Central Motor Conduction Time Research Articles

Yoga as an Add-on Therapy in Parkinson's Disease: A Single Group Open-label Trial.

We aimed to evaluate the effect of yoga on motor and non-motor symptoms and cortical excitability in patients with Parkinson's disease (PD). We prospectively evaluated 17 patients with PD at baseline, after one month of conventional care, and after one month of supervised yoga sessions. The motor and non-motor symptoms were evaluated using the Unified Parkinson's disease Rating Scale (motor part III), Hoehn and Yahr stage, Montreal Cognitive Assessment, Hamilton depression rating scale, Hamilton anxiety rating scale, non-motor symptoms questionnaire and World Health Organization quality of life questionnaire. Transcranial magnetic stimulation was used to record resting motor threshold, central motor conduction time, ipsilateral silent period (iSP), contralateral silent period (cSP), short interval intracortical inhibition (SICI), and intracortical facilitation. The mean age of the patients was 55.5 ± 10.8 years, with a mean duration of illness of 4.0 ± 2.5 years. The postural stability of the patients significantly improved following yoga (0.59 ± 0.5 to 0.18 ± 0.4, p = 0.039). There was a significant reduction in the cSP from baseline (138.07 ± 27.5 ms) to 4 weeks of yoga therapy (116.94 ± 18.2 ms, p = 0.004). In addition, a significant reduction in SICI was observed after four weeks of yoga therapy (0.22 ± 0.10) to (0.46 ± 0.23), p = 0.004). Yoga intervention can significantly improve postural stability in patients with PD. A significant reduction of cSP and SICI suggests a reduction in GABAergic neurotransmission following yoga therapy that may underlie the improvement observed in postural stability. CTRI/2019/02/017564.

Comparative efficacy of different noninvasive brain stimulation protocols on upper-extremity motor function and activities of daily living after stroke: a systematic review and network meta-analysis.

The objectives of the study were to systematically evaluate the rehabilitation effect of noninvasive brain stimulation (NIBS) on upper extremity motor function and activities of daily living in stroke patients and to prioritize various stimulation protocols for reliable evidence-based medical recommendations in patients with upper extremity motor dysfunction after stroke. Web of Science, PubMed, Embase, Cochrane Library, CNKI, Wanfang, VIP, and CBM were searched to collect all randomized controlled trials (RCTs) of NIBS to improve upper extremity motor function in stroke patients. The retrieval time was from the establishment of all databases to May 2023. According to the Cochrane system evaluation manual, the quality of the included studies was evaluated, and the data were extracted. Statistical analysis was carried out by using RevMan 5.3, R 4.3.0, and Stata 17.0 software. Finally, 94 RCTs were included, with a total of 5546 patients. Meta-analysis showed that NIBS improved the Fugl-Meyer assessment (FMA) score (mean difference (MD) = 6.51, 95% CI 6.20 ~ 6.82, P < 0.05), MBI score (MD = 7.69, 95% CI 6.57 ~ 8.81, P < 0.05), ARAT score (MD = 5.06, 95% CI 3.85 ~ 6.27, P < 0.05), and motor evoked potential (MEP) amplitude. The modified Ashworth scale score (MD = - 0.37, 95% CI - 0.60 to - 0.14, P < 0.05), National Institutes of Health Stroke Scale score (MD = - 2.17, 95% CI - 3.32 to - 1.11, P < 0.05), incubation period of MEP (MD = - 0.72, 95% CI - 1.06 to - 0.38, P < 0.05), and central motor conduction time (MD = - 0.90, 95% CI - 1.29 to - 0.50, P < 0.05) were decreased in stroke patients. Network meta-analysis showed that the order of interventions in improving FMA scores from high to low was anodal-transcranial direct current stimulation (tDCS) (surface under the cumulative ranking curve (SUCRA) = 83.7%) > cathodal-tDCS (SUCRA = 80.2%) > high-frequency (HF)-repetitive transcranial magnetic stimulation (rTMS) (SUCRA = 68.5%) > low-frequency (LF)-rTMS (SUCRA = 66.5%) > continuous theta burst stimulation (cTBS) (SUCRA = 54.2%) > bilateral-tDCS (SUCRA = 45.2%) > intermittent theta burst stimulation (iTBS) (SUCRA = 34.1%) > sham-NIBS (SUCRA = 16.0%) > CR (SUCRA = 1.6%). In terms of improving MBI scores, the order from high to low was anodal-tDCS (SUCRA = 88.7%) > cathodal-tDCS (SUCRA = 85.4%) > HF-rTMS (SUCRA = 63.4%) > bilateral-tDCS (SUCRA = 56.0%) > LF-rTMS (SUCRA = 54.2%) > iTBS (SUCRA = 32.4%) > sham-NIBS (SUCRA = 13.8%) > CR (SUCRA = 6.1%). NIBS can effectively improve upper extremity motor function and activities of daily living after stroke. Among the various NIBS protocols, anodal-tDCS demonstrated the most significant intervention effect, followed by cathodal-tDCS and HF-rTMS.

