Compensatory Hyperactivity of the Ipsilesional Red Nucleus in a Patient With Somatosensory Cortex Damage: A Case Report.

This case study describes a patient who experienced motor recovery and involuntary movements following damage to the right primary somatosensory cortex caused by an intracranial hemorrhage. The patient initially suffered from paralysis in her left arm and leg, but exhibited significant motor recovery later, accompanied by multiple episodes of ballistic movement during the recovery process. A diffusion tensor imaging analysis was performed to investigate changes in sensorimotor-related brain areas in the patient. The patient had higher fractional anisotropy and lower mean diffusivity values in the ipsilesional red nucleus (RN) than age-matched controls. We assume that hyperactivity of the ipsilesional RN might play a role in motor recovery after damage to the primary somatosensory cortex, potentially through its involvement in sensorimotor integration. Our findings demonstrated the potential for adaptive changes in the ipsilesional RN following damage to the primary somatosensory cortex.

Heterogeneous Diffusion Metrics Patterns in Delayed Encephalopathy After Acute Carbon Monoxide Poisoning: A Case Report.

Delayed encephalopathy (DE) following acute carbon monoxide (CO) poisoning is characterized by a wide range of neurological symptoms, including akinetic mutism, cognitive impairment, and gait disturbances. Herein, we reported the case of a 61-year-old patient with DE after acute CO poisoning, who displayed heterogeneous patterns of cortical and subcortical structural integrity on diffusion tensor imaging (DTI). Four distinct patterns of diffusion tensor metrics (fractional anisotropy [FA] and mean diffusivity [MD]) were observed in the patient compared to age-matched controls (a decrease in FA and an increase in MD, a decrease in FA only, an increase in MD only, and an increase in FA and MD). This study revealed heterogeneous patterns of cortical and subcortical damage associated with DE after CO poisoning, contributing to a deeper understanding of the diverse clinical symptoms observed in this patient.

Pharyngeal Structure and Dysphagia in Patients with Parkinson's Disease and Related Disorders.

Pharyngeal muscle changes occur in patients with Parkinson's disease and related disorders (PRD); however, the association between the structural alterations in the pharynx and the symptoms of dysphagia remains unclear. We assessed structural changes and contractile forces by measuring pharyngeal wall thickness and width. We aimed to define the pharyngeal measurements and determine their value as diagnostic tools for dysphagia. The pharyngeal wall thickness (PWT), pharyngeal width at rest (PWR), and shortest pharyngeal width at swallowing (PWS) were measured using lateral neck roentgenograms and videofluoroscopic swallowing study. We compared the PWR and PWT between the PRD and control groups using an independent t-test. The Kendall correlation test was performed on the radiological data of the pharynx (PWT, PWR and PWS), dysphagia scales (Penetration-Aspiration scale [PAS] and Dysphagia Outcome and Severity Scale [DOSS]), and Hoehn and Yahr scale (HY scale). The PWT was smaller and the PWR greater in the PRD than in the control group (p < 0.05). The dysphagia scales (PAS and DOSS) were correlated with the radiological data (PWT and PWS) and the HY scale (p < 0.05). The HY scale score also correlated with the PWT (p < 0.05). The optimal cutoff points of the PWT and PWR for predicting aspiration were 4.05 and 16.05 mm in the PRD group, respectively. Using the PWT, PWR and PWS, muscle atrophy and contractile strength of the pharynx can be estimated. The combination of the PWT and PWR can be a simple indicator for predicting swallowing disorders at the bedside.

Role of Thioredoxin System in Regulating Cellular Redox Status in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common form of dementia and a public health problem. It exhibits significant oxidative stress and redox alterations. The antioxidant enzyme systems defend the cellular environment from oxidative stress. One of the redox systems is the thioredoxin system (TS), which exerts decisive control over the cellular redox environment. We aimed to review the protective effects of TS, which include thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. In the following, we discussed the physiological functioning and the role of the TS in maintaining the cellular redox-homeostasis in the AD-damaged brain. Trx protects the cellular environment from oxidative stress, while TrxR is crucial for the cellular detoxification of reactive oxygen species in the brain. However, TS dysregulation increases the susceptibility to cellular death. The changes in Trx and TrxR levels are significantly associated with AD progression. Though the data from human, animal, and cellular models support the neuroprotective role of TS in the brain of AD patients, the translational potential of these findings to clinical settings is not yet applied. This review summarizes the current knowledge on the emerging role of the TrxR-Trx system in AD.

Factors Affecting Participation in Telerehabilitation Using Transcranial Direct Current Stimulation for Patients with Poststroke Paralysis in South Korea.

