Comparison of Transcallosal Inhibition Between Hemispheres and Its Relationship with Motor Behavior in Patients with Severe Upper Extremity Impairment After Subacute Stroke

ObjectiveTo compare corticospinal excitability and transcallosal inhibition between contralesional primary motor cortex (M1) and ipsilesional M1. We also investigated the correlation between transcallosal inhibition and upper extremity motor behavior.Materials and methods19 individuals with unilateral ischemic subacute stroke who had severe upper extremity impairment participated in this study. Corticospinal excitability was assessed by measuring the resting motor threshold, active motor threshold and motor evoked potential amplitude. Transcallosal inhibition was investigated by measuring the duration and depth of the ipsilateral silent period (ISP). The data from the two hemispheres were compared and the relationships of transcallosal inhibition with upper extremity motor impairment, grip strength and pinch strength were analyzed.ResultsResting motor threshold (p = 0.001) and active motor threshold (p = 0.001) were lower and motor evoked potential amplitude was higher (p = 0.001) in the contralesional M1 compared to the ipsilesional M1. However, there were no differences between the two M1s in ISP duration (p = 0.297) or ISP depth (p =0. 229). Transcallosal inhibition from the contralesional M1 was positively associated with motor impairment (ISP duration, p = 0.003; ISP depth, p = 0.017) and grip strength (ISP duration, p = 0.016; ISP depth, p = 0.045).ConclusionsSymmetric transcallosal inhibition between hemispheres and positive association of transcallosal inhibition from contralesional M1 with upper extremity motor behavior indicate that recruitment of contralesional M1 may be necessary for recovery in patients with severe upper extremity impairment after subacute ischemic stroke.     

Central motor conduction time reveals upper motor neuron involvement masked by lower motor neuron impairment in a significant portion of patients with amyotrophic lateral sclerosis

ObjectiveWe retrospectively investigated the utility of the central motor conduction time (CMCT) in detecting upper motor neuron (UMN) involvements in patients with amyotrophic lateral sclerosis (ALS).MethodsFifty-two ALS patients and 12 disease control patients participated in this study. Surface electromyograms were recorded from the first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. We stimulated the motor cortex, brainstem, and spinal nerve using transcranial magnetic stimulation (TMS) in order to measure the cortical, brainstem, and spinal latencies. We divided the ALS patients into 2 subgroups (with UMN impairment vs. without UMN impairment) and calculated the rates of abnormal CMCT prolongation judged by their comparison with the normal ranges obtained by the measurement in the control patients.ResultsThe CMCTs in the FDI and TA were abnormally prolonged in over 40% of the ALS patients with UMN impairment and in nearly 30% of those without UMN impairment.ConclusionsCMCT shows UMN dysfunction in ALS patients without clinical UMN impairment.SignificanceTMS still has diagnostic utility in a significant portion of ALS patients.     

脑电仿生电刺激对脑梗死后认知功能障碍的影响

目的观察脑电仿生电刺激小脑顶核对脑梗死后认知功能障碍的影响,并探讨其可能的机制。方法选取脑梗死后并发认知功能障碍患者50例,随机分成治疗组与对照组各25例。2组患者均接受康复治疗及认知功能训练,治疗组同时加用脑电仿生电刺激进行干预。2组患者分别于治疗前后应用蒙特利尔认知评估量表(MoCA)、简易精神状态量表(MMSE)评定认知功能变化,采用经颅多普勒超声(TCD)评估颅内动脉血流动力学改变。结果治疗后2组患者MoCA评分、MMSE评分均较组内治疗前提高(P<0.05),且治疗组评分明显较对照组高,差异有统计学意义(P<0.05)。治疗后2组患者颅内动脉血流动力学较组内治疗前改善(P<0.05),且治疗组较对照组改善更显著,差异有统计学意义(P<0.05)。治疗组与对照组总有效率分别为92%和64%,差异有统计学意义(P<0.05)。结论脑电仿生电刺激小脑顶核可有效改善脑梗死患者的认知功能,其可能机制是通过改善患者的脑循环进一步改善认知功能。     

Paired associated magnetic stimulation promotes neural repair in the rat middle cerebral artery occlusion model of stroke