Evaluation of Epiconus and Conus Medullaris Disorders due to Thoracolumbar Vertebral Fracture using Motor Evoked Potentials.

A retrospective case-control study. To characterize the motor evoked potential (MEP) when the epiconus or conus medullaris is compressed by a fracture of the T12 or L1 vertebra. Although the characteristics of compressive cervical and thoracic myelopathy with transcranial magnetic stimulation MEP have been reported, the MEP parameters in compressive disorders of the epiconus and conus medullaris have not yet been characterized. Twenty patients with T12 or L1 vertebral fractures who had lower extremity symptoms due to compression of the epiconus or conus medullaris were included. These patients were compared with 28 healthy controls and 32 patients with cervical spondylotic radiculopathy (CSR) without spinal cord compression. MEPs of abductor hallucis muscles were recorded using transcranial magnetic stimulation and electrical stimulation of the tibial nerve. MEP latency, central motor conduction time (CMCT), and peripheral conduction time (PCT) were evaluated. MEP latency, CMCT, and PCT were significantly longer in patients with fractures than in healthy controls and patients with CSR. MEP latency was most accurate for differentiating patients with fracture from healthy controls (cutoff value, 40.0 ms, sensitivity, 95.0%; specificity, 100%), and CMCT was most accurate for comparing patients with fracture and CSR (cutoff value, 15.5 ms, sensitivity, 80.0%; specificity, 93.8%). In the distinction between patients with fracture and CSR, 16 of the 20 patients with fracture exceeded the cutoff values for any of the parameters, and 12 of them exceeded the cutoff values for all parameters. There was no significant correlation between the linear distance from the most inferior end of the spinal cord to the site of compression and any of the MEP parameters. Both CMCT and PCT are often prolonged in compressive lesions of the epiconus and conus medullaris, and MEP latency and CMCT are useful in the diagnosis.

Shock waves modulate corticospinal excitability: A proof of concept for further rehabilitation purposes?

Focal extracorporeal shock wave therapy (fESWT) is a physical therapy vastly studied and used for various musculoskeletal disorders. However, the effect of fESWT on central nervous system is still to be determined. To elucidate spinal and supra-spinal mechanisms of fESWT in healthy subjects, in order to widen the spectrum of its clinical applications. In this quasi-experimental, unblinded, proof-of-concept clinical study, 10 voluntary healthy subjects underwent fESWT and were assessed immediately before (T0), immediately after (T1) and seven days after (T2) the intervention. As neurophysiological outcomes, motor evoked potentials (resting motor threshold, maximal motor evoked potential and maximal compound muscle action potential ratio, cortical silent period, total conduction motor time, direct and indirect central motor conduction time), F-waves (minimal and mean latency, persistence and temporal dispersion) and H-reflex (threshold, amplitude, maximal H reflex and maximal compound muscle action potential ratio, latency) were considered. Resting motor threshold and F-waves temporal dispersion significantly decreased, respectively, from T1 and T2 and from T0 and T2 (for both, p < 0.05). H-reflex threshold increase between T0 and T1. Analysis disclosed a strong negative correlation between Δ3 cortical silent period (i.e., T2 -T1 recordings) and Δ1 Hr threshold (i.e., T1 -T0 recordings) (r = -0.66, p < 0.05), and a positive strong relationship between Δ3 cortical silent period and Δ3 Hr threshold (r = 0.63, p < 0.05). fESWT modulates corticospinal tract excitability in healthy volunteers, possibly inducing an early inhibition followed by a later facilitation after one week.

