Unilateral Motor Research Articles

Unilateral motor weakness with kidney failure: Questions.

Unilateral motor weakness with kidney failure: Questions.

Unilateral motor weakness with kidney failure: Answers.

Unilateral motor weakness with kidney failure: Answers.

Effect of Health Educational Guidelines on knowledge and practices of Mothers having Children with Bell's Palsy

Background: Bell’s palsy (BP) is a common cranial neuropathy causing acute unilateral lower motor neuron facial paralysis and idiopathic, unilateral or bilateral paralysis of the facial nerve without any associated disorders. Aim: To evaluate the effect of health educational guidelines on knowledge and practices of mothers having children with Bell's Palsy. Design: A quasi-experimental research design was used. Setting: This study was conducted at physical therapy department of Beni-Suef Hospital. Subject: 100 mothers and their children were selected randomly. Tools: Two tools were used for data collection, Tool1: A Self-administered questionnaire: Developed by the researchers and used to assess characteristics of mothers and their children also mothers’ knowledge about Bell's palsy (pre, post, and at follow up) phases of guidelines implementation. Tool2: An observational checklist (pre/post and follow up tests) to evaluate mothers’ practices in relation to their children with Bell's palsy such as pain relieving, eye care, follow up with doctor, mouth and dental hygiene, maintaining muscle tone and facial palsy yoga exercise. Results: There were highly statistically significant differences (P<.0001) regarding mothers knowledge and practices before, immediately after and at follow up phases of guidelines implementation. Conclusion: The present study concluded that, the educational guidelines had a positive effect on mothers' knowledge and their practices about their children with Bell’s palsy. Recommendations: Continuous ongoing in-service educational programs to nurses, mothers and caregivers are necessary to improve their knowledge, increase their awareness, follow-up and care of their children to decrease health complications.

Contralateral Posterior Putaminal 18F-Fluorodopa Uptake in Mild Stage Parkinson's Disease: A PET/CT Study.

Previous studies revealed that 18F-FDOPA uptake was significantly decreased in the subregions of striatum contralateral to the side with predominant symptoms and was helpful for improving the early diagnostic accuracy of PD. However, in these studies, more than half of the PD patients already have bilateral motor symptoms (mH&Y stage≥2). This study was aimed to extend previous findings to a milder disease stage. Sixteen PD patients with only mild and unilateral motor symptoms (mH&Y stage=1 and disease duration≤2 years) and 22 healthy controls were involved. Striatal 18F-FDOPA uptake was analyzed using a ratio approach. The SORs in the subregions of the contralateral striatum, including caudate, anterior putamen and posterior putamen were significantly decreased in the mild stage PD patients. The SOR for the contralateral posterior putamen had the largest area under the receiver operating characteristic curve (0.963) and separated mild stage PD patients from healthy controls with a sensitivity of 93.75% and a specificity of 95.45% when the cut-off value of <2.160 was selected. These data indicate that contralateral posterior putaminal 18F-FDOPA uptake may represent a potential marker for early diagnosis of PD, especially in patients with only mild and unilateral motor symptoms.

Bilateral Interference in Motor Performance in Homologous vs. Non-homologous Proximal and Distal Effectors.

Performance of bimanual motor actions requires coordinated and integrated bilateral communication, but in some bimanual tasks, neural interactions and crosstalk might cause bilateral interference. The level of interference probably depends on the proportions of bilateral interneurons connecting homologous areas of the motor cortex in the two hemispheres. The neuromuscular system for proximal muscles has a higher number of bilateral interneurons connecting homologous areas of the motor cortex compared to distal muscles. Based on the differences in neurophysiological organization for proximal vs. distal effectors in the upper extremities, the purpose of the present experiment was to evaluate how the level of bilateral interference depends on whether the bilateral interference task is performed with homologous or non-homologous effectors as the primary task. Fourteen participants first performed a unilateral primary motor task with the dominant arm with (1) proximal and (2) distal controlled joysticks. Performance in the unilateral condition with the dominant arm was compared to the same effector’s performance when two different bilateral interference tasks were performed simultaneously with the non-dominant arm. The two different bilateral interference tasks were subdivided into (1) homologous and (2) non-homologous effectors. The results showed a significant decrease in performance for both proximal and distal controlled joysticks, and this effect was independent of whether the bilateral interference tasks were introduced with homologous or non-homologous effectors. The overall performance decrease as a result of bilateral interference was larger for proximal compared to distal controlled joysticks. Furthermore, a proximal bilateral interference caused a larger performance decrement independent of whether the primary motor task was controlled by a proximal or distal joystick. A novel finding was that the distal joystick performance equally interfered with either homologous (distal bilateral interference) or non-homologous (proximal bilateral interference) interference tasks performed simultaneously. The results indicate that the proximal–distal distinction is an important organismic constraint on motor control and for understanding bilateral communication and interference in general and, in particular, how bilateral interference caused by homologous vs. non-homologous effectors impacts motor performance for proximal and distal effectors. The results seem to map neuroanatomical and neurophysiological differences for these effectors.

