Silent Period Research Articles

Segmental reflex, long-latency reflex, and mixed nerve silent period in dystonia.

ABSTRACT We hypothesized that “long latency reflexes” (LLRs), associated segmental reflex (SR), and mixed nerve silent periods (MnSPs) recorded on the distal upper extremity muscles would behave differently in patients with cervical dystonia and focal hand dystonia. We enrolled patients with cervical dystonia, generalized dystonia, focal hand dystonia, and healthy individuals. We recorded SR, LLRs, and MnSPs. The mean amplitude of SR on the affected side of focal hand dystonia was significantly lower (p = 0.010). The parameters related to LLRs and MnSPs were not different between groups. We suggest, using SR, LLRs, and MnSPs, we could not show an electrophysiological signature specific to dystonia.

Psychophysiological and Neurophysiological Correlates of Dropping Objects from Hands in Carpal Tunnel Syndrome.

Dropping objects from hands (DOH) is a common symptom of carpal tunnel syndrome (CTS). We evaluated the clinical, neurophysiological, and psychophysiological features of 120 CTS patients to elucidate the DOH pathophysiology. Forty-nine healthy controls were included. In the patients, the Boston Carpal Tunnel Questionnaire (BCTQ), the Douleur Neuropathique 4 questions (DN4), and a numeric rating scale for pain (NRS) were evaluated. In patients and controls, we evaluated bilateral median and ulnar motor and sensory nerve conduction studies, cutaneous silent period and cutaneomuscular reflexes (CMR) of the abductor pollicis brevis, cold-detection threshold (CDT) and heat-pain detection threshold (HPT) at the index, little finger, and dorsum of the hand, and vibratory detection threshold at the index and little finger by quantitative sensory testing. CTS with DOH had higher BCTQ, DN4 and NRS, lower median sensory action potential, longer CMR duration, lower CDT and higher HPT at all tested sites than controls and CTS without DOH. Predictive features for DOH were abnormal CDT and HPT at the right index and dorsum (OR: 3.88, p: 0.03) or at the little finger (OR: 3.27, p: 0.04) and a DN4 higher than 4 (OR: 2.16, p < 0.0001). Thermal hypoesthesia in median and extra-median innervated territories and neuropathic pain are predictive of DOH in CTS.

Effects of A Single Balance Training Session on Neural Excitability in Individuals With Chronic Ankle Instability.

Individuals with chronic ankle instability (CAI) demonstrate reduced spinal reflex modulation and corticospinal excitability of the soleus, which may contribute to decreased balance performance. To determine the effects of a single session of balance training on Spinal-reflexive excitability modulation and corticospinal excitability in those with CAI. Randomized controlled trials. Research laboratory. Thirty participants with CAI were randomly assigned to the balance training (BAL) or control (CON) group. Modulation of soleus spinal-reflexive excitability was measured by calculating relative change in normalized Hoffmann reflexes (ratio of the H-reflex to the M-wave) from prone to single-leg standing. Corticospinal excitability was assessed during single-leg stance using transcranial magnetic stimulation, outcomes of which included active motor threshold (AMT), motor evoked potential, and cortical silent period (CSP). Balance performance was measured with center of pressure velocity in anterior to posterior and medial to lateral directions. Separate 2 × 2 repeated-measures analyses of variance were employed to determine the effect of group (BAL and CON) and time (baseline and posttraining) on each dependent variable. There were significant group by time interactions in the modulation of soleus spinal-reflexive excitability (F1,27 = 4.763, P = .04); CSP at 100% AMT (F1,27 = 4.727, P = .04); and CSP at 120% AMT (F1,27 = 16.057, P < .01). A large effect size suggests increased modulation of spinal-reflexive excitability (d = 0.81 [0.03 to 1.54]) of the soleus in BAL compared with CON at posttest, while CSP at 100% (d = 0.95 [0.17 to 1.70]) and 120% AMT (d = 1.10 [0.29 to 1.84]) was reduced in BAL when compared with CON at posttest. After a single session of balance training, individuals with CAI initiated increases in spinal reflex modulation and corticospinal excitability of the soleus. Thus, individuals with CAI who undergo balance training exhibit positive neural adaptations that are linked to improvements in balance performance.