Effectiveness and brain mechanism of multi-target transcranial alternating current stimulation (tACS) on motor learning in stroke patients: study protocol for a randomized controlled trial

BackgroundTranscranial alternating current stimulation (tACS) has proven to be an effective treatment for improving cognition, a crucial factor in motor learning. However, current studies are predominantly focused on the motor cortex, and the potential brain mechanisms responsible for the therapeutic effects are still unclear. Given the interconnected nature of motor learning within the brain network, we have proposed a novel approach known as multi-target tACS. This study aims to ascertain whether multi-target tACS is more effective than single-target stimulation in stroke patients and to further explore the potential underlying brain mechanisms by using techniques such as transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI).MethodsThis study employs a double-blind, sham-controlled, randomized controlled trial design with a 2-week intervention period. Both participants and outcome assessors will remain unaware of treatment allocation throughout the study. Thirty-nine stroke patients will be recruited and randomized into three distinct groups, including the sham tACS group (SS group), the single-target tACS group (ST group), and the multi-target tACS group (MT group), at a 1:1:1 ratio. The primary outcomes are series reaction time tests (SRTTs) combined with electroencephalograms (EEGs). The secondary outcomes include motor evoked potential (MEP), central motor conduction time (CMCT), short interval intracortical inhibition (SICI), intracortical facilitation (ICF), magnetic resonance imaging (MRI), Box and Block Test (BBT), and blood sample RNA sequencing. The tACS interventions for all three groups will be administered over a 2-week period, with outcome assessments conducted at baseline (T0) and 1 day (T1), 7 days (T2), and 14 days (T3) of the intervention phase.DiscussionThe study’s findings will determine the potential of 40-Hz tACS to improve motor learning in stroke patients. Additionally, it will compare the effectiveness of multi-target and single-target approaches, shedding light on their respective improvement effects. Through the utilization of techniques such as TMS and MRI, the study aims to uncover the underlying brain mechanisms responsible for the therapeutic impact. Furthermore, the intervention has the potential to facilitate motor learning efficiency, thereby contributing to the advancement of future stroke rehabilitation treatment.Trial registrationChinese Clinical Trial Registry ChiCTR2300073465. Registered on 11 July 2023.

Resting-state functional magnetic resonance imaging indices are related to electrophysiological dysfunction in degenerative cervical myelopathy

The age-related degenerative pathologies of the cervical spinal column that comprise degenerative cervical myelopathy (DCM) cause myelopathy due spinal cord compression. Functional neurological assessment of DCM can potentially reveal the severity and pathological mechanism of DCM. However, functional assessment by conventional MRI remains difficult. This study used resting-state functional MRI (rs-fMRI) to investigate the relationship between functional connectivity (FC) strength and neurophysiological indices and examined the feasibility of functional assessment by FC for DCM. Preoperatively, 34 patients with DCM underwent rs-fMRI scans. Preoperative central motor conduction time (CMCT) reflecting motor functional disability and intraoperative somatosensory evoked potentials (SEP) reflecting sensory functional disability were recorded as electrophysiological indices of severity of the cervical spinal cord impairment. We performed seed-to-voxel FC analysis and correlation analyses between FC strength and the two electrophysiological indices. We found that FC strength between the primary motor cortex and the precuneus correlated significantly positively with CMCT, and that between the lateral part of the sensorimotor cortex and the lateral occipital cortex also showed a significantly positive correlation with SEP amplitudes. These results suggest that we can evaluate neurological and electrophysiological severity in patients with DCM by analyzing FC strengths between certain brain regions.

Transcranial Magnetic Stimulation in the Diagnosis of Compressive Myelopathy at the Thoracolumbar Junction.

