Role of the medial agranular cortex in unilateral spatial neglect.

Unilateral spatial neglect (USN) results from impaired attentional networks and can affect various sensory modalities, such as visual and somatosensory. The rodent medial agranular cortex (AGm), located in the medial part of the forebrain from rostral to caudal direction, is considered a region associated with spatial attention. The AGm selectively receives multisensory input with the rostral AGm receiving somatosensory input and caudal part receiving visual input. Our previous study showed slower recovery from neglect with anterior AGm lesion using the somatosensory neglect assessment. Conversely, the functional differences in spatial attention across the entire AGm locations (anterior, intermediate, and posterior parts) are unknown. Here, we investigated the relationship between the severity of neglect and various locations across the entire AGm in a mouse stroke model using a newly developed program-based analysis method that does not require human intervention. Among various positions of the lesions, the recovery from USN during recovery periods (postoperative day; POD 10-18) tended to be slower in cases with more rostral lesions in the AGm (r = - 0.302; p = 0.028). Moreover, the total number of arm entries and maximum moving speed did not significantly differ between before and after AGm infarction. According to these results, the anterior lesions may slowly recover from USN-like behavior, and there may be a weak association between the AGm infarct site and recovery rate. In addition, all unilateral focal infarctions in the AGm induced USN-like behavior without motor deficits.

Effects of short-term upper limb immobilization on sensory information processing and corticospinal excitability.

Several studies have reported the effects of short-term immobilization of the upper limb on the excitability of the primary motor cortex. In a report examining the effects of upper limb immobilization on somatosensory information processing using somatosensory-evoked potentials (SEPs), short-term upper limb immobilization reduced the amplitude and increased the latency of the P45 component recorded over the contralateral sensorimotor cortex of SEPs. However, the effects of upper limb immobilization on other regions involved in somatosensory information processing are unknown. Therefore, we investigated the effects of short-term right upper limb immobilization on sensory information processing, particularly in motor-related areas, by measuring the cortical components of SEPs. We also evaluated the excitability of the primary motor cortex and corticospinal tract as well as motor performance (visual simple reaction time and pinch force) related to these areas. All subjects were divided into two groups: the SEP group, in which the effects of upper limb immobilization on the excitability of somatosensory processing were investigated, and the transcranial magnetic stimulation (TMS) group, in which the effects of upper limb immobilization on the excitability of the corticospinal tract and primary motor cortex were investigated. Motor performance was evaluated in all subjects. We showed that 10-h right upper limb immobilization increased the cortical component of SEPs (N30) in the SEP group and decreased the excitability of the corticospinal tract, but not of the primary motor cortex, in the TMS group. The pinch force decreased after upper limb immobilization. However, the visual simple reaction time did not change between pre- and post-immobilization. The supplementary motor area and premotor cortex are believed to be the source of the N30. Therefore, these results suggest that upper limb immobilization affected somatosensory information processing in motor-related areas. Moreover, 10-h right upper limb immobilization reduced the excitability of corticospinal tracts but not that of the primary motor cortex, suggesting that circuits outside the M1, such as the intra- and inter-hemispheric inhibitory and facilitatory circuits rather than circuits within the M1, may be responsible for the reduced excitability of the central nervous system after restraint.

Relationship Between Motor Function, DTI, and Neurophysiological Parameters in Patients with Stroke in the Recovery Rehabilitation unit.