Voluntary suppression of associated activity decreases force steadiness in the active hand.

Unilateral muscle contractions are often accompanied by the activation of the ipsilateral hemisphere, producing associated activity (AA) in the contralateral homologous muscles. However, the functional role of AA is not fully understood. We determined the effects of voluntary suppression of AA in the first dorsal interosseous (FDI), on force steadiness during a constant force isometric contraction of the contralateral FDI. Participants (n = 17, 25.5 years) performed two trials of isometric FDI contractions as steadily as possible. In Trial 1, they did not receive feedback or explicit instructions for suppressing the AA in the contralateral homologous FDI. In Trial 2, participants received feedback and were asked to voluntarily suppress the AA in the contralateral nontarget FDI. During both trials, corticospinal excitability and motor cortical inhibition were measured. The results show that participants effectively suppressed the AA in the nontarget contralateral FDI (-71%), which correlated with reductions in corticospinal excitability (-57%), and the suppression was also accompanied by increases in inhibition (27%) in the ipsilateral motor cortex. The suppression of AA impaired force steadiness, but the decrease in force steadiness did not correlate with the magnitude of suppression. The results show that voluntary suppression of AA decreases force steadiness in the active hand. However, due to the lack of association between suppression and decreased steadiness, we interpret these data to mean that specific elements of the ipsilateral brain activation producing AA in younger adults are neither contributing nor detrimental to unilateral motor control during a steady isometric contraction.

Prospective Investigation of Postoperative Complications in Anterior Decompression with Fusion for Severe Cervical Ossification of the Posterior Longitudinal Ligament: A Multi-institutional Study.

A prospective multicenter study. This study aims to investigate the postoperative complications of anterior decompression with fusion (ADF) for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). Surgical treatment for cervical OPLL has a high risk of various complications. ADF is reported to be effective for cervical OPLL, especially for massive OPLL. However, few studies have focused on the surgical complications of ADF. We prospectively included 102 patients undergoing ADF for severe cervical OPLL with average canal occupying ratio of 49.8%. We evaluated systemic and local complications, neurological complications, and risk factors related to the postoperative complications. Frequently observed complications included graft/ implant complications (18.6%), neurological complications (11.8%), and cerebrospinal fluid leak (11.8%). Motor palsy involving only the upper extremity was found in nine patients (8.8%), and other motor palsies involving the lower extremities were found in three patients (2.9%). None of the preoperative factors were significantly associated with the occurrence of neurological palsies, whereas the number of operated levels was a significant factor related to the postoperative graft/implant complications (P = 0.003; odds ratio, 2.112). The incidence of graft/implant complications and related reoperation increased as the number of operated levels increased (especially four levels or more). Most motor palsies were observed immediately after surgery. Of the motor palsies in the bilateral upper extremities and palsies involving the lower extremities, 85.7% showed good recovery, whereas only 40% of unilateral upper extremity motor palsies showed good recovery during the follow-up period. In ADF for cervical OPLL, the number of operated levels was a significant factor related to the postoperative complication. Specifically, the incidence of graft/implant complications and reoperation rate increased in ADF with four or more levels.Level of Evidence: 3.