Background: The coronavirus disease 2019 pandemic has expanded noncontact health care systems worldwide. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technology that enables treatment monitoring under remote supervision. We investigated the factors affecting patients' decision to participate in telerehabilitation (TR) using tDCS for motor function recovery after suffering a stroke. Materials and Methods: Four medical institutions surveyed 156 patients with poststroke paralysis. The participants were asked whether they would participate in TR therapy using tDCS in the future. We performed logistic regression analysis to examine the factors-demographic data, stroke characteristics, arm function, gait, and cognitive function-that influenced participants' decisions. Results: Of the participants, 66% (103/156) reported that they would participate in TR using tDCS in the future. Participants' monthly salary was a single significant independent factor influencing their decision to participate. Those earning greater than 5 million KRW (4,000 USD) were more likely to engage in TR via tDCS than those earning less than 1 million KRW (800 USD). The most common barriers to participation in telemedicine included the preference for face-to-face treatment and unfamiliarity. The expected medical expenses of TR using tDCS were 46,154 KRW (37 USD) per session. Conclusions: Most participants with poststroke paralysis responded positively to TR using tDCS for hand function recovery. For telemedicine to work effectively in a situation wherein face-to-face rehabilitation is impossible, prior discussion at the governmental level is essential for determining medical finances.

Neurobiology of Amphetamine use in Stroke Recovery Combined with Rehabilitative Training and Brain Stimulation.

Stroke is a physiological disorder involving a prolonged local interruption of cerebral blood flow. It leads to massive neuronal death and causes short-term or long-lasting functional impairment. Most stroke victims regain some neural function weeks or months following a stroke, but this recovery can plateau six months or more after the injury. The goal of stroke therapy is the rehabilitation of functional capabilities, especially those affecting the patient's autonomy and quality of life. Recent clinical and animal studies combining acute dextro-amphetamine (d-AMPH) administration with rehabilitative training (RT) have revealed that this treatment has significant remedial effects. The review aims to examine the synergistic therapeutic effects of d-amphetamine coupled with RT, administered during the early or late subacute period, on neuronal activation, anatomic plasticity, and skilled motor function in a middle-aged rodent stroke model. The treatment will also include magnetic field stimulation. This review will help increase understanding of the mechanism of d-amphetamine coupled with RT and magnetic field stimulation and their converging therapeutic effects for stroke recovery.

Continuous theta-burst stimulation over the left posterior inferior frontal gyrus induced compensatory plasticity in the language network.

Introduction: Continuous theta-burst stimulation (cTBS) has been used as an effective tool in inducing inhibitory aftereffect within a short time periods in the motor cortex; this has been demonstrated in the language network to a limited degree with controversial effect. In this study, we aimed to delineate the offline effect of cTBS-induced changes to the left posterior inferior frontal gyrus (pIFG) in healthy subjects using functional magnetic resonance imaging (fMRI). Methods: Twenty healthy, normal subjects (mean age: 30.84 years) were recruited. They all were right-handed and had no contra-indications for fMRI or cTBS. They were randomly assigned into the treatment group or the sham control group. Results: ANOVA showed that cTBS had a significant main effect only when the sham treatment was subtracted from the real stimulation in left superior temporal, left inferior frontal gyrus, thalamus, and right insular cortex (uncorrected p < 0.002). The subjects' post-cTBS condition differed significantly from their pre-cTBS condition in the left pIFG (uncorrected p < 0.002). There were interactions in the pIFG, bilateral superior parietal lobules, left superior temporal, left supramarginal, and left cuneus areas. The application of cTBS induced increased BOLD signals in language-related networks by stimulating the left pIFG (BA 44). This implies that inhibiting the pIFG led to increased use of language network resources. Conclusion: This study demonstrated cTBS-induced changes in the language network caused by stimulation of the left pIFG. Based on these findings, future studies on the therapeutic effects of cTBS on the right Broca's homolog area are warranted.

Utility of Diffusion and Magnetization Transfer MRI in Cervical Spondylotic Myelopathy: A Pilot Study.