Detecting negative myoclonus during long-term home measurements using wearables

ObjectiveThe aim of this study was to develop a feasible method for the detection of negative myoclonus (NM) through long-term home measurements in patients with progressive myoclonus epilepsy type 1. MethodsThe number and duration of silent periods (SP) associated with NM were detected during a 48 h home recording using wearable surface electromyography (EMG) sensors. ResultsA newly developed algorithm was able to find short (50–69 ms), intermediate (70–100 ms), and long (101– 500 ms) SPs from EMG data. Negative myoclonus assessed by the algorithm correlated significantly with the video-recorded and physician-evaluated unified myoclonus rating scale (UMRS) scores of NM and action myoclonus. Silent period duration, number, and their combination, correlated strongly and significantly also with the Singer score, which assesses functional status and ambulation. ConclusionsNegative myoclonus can be determined objectively using long-term EMG measurements in home environment. With long-term measurements, we can acquire more reliable quantified information about NM as a symptom, compared to short evaluation at the clinic. SignificanceAs measured using SPs, NM may be a clinically useful measure for monitoring disease progression or assessing antimyoclonic drug effects objectively.

A new Audio Encryption Algorithm Based on Hyper-Chaotic System

a new algorithm for audio encryption is presented in this work, the simple structure chaotic logistic map based to perform permutation mechanism where the position of the audio samples are rearrangement again with the purpose of break correlation, lately based on key stream generated from complex hyper-chaotic system diffusion operation is done with the aim of fill silent periods within the speech conversation to ambiguity the critical information and successful encryption operation. to ensure the security and efficiency of proposed method many quality metrics analysis are done such as histogram, waveform, entropy, key space, correlation coefficient, differential and speed performance, the experimental results demonstrate that the proposed algorithm characteristics with high level of security, resistant attacks and can realize the real time.

Resumption of production operations during the silent disposal period of African swine fever outbreaks: a case study

BackgroundBatch production, a widely implemented production model in large-scale pig farms, was characterized by its long-term duration, cost-effectiveness, and efficiency. Nevertheless, the recent occurrence of African swine fever (ASF) outbreaks in China has necessitated the implementation of discreet mating operations within this model, leading to disruptions in production cycles and substantial indirect losses.Case presentationThis study implemented a novel operational procedure, which involved the division of risk areas for zone management and allowed mating operations, in 12 farms experiencing ASF outbreaks. Another 12 farms were used as a control group, employing the old procedure. Subsequently, the prognoses of both the old and new procedures were calculated and analyzed. The findings indicate that the new method resulted in an enhanced retention rate and reduced non-productive days (NPD), without impacting the positive detection rate and disposal time. Consequently, this approach significantly mitigated economic losses (p < 0.05).ConclusionThe efficacy of the novel procedure in mitigating the indirect economic losses stemming from ASF outbreaks, through the reduction of NPD while maintaining retention rates and disposition days, has been substantiated. This methodology has demonstrated feasibility in extensive pig farming operations and exhibits promise for broader application.

GCLP: An automated asthma detection model based on global chaotic logistic pattern using cough sounds

Asthmatic patients suffer episodic attacks of breathing difficulty and cough. Cough sounds may be used to distinguish asthma from other lung conditions or normal, especially in the acute period. We aimed to develop a novel architecture using lightweight, handcrafted components that could still extract meaningful features. Cough sounds were recorded using mobile phones from 1428 asthmatic and healthy subjects. As cough sounds behave similarly to random noises, we used a global chaotic logistic pattern (GCLP) as a kernel for feature generation based on its ability to detect random relations among input signal values. Further, each cough sound was preprocessed to remove speech and silent periods before undergoing signal decomposition using tunable Q wavelet transformation (TQWT). The latter enabled downstream GCLP-based feature generation at multiple levels, which yielded four final feature vectors (which corresponded to the four types of TQWT-generated wavelet subbands), each of length 3584. Four feature selectors were applied to the latter, generating 16 selected feature vectors, each of length 256. A standard shallow cubic support vector machine was deployed to calculate 16 prediction vectors, which were collectively input to a mode-based iterative hard majority voting function to generate additional 15-voted results. Finally, a greedy algorithm automatically chose the best overall result, which made the model self-organized. Our model attained 99.44% classification accuracy for the collected dataset. Furthermore, our model obtained an accuracy of 98.53% with leave-one- subject-out cross-validation (LOSO CV) strategy, which justifies the robustness of the developed model.