The disc level in the thoracolumbar junction at which measurement of the central motor conduction time in the lower limbs (CMCT-LL) is useful for a diagnosis remains unclear. Therefore, this study investigated the spinal vertebral level at which compressive myelopathy due to ossification of the ligamentum flavum in the thoracolumbar junction is detectable using CMCT-LL. We preoperatively measured CMCT-LL in 57 patients (42 men, 15 women; aged 35-85 years) with a single ossification of the ligamentum flavum from the T10-11 to T12-L1 disc levels and in 53 healthy controls. Motor evoked potentials after transcranial magnetic stimulation, compound muscle action potentials, and F waves were recorded from the abductor hallucis. Central motor conduction time in the lower limbs was calculated as follows: Motor evoked potential latency - (compound muscle action potential latency + F latency - 1)/2 (ms). Central motor conduction time in the lower limbs was compared between patients and controls. Compressive lesions were located at the T10 to 11 level in 27 patients, the T11 to 12 level in 28, and the T12-L1 level in 2. Central motor conduction time values in the lower limbs at the T10 to 11 level (19.9 ± 4.7 ms) and T11 to 12 level (18.1 ± 3.4 ms) were significantly longer than control values (11.8 ± 1.1 ms; P < 0.01). Central motor conduction time in the lower limbs was not calculated at the T12-L1 level because motor evoked potentials were not recorded in any patient. We confirmed that CMCT-LL was significantly longer in patients with ossification of the ligamentum flavum at the T10 to 11 and T11 to 12 levels because the S2 segment of the spinal cord is caudal at the T12 vertebral body level. Therefore, CMCT-LL is useful for diagnosing thoracolumbar junction disorders proximal to the T12 vertebral body level.

Abnormal cortical excitability in patients with spinocerebellar ataxia type 12

BackgroundSpinocerebellar ataxia type 12 (SCA-12) is an uncommon autosomal dominant cerebellar ataxia characterized by action tremors in the upper limbs, dysarthria, head tremor, and gait ataxia. We aimed to evaluate the motor cortical excitability in patients with SCA-12 using transcranial magnetic stimulation (TMS). MethodsThe study was done in the department of Neurology at the National Institute of Mental Health and Neuro Sciences (NIMHANS), Bangalore. Nine patients with SCA-12 (2 females) and 10 healthy controls (2 females) were included in the study. TMS was performed in all the subjects and various parameters such as resting motor threshold (RMT), central motor conduction time (CMCT) and contralateral silent period (cSP) were recorded. The left motor cortex was stimulated and the recording was done from right first dorsal interossei muscle. The severity of ataxia was assessed using the scale for assessment and rating in ataxia (SARA). ResultsThe mean age of the patients was 58.11 ± 7.56 years mean age at onset: 51.67 ± 4.18 years. The mean duration of illness was 9.44 ± 4.88 years. The mean SARA score was 13.83 ± 3.60. Patients with SCA-12 had significantly increased RMT (88.80 ± 12.78 %) compared to HC (44.90 ± 9.40 %, p < 0.05). A significantly prolonged CMCT was observed in patients (13.70 ± 2.52 msec) compared to HC (7.31 ± 1.21 msec, p < 0.05). In addition, cSP was significantly increased in SCA-12 patients (144.43 ± 25.79 msec) compared to HC (82.14 ± 28.90 msec, p < 0.05). ConclusionsPatients with SCA-12 demonstrate a reduced cortical excitability and increased cortical inhibition suggesting an increase in the GABAergic neurotransmission.

Central and Peripheral Motor Conduction Studies by Single-Pulse Magnetic Stimulation.

Single-pulse magnetic stimulation is the simplest type of transcranial magnetic stimulation (TMS). Muscle action potentials induced by applying TMS over the primary motor cortex are recorded with surface electromyography electrodes, and they are called motor-evoked potentials (MEPs). The amplitude and latency of MEPs are used for various analyses in clinical practice and research. The most commonly used parameter is the central motor conduction time (CMCT), which is measured using motor cortical and spinal nerve stimulation. In addition, stimulation at the foramen magnum or the conus medullaris can be combined with conventional CMCT measurements to evaluate various conduction parameters in the corticospinal tract more precisely, including the cortical-brainstem conduction time, brainstem-root conduction time, cortical-conus motor conduction time, and cauda equina conduction time. The cortical silent period is also a useful parameter for evaluating cortical excitability. Single-pulse magnetic stimulation is further used to analyze not only the central nervous system but also the peripheral nervous system, such as for detecting lesions in the proximal parts of peripheral nerves. In this review article we introduce four types of single-pulse magnetic stimulation-of the motor cortex, spinal nerve, foramen magnum, and conus medullaris-that are useful for the diagnosis, elucidation of pathophysiology, and evaluation of clinical conditions and therapeutic effects. Single-pulse magnetic stimulation is a clinically useful technique that all neurologists should learn.

