presence of a conditioning stimulus, and noting the relative change in stimulation intensity. The suitability of each approach may depend on the induced current direction, which probe separate M1 interneuronal populations.Objective
To examine the influence of conditioning stimulus intensity, interstimulus interval (ISI) and current direction for adaptive threshold-hunting and conventional SICI using equivalent TMS intensities.Methods
In 16 participants (21–32 years), SICI was examined using adaptive threshold-hunting and conventional paired-pulse TMS with posterior-anterior and anterior-posterior stimulation, ISIs of 2 and 3?ms, and a range of conditioning intensities.Results
Inhibition with adaptive threshold-hunting was greater for anterior-posterior stimulation with an ISI of 3?ms (23.6?±?9.0%) compared with 2?ms (7.5?±?7.8%, P?<?0.001) and posterior-anterior stimulation at both ISIs (2?ms 8.6?±?8.7%, 3?ms 5.9?±?4.8%; P?<?0.001). There was an association between inhibition obtained with conventional and adaptive threshold-hunting for posterior-anterior but not anterior-posterior stimulation (2?ms only, r?=?0.68, P?=?0.03).Conclusions
More inhibition was evident with anterior-posterior than posterior-anterior current for both adaptive threshold-hunting and conventional paired-pulse TMS. Assessment of SICI with anterior-posterior stimulation was not directly comparable between the two approaches. However, the amount of inhibition was dependent on conditioning stimulus intensity and ISI for both SICI techniques. 相似文献11.
Pia Baldinger-Melich Gregor Gryglewski Cécile Philippe Gregory M. James Chrysoula Vraka Leo Silberbauer Theresa Balber Thomas Vanicek Verena Pichler Jakob Unterholzner Georg S. Kranz Andreas Hahn Dietmar Winkler Markus Mitterhauser Wolfgang Wadsak Marcus Hacker Siegfried Kasper Richard Frey Rupert Lanzenberger 《Brain stimulation》2019,12(3):714-723
Background
Electroconvulsive therapy (ECT) constitutes one of the most effective antidepressant treatment strategies in major depression (MDD). Despite its common use and uncontested efficacy, its mechanism of action is still insufficiently understood. Previously, we showed that ECT is accompanied by a global decrease of serotonin-1A receptors in MDD; however, further studies to investigate the involvement of the serotonergic system in the mechanism of action of ECT are warranted. The monoamine oxidase A (MAO-A) represents an important target for antidepressant treatments and was found to be increased in MDD. Here, we investigated whether ECT impacts on MAO-A levels in treatment-resistant patients (TRD).Methods
16 TRD patients (12 female, age 45.94?±?9.68 years, HAMD 25.12?±?3.16) with unipolar depression according to DSM-IV were scanned twice before (PET1 and PET2, to assess test-retest variability under constant psychopharmacotherapy) and once after (PET3) completing a minimum of eight unilateral ECT sessions using positron emission tomography and the radioligand [11C]harmine to assess cerebral MAO-A distribution volumes (VT). Age- and sex-matched healthy subjects (HC) were measured once.Results
Response rate to ECT was 87.5%. MAO-A VT was found to be significantly reduced after ECT in TRD patients (?3.8%) when assessed in 27 a priori defined ROIs (p?<?0.001). Test-retest variability between PET1 and PET2 was 3.1%. MAO-A VT did not significantly differ between TRD patients and HC at baseline.Conclusions
The small effect size of the significant reduction of MAO-A VT after ECT in the range of test-retest variability does not support the hypothesis of a clinically relevant mechanism of action of ECT based on MAO-A. Furthermore, in contrast to studies reporting elevated MAO-A VT in unmedicated depressed patients, MAO-A levels were found to be similar in TRD patients and HC which might be attributed to the continuous antidepressant pharmacotherapy in the present sample. 相似文献12.
Chenxi Dai Gang Chen Bihua Chen Juan Wang Changlin Yin Jianjie Wang Yushun Gong Liang Wei Yuanyuan Huang Yongqin Li 《Brain stimulation》2019,12(3):659-667
Background
Transcranial direct current stimulation (tDCS) modulates neuronal activity and is a potential therapeutic tool for many neurological diseases. However, its beneficial effects on post cardiac arrest syndrome remains uncertain.Objective/hypothesis
We investigated the effects of repetitive anodal tDCS on neurological outcome and survival in a ventricular fibrillation (VF) cardiac arrest rat model.Methods
Cardiopulmonary resuscitation was initiated after 6?min of VF in 36 Sprague-Dawley rats. The animals were randomized into three groups immediately after resuscitation (n?=?12 each): no-treatment control (NTC) group, targeted temperature management (TTM) group, and tDCS group. For tDCS, 1?mA anodal tDCS was applied on the dorsal scalp for 0.5?h. The stimulation was repeated for four sessions with 1-h resting interval under normothermia. Post-resuscitation hemodynamic, cerebral, and myocardial injuries, 96-h neurological outcome, and survival were evaluated.Results
Compared with the NTC group, post-resuscitation serum astroglial protein S100 beta and cardiac troponin T levels and 96-h neuronal and myocardial damage scores were markedly reduced in the tDCS and TTM groups. Myocardial ejection fraction, neurological deficit score, and 96-h survival rate were also significantly better for the tDCS and TTM groups. The period of post-resuscitation arrhythmia with hemodynamic instability was considerably shorter in the tDCS group, but no differences were observed in neurological outcome and survival between the tDCS and TTM groups.Conclusions
In this cardiac arrest rat model, repeated anodal tDCS commenced after resuscitation improves 96-h neurological outcome and survival to an extent comparable to TTM by attenuating post-resuscitation cerebral and cardiac injuries. 相似文献13.