Test-retest reliability of cortico-spinal measurements in the rectus femoris at different contraction levels.

Single-pulse Transcranial Magnetic Stimulation (TMS) and, very recently, lumbar stimulation (LS) have been used to measure cortico-spinal excitability from various interventions using maximal or submaximal contractions in the lower limbs. However, reliability studies have overlooked a wide range of contraction intensities for MEPs, and no reliability data is available for LEPs. This study investigated the reliability of motor evoked potentials and lumbar evoked potentials at different stimulation intensities and contraction levels in m.rectus femoris. Twenty-two participants performed non-fatiguing isometric knee extensions at 20 and 60% of maximum voluntary contraction (MVC). LS induced a lumbar-evoked potential (LEP) of 25 and 50% resting maximal compound action potential (M-max). TMS stimulator output was adjusted to 120, 140, and 160% of active motor threshold (aMT). In each contraction, a single MEP or LEP was delivered. Ten contractions were performed at each stimulator intensity and contraction level in random order. Moderate-to-good reliability was found when LEP was normalized to M-max/Root Mean Square in all conditions (ICC:0.74-0.85). Excellent reliability was found when MEP was normalized to Mmax for all conditions (ICC > 0.90) at 60% of MVC. Good reliability was found for the rest of the TMS conditions. Moderate-to-good reliability was found for silent period (SP) elicited by LS (ICC: 0.71-0.83). Good-to-excellent reliability was found for SP elicited by TMS (ICC > 0.82). MEPs and LEPs elicited in m.rectus femoris appear to be reliable to assess changes at different segments of the cortico-spinal tract during different contraction levels and stimulator output intensities. Furthermore, the TMS- and LS- elicited SP was a reliable tool considered to reflect inhibitory processes at spinal and cortical levels.

Influence of ship emissions on PM2.5 in Shanghai: From COVID19 to OMICRON22 lockdown episodes

Air quality has improved significantly in the recent 10 years, but there is still a wide gap compared to the WHO AQG level. The concentration of PM2.5 during OMICRON in 2022 was 21.7 μg m−3, which marked the lowest historical record under the lockdown status of the whole urban area, still exceeding the national Level 1 standard. PMF results have shown that the contributions of ship emissions increased from 2020 to 2022 during the historical OMICRON episodes, with growth rates of 9.7% and 10.7%, respectively. AIS data indicated an overall increase in shipping activities around Shanghai during the OMICRON22-2021 period. The strict control of urban activities during the silent period in 2022 reduced ship activities by 21.0% and 31.8% in the ChongMingMsa and WuSongMsa ranges close to Shanghai, respectively. However, significant growth was observed in the sea regions of ShanghaiMsa and ZhouShan-NingBoMsa, with growth rates of 44.2% and 33.7%, respectively. The total number of anchored ships in the sea region of YangShanGangMsa increased by 56.7%. CWT analysis indicated that the lockdown measures only changed the distributions of the ship emissions. More forceful measures for the reductions of the ship emissions should be considered.

Cortical excitability and multifidus activation responses to transcranial direct current stimulation in patients with chronic low back pain during remission

Evidence indicates that patients with chronic low back pain (CLBP) have lumbar multifidus muscle (LM) activation deficit which might be caused by changes in cortical excitability. Anodal transcranial direct current stimulation (a-tDCS) can be used to restore cortical excitability. This study aimed to (1) determine the immediate effects of a-tDCS on the cortical excitability and LM activation and (2) explore the relationship between cortical excitability and LM activation. Thirteen participants with CLBP during remission and 11 healthy participants were recruited. Cortical excitability (peak-to-peak motor evoked potential amplitude; P2P and cortical silent period; CSP) and LM activation were measured at pre- and post-intervention. We found significant difference (P < 0.05) in P2P between groups. However, no significant differences (P > 0.05) in P2P, CSP and LM activation were found between pre- and post-intervention in CLBP. The CLBP group demonstrated significant correlation (P = 0.05) between P2P and LM activation. Although our finding demonstrates change in P2P in the CLBP group, one-session of a-tDCS cannot induce changes in cortical excitability and LM activation. However, moderate to strong correlation between P2P and LM activation suggests the involvement of cortical level in LM activation deficit. Therefore, non-significant changes could have been due to inadequate dose of a-tDCS.