Diffusion tensor imaging (DTI) and magnetization transfer (MT) magnetic resonance imaging (MRI) can help detect spinal cord pathology, and tract-specific analysis of their parameters, such as fractional anisotropy (FA), mean diffusivity, axial diffusivity (AD), radial diffusivity (RD) and MT ratio (MTR), can give microstructural information. We performed the tract-based acquisition of MR parameters of three major motor tracts: the lateral corticospinal (CS), rubrospinal (RuS) tract, and lateral reticulospinal (RS) tract as well as two major sensory tracts, i.e., the fasciculus cuneatus (FC) and spinal lemniscus, to detect pathologic change and find correlations with clinical items. MR parameters were extracted for each tract at three levels: the most compressed lesion level and above and below the lesion. We compared the MR parameters of eight cervical spondylotic myelopathy patients and 12 normal controls and analyzed the correlation between clinical evaluation items and MR parameters in patients. RuS and lateral RS showed worse DTI parameters at the lesion level in patients compared to the controls. Worse DTI parameters in those tracts were correlated with weaker power grasp at the lesion level. FC and lateral CS showed a correlation between higher RD and lower FA and MTR with a weaker lateral pinch below the lesion level.

Correlations between COMT polymorphism and brain structure and cognition in elderly subjects: An observational study.

ABSTRACT: The catechol-O-methyltransferase (COMT) gene has been noted to play an important role in individual variations in the aging process. We investigated whether COMT polymorphism could influence cognition related to white matter networks. More specifically, we examined whether methionine (Met) allele loading is associated with better individual cognitive performance. Thirty-four healthy elderly participants were recruited; each participant's COMT genotype was determined, and Korean version of Montreal Cognitive Assessment scores and a diffusion tensor image were obtained for all participants. The Met carrier group showed significantly lower mean diffusivity, axial diffusivity, and radial diffusivity values for the right hippocampus, thalamus, uncinate fasciculus, and left caudate nucleus than the valine homozygote group. The Met carrier group also scored higher for executive function and attention on the Korean version of Montreal Cognitive Assessment. Based on these results, we can assume that the COMT Met allele has a protective effect on cognitive decline contributing to individual differences in cognitive function in late life period.

Effects of transcranial magnetic stimulation on neurobiological changes in Alzheimer's disease (Review).

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and brain neuronal loss. A pioneering field of research in AD is brain stimulation via electromagnetic fields (EMFs), which may produce clinical benefits. Noninvasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS), have been developed to treat neurological and psychiatric disorders. The purpose of the present review is to identify neurobiological changes, including inflammatory, neurodegenerative, apoptotic, neuroprotective and genetic changes, which are associated with repetitive TMS (rTMS) treatment in patients with AD. Furthermore, it aims to evaluate the effect of TMS treatment in patients with AD and to identify the associated mechanisms. The present review highlights the changes in inflammatory and apoptotic mechanisms, mitochondrial enzymatic activities, and modulation of gene expression (microRNA expression profiles) associated with rTMS or sham procedures. At the molecular level, it has been suggested that EMFs generated by TMS may affect the cell redox status and amyloidogenic processes. TMS may also modulate gene expression by acting on both transcriptional and post­transcriptional regulatory mechanisms. TMS may increase brain cortical excitability, induce specific potentiation phenomena, and promote synaptic plasticity and recovery of impaired functions; thus, it may re­establish cognitive performance in patients with AD.

Transcranial magnetic stimulation in animal models of neurodegeneration.

Brain stimulation techniques offer powerful means of modulating the physiology of specific neural structures. In recent years, non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, have emerged as therapeutic tools for neurology and neuroscience. However, the possible repercussions of these techniques remain unclear, and there are few reports on the incisive recovery mechanisms through brain stimulation. Although several studies have recommended the use of non-invasive brain stimulation in clinical neuroscience, with a special emphasis on TMS, the suggested mechanisms of action have not been confirmed directly at the neural level. Insights into the neural mechanisms of non-invasive brain stimulation would unveil the strategies necessary to enhance the safety and efficacy of this progressive approach. Therefore, animal studies investigating the mechanisms of TMS-induced recovery at the neural level are crucial for the elaboration of non-invasive brain stimulation. Translational research done using animal models has several advantages and is able to investigate knowledge gaps by directly targeting neuronal levels. In this review, we have discussed the role of TMS in different animal models, the impact of animal studies on various disease states, and the findings regarding brain function of animal models after TMS in pharmacology research.

Relationship between lower limb muscle activity and cortical activation among elderly people during walking: Effects of fast speed and cognitive dual task.