Guoqiao Wang Dean Coble Eric M. McDade Jason Hassenstab Anne M. Fagan Tammie L.S. Benzinger Randall J. Bateman John C. Morris Chengjie Xiong 《Alzheimer's & dementia》2019,15(4):506-514
Introduction
Staging preclinical Alzheimer disease (AD) by the expected years to symptom onset (EYO) in autosomal dominant AD (ADAD) through biomarker correlations is important.Methods
We estimated the correlation matrix between EYO/cognition and imaging/CSF biomarkers, and searched for the EYO cutoff where a change in the correlations occurred before and after the cutoff among the asymptomatic mutation carriers of ADAD. We then estimated the longitudinal rate of change for biomarkers/cognition within each preclinical stage defined by the EYO.Results
Based on the change in the correlations, the preclinical ADAD was divided by EYOs ?7 and ?13 years. Mutation carriers demonstrated a temporal ordering of biomarker/cognition changes across the three preclinical stages.Discussion
Duration of each preclinical stage can be estimated in ADAD, facilitating better planning of prevention trials with the EYO cutoffs under the recently released FDA guidance. The generalization of these results to sporadic AD warrants further investigation. 相似文献14.
Federico Ranieri Gianluca Coppola Gabriella Musumeci Fioravante Capone Giovanni Di Pino Vincenzo Parisi Vincenzo Di Lazzaro 《Brain stimulation》2019,12(3):705-713
Background
Repetitive convergent inputs to a single post-synaptic neuron can induce long-term potentiation (LTP) or depression (LTD) of synaptic activity in a spike timing-dependent manner.Objective
Here we set a protocol of visual paired associative stimulation (vPAS) of the primary visual cortex (V1) in humans to induce persistent changes in the excitatory properties of V1 with a spike timing rule.Methods
We provided convergent inputs to V1 by coupling transcranial magnetic stimulation (TMS) pulses of the occipital cortex with peripheral visual inputs, at four interstimulus intervals of ?50/-25/+25/+50 ms relative to the visual evoked potential (VEP) P1 latency. We analysed VEP amplitude and delayed habituation before and up to 10 min after each vPAS protocol.Results
VEP amplitude was reduced after vPAS+25. Delayed VEP habituation was increased after vPAS-25 while it was reduced after vPAS+25.Conclusions
We provide evidence that associative bidirectional synaptic plasticity is a feature not only of the sensorimotor but also of the human visual system. 相似文献15.
Francesco Di Lorenzo Caterina Motta Sonia Bonnì Nicola Biagio Mercuri Carlo Caltagirone Alessandro Martorana Giacomo Koch 《Brain stimulation》2019,12(1):148-151
Background
Alzheimer's disease (AD) is characterized by a primary impairment of long-term declarative memory caused by deposition of misfolded protein aggregates. Experimental studies showed that AD neuropathological alterations impair synaptic plasticity and memory performance. Transcranial Magnetic Stimulation protocols have been recently introduced to investigate altered mechanisms of cortical plasticity in AD patients.Aim
To investigate relationship between Long-Term Potentiation (LTP)-like cortical plasticity and patients’ neuropsychological performance.Methods
We applied intermittent theta burst stimulation and extensive neuropshycological battery in 75 newly diagnosed AD patients.Results
We found that LTP-like cortical plasticity impairment is selectively associated to a less efficient verbal memory (r?=?0.45; p?=?0.002), but not to other cognitive functions, independently from biomarkers and other demographic and clinical factors.Conclusion
These findings suggest that LTP-like cortical plasticity may represent a neurophysiological surrogate of memory in AD patients by evaluating the weight of pathological changes responsible for cognitive dysfunction. 相似文献16.