A case of aphemia following non-dominant sub-insular stroke: unveiling the Foix-Chavany-Marie phenomenon

ABSTRACT Aphemia refers to the clinical syndrome of inability to orally produce speech with intact comprehension and written expression. Aphemia has been primarily reported in dominant frontal lobe strokes resulting in apraxia of speech (AoS), and in Foix-Chavany-Marie (FCM) syndrome where bilateral opercular or sub-opercular lesions result in anarthria due to deafferentation of brainstem nuclei supplying the oro-facio-lingual and pharyngeal musculature. Aphemia is not reported in non-dominant sub-insular strokes. Here, we present a case of aphemia following non-dominant sub-insular stroke in a patient who had previously recovered from a homologous dominant sub-insular stroke without any apparent residual deficits. We discuss the accepted definitions, theories and controversies in the use of the terminology – aphemia, apraxia of speech (AoS), anarthria related to FCM syndrome, a concomitant pathology – unilateral upper motor neuron (UUMN) dysarthria, and their neuro-anatomical bases. We also highlight the importance of attributing localization value to sequential homologous lesions of the brain that can unveil symptoms due to a “loss of compensation phenomenon” that we propose be termed as “FCM phenomenon.” These pathological mechanisms may alone or in certain combinations contribute to the clinical syndrome of aphemia included in the diagnostic approach proposed here. The distinction between these mechanisms requires serial careful neurological examination and detailed speech evaluation including in the recovery phase.

Using Modified Equipment in Field Hockey Leads to Positive Transfer of Learning Effect.

Cross-education is the phenomenon in which repeated practice of a unilateral motor task does not only result in performance improvement of the trained limb, but also in the untrained contralateral limb. The aim of this study was to test whether cross-education or positive transfer of learning is also achieved for tasks in which both limbs contribute in different ways by using modified equipment that switches the limbs’ role. To this end, a reverse field hockey stick was used that requires a mirroring of arm and hand use and dominance (i.e., right hand on top of the hockey stick instead of the left hand). Two groups of young skilled female field hockey players participated in a crossover-design, in which participants received four training sessions with a reverse hockey stick followed by four training sessions with a regular hockey stick, or vice versa. In a pre-test, intermediate test (following the first intervention period), a post-test (after the second intervention period) and a retention test, participants’ performance on a field hockey skill test with a regular hockey stick was measured. The results revealed that training with the reversed hockey stick led to significantly increased improvements compared to training with a regular hockey stick. We conclude that modified equipment can be used to exploit positive transfer of learning by switching the limbs’ roles. The findings are discussed by referring to the symmetry preservation principle in dynamic systems theory and have clear practical relevance for field hockey trainers and players seeking to further improve field hockey skills.

Additive Effects of Environmental Enrichment and Ketamine on Neuropathic Pain Relief by Reducing Glutamatergic Activation in Spinal Cord Injury in Rats.

Spinal cord injury (SCI) impairs mobility and often results in complications like intractable neuropathic pain. A multi-approach management of this chronic pain condition has been encouraged, but little has been explored of the field. Here, we focus on the effect and underlying mechanism of environmental enrichment (EE), which promotes voluntary social and physical activities, combined with a clinical analgesic, ketamine, on SCI-induced neuropathic pain as well as motor dysfunction. We performed T13 spinal hemisection in rats, which induced unilateral motor impairment and neuropathic pain-like behaviors in the hindlimb. Treatment regimen started a week after SCI, which consists of ketamine administration (30 mg kg–1 day–1; intramuscular) for 10 days, or EE housing for 20 days, or their combination. Paw withdrawal response to mechanical and thermal stimuli, motor function, burrowing behaviors, and body weight was monitored. Spinal segments at T13 lesion and L4–L6 were collected for histopathological and protein analyses. The joint treatment of EE and ketamine provided greater relief of pain-like behaviors and locomotor recovery than did either paradigm alone. These improvements were associated with reduced cavitation area, astrogliosis, and perilesional phosphorylation of glutamate N-methyl-D-aspartate receptor (NMDAR). Concurrently, lumbar spinal analysis of NMDAR-linked excitatory markers in hypersensitization showed reduced activation of NMDAR, mitogen-activated protein kinase (MAPK) family, nuclear factor (NF)-κB, interleukin (IL)-1β signaling, and restored excitatory amino acid transporter 2 level. Our data support a better therapeutic efficacy of the combination, EE, and ketamine, in the attenuation of neuropathic pain and motor recovery by reducing spinal glutamatergic activation, signifying a potential multifaceted neurorehabilitation strategy to improve SCI patient outcome.