Neurometabolic therapy of mild cognitive impairment in patients with chronic cerebral ischemia

To evaluate the effect of a sequential therapy regimen with Mexidol (500 mg injections intravenously for 14 days) and Mexidol FORTE 250 (250 mg tablets 3 times a day for 60 days) on higher cortical functions in patients with moderate cognitive disorders in chronic cerebral ischemia. A comparative, prospective study included 63 patients with chronic cerebral ischemia with moderate cognitive impairment. All patients received basic therapy aimed at reducing risk factors (antihypertensive, antithrombotic drugs as indicated). Patients of the main group (30 people: 12 men, 18 women) received Mexidol intravenously 500 mg in 100 ml of 0.9% NaCl solution once a day for 14 days, then Mexidol FORTE 250 (film-coated tablets) 250 mg 3 times a day for the next 60 days. The comparison group consisted of 33 patients (14 men, 19 women) who received only basic therapy. The groups were comparable in terms of age, sex characteristics and severity of cognitive deficit. We examined cognitive status (MoCA scale, Frontal Dysfunction Battery, 10 Word Memorization tests), severity of asthenia (MFI-20 scale), anxiety and depression (HADS scale), patient's subjective assessment of the dynamics of the condition (CGI-improvement scale) in 1st, 14th and 74th±5 days of observation. On days 1 and 74±5 of observation, patients were examined using transcranial magnetic stimulation to study the neuronal activity of the cerebral cortex. In the main group, at the time of completion of taking Mexidol and Mexidol FORTE 250, a pronounced cognitive regression was noted (MoCA scale +3 points, difference with the comparison group 1 point (p<0.0001); Frontal Dysfunction Battery test +4 points, difference with comparison group 2 points (p<0.001); memory test «10 words» +2 points, difference with the comparison group 1 point (p<0.05), emotional (HADS anxiety scale -8 points, difference with the comparison group 3 points (p<0.001), depression -3.5 points, difference with the comparison group 1.5 points (p<0.01), asthenic disorders (MFI-20 scale -30 points, difference with the comparison group 15.5 points (p<0.01), improvement in the well-being of patients (CGI-improvement scale -2 points, difference with the comparison group 1 point (p<0.0001). According to the transcranial magnetic stimulation performed, a statistically significant decrease in the central motor conduction time at the level of 1 and 2 motor neurons of the pyramidal tract bilaterally from the start to the end of therapy with Mexidol and Mexidol FORTE 250 was determined (p<0.01). An inverse correlation was found between the time of central motor conduction and the results of the Frontal Dysfunction Battery test at the same time points with left-sided localization of 1 motor neuron (p<0.01). The results of a study of the use of sequential therapy with Mexidol 500 mg IV drip 1 time per day for 14 days followed by oral administration of Mexidol FORTE 250 1 tablet 3 times a day for 60 days indicate its clinical effectiveness and safety in patients with chronic cerebral ischemia with mild cognitive impairment, and also confirm its importance for preventing the progression of cognitive disorders.

Acupuncture combined with repeated transcranial magnetic stimulation for upper limb motor function after stroke: A systematic review and meta-analysis.

Upper limb motor dysfunction after stroke is an important factor affecting patients' motor function and daily life. Acupuncture and repetitive transcranial magnetic stimulation are effective methods for stroke rehabilitation. However, a systematic and comprehensive overview of the combined efficacy of the two is lacking. Through a systematic review and meta-analysis of randomized controlled trials, this study aimed to assess the effectiveness of acupuncture combined with repetitive transcranial magnetic stimulation on upper extremity motor function in post-stroke patients. The relevant randomized controlled trials on acupuncture combined with repetitive transcranial magnetic stimulation in the treatment of upper limb motor disorders after stroke were searched in PubMed, Embase, Cochrane Library, Web of Science CNKI, VIP, Wanfang, and CBM databases. After screening clinical trials that met the inclusion criteria, data extraction was conducted independently by two investigators. Meta-analysis was performed using RevMan 5.4 software. After the screening, 18 articles were included, with a total of 1083 subjects. The results of meta-analysis showed that combination therapy could effectively improve the patients' upper limb motor function (MD = 7.77, 95%CI [6.32, 9.22], P < 0.05), ability of daily living (MD = 8.53, 95%CI [6.28, 10.79], P < 0.05), and hemiplegic shoulder pain (MD = - 1.72, 95%CI [- 2.26, - 1.18], P < 0.05). Meanwhile, for neurophysiological indexes, combined treatment could significantly shorten the latency of motor evoked potential and central motor conduction time (MD = - 1.42, 95%CI [- 2.14, - 0.71], P < 0.05); (MD = - 0.47, 95%CI [- 0.66, - 0.29], P < 0.05), and also could increase the amplitude of motor evoked potential (SMD = 0.71, 95%CI [0.28, 1.14], P < 0.05). According to the results of the meta-analysis, we can conclude that acupuncture combined with repeated transcranial magnetic stimulation can significantly improve the upper limb motor function and daily living ability of stroke patients.