Cortical excitability changes in patients of vascular parkinsonism with cognitive impairment

IntroductionVascular parkinsonism (VaP), type of lower body parkinsonism, occurs in relation to ischemic cerebrovascular disease. It can be associated with cognitive impairment. We aimed to study the cortical excitability changes in these patients using transcranial magnetic stimulation (TMS). MethodsWe included 20 patients with VaP and 22 healthy controls (HC). All subjects underwent TMS over left motor cortex with recording of resting motor threshold (RMT), central motor conduction time (CMCT), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), contralateral and ipsilateral silent period (SP) along with RMT and CMCT in the contralateral lower limb. Cognitive assessments were done using Montreal cognitive assessment (MoCA) and Addenbrooke's cognitive evaluation III (ACE III). ResultsMean age of patients (63.90 ± 7.36 years) was comparable with controls (59.77 ± 6.94 years; p = 0.07). Duration of disease was 2.58 ± 2.57 years. The upper and lower limb RMT of patients (32.45 ± 4.81%; 57.20 ± 11.54%) was significantly low compared to HC (43.64 ± 7.73%; 69.18 ± 14.27%; p < 0.001). There was a significant reduction in SICI in patients (1.87 ± 2.03) compared to HC (0.38 ± 0.29; p < 0.001). In addition, there was a significant prolongation of ipsilateral SP in patients (48.49 ± 24.49) compared to controls (32.04 ± 12.26, p = 0.01). However, there was no significant difference in contralateral SP (p = 0.66) and ICF (p = 0.25) between the two groups. There was a significant prolongation of lower limb CMCT in patients (p < 0.01). There was a positive correlation of SICI with MoCA (r = 0.45, p < 0.05) and ACE-III (r = 0.33, p < 0.05) scores. ConclusionReduction in RMT and SICI in patients with VaP suggests abnormalities in GABAergic neurotransmission that may underlie cognitive impairment observed in them.

The impact of upper motor neuron involvement on clinical features, disease progression and prognosis in amyotrophic lateral sclerosis.

ObjectivesIn amyotrophic lateral sclerosis (ALS) both upper (UMNs) and lower motor neurons (LMNs) are involved in the process of neurodegeneration, accounting for the great disease heterogeneity. We evaluated the associations of the burden of UMN impairment, assessed through the Penn Upper Motor Neuron Score (PUMNS), with demographic and clinical features of ALS patients to define the independent role of UMN involvement in generating disease heterogeneity, predicting disease progression and prognosis.MethodsWe collected the following clinical parameters on a cohort of 875 ALS patients: age and site of onset, survival, MRC scale, lower motor neuron score (LMNS), PUMNS, ALSFRS-R, change in ALSFRS-R over time (DFS), MITOS and King’s staging systems (KSS). Transcranial magnetic stimulation was performed on a subgroup of patients and central motor conduction time (CMCT) and cortical silent period (CSP) were calculated.ResultsWe observed that patients with an earlier age at onset and bulbar onset had higher PUMNS values. Higher values were also associated to lower ALSFRS-R and to higher DFS scores, as well as to higher MITOS and KSS, indicating that a greater UMN burden correlates with disease severity. Conversely, we did not appreciate any association between UMN involvement and survival or markers of LMN impairment. Moreover, PUMNS values showed a positive association with CMCT and a negative one with CSP values.InterpretationOur results suggest that the burden of UMN pathology, assessed through PUMNS, has an important independent role in defining clinical characteristics, functional disability, disease progression and prognosis in ALS patients. We also support the role of TMS in defining severity of UMN involvement.