AYURVEDIC MANAGEMENT OF BELL’S PALSY IN CHILDREN: A CLINICAL CASE STUDY

Bell’s palsy is the most common, acute unilateral lower motor neuron nerve palsy and is characterized by sudden onset of weakness in the facial muscles to one side of the face controlled by the facial nerve due to uncertain post infective autoimmune disease. Incidence is approximately 40-75% and the cause is obscure. The therapeutic approach in children often involves a multidisciplinary team comprehending pediatrician, neurologist and physiotherapists. A 4 years old male child with chief complaints of deviation of mouth to left side for one day while attempt to speak and smile and partially opened right eye while sleeping since few hours associated with excessive lacrimation of right eye without any cause. Then the case has been diagnosed as Bell’s palsy based on clinical examination and internal medication along with Nasya procedure is administered there by child improved with this experience same treatment is being practiced in few more cases. In Ayurveda present condition can be compared with Ardita vata under one of Ashta mahagada i.e. under Vata vyadhi. Ardita vata is the broad term which includes all the kinds of facial palsies including Bell’s palsy. There is no exclusive treatment for Bell’s palsy but treatment mentioned for Ardita vata can be adopted like abhyanga, pata sweda and Nasya along with few internal medicines and considering these concepts treatment protocol has been made and executing in hospital of SJG Ayurvedic medical college and getting satisfactory treatment out come within 1-2 weeks without steroidal, antiviral and physiotherapy.

Dysarthria following acute ischemic stroke: Prospective evaluation of characteristics, type and severity

Dysarthria is a common symptom following stroke and represents an important cause of functional impairment in stroke patients. A better characterization of dysarthria could facilitate differential diagnosis and optimize healthcare service distribution. To determine the speech characteristics, dysarthria type and severity in the acute phase following ischemic stroke in a comprehensive stroke centre. First-ever ischemic stroke patients consecutively admitted to the Stroke Unit of Ghent University Hospital were included in this prospective clinical study between March 2018 and October 2019. All participants admitted to the Stroke Unit were screened for dysarthria by a speech-language pathologist within 72 h after admission. When dysarthria was identified, speech characteristics were evaluated via auditory-perceptual assessment and objective measurement of acoustic parameters. Dysarthria type was determined based on the Mayo Classification System. Severity of impairment was scored at function and activity level using the Radboud Dysarthria Assessment and the evaluation of speech intelligibility at sentence level using the Dutch Speech Intelligibility Assessment. In addition, dysarthria recovery was separately evaluated in all participants using the National Institutes of Health Stroke Scale (NIHSS) at hospital admission, day 3 ± 2 and day 7. A total of 67 out of 151 participants (44%; mean age = 69 years; SD = 13; 28 females) were diagnosed with dysarthria in the acute phase following stroke. Standardized assessments were possible in 72% (48/67) of participants. Imprecise articulation of consonants, harsh voice quality and audible inspiration were the most frequent observed speech characteristics. The acoustic parameters maximum phonation time and maximum loudness deviated most from normative values. Unilateral upper motor neuron (UUMN) was the main dysarthria type present in 52% (25/48) of participants. A total of 58% (28/48) and 71% (34/48) of participants had no/minimal/mild difficulties at the functional and activity levels, respectively. Speech intelligibility was mildly impaired (median = 91%; IQR = 73-97). According to the NIHSS, sub-item speech score at hospital admission, 46% (70/151) of participants had dysarthria, of which half recovered completely from their dysarthria within 1 week after stroke symptom onset. UUMN was the dominant dysarthria type, and the majority of participants had a mild dysarthria. Half the participants showed complete recovery within 1 week following symptom onset. The observed speech characteristics mainly reflect impairments in the subsystem's articulation, phonation and respiration. Objective measurements of acoustic parameters corroborate these findings. Future research should focus on longitudinal assessment to investigate recovery of symptoms and the long-term impact of dysarthria on social participation. What this paper adds What is already known on the subject There are few data concerning the presentation of dysarthria following acute ischemic stroke. Moreover, previous research did not include objective measurements of speech characteristics and dysarthria severity. There was a need to determine prospectively speech characteristics, dysarthria type and severity in a stroke population using standardized assessments. What this paper adds to existing knowledge The findings of this study show a high prevalence of dysarthria following acute ischemic stroke. This study confirms previous findings that the speech of dysarthric patients following acute ischemic stroke was mostly characterized by imprecise articulation of consonants, a harsh voice quality and audible inspiration. The results of the objective measures confirm these findings. We added evidence that UUMN is the most prevalent dysarthria type in a stroke population, and that the majority of participants had mild dysarthria. A high rate of dysarthria recovery was seen in the first week following symptom onset. What are the potential or actual clinical implications of this work? The findings of this study contribute to the limited research performed regarding post-stroke dysarthria. The results can help optimize the distribution of healthcare resources. The majority of participants have a mild dysarthria, making the identification of the specific needs of this group an important area of concern. The evaluation of impaired speech subsystems and characteristics, especially supplemented with objective measures of acoustic parameters, and the classification of the type and severity of dysarthria can be helpful to monitor early progress in the acute phase post-stroke.