An Overview of Transcranial Magnetic Stimulation and Its Application in Multiple Sclerosis

Transcranial magnetic stimulation (TMS) is a flexible, non-invasive technique that involves the production of a brief magnetic field to stimulate the conductive structures of the brain. When TMS is specifically employed as a single- or paired-pulse over the motor cortex, the function and integrity of the descending motor pathways can be assessed through the generation of a motor evoked potential (MEP). Important MEP-derived measures include the motor threshold, MEP amplitude and latency, central motor conduction time, silent period, intracortical inhibition, and intracortical facilitation. These functional measures may have use in individuals with multiple sclerosis (MS), a common chronic autoimmune disorder of the central nervous system, due to their useful diagnostic and prognostic implications. As a representation of excitability and conductivity, TMS measures may have the potential to serve as objective markers of corticospinal tract integrity, which is a major aspect of clinical disability in MS. Additionally, TMS may be employed to help monitor and provide insight on the effects of therapies for patients with MS over a longitudinal timeframe. In this review, we focus on the application of TMS in the context of MS, with an emphasis on the relationship between TMS measures and widely used clinical assessment measures used for patients with MS.

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.

Corticospinal excitability after 5-day Dry Immersion in women.

In light of the development of manned astronautics and the increasing participation of women in space flights, the question of female body adaptation to microgravity conditions becomes relevant. Currently, one of the important directions in this issue is to study the effects of support withdrawal as a factor of weightlessness on the human sensorimotor system. Dry Immersion is one of the well-known ground-based models, which adequately reproduces the main physiological effects of space flight. The aim of this study was to evaluate the changes in motor evoked potentials of the lower leg gravity-dependent muscles in women after a 5-day Dry Immersion. We analyzed evoked responses to transcranial and trans-spinal magnetic stimulation. In this method, areas of interest (the motor cortex and lumbosacral thickening of the spinal cord) are stimulated with an electromagnetic stimulus. The experiment was conducted with the participation of 16 healthy female volunteers with a natural menstrual cycle. The thresholds, amplitudes, and latencies of motor potentials evoked by magnetic stimulation were assessed. We showed that 5-day exposure to support withdrawal leads to a decrease in motor-evoked potential thresholds and central motor conduction time, although changes in motor response amplitudes were ambiguous. The data obtained correspond to the results of previous research on Dry Immersion effects on the sensorimotor system in men.

Protocol for a single-blind randomized clinical trial to test the efficacy of bilateral transcranial magnetic stimulation on upper extremity motor function in patients recovering from stroke

BackgroundNo consensus currently exists regarding the optimal protocol for repetitive transcranial magnetic stimulation (rTMS) treatment of upper-extremity motor dysfunction after stroke. Studies have shown that combined low- and high-frequency stimulation (LF-HF-rTMS) of the bilateral cerebral hemispheres is more effective than sham stimulation or stimulation of one cerebral hemisphere alone in treating motor dysfunction in the subacute stage of stroke. The efficacy of this protocol in the convalescence phase of stroke has rarely been reported, and its mechanism of action has not been clarified. In this study, we designed a prospective, single-blind, randomized controlled trial to investigate the efficacy and safety of different stimulation regimens for the treatment of upper extremity motor disorders in patients with convalescent stage stroke and aimed to explore the underlying mechanisms based on biomarkers such as brain-derived neurotrophic factor (BDNF).MethodsSeventy-six subjects will be randomly divided into combined, low-frequency, high-frequency, and control groups based on the proportion of 1:1:1:1, with 19 cases in each group. All groups will have conventional rehabilitation, on top of which the combined group will receive 1 Hz rTMS in the unaffected hemisphere and 10 Hz rTMS in the affected hemisphere. The low-frequency group will be administered 1 Hz rTMS in the unaffected hemisphere and sham stimulation in the contralateral hemisphere. The high-frequency group will be administered 10 Hz rTMS in the affected hemisphere and contralateral sham stimulation. The control group will receive bilateral sham stimulation. Assessments will be performed at baseline, after 2 weeks of treatment, and at post-treatment follow-up at week 6. The primary outcomes are FMA-UE (Fugl-Meyer assessment-upper extremity), latency, and serum BDNF levels. The secondary outcomes are the National Institute of Health Stroke Scale (NIHSS), Brunnstrom staging (BS), modified Ashworth scale (MAS), Modified Barthel Index (MBI), central motor conduction time (CMCT), precursor proteins of mature BDNF (proBDNF), and matrix metalloproteinase-9 (MMP-9) levels. Adverse events, such as headaches and seizures, will be recorded throughout the study.DiscussionThe findings of this study will help develop optimal stimulation protocols for motor recovery in stroke patients and identify biomarkers that respond to post-stroke motor rehabilitation, for better guidance of clinical treatment.Trial registrationThe study protocol was passed by the Medical Research Ethics Committee of the General Hospital of Ningxia Medical University on January 1, 2022 (no. KYLL-2021–1082). It was registered into the Chinese Clinical Trials Registry on May 22, 2022 (no. ChiCTR2200060201). This study is currently in progress.Graphical