OBJECTIVES: We investigated the relationship between pyramidal tract evaluation indexes (i.e., diffusion tensor imaging, transcranial magnetic stimulation (TMS)-induced motor-evoked potential (MEP), and central motor conduction time (CMCT) on admission to the recovery rehabilitation unit) and motor functions at discharge in patients with ischemic or hemorrhagic stroke. MATERIALS AND METHODS: Seventeen patients were recruited (12 men; 57.9 ± 10.3 years). The mean fractional anisotropy (FA) values of the right and left posterior limbs of the internal capsule were estimated using a computer-automated method. We determined the ratios of FA values in the affected and unaffected hemispheres (rFA), TMS-induced MEP, and the ratios of CMCT in the affected and unaffected hemispheres (rCMCT) and examined their association with motor functions (Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT)) at discharge. RESULTS: Higher rFA values of the posterior limb of the internal capsule on admission to the recovery rehabilitation unit led to a better recovery of upper limb function (FMA: r = 0.78, p < 0.001; ARAT: r = 0.74, p = 0.001). Patients without MEP had poorer recovery of upper limb function than those with MEP (FMA: p < 0.001; ARAT: p = 0.001). The higher the rCMCT, the poorer the recovery of upper limb function (ARAT: r = -0.93, p < 0.001). However, no association was observed between the pyramidal tract evaluation indexes and recovery of lower limb motor function. CONCLUSIONS: Evaluating the pyramidal tract is useful for predicting upper limb function prognosis, but not for lower limb function prognosis.

Robotic rehabilitation of the paralyzed upper limb for a stroke patient using the single-joint hybrid assistive limb: a case study assessed by accelerometer on the wrist.

[Purpose] Recent studies have reported the effectiveness of robotic rehabilitation of paralyzed upper limbs in stroke patients. For example, the Single-Joint Hybrid Assistive Limb has been shown to improve upper limb impairments. However, limited data are available on the effectiveness of robotic rehabilitation of the upper limb with regards to daily living. In this case study, an accelerometer was adopted to examine whether rehabilitation using the Single-Joint Hybrid Assistive Limb improved upper limb activity during daily living in a stroke patient. [Participant and Methods] The participant was a 69-year-old male diagnosed with stroke and left hemiparesis. The Single-Joint Hybrid Assistive Limb was applied to the participant's elbow on the paralyzed side. The participant wore an accelerometer on each wrist to measure the activities of the upper limbs. Clinical tests of the paralyzed upper limb were also performed. [Results] The activity of the paralytic limb was significantly higher after Single-Joint Hybrid Assistive Limb intervention than before the intervention. On the other hand, none of the results of the clinical tests changed beyond a clinically important difference. [Conclusion] The Single-Joint Hybrid Assistive Limb could be useful for promoting active use of a paralyzed upper limb in daily living. In addition, an accelerometer could be especially useful for evaluating the effects of robotic rehabilitation.

A Short-Duration Combined Exercise and Education Program to Improve Physical Function and Social Engagement in Community-Dwelling Elderly Adults.

Exercise is a key intervention for improving older adults' physical function and life expectancy. Here, we investigated a short-term intervention program designed to improve the physical functioning of elderly adults in a community-dwelling setting. We examined the effect of a 5-week combined exercise and education program on the physical function, social engagement, mobility performance, and fear of falling in 42 subjects older than 65 years. Eleven subjects dropped out. There was significant improvement in the 30-second chair stand test (p < .001) and timed up-and-go test (p < .001) between the baseline and the last session. At the end of the intervention, the subjects' social engagement was significantly higher than at baseline (p = .022), but this improvement was not maintained in the follow-up assessment. These results suggest that a combined exercise and education program can improve the physical function and social engagement of elderly individuals living in a community dwelling.

Neural mechanism of selective finger movement independent of synergistic movement.