Mechanomyography and acceleration show interlimb asymmetries in Parkinson patients without tremor compared to controls during a unilateral motor task

The mechanical muscular oscillations are rarely the objective of investigations regarding the identification of a biomarker for Parkinson’s disease (PD). Therefore, the aim of this study was to investigate whether or not this specific motor output differs between PD patients and controls. The novelty is that patients without tremor are investigated performing a unilateral isometric motor task. The force of armflexors and the forearm acceleration (ACC) were recorded as well as the mechanomyography of the biceps brachii (MMGbi), brachioradialis (MMGbra) and pectoralis major (MMGpect) muscles using a piezoelectric-sensor-based system during a unilateral motor task at 70% of the MVIC. The frequency, a power-frequency-ratio, the amplitude variation, the slope of amplitudes and their interlimb asymmetries were analysed. The results indicate that the oscillatory behavior of muscular output in PD without tremor deviates from controls in some parameters: Significant differences appeared for the power-frequency-ratio (p = 0.001, r = 0.43) and for the amplitude variation (p = 0.003, r = 0.34) of MMGpect. The interlimb asymmetries differed significantly concerning the power-frequency-ratio of MMGbi (p = 0.013, r = 0.42) and MMGbra (p = 0.048, r = 0.39) as well as regarding the mean frequency (p = 0.004, r = 0.48) and amplitude variation of MMGpect (p = 0.033, r = 0.37). The mean (M) and variation coefficient (CV) of slope of ACC differed significantly (M: p = 0.022, r = 0.33; CV: p = 0.004, r = 0.43). All other parameters showed no significant differences between PD and controls. It remains open, if this altered mechanical muscular output is reproducible and specific for PD.

Mapping grip force to motor networks

AimThere is ongoing debate about the role of cortical and subcortical brain areas in force modulation. In a whole-brain approach, we sought to investigate the anatomical basis of grip force whilst acknowledging interindividual differences in connectivity patterns. We tested if brain lesion mapping in patients with unilateral motor deficits can inform whole-brain structural connectivity analysis in healthy controls to uncover the networks underlying grip force. MethodsUsing magnetic resonance imaging (MRI) and whole-brain voxel-based morphometry in chronic stroke patients (n=55) and healthy controls (n=67), we identified the brain regions in both grey and white matter significantly associated with grip force strength. The resulting statistical parametric maps (SPMs) provided seed areas for whole-brain structural covariance analysis in a large-scale community dwelling cohort (n=977) that included beyond volume estimates, parameter maps sensitive to myelin, iron and tissue water content. ResultsThe SPMs showed symmetrical bilateral clusters of correlation between upper limb motor performance, basal ganglia, posterior insula and cortico-spinal tract. The covariance analysis with the seed areas derived from the SPMs demonstrated a widespread anatomical pattern of brain volume and tissue properties, including both cortical, subcortical nodes of motor networks and sensorimotor areas projections. ConclusionWe interpret our covariance findings as a biological signature of brain networks implicated in grip force. The data-driven definition of seed areas obtained from chronic stroke patients showed overlapping structural covariance patterns within cortico-subcortical motor networks across different tissue property estimates. This cumulative evidence lends face validity of our findings and their biological plausibility.