Paired associative stimulation has been used in stroke patients as an innovative recovery treatment. However, the mechanisms underlying the therapeutic effectiveness of paired associative stimulation on neurological function remain unclear. In this study, rats were randomly divided into middle cerebral occlusion model(MCAO) and paired associated magnetic stimulation(PAMS) groups. The MCAO rat model was produced by middle cerebral artery embolization. The PAMS group received PAMS on days 3 to 20 post MCAO. The MCAO group received sham stimulation, three times every week. Within 18 days after ischemia, rats were subjected to behavioral experiments—the foot-fault test, the balance beam walking test, and the ladder walking test. Balance ability was improved on days 15 and 17, and the footfault rate was less in their affected limb on day 15 in the PAMS group compared with the MCAO group. Western blot assay showed that the expression levels of brain derived neurotrophic factor, glutamate receptor 2/3, postsynaptic density protein 95 and synapsin-1 were significantly increased in the PAMS group compared with the MCAO group in the ipsilateral sensorimotor cortex on day 21. Resting-state functional magnetic resonance imaging revealed that regional brain activities in the sensorimotor cortex were increased in the ipsilateral hemisphere, but decreased in the contralateral hemisphere on day 20. By finite element simulation, the electric field distribution showed a higher intensity, of approximately 0.4 A/m~2, in the ischemic cortex compared with the contralateral cortex in the template. Together, our findings show that PAMS upregulates neuroplasticity-related proteins, increases regional brain activity, and promotes functional recovery in the affected sensorimotor cortex in the rat MCAO model. The experiments were approved by the Institutional Animal Care and Use Committee of Fudan University, China(approval No. 201802173 S) on March 3, 2018.     

Using EMG to deliver lumbar dynamic electrical stimulation to facilitate cortico-spinal excitability

BackgroundPotentiation of synaptic activity in spinal networks is reflected in the magnitude of modulation of motor responses evoked by spinal and cortical input. After spinal cord injury, motor evoked responses can be facilitated by pairing cortical and peripheral nerve stimuli.ObjectiveTo facilitate synaptic potentiation of cortico-spinal input with epidural electrical stimulation, we designed a novel neuromodulation method called dynamic stimulation (DS), using patterns derived from hind limb EMG signal during stepping.MethodsDS was applied dorsally to the lumbar enlargement through a high-density epidural array composed of independent platinum-based micro-electrodes.ResultsIn fully anesthetized intact adult rats, at the interface array/spinal cord, the temporal and spatial features of DS neuromodulation affected the entire lumbosacral network, particularly the most rostral and caudal segments covered by the array. DS induced a transient (at least 1 min) increase in spinal cord excitability and, compared to tonic stimulation, generated a more robust potentiation of the motor output evoked by single pulses applied to the spinal cord. When sub-threshold pulses were selectively applied to a cortical motor area, EMG responses from the contralateral leg were facilitated by the delivery of DS to the lumbosacral cord. Finally, based on motor-evoked responses, DS was linked to a greater amplitude of motor output shortly after a calibrated spinal cord contusion.ConclusionCompared to traditional tonic waveforms, DS amplifies both spinal and cortico-spinal input aimed at spinal networks, thus significantly increasing the potential and accelerating the rate of functional recovery after a severe spinal lesion.     

Intermittent theta-burst stimulation moderates interaction between increment of N-Acetyl-Aspartate in anterior cingulate and improvement of unipolar depression

BackgroundIntermittent theta-burst stimulation (iTBS), a novel repetitive transcranial magnetic stimulation (rTMS) technique, appears to have antidepressant effects when applied over left dorsolateral prefrontal cortex (DLPFC). However, its underlying neurobiological mechanisms are unclear. Proton magnetic resonance spectroscopy (¹H-MRS) provides in vivo measurements of cerebral metabolites altered in major depressive disorder (MDD) like N-acetyl-aspartate (NAA) and choline-containing compounds (Cho). We used MRS to analyse effects of iTBS on the associations between the shifts in the NAA and Cho levels during therapy and MDD improvement.MethodsIn-patients with unipolar MDD (N = 57), in addition to treatment as usual, were randomized to receive 20 iTBS or sham stimulations applied over left DLPFC over four weeks. Single-voxel ¹H-MRS of the anterior cingulate cortex (ACC) was performed at baseline and follow-up. Increments of concentrations, as well as MDD improvement, were defined as endpoints. We tested a moderated mediation model of effects using the PROCESS macro (an observed variable ordinary least squares and logistic regression path analysis modeling tool) for SPSS.ResultsImprovement of depressive symptoms was significantly associated with decrease of Cho/NAA ratio, mediated by NAA. iTBS had a significant moderating effect enhancing the relationship between NAA change and depression improvement.ConclusionsOur findings suggest a potential neurochemical pathway and mechanisms of antidepressant action of iTBS, which may moderate the improvement of metabolic markers of neuronal viability. iTBS might increase neuroplasticity, thus facilitating normalization of neuronal circuit function.     