Muscle synergy is important for simplifying functional movement, which constitutes spatiotemporal patterns of activity across muscles. To execute selective finger movements that are independent of synergistic movement patterns, we hypothesized that inhibitory neural activity is necessary to suppress enslaved finger movement caused by synergist muscles. To test this hypothesis, we focused on a pair of synergist muscles used in the hand opening movement, namely the index finger abductor and little finger abductor (abductor digiti minimi; ADM), and examined whether inhibitory neural activity in ADM occurs during selective index finger abduction/adduction movements and/or its imagery using transcranial magnetic stimulation and F-wave analysis. During the index finger adduction movement, background EMG activity, F-wave persistence, and motor evoked potential (MEP) amplitude in ADM were elevated. However, during the index finger abduction movement, ADM MEP amplitude remained unchanged despite increased background EMG activity and F-wave persistence. These results suggest that increased spinal excitability in ADM is counterbalanced by cortical-mediated inhibition only during selective index finger abduction movement. This assumption was further supported by the results of motor imagery experiments. Although F-wave persistence in ADM increased only during motor imagery of index finger abduction, ADM MEP amplitude during motor imagery of index finger abduction was significantly lower than that during adduction. Overall, our findings indicate that cortical-mediated inhibition contributes to the execution of selective finger movements that are independent of synergistic hand movement patterns.

Gait Training Using the Honda Walking Assistive Device® in a Patient Who Underwent Total Hip Arthroplasty: A Single-Subject Study.

BACKGROUND AND OBJECTIVES: The Honda Walking Assistive device® (HWA) is a light and easywearable robot device for gait training, which assists patients' hip flexion and extension movementsto guide hip joint movements during gait. However, the safety and feasibility of robot-assisted gaittraining after total hip arthroplasty (THA) remains unclear. Thus, we aimed to evaluate the safetyand feasibility of this gait training intervention using HWA in a patient who underwent THA. MATERIALS AND METHODS: The patient was a 76-year-old woman with right hip osteoarthritis. Gaittraining using HWA was implemented for 20 sessions in total, five times per week from 1 week to5 weeks after THA. Self-selected walking speed (SWS), step length (SL), cadence, timed up and go(TUG), range of motion (ROM) of hip extension, and hip abduction and extension torque weremeasured preoperatively, and at 1 (pre-HWA), 2, 3, 4, 5 (post-HWA), and 10 weeks (follow-up) afterTHA. The gait patterns at SWS without HWA were measured by using three-dimensional (3D) gaitanalysis and an integrated electromyogram (iEMG). RESULTS: The patient completed 20 gait trainingsessions with no adverse event. Hip abduction torque at the operative side, hip extension torque,SWS, SL, and cadence were higher at post-HWA than at pre-HWA. In particular, SWS, TUG, andhip torque were remarkably increased 3 weeks after THA and improved to almost the same levelsat follow-up. Maximum hip extension angle and hip ROM during gait were higher at post-HWAthan at pre-HWA. Maximum and minimum anterior pelvic tilt angles were lower at post-HWA thanat pre-HWA. The iEMG of the gluteus maximus and gluteus medius in the stance phase were lowerat post-HWA than preoperatively and at pre-HWA. CONCLUSIONS: In this case, the gait training usingHWA was safe and feasible, and could be effective for the early improvement of gait ability, hipfunction, and gait pattern after THA.

Safety and efficacy of robotic elbow training using the upper limb single-joint hybrid assistive limb combined with conventional rehabilitation for bilateral obstetric brachial plexus injury with co-contraction: a case report.

[Purpose] Obstetric brachial plexus injuries are accompanied by co-contractions due to misdirection of regenerated nerve fibers. The result is inhibition of arm movement necessary for activities of daily living. Rehabilitation is important to prevent joint contracture and muscle atrophy in such cases. A single-joint hybrid assistive limb is a new wearable robot that can assist in elbow joint motion by detecting muscle action potentials on the upper limb surface. Inhibiting co-contractions due to obstetric brachial plexus injuries with this device may help with performance of activities of daily living. This study aimed to evaluate the safety and efficacy of using a single-joint hybrid assistive limb combined with conventional rehabilitation in a patient with obstetric brachial plexus injuries. [Participant and Methods] A 40-year-old male with bilateral obstetric brachial plexus injuries and co-contractions of the biceps and deltoid underwent rehabilitation training using the single-joint hybrid assistive limb 3 times a week for 12 sessions (4 weeks) in both upper limbs. [Results] The patient completed all 12 sessions of training using the single-joint hybrid assistive limb with no adverse events. Improvements in flexion strength in the left elbow, active flexion range of motion in both elbows, and functional tests in the right arm were observed. [Conclusion] Elbow training using the newly developed single-joint hybrid assistive limb combined with conventional rehabilitation can be performed without severe adverse events and may improve muscle strength, range of motion, and arm functions in adults with obstetric brachial plexus injuries and bilateral co-contractions of the deltoid and biceps muscles.