Electrophysiology of Guillain-Barré syndrome in Bangladesh: A prospective study of 312 patients

ObjectiveTo describe the electrophysiological features in relation to clinical and serological findings of Guillain-Barré syndrome (GBS) in the national neuroscience hospital in Bangladesh. This is one of the few studies that investigated GBS patients using standardized electrophysiology in low-income countries. MethodsIn a prospective and observational study, we investigated 312 GBS patients by standardized clinical, serological and electrophysiological methods. Unilateral motor and sensory nerve conduction studies (NCS) were performed within two weeks of onset of weakness. Follow up NCS were performed in 189 patients and classified according to eight sets of established GBS criteria. Serology included assessment of anti-GM1 antibodies and anti-campylobacter jejuni lipo-oligosaccharide (LOS) antibodies. ResultsDepending on the criteria used, 44–59% patients had axonal GBS with anti-GM1 antibodies being present in 55–58% and 9–42% patients had demyelinating GBS with anti-GM1 antibodies being present in 7–35%. Conduction block (CB) with demyelinative slowing in the same nerve segment was found in 24% (74/312) patients, and CB without demyelinative slowing in the same nerve segment was found in 18% (56/312) patients, of whom anti-GM1 antibodies were found in 27% and 57% patients respectively. Follow-up NCS showed a change in GBS classification in 11–26% of patients, mainly from demyelinating to axonal GBS. ConclusionsThe predominant subtype of GBS in Bangladesh is axonal but demyelinating GBS also occurs with classification being strongly dependent on the applied criteria. SignificanceThe present study demonstrates the importance of reaching international agreement on GBS criteria that should be based on the best evidence.

Infantile hemiconvulsion-hemiplegia epilepsy syndrome associated with GRIN2A gene mutation

Introduction. Infantile hemiconvulsion?hemiplegia and epilepsy (IHHE) syndrome is defined as a specific syndrome in patients &lt; 2 years of age, presenting as a new onset refractory status epilepticus with unilateral motor seizures and acute imaging abnormalities, fever, hemiparesis &gt; 24 hours, and excluding infectious encephalitis. Case outline. We present the results of a follow-up in a 11-year-old girl with IHHE, associated with GRIN2A mutation. The girl had normal development until the first febrile hemiconvulsive status epilepticus at the age of seven months. Neuroimaging initially showed right hemisphere edema, followed by progressive right side hemiatrophy. The patient has resistant epilepsy, left side hemiparesis, and good language and cognitive development. Conclusion. Despite IHHE described many years ago, some syndrome?s features, including etiology, have remained unexplained. The association between IHHE and GRIN2A mutation stated in the current manuscript is described in scientific literature for the first time.

Time Series Analysis Applied to EEG Shows Increased Global Connectivity during Motor Activation Detected in PD Patients Compared to Controls

Background: Brain connectivity has shown to be a key characteristic in the study of both Parkinson’s Disease (PD) and the response of the patients to the dopaminergic medication. Time series analysis has been used here for the first time to study brain connectivity changes during motor activation in PD. Methods: A 64-channel EEG signal was registered during unilateral motor activation and resting-state in 6 non-demented PD patients before and after the administration of levodopa and in 6 matched healthy controls. Spectral entropy correlation, coherence, and interhemispheric divergence differences among PD patients and controls were analyzed under the assumption of stationarity of the time series. Results: During the motor activation test, PD patients showed an increased correlation coefficient (both hands p &lt; 0.001) and a remarkable increase in coherence in all frequency range compared to the generalized reduction observed in controls (both hands p &lt; 0.001). The Kullback­–Leibler Divergence (KLD) of the Spectral Entropy between brain hemispheres was observed to increase in controls (right hand p = 0.01; left hand p = 0.015) and to decrease in PD patients (right hand p = 0.02; left hand p = 0.002) with motor activation. Conclusions: Our results suggest that the oscillatory activity of the different cortex areas within healthy brains is relatively independent of the rest. PD brains exhibit a stronger connectivity which grows during motor activation. The levodopa mitigates this anomalous performance.