A prefix‐based approach for joint Doppler and channel estimation in underwater communication

SummaryDeveloping a reliable and robust underwater acoustic communication system is a difficult task due to the complicated nature of the underwater channel, non‐stationary noise, and several other factors. Indeed, channel estimation or equalization presents numerous challenges in this non‐stationary, highly Doppler, multipath environment; as a result, traditional equalizers and PLL‐based methods have limited performance. Generally, communication over such time‐varying channels is accomplished via packets that contain a prefix/preamble signal for training, a payload containing the actual data, and a silent period for proper alignment. The prefix signal must be designed properly because it is used to estimate the channel and determine the start of the packet. In this paper, we propose a new prefix signal based on the hyperbolic chirp signal, which has Doppler invariance properties. These properties enable the extraction of the entire packet even under severe multipath and Doppler. Our new proposed prefix signal can accurately and efficiently characterize an underwater channel by estimating the multipath delay, amplitude, and Doppler scales. Our new method has been validated through extensive simulations using various channel models for its robustness and effectiveness under various conditions. It has also been tested on a real‐world channel.

Abstract P410: A Novel Method For The Analysis Of Renal Sympathetic Nerve Activity From Multi-fiber Nerve Recordings

Introduction: Measurement of renal sympathetic nerve activity (RSNA) via bipolar electrodes from multi-fiber preparations in various species has been used for decades in the context of autonomic regulation research. Traditionally, raw neurograms are usually integrated over short time intervals and this approach works perfectly for the analysis of dynamic RSNA changes due to acute intervention. However, comparability of baseline activities between groups is limited. We present a novel analysis method, based on the raw neurogram sampled at rate of 25 kHz. Material and methods: For RSNA-burst analysis a software based programmable algorithm was used. Continuous activities longer than three single spikes (i.e., &gt;8ms) were defined as bursts, followed by silent periods with some single spikes. Approximately 10.000 bursts/rat were analyzed and burst amplitude, burst duration, burst area (i.e., duration integral), as well as the burst frequencies were analyzed. Results: In rats with myocardial infarction (n=11) we found no difference in integrated baseline RSNA as compared to controls ((n=10). However, the new method revealed higher higher burst rate per cardiac cycle [CC] (2.65 ± 0.39 vs. 1.61 ± 0.38 bursts/CC; P&lt;0.001) and burst frequency (15.09 ± 2.42 vs. 8.52 ±1.54 Hz; P&lt;0.001) compared to healthy controls, indicating increased RSNA. Conclusion: Our new method of RSNA baseline analysis was able to detect subtle differences between groups of animals that could not be detected by the traditional method of integrated RSNA analysis. Furthermore, this method has the potential to give further insights into RNSA patterns and synchronization to afferent regulatory input form the kidney itself or other organs.

Evidence of altered corticomotor inhibition in older adults with a history of repetitive neurotrauma. A transcranial magnetic stimulation study

International concern continues regarding the association between the long-term neurophysiologic changes from repetitive neurotrauma associated with contact and collision sports. This study describes corticomotor changes in retired contact/collision sport athletes and controls, between the ages of 30 and 70 years. Retired athletes (n = 152; 49.1 ± 8.5 years) and controls (n = 72; 47.8 ± 9.5 years) were assessed using single and paired-pulse transcranial magnetic stimulation (TMS) for active motor threshold (aMT), motor evoked potential and cortical silent period duration (expressed as MEP:cSP ratio), and short- and long-interval intracortical inhibition (SICI and LICI). Motor threshold, MEP:cSP, SICI and LICI for both groups were correlated across age. Controls showed significant moderate correlations for MEP:cSP ratios at 130% (rho = 0.48, p < 0.001), 150% (rho = 0.49, p < 0.001) and 170% aMT (rho = 0.42; p < 0.001) and significant small negative correlation for SICI (rho = −0.27; p = 0.030), and moderate negative correlation for LICI (rho = −0.43; p < 0.001). Group-wise correlation analysis comparisons showed significant correlation differences between groups for 130% (p = 0.016) and 150% aMT (p = 0.009), specifically showing retired athletes were displaying increased corticomotor inhibition. While previous studies have focussed studies on older athletes (>50 years), this study is the first to characterize corticomotor differences between retired athletes and controls across the lifespan. These results, demonstrating pathophysiological differences in retired athletes across the lifespan, provide a foundation to utilise evoked potentials as a prodromal marker in supplementing neurological assessment for traumatic encephalopathy syndrome associated with contact/collision sport athletes that is currently lacking physiological biomarkers.