Objective: Gait is a complex behavior that involves not only the musculoskeletal system, but also higher-order brain functions, including cognition. This study was performed to investigate the correlation between lower limb muscle activity and cortical activation during treadmill walking in two groups of elderly people: the young-old (aged 65-74 years) and the old-old (aged 75-84 years). Methods: Thirty-one young-old and 31 old-old people participated in this study. All participants were sequentially subjected to three gait conditions on a treadmill: (1) comfortable walking, (2) fast walking, and (3) cognitive dual-task walking. During treadmill walking, the activity of the lower limb muscles was measured using a surface electromyography system, and cortical activation was measured using a functional near-infrared spectroscopy system. The correlation between muscle activity and cortical activation during treadmill walking was analyzed and compared between the two groups. Results: During comfortable walking, lower extremity muscle activity had a strong correlation with cortical activation, especially in the swing phase; this was significantly stronger in the young-old than the old-old. During fast walking, the correlations between lower limb muscle activity and cortical activation were stronger than those during comfortable walking in both groups. In cognitive dual-task walking, cortical activation in the frontal region and motor area was increased, although the correlation between muscle activity and cortical activation was weaker than that during comfortable walking in both groups. Conclusion: The corticomotor correlation differed significantly between the old-old and the young-old. These results suggest that gait function is compensated by regulating corticomotor correlation as well as brain activity during walking in the elderly. These results could serve as a basis for developing gait training and fall prevention programs for the elderly.

Physical exercise keeps the brain connected by increasing white matter integrity in healthy controls.

ABSTRACT: Physical exercise leads to structural changes in the brain. However, it is unclear whether the initiation or continuous practice of physical exercise causes this effect and whether brain connectivity benefits from exercise. We examined the effect of 6 months of exercise on the brain in participants who exercise regularly (n = 25) and in matched healthy controls (n = 20). Diffusion tensor imaging brain scans were obtained from both groups. Our findings demonstrate that regular physical exercise significantly increases the integrity of white matter fiber tracts, especially those related to frontal function. This implies that exercise improves brain connectivity in healthy individuals, which has important implications for understanding the effect of fitness programs on the brains of healthy subjects.

The influence of pharyngeal width on post-stroke laryngeal aspiration.

BACKGROUND: Laryngeal penetration, which is a less serious form of aspiration, should be considered in patients with stroke to ensure early detection of risk of laryngeal aspiration and prevention of pneumonia. OBJECTIVE: As a follow-up to a previous study that demonstrated the association of pharyngeal width to laryngeal aspiration, the present study sought to determine whether the pharyngeal width was related to not only laryngeal aspiration but also laryngeal penetration in patients with deglutition disorder following stroke. METHODS: The pharyngeal width on the roentgenogram was measured and compared based on the severity of aspiration. Moreover, the optimal cut-off points were determined for predicting the penetration and aspiration so that the difference between the penetration and the aspiration could be elucidated. RESULTS: The pharyngeal width of the patients was wider than the controls. The increase of the pharyngeal width by aspiration severity was more evident in the patients with chronic and right cerebral stroke. The optimal cut-off point of the pharyngeal width was approximately 1 mm lesser for the prediction of penetration than for aspiration. CONCLUSIONS: The pharyngeal width could be an ancillary method for detecting penetration and aspiration in stroke patients.

The effect of transcranial direct current stimulation combined with functional task training on motor recovery in stroke patients.

BACKGROUND: Motor deficits are common after stroke and are a major contributor to stroke-related disability and the potential for long-lasting neurobiological consequences of stroke remains unresolved. There are only a few treatments available for the improvement of motor function in stroke patients. However, the mechanisms underlying stroke recovery remain poorly understood, and effective neurorehabilitation interventions remain insufficiently proven for widespread implementation. METHODS: Herein, we propose to enhance the effects of brain plasticity using a powerful noninvasive technique for brain modulation consisting of navigated transcranial magnetic stimulation (TMS) priming with transcranial direct current stimulation (tDCS) in combination with motor-training-like constraint-induced movement therapy (CIMT). Our hypothesis is that navigated low-frequency rTMS stimulus priming with precise location provided by neuronavigation on the healthy side of the brain and with anodal tDCS on the affected side combined with CIMT will induce a greater motor function improvement than that obtained with sham tDCS combined with CIMT alone. We predict that the application of this technique will result in a large reduction in cortical excitability and dis-inhibition in the affected hemisphere and lead to improvements in behavioral measures of hand function in stroke patients. DISCUSSION: The proposed study, therefore, is important for several reasons. The results could potentially lead to improved stroke therapeutics, and the approach makes use of 2 potential pathways to modulate brain function. TRIAL REGISTRATION: This study protocol was registered in Clinical Trials Registry (https://clinicaltrials.gov/ct2/show/NCT04646577). ETHICS AND DISSEMINATION: The study has been reviewed and approved by the Human Research Ethics Committee of the King Fahad Specialist Hospital Dammam. The results will be actively disseminated through peer-reviewed journals, conference presentations, social media, broadcast media, print media, the internet and various community/stakeholder engagement activities.