Continuous electroencephalography characteristics and acute symptomatic seizures in COVID-19 patients

ObjectiveAs concerns regarding neurological manifestations in COVID-19 (coronavirus disease 2019) patients increase, limited data exists on continuous electroencephalography (cEEG) findings in these patients. We present a retrospective cohort study of cEEG monitoring in COVID-19 patients to better explore this knowledge gap.MethodsAmong 22 COVID-19 patients, 19 underwent cEEGs, and 3 underwent routine EEGs (<1 h). Demographic and clinical variables, including comorbid conditions, discharge disposition, survival and cEEG findings, were collected.ResultscEEG was performed for evaluation of altered mental status (n = 17) or seizure-like events (n = 5). Five patients, including 2 with epilepsy, had epileptiform abnormalities on cEEG. Two patients had electrographic seizures without a prior epilepsy history. There were no acute neuroimaging findings. Periodic discharges were noted in one-third of patients and encephalopathic EEG findings were not associated with IV anesthetic use.ConclusionsInterictal epileptiform abnormalities in the absence of prior epilepsy history were rare. However, the discovery of asymptomatic seizures in two of twenty-two patients was higher than previously reported and is therefore of concern.SignificancecEEG monitoring in COVID-19 patients may aid in better understanding an epileptogenic potential of SARS-CoV2 infection. Nevertheless, larger studies utilizing cEEG are required to better examine acute epileptic risk in COVID-19 patients.     

Differences in EEG patterns between tonic and high frequency spinal cord stimulation in chronic pain patients

ObjectiveTo investigate the differences in neural patterns between spinal cord stimulation (SCS) waveforms (60-Hz tonic vs 10-KHz high frequency stimulation, HFS) and their correlation to stimulation-induced pain relief.MethodsWe recorded 10-channel electroencephalogram (EEG) in response to stimulation ON and OFF in 9 chronic pain patients (4 women, 5 men) during SCS surgery and examined the intraoperative spatio-spectral EEG features.ResultsWe discovered stronger relative alpha power in the somatosensory region and higher trend in alpha/theta peak power ratio in frontal cortex with HFS. We also observed a shift in peak frequency from theta to alpha rhythms in HFS as compared to baseline and tonic stimulation, where slower theta activity was maintained. Further, a positive correlation was found between changes in Oswestry disability index (ODI) scores (from preoperative to postoperative) and HFS-induced alpha/theta peak power ratio in frontal and somatosensory regions.ConclusionsAltogether, our findings suggest that dynamic spectral interactions in theta-alpha band and their spatial distributions might be the first intraoperative neural signatures of pain relief induced by HFS in chronic pain.SignificanceExamining electrophysiological changes intraoperatively has a potential to elucidate response to SCS therapy prior to device selection, reducing the healthcare expenditures associated with failed implants.     

Evaluation of a Desensitization Program for Continuous Positive Airway Pressure–Intolerant Patients

This is a retrospective chart review evaluating the effectiveness of a nurse practitioner–implemented continuous positive airway pressure (CPAP) desensitization protocol on adherence in CPAP-intolerant OSA patients. CPAP adherence (use for ≥ 4 hours/night, ≥ 70% of nights) was calculated after 90 days of CPAP desensitization. The CPAP desensitization protocol resulted in a 1-hour increase in use in one-third of the patients. Only 4 of 22 (18%) patients achieved adequate adherence. Adherence was not associated with demographic, clinical, or polysomnographic variables. A CPAP desensitization protocol for CPAP-intolerant patients can enhance adherence. A larger, multicenter, randomized controlled trial is needed to validate our findings.     

延续性护理对提高老年慢性支气管炎患者生活质量的影响

目的:探讨延续性护理对提高老年慢性支气管炎患者生活质量及降低并发症的影响。方法:2017年5月至2018年2月收治的45例患者为对照组,应用常规护理方法;2018年3-12月收治的46例为干预组,在对照组的基础上采取出院后延续性护理。比较干预前、干预3个月后2组患者生活质量及并发症发生的情况。结果:SF-36生活质量量表中除日常活动功能(RP)维度外(62.61±9.79VS63.76±8.53,P>0.05),干预组患者在躯体功能(60.88±7.86)、社会活动功能(58.32±6.74)、身体疼痛(53.37±8.67)、活力(59.67±11.41)、总体健康(58.94±7.62)5个维度评分均高于对照组(66.18±8.81、63.27±7.19、56.47±7.34、65.38±9.47、62.71±10.08)P<0.05;干预组并发症发生率低于对照组(10.87%VS26.67%,P<0.05)。结论:延续性护理能提高老年慢性支气管炎患者的生活质量,降低并发症的发生率。