Excessive excitability of inhibitory cortical circuit and disturbance of ballistic targeting movement in degenerative cerebellar ataxia

This study aimed to investigate abnormalities in inhibitory cortical excitability and motor control during ballistic-targeting movements in individuals with degenerative cerebellar ataxia (DCA). Sixteen participants took part in the study (DCA group [n = 8] and healthy group [n = 8]). The resting motor-threshold and cortical silent period (cSP) were measured in the right-hand muscle using transcranial magnetic stimulation over the left primary motor cortex. Moreover, the performance of the ballistic-targeting task with right wrist movements was measured. The Scale for the Assessment and Rating of Ataxia was used to evaluate the severity of ataxia. The results indicated that the cSP was significantly longer in participants with DCA compared to that in healthy controls. However, there was no correlation between cSP and severity of ataxia. Furthermore, cSP was linked to the ballistic-targeting task performance in healthy participants but not in participants with DCA. These findings suggest that there is excessive activity in the gamma-aminobutyric acid-mediated cortical inhibitory circuit in individuals with DCA. However, this increase in inhibitory activity not only fails to contribute to the control of ballistic-targeting movement but also shows no correlation with the severity of ataxia. These imply that increased excitability in inhibitory cortical circuits in the DCA may not contribute the motor control as much as it does in healthy older adults under limitations associated with a small sample size. The study's results contribute to our understanding of motor control abnormalities in people with DCA and provide potential evidence for further research in this area.

Increased corticospinal inhibition following brief maximal and submaximal contractions in humans.

A potentiating conditioning contraction (CC) has been shown to increase silent period duration, an index of corticospinal inhibition; however, it is unknown if the CC must induce potentiation for corticospinal inhibition to increase. Ten healthy, young adults (four females) completed this study to assess potentiation and silent period (SP) duration before and after four types of CCs: voluntary and electrically evoked maximal CCs to optimize potentiation, and voluntary and electrically evoked submaximal CCs (∼40% of maximal voluntary force) that induced minimal potentiation. Stimulation was applied to the ulnar nerve to evoke twitches for the assessment of potentiation and to evoke tetanic CCs of the first dorsal interosseous muscle. The SP was elicited by applying transcranial magnetic stimulation to the motor cortex during brief contractions at 25% of maximal voluntary force. Changes to twitch force and SP duration were not different for voluntary and tetanic contractions, so data were pooled. Twitch force increased by 81.2 ± 35.7% (P < 0.001) and 3.2 ± 6.5% (P = 0.039) following maximal and submaximal CCs, respectively. The SP was prolonged following maximal (12.6 ± 6.3%; P < 0.001) and submaximal (4.8 ± 4.9%; P < 0.001) CCs. Correlations between post-CC twitch force and SP duration were not significant for maximal or submaximal conditions (r = -0.068; r = 0.067; P ≥ 0.780, respectively). Duration of the SP increased not only following maximal-intensity CCs but also after submaximal-intensity CCs that induced virtually no potentiation (∼3%). Thus, we suggest that corticospinal inhibition is not directly related to mechanisms of muscle potentiation per se, but, rather, the level of muscle contraction likely mediates feedback from large diameter afferents that affect the SP.NEW & NOTEWORTHY The transcranial magnetic stimulation-induced silent period reflects a transient state of corticospinal inhibition that is influenced by recent history of muscle activation, which may include an effect of potentiation. We demonstrate that silent period duration increases following both voluntary and electrically evoked maximal and submaximal conditioning contractions, even though the latter intensity produced virtually no muscle potentiation. Feedback from group Ia and Ib muscle afferents is proposed as the cause of the increased corticospinal inhibition.

Probing the inhibitory motor circuits in adductor laryngeal dystonia during a dystonia-unrelated task