A motor-imagery channel-selection method based on SVM-CCA-CS

In electroencephalography, multi-channel electroencephalogram (EEG) signals are usually utilized to improve classification accuracy. However, a large set of EEG channels increases the computational complexity, reduces the real-time performance and causes wearability difficulties. Channel selection methods have been widely investigated to reduce the number of channels with an acceptable loss of accuracy for EEG-based motor-imagery recognition. In this paper, we present a novel algorithm, called Support Vector Machine-Canonical Correlation Analysis-Channel Selection (SVM-CCA-CS). First, the energy features of the wavelet packet subnodes of the motor-imagery EEG signals are extracted. Then the weights of feature groups are calculated as initial channel weights, based on the CCA algorithm. The initial channel weights are further adjusted, according to the contribution of each channel to the classification accuracy via SVM, and the top channels with larger weights are eventually selected. The results show that the average accuracy of all subjects can reach 80.03% by using the first 30 channels with the largest weights from among the total of 118 channels. For the right hand and foot motor-imagery tasks, the generally applicable optimal channels are mostly located in the left hemisphere. Our generally applicable channel observation of the whole brain cortex suggests contralateral control correspondence: for unilateral motor imagery, the optimal channels are concentrated in the contralateral hemisphere. This is consistent with the contralateral control of the body by the human brain: the majority of the human motor and sensory fibers tend to control the contralateral limbs and pass through the midline of the body. Our proposed method provides optimal acquisition and analysis of the positions of EEG signals in specific motor-imagery tasks.

More Pronounced Bimanual Interference in Proximal Compared to Distal Effectors of the Upper Extremities

Bimanual performance depends on effective and modular bilateral communication between the two bodysides. Bilateral neural interactions between the bodysides could cause bimanual interference, and the neuromuscular system for proximal and distal muscles is differently organized, where proximal muscles have more bilateral interneurons at both cortical and spinal level compared to distal muscles. These differences might increase the potential for bimanual interference between proximal arm muscles, because of greater proportions of bilateral interneurons to proximal muscles. The purpose of the present experiment was to evaluate potential differences in bimanual interference between proximal versus distal effectors in the upper extremities. 14 participants first performed a unilateral primary motor task with dominant arm with (1) a proximal and (2) distal controlled joysticks (condition A). Performance in condition A, was compared with the same effector’s performance when a bimanual interference task was performed simultaneously with the non-dominant arm (condition B). The results showed a significant bimanual interference for both the proximal and distal controlled joysticks. Most interestingly, the bimanual interference was larger for the proximal joystick compared to the distal controlled joystick. The increase in spatial accuracy error was higher for the proximal controlled joystick, compared with the distal controlled joystick. These results indicate that the proximal-distal distinction is an important organismic constraint on motor control, and especially for bilateral communication. There seem to be an undesired bilateral interference for both proximal and distal muscles. The interference is higher in the case of proximal effectors compared distal effectors, and the results seem to map the neuroanatomical and neurophysiological differences for these effectors.

Age-related trends in neuromagnetic transient beta burst characteristics during a sensorimotor task and rest in the Cam-CAN open-access dataset

Non-invasive neurophysiological recordings, such as those measured by magnetoencelography (MEG), provide insight into the behaviour of neural networks and how these networks change with factors such as task performance, disease state, and age. Recently, there has been a trend in describing neurophysiological recordings as a series of transient bursts of neural activity rather than averaged sustained oscillations as burst characteristics may be more directly correlated with the neurological generators of brain activity. In this work, we investigate how beta burst characteristics change with age in a large open access dataset. The objectives are (1) to detect and characterize transient beta bursts over the ipsilateral and contralateral primary sensorimotor cortices during a unilateral motor task performance and during wakeful resting, and (2) to identify age-related changes in beta burst characteristics, in the context of earlier reports of age-related changes in beta suppression and the post-movement beta rebound. MEG data, acquired at the Cambridge Centre for Ageing and Neuroscience, of roughly 600 participants with a nearly uniform distribution of ages between 18 and 88 years old was used for analysis. We found that burst rate is the predominant factor related to age-related changes in the amplitude of the induced beta rhythm responses associated with a button press task. Furthermore, we present a cross-validation of burst parameters detected at the sensor- (peak sensor and sensor ROI) and source-level (beamformer spatial filter). This work is as an important step in characterizing transient bursts in neuromagnetic signals in the temporal domain, towards a better understanding of the healthy aging human brain.