Antonella Conte Gina Ferrazzano Daniele Belvisi Nicoletta Manzo Emanuele Battista Pietro Li Voti Andrea Nardella Giovanni Fabbrini Alfredo Berardelli 《Clinical neurophysiology》2018,129(9):1849-1853
Objective
To investigate whether changes in the somatosensory temporal discrimination threshold (STDT) in Parkinson’s disease (PD) and dystonia reflect the involvement of specific neural structures or mechanisms related to tremor, and whether the STDT can discriminate patients with PD, dystonia or essential tremor (ET).Methods
We tested STDT in 223 patients with PD, dystonia and ET and compared STDT values in patients with PD and dystonia with tremor with those of PD and CD without tremor. Data were compared with those of age-matched healthy subjects.Results
STDT values were high in patients with dystonia and PD but normal in ET. In PD, STDT values were similar in patients with resting or postural/action tremor and in those without tremor. In dystonia, STDT values were higher in patients with tremor than in those without tremor. The ROC curve showed that STDT discriminates tremor in dystonia from ET.Conclusions
In PD, STDT changes likely reflect basal ganglia abnormalities and are unrelated to tremor mechanisms. In dystonia, the primary somatosensory cortex and cerebellum play an additional role.Significance
STDT provides information on the pathophysiological mechanisms of patients with movement disorders and may be used to differentiate patients with dystonia and tremor from those with tremor due to ET. 相似文献17.
Dalia Khammash Molly Simmonite Thad A. Polk Stephan F. Taylor Sean K. Meehan 《Brain stimulation》2019,12(3):702-704
Background
Transcranial magnetic stimulation (TMS) is a non-invasive method to stimulate localized brain regions. Despite widespread use in motor cortex, TMS is seldom performed in sensory areas due to variable, qualitative metrics.Objective
Assess the reliability and validity of tracing phosphenes, and to investigate the stimulation parameters necessary to elicit decreased visual cortex excitability with paired-pulse TMS at short inter-stimulus intervals.Methods
Across two sessions, single and paired-pulse recruitment curves were derived by having participants outline elicited phosphenes and calculating resulting average phosphene sizes.Results
Phosphene size scaled with stimulus intensity, similar to motor cortex. Paired-pulse recruitment curves demonstrated inhibition at lower conditioning stimulus intensities than observed in motor cortex. Reliability was high across sessions.Conclusions
TMS-induced phosphenes are a valid and reliable tool for measuring cortical excitability and inhibition in early visual areas. Our results also provide appropriate stimulation parameters for measuring short-latency intracortical inhibition in visual cortex. 相似文献18.
G. Kramer A.M.M. Van der Stouwe N.M. Maurits M.A.J. Tijssen J.W.J. Elting 《Clinical neurophysiology》2018,129(1):13-20
Objective
To distinguish tremor subtypes using wavelet coherence analysis (WCA). WCA enables to detect variations in coherence and phase difference between two signals over time and might be especially useful in distinguishing functional from organic tremor.Methods
In this pilot study, polymyography recordings were studied retrospectively of 26 Parkinsonian (PT), 26 functional (FT), 26 essential (ET), and 20 enhanced physiological (EPT) tremor patients. Per patient one segment of 20 s in duration, in which tremor was present continuously in the same posture, was selected. We studied several coherence and phase related parameters, and analysed all possible muscle combinations of the flexor and extensor muscles of the upper and fore arm. The area under the receiver operating characteristic curve (AUC-ROC) was applied to compare WCA and standard coherence analysis to distinguish tremor subtypes.Results
The percentage of time with significant coherence (PTSC) and the number of periods without significant coherence (NOV) proved the most discriminative parameters. FT could be discriminated from organic (PT, ET, EPT) tremor by high NOV (31.88 vs 21.58, 23.12 and 10.20 respectively) with an AUC-ROC of 0.809, while standard coherence analysis resulted in an AUC-ROC of 0.552.Conclusions
EMG-EMG WCA analysis might provide additional variables to distinguish functional from organic tremor.Significance
WCA might prove to be of additional value to discriminate between tremor types. 相似文献19.
Mascha van &#x;t Wout-Frank M. Tracie Shea Victoria C. Larson Benjamin D. Greenberg Noah S. Philip 《Brain stimulation》2019,12(1):41-43
Background
Facilitating neural activity using non-invasive brain stimulation may improve extinction-based treatments for posttraumatic stress disorder (PTSD).Objective/hypothesis
Here, we examined the feasibility of simultaneous transcranial direct current stimulation (tDCS) application during virtual reality (VR) to reduce psychophysiological arousal and symptoms in Veterans with PTSD.Methods
Twelve Veterans with PTSD received six combat-related VR exposure sessions during sham-controlled tDCS targeting ventromedial prefrontal cortex. Primary outcome measures were changes in skin conductance-based arousal and self-reported PTSD symptom severity.Results
tDCS + VR components were combined without technical difficulty. We observed a significant interaction between reduction in arousal across sessions and tDCS group (p = .03), indicating that the decrease in physiological arousal was greater in the tDCS + VR versus sham group. We additionally observed a clinically meaningful reduction in PTSD symptom severity.Conclusions
This study demonstrates feasibility of applying tDCS during VR. Preliminary data suggest a reduction in psychophysiological arousal and PTSD symptomatology, supporting future studies. 相似文献20.
Feng Zhang Rujia Zhong Song Li Zhenfa Fu Renfei Wang Tianxiao Wang Zhili Huang Weidong Le 《Alzheimer's & dementia》2019,15(4):590-597