BackgroundThe pathophysiology of adductor laryngeal dystonia (AdLD) remains unknown; however, there is growing evidence that dystonia is associated with disruptions in the inhibitory regulation of sensorimotor cortical areas. Using functional MRI (fMRI) and transcranial magnetic stimulation (TMS) complementarily, we previously demonstrated an overly activated laryngeal motor cortex and revealed correlations between blood-oxygen-level dependent (BOLD) activation and intracortical inhibition in a phonation (dystonia-related) task in adductor laryngeal dystonia (AdLD). ObjectiveHere, we aimed to characterize the brain-based findings in the primary motor cortex (M1) during a dystonia-unrelated (finger tapping) task in AdLD and controls (CTL). MethodsWe examined the between-group differences in task-dependent BOLD activation and intracortical inhibition, measured by the TMS-evoked cortical silent period (cSP), in the M1. The correlations between fMRI and TMS responses were assessed. ResultsThere is more broadly dispersed BOLD activation, not confined to the hand motor cortex, and reduced intracortical inhibition in AdLD compared to CTL. Further, there are more positive correlations between cSP and BOLD activation in a task unrelated to dystonic symptoms in AdLD compared with CTL. This is in contrast to our previous work that demonstrated fewer positive correlations in AdLD during a dystonic phonation task. ConclusionsIn unaffected musculature activation, there is dispersed BOLD activation that is correlated with intracortical inhibition suggesting a possible compensatory strategy in the non-dystonic muscles.

Identification of small diameter nerve fiber damage in hemodialysis patients' hands using the cutaneous silent period

BackgroundThe arteriovenous fistula is the most effective vascular access option for hemodialysis patients. An important and largely unreported concern detected at follow-up is the complaints of tingling or numbness in the hands of those patients. Furthermore, the cutaneous silent period qualifies as a straightforward evaluation of small nerve fiber function. This study aims to evaluate the function of small-diameter nerve fibers in the hands of patients undergoing continuous hemodialysis (HD) on the side with the arteriovenous fistula (AVF) and on the contralateral side.ResultsA cross-sectional study of 40 randomly chosen patients with chronic kidney disease on regular hemodialysis three times weekly the cutaneous silent period (CSP) was recorded on the hand with and without AV fistula. The cutaneous silent period (CSP) CSP was elicited by electrical square pulse stimulation using standard bipolar electrodes. The average cutaneous silent period onset and end latencies demonstrated significant prolongation in the hemodialysis patient group (arteriovenous fistula and non-arteriovenous fistula) compared with the control group. Correlation between cutaneous silent period with hemodialysis duration and adequacy of hemodialysis (KT\\V). There was a statistically negative correlation observed between cutaneous silent period onset latency on the arteriovenous side and a positive correlation with KT\\V on non-arteriovenous fistula. side.ConclusionsHemodialysis patients recommended to undergo regular neurophysiological testing to check for small nerve fiber affection. In particular, measuring the cutaneous Silent period that provides a quick and noninvasive way to rule out small A-delta nerve malfunction. In addition, less nerve injury results from hemodialysis's increased efficiency.

Intracortical and intercortical networks in patients after stroke: a concurrent TMS-EEG study

BackgroundConcurrent transcranial magnetic stimulation and electroencephalography (TMS-EEG) recording provides information on both intracortical reorganization and networking, and that information could yield new insights into post-stroke neuroplasticity. However, a comprehensive investigation using both concurrent TMS-EEG and motor-evoked potential-based outcomes has not been carried out in patients with chronic stroke. Therefore, this study sought to investigate the intracortical and network neurophysiological features of patients with chronic stroke, using concurrent TMS-EEG and motor-evoked potential-based outcomes.MethodsA battery of motor-evoked potential-based measures and concurrent TMS-EEG recording were performed in 23 patients with chronic stroke and 21 age-matched healthy controls.ResultsThe ipsilesional primary motor cortex (M1) of the patients with stroke showed significantly higher resting motor threshold (P = 0.002), reduced active motor-evoked potential amplitudes (P = 0.001) and a prolonged cortical silent period (P = 0.007), compared with their contralesional M1. The ipsilesional stimulation also produced a reduction in N100 amplitude of TMS-evoked potentials around the stimulated M1 (P = 0.007), which was significantly correlated with the ipsilesional resting motor threshold (P = 0.011) and motor-evoked potential amplitudes (P = 0.020). In addition, TMS-related oscillatory power was significantly reduced over the ipsilesional midline-prefrontal and parietal regions. Both intra/interhemispheric connectivity and network measures in the theta band were significantly reduced in the ipsilesional hemisphere compared with those in the contralesional hemisphere.ConclusionsThe ipsilesional M1 demonstrated impaired GABA-B receptor-mediated intracortical inhibition characterized by reduced duration, but reduced magnitude. The N100 of TMS-evoked potentials appears to be a useful biomarker of post-stroke recovery.