Increased adiponectin is associated with cerebral white matter lesions in the elderly with cognitive impairment.

Adiponectin is an adipocyte-derived peptide that increases with age and is thought to protect against atherosclerotic vascular changes and organ damage. However, paradoxically, higher adiponectin levels are associated with increased risk for cardiovascular events and mortality. We investigated whether this adiponectin paradox occurs in elderly people with cognitive impairment. Fifty-two elderly participants with mild cognitive impairment or dementia (20 male and 32 female, aged 60-93 years, mean 80.0) were recruited. We evaluated serum adiponectin levels and cerebral white matter lesions (WML), which are involved in cognitive decline and dementia, by computed tomography. Body mass index (BMI), Mini-Mental State Examination score, history of hypertension (HT), chronic kidney disease, and diabetes mellitus were also assessed. Stepwise multiple regression analysis was used to reveal the relationships between serum adiponectin and age, sex, BMI, HT, diabetes mellitus, chronic kidney disease, Mini-Mental State Examination, and WML scores. High serum adiponectin levels correlated with more severe WML (P = 0.013). Low BMI (P < 0.001), female sex (P = 0.025), and high WML scores (P = 0.039) were significant determinants of high serum adiponectin. HT (P = 0.032) and high adiponectin levels (P = 0.021) were independent risk factors for WML. Overall, we observed an association between serum adiponectin levels and WML severity in elderly people with cognitive decline. Our findings reveal that the adiponectin paradox occurs in this population, and this study may help guide future treatments for elderly people with mild cognitive impairment or dementia.

Clinicopathological features of adult-onset neuronal intranuclear inclusion disease.

Neuronal intranuclear inclusion disease (NIID) is a slowly progressive neurodegenerative disease characterized by eosinophilic hyaline intranuclear inclusions in the central and peripheral nervous system, and also in the visceral organs. NIID has been considered to be a heterogeneous disease because of the highly variable clinical manifestations, and ante-mortem diagnosis has been difficult. However, since we reported the usefulness of skin biopsy for the diagnosis of NIID, the number of NIID diagnoses has increased, in particular adult-onset NIID. In this study, we studied 57 cases of adult-onset NIID and described their clinical and pathological features. We analysed both NIID cases diagnosed by post-mortem dissection and by ante-mortem skin biopsy based on the presence of characteristic eosinophilic, hyaline and ubiquitin-positive intanuclear inclusion: 38 sporadic cases and 19 familial cases, from six families. In the sporadic NIID cases with onset age from 51 to 76, dementia was the most prominent initial symptom (94.7%) as designated 'dementia dominant group', followed by miosis, ataxia and unconsciousness. Muscle weakness and sensory disturbance were also observed. It was observed that, in familial NIID cases with onset age less than 40 years, muscle weakness was seen most frequently (100%), as designated 'limb weakness group', followed by sensory disturbance, miosis, bladder dysfunction, and dementia. In familial cases with more than 40 years of onset age, dementia was most prominent (100%). Elevated cerebrospinal fluid protein and abnormal nerve conduction were frequently observed in both sporadic and familial NIID cases. Head magnetic resonance imaging showed high intensity signal in corticomedullary junction in diffusion-weighted image in both sporadic and familial NIID cases, a strong clue to the diagnosis. All of the dementia dominant cases presented with this type of leukoencephalopathy on head magnetic resonance imaging. Both sporadic and familial NIID cases presented with a decline in Mini-Mental State Examination and Frontal Assessment Battery scores. Based on these clinicopathological features, we proposed a diagnosis flow chart of adult-onset NIID. Our study suggested that the prevalence rate of adult-onset NIID may be higher than previously thought, and that NIID may be underdiagnosed. We should take NIID into account for differential diagnosis of leukoencephalopathy and neuropathy.