Diagnostic and prognostic significance of preoperative evoked potential tests in degenerative cervical myelopathy

BACKGROUND CONTEXTDecompression surgery is a treatment option for patients with degenerative cervical myelopathy (DCM). Surgical decisions primarily depend on clinical symptoms and radiological examinations. The diagnostic and prognostic significance of evoked potential tests for surgical outcomes in patients with DCM has not been thoroughly examined. PURPOSETo identify the diagnostic and prognostic significance of preoperative evoked potential tests in patients with DCM who underwent decompression surgery. STUDY DESIGNThis was a retrospective observational study. PATIENT SAMPLEOne hundred two consecutive patients who underwent evoked potential tests and surgical treatment between January 2016 and December 2020 in a single spine center and had a minimum follow-up of 6 months. OUTCOME MEASURESJapanese Orthopedic Association (JOA) scores obtained preoperatively and 6 months after surgery. METHODSThis study evaluated the preoperative central motor conduction time (CMCT), somatosensory evoked potentials, and Japanese Orthopedic Association (JOA) scores obtained preoperatively and 6 months after surgery. RESULTSAbnormal CMCT findings were observed in 94 patients (92.2%). Abnormal somatosensory evoked potentials were observed in 77 patients (75.5%). There was a statistically significant correlation between preoperative JOA score and abductor pollicis brevis (APB)-CMCT (r=−0.546, p=.001), tibialis anterior (TA)-CMCT (r=−0.517, p<.001), median nerve (MN)-SSEP (r=−0.353, p=.001), and tibial nerve (TN)-SSEP (r=−0.349, p=.003). There were significant differences in recovery rates associated with diabetes mellitus (DM), preoperative severity of myelopathy, TA-CMCT, MN-SSEP, and TN-SSEP. Stepwise multiple regression analysis showed that the major factors affecting the clinical outcomes were TN-SSEP (β=0.327, p=.004), preoperative JOA score (β=0.278, p=.012), and DM (β=0.241, p=.025). CONCLUSIONSEvoked potential testing is a functional diagnostic tool that can indicate the severity of myelopathic symptoms in patients with DCM. Additionally, preoperative TN-SSEP may have significant prognostic value in predicting postoperative clinical outcomes. Thus, preoperative evoked potential tests could be helpful for determining suitable surgical treatment candidates and forecasting postoperative prognosis.

Treatment effects of low-frequency repetitive transcranial magnetic stimulation combined with motor relearning procedure on spasticity and limb motor function in stroke patients.

Limb paralysis, which is a sequela of stroke, limits patients' activities of daily living and lowers their quality of life. The purpose of this study was to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) combined with a motor relearning procedure (MRP) on motor function and limb spasticity in stroke patients. Stroke patients were randomly divided into a combined treatment group (rTMS + MRP) and a control group (MRP) (n = 30 per group). The control group was given MRP in addition to conventional rehabilitation, and the combined treatment group was given 1 Hz rTMS combined with MRP. The treatment efficacy was assessed by the modified Ashworth scale (MAS), Fugl-Meyer motor function scale, and motor evoked potential (MEP) testing. After 4 weeks of treatment, the Brunnstrom score, Fugl-Meyer lower extremity motor function, and Fugl-Meyer balance function were significantly higher in the combination treatment group compared to the control group, while the MAS score was lower in the combination treatment group compared to the control group. The MEP extraction rate was higher in the combined treatment group compared to the control group, while the threshold and central motor conduction time (CMCT) were lower in the combined treatment group compared to the control group. Low-frequency rTMS combined with MRP had better efficacy on spasticity and motor function in stroke patients with hemiparesis than MRP alone.