An Exploration of the Neural Network of Lance-Adams Syndrome: a Case Report.

Lance-Adams syndrome (LAS) is a rare neurological disorder that may occur after cardiopulmonary resuscitation. The LAS is usually caused by hypoxic changes. Neuroimaging studies show that the brain pathology of LAS patients is not uniform, and the pathophysiology of the myoclonus can vary from patient to patient. Our case study contributes to this etiological heterogeneity by neuroimaging and transcranial magnetic stimulation (TMS). In patients with rare brain conditions such as LAS, a combination of brain stimulation methods, such as TMS, and diffusion tensor imaging can provide insights into this condition's pathophysiology. These insights can facilitate the development of more effective therapies.

Effects of transcranial direct current stimulation on cortex modulation by stimulation of the primary motor cortex and parietal cortex in humans.

AIM OF THE STUDY: Transcranial magnetic stimulation (TMS) is used to measure corticospinal excitability (CSE) from the primary motor cortex (M1) in humans through motor-evoked potentials (MEPs). The variability of CSE responses to transcranial direct current stimulation (tDCS) protocols is high and needs to be reproduced in the healthy population. The M1 and posterior parietal cortex (PPC) are anatomically and functionally connected and could play a role in understanding the variability in CSE responses. We tested the individual MEPs following a common cathodal (ctDCS) protocol over the M1 and PPC. MATERIALS AND METHODS: Twenty-eight healthy subjects were randomized for a ctDCS stimulation over the left M1 and PPC for 20 min on a separate days. The first dorsal interosseous muscle (FDI) contralateral stimulation of the left M1 was used as the resting motor threshold (RMT), while 15 single pulses 4-8 s apart at an intensity of 120% RMT were used to determine the baseline MEP amplitude and at T0, 5, 10, 20, 30, 40, 50, and 60 min after ctDCS stimulation in both sessions. RESULTS: A 20 min duration of ctDCS stimulation significantly deceased the CSE only at T0 (p = 0.046 at M1, p = 0.010 at PPC). CONCLUSION: Our results suggested that PPC stimulation can modulate M1 excitability and PPC-M1 connectivity, but a significant effect is only observed immediately post ctDCS. The tDCS showed variability in response to the tDCS protocol is consistent with other non-invasive brain stimulation studies.

The Role of Primary Motor Cortex: More Than Movement Execution.

The predominant role of the primary motor cortex (M1) in motor execution is well acknowledged. However, additional roles of M1 are getting evident in humans owing to advances in noninvasive brain stimulation (NIBS) techniques. This review collates such studies in humans and proposes that M1 also plays a key role in higher cognitive processes. The review commences with the studies that have investigated the nature of connectivity of M1 with other cortical regions in light of studies based on NIBS. The review then moves on to discuss the studies that have demonstrated the role of M1 in higher cognitive processes such as attention, motor learning, motor consolidation, movement inhibition, somatomotor response, and movement imagery. Overall, the purpose of the review is to highlight the additional role of M1 in motor cognition besides motor control, which remains unexplored.

Non-Powered automatic velocity-controlled wheeled walker improves gait and satisfaction in patients with hip fracture when walking downhill: A cross-over study.

BACKGROUND: A standard four-wheeled walker is commonly used after surgery for hip fracture to aid ambulation. However, elderly patients experience some difficulties and are at risk for falls; therefore, attempts are being made to address these issues. RESEARCH QUESTION: Does the non-powered automatic velocity-controlled (NPAVEC) wheeled walker improves the gait and satisfaction of patients with hip fractures when walking downhill using it? METHODS: In this cross-over study, 21 participants performed three trials of walking downhill with two walkers (an NPAVEC wheeled walker and a standard four-wheeled walker) at a self-selected speed. We compared the lower limb surface electromyography data and self-reported satisfaction scores for both walkers. RESULTS: Regarding the affected limb, the NPAVEC wheeled walker increased contraction in the vastus medialis (p = 0.003) and tibialis anterior (p = 0.014), and biceps femoris of the unaffected limb (p = 0.01). Additionally, participants reported greater satisfaction when using the NPAVEC wheeled walker (p < 0.001). SIGNIFICANCE: An NPAVEC wheeled walker, compared to a four-wheeled walker, can assist patients recovering from hip fracture when walking downhill by improving the gait and increasing satisfaction.

Corrigendum: Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects.

[This corrects the article DOI: 10.3389/fnhum.2020.00063.].