Clinical analysis in patients with SPG11 hereditary spastic paraplegia.

To analyze the clinical phenotype of hereditary spastic paraplegia (HSP) caused by SPG11 mutations (SPG11-HSP). Among the 17 patients with sporadic HSP who performed whole exome sequencing analysis, six were diagnosed with SPG11-HSP. The clinical and radiologic findings and the results of the electrodiagnostic and neuropsychologic tests were reviewed retrospectively. The median age at onset was 16.5 years (range, 13-38 years). Progressive spastic paraparesis was a core feature, and the median spastic paraplegia rating scale score was 24/52 (range, 16-31 points). Additional major symptoms were pseudobulbar dysarthria, intellectual disability, bladder dysfunction, and being overweight. Minor symptoms included upper limbs rigidity and sensory axonopathy. The median body mass index was 26.2 kg/m2 (range, 25.2-32.3 kg/m2). The thin corpus callosum (TCC) was predominant at the rostral body or anterior midbody, and the ears of the lynx sign was seen in all. The follow-up MRI showed the worsening of periventricular white matter (PVWM) signal abnormalities with ventricular widening or the extension of the TCC. Motor evoked potentials (MEP) to the lower limbs showed an absent central motor conduction time (CMCT) in all subjects. The upper limb CMCT was initially absent in three subjects, although it became abnormal in all at the follow-up. The mini-mental state examination median score was 27/30 (range, 26-28) with selective impairment of the attention/calculation domain. The median score of the full-scale intelligence quotient was 48 (range, 42-72) on the Wechsler Adult Intelligence Scale test. Attention/calculation deficits and being overweight as well as pseudobulbar dysarthria were common additional symptoms in patients with SPG11-HSP. The rostral body and anterior midbody of the corpus callosum were preferentially thinned, especially in the early stage of the disease. The TCC, PVWM signal changes, and MEP abnormality worsened as the disease progressed.

Sex-specific reference values for total, central, and peripheral latency of motor evoked potentials from a large cohort.

Differentiating between physiologic and altered motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) is crucial in clinical practice. Some physical characteristics, such as height and age, introduce sources of variability unrelated to neural dysfunction. We provided new age- and height-adjusted normal values for cortical latency, central motor conduction time (CMCT), and peripheral motor conduction time (PMCT) from a large cohort of healthy subjects. Previously reported data from 587 participants were re-analyzed. Nervous system disorders were ruled out by clinical examination and magnetic resonance imaging. MEP latency was determined as stimulus-to-response latency through stimulation with a circular coil over the "hot spot" of the First Dorsal Interosseous and Tibialis Anterior muscles, during mild tonic contraction. CMCT was estimated as the difference between MEP cortical latency and PMCT by radicular magnetic stimulation. Additionally, right-to-left differences were calculated. For each parameter, multiple linear regression models of increasing complexity were fitted using height, age, and sex as regressors. Motor evoked potential cortical latency, PMCT, and CMCT were shown to be age- and height-dependent, although age had only a small effect on CMCT. Relying on Bayesian information criterion for model selection, MEP cortical latency and PMCT were explained best by linear models indicating a positive correlation with both height and age. Also, CMCT to lower limbs positively correlated with height and age. CMCT to upper limbs positively correlated to height, but slightly inversely correlated to age, as supported by non-parametric bootstrap analysis. Males had longer cortical latencies and CMCT to lower limbs, as well as longer PMCT and cortical latencies to upper limbs, even when accounting for differences in body height. Right-to-left-differences were independent of height, age, and sex. Based on the selected regression models, sex-specific reference values were obtained for all TMS-related latencies and inter-side differences, with adjustments for height and age, where warranted. A significant relationship was observed between height and age and all MEP latency values, in both upper and lower limbs. These set of reference values facilitate the evaluation of MEPs in clinical studies and research settings. Unlike previous reports, we also highlighted the contribution of sex.