Spatiotemporal patterns of throwing muscle synergies in yips-affected baseball players.

"Yips" are involuntary movements that interfere with the automatic execution of sports movements. However, how the coordination among the various muscles necessary for sports movements is impaired in athletes with yips remains to be fully understood. This study aimed to assess whether muscle synergy analysis through non-negative matrix factorization (NMF) could identify impaired spatiotemporal muscle coordination in baseball players with throwing yips. Twenty-two college baseball players, including 12 with and 10 without yips symptoms participated in the study. Electromyographic activity was recorded from 13 ipsilateral upper extremity muscles during full-effort throwing. Muscle synergies were extracted through NMF. Cluster analysis was conducted to identify any common spatiotemporal patterns of muscle synergies in players with yips. Whether individual players with yips showed deviations in spatiotemporal patterns of muscle synergies compared with control players was also investigated. Four muscle synergies were extracted for each player, but none were specific to the yips group. However, a more detailed analysis of individual players revealed that two of the three players who presented dystonic symptoms during the experiment exhibited specific patterns that differed from those in control players. By contrast, each player whose symptoms were not reproduced during the experiment presented spatiotemporal patterns of muscle synergies similar to those of the control group. The results of this study indicate no common spatiotemporal pattern of muscle synergies specific to the yips group. Furthermore, these results suggest that the spatiotemporal pattern of muscle synergies in baseball throwing motion is not impaired in situations where symptoms are not reproduced even if the players have yips symptoms. However, muscle synergy analysis can identify the characteristics of muscle coordination of players who exhibit dystonic movements. These findings can be useful in developing personalized therapeutic strategies based on individual characteristics of yips symptoms.

Decreased and Improved Movement Abilities in a Case of Myotonic Dystrophy Type 1: Examining Longitudinal Characteristics Based on Repeated Evaluations.

Several large longitudinal studies on myotonic dystrophy type 1 (DM1) patients have revealed that proximal muscles show more gradual muscle weakness than distal muscles and that the progression of muscle weakness might differ between the sexes. However, these longitudinal studies were based on two follow-up time points. The present report aimed to verify the longitudinal characteristics of muscle strength and various movement abilities in a case of DM1 by examining the results of 44 repeated evaluations for approximately two years. A 40-year-old male patient with DM1 could walk independently without any aid. We recorded the longitudinal changes in his muscle strength and movement ability during outpatient rehabilitation. During follow-up, he had a fall and was diagnosed with a right ankle sprain. To evaluate the effects of the fall, we examined his recorded data. He had a significant decrease in right knee extensor muscle strength after the fall, suggesting muscle weakness due to disuse syndrome. Although his right knee extensor muscle strength and walking speed decreased, the timed up-and-go test score was improved, and walking endurance in the 2-minute walk test was maintained. In the present case, there were some motor tasks in which the movement ability was maintained or improved, likely due to the use of compensation by residual function, even when muscle weakness was present. Regular and repeated evaluations of patients with DM1 lead to reveal longitudinal characteristics of their dysfunction and movement ability.

White matter hyperintensity predicts independent walking function at 6 months after stroke: A retrospective cohort study.

BACKGROUND: White matter hyperintensity (WMH) is reported to have a potential prevalence in healthy people and is a predictor of walking disability. However, WMH has not been adequately considered as a predictor of independent walking after stroke. OBJECTIVE: To investigate the effects of WMH severity on walking function in patients with acute stroke. METHODS: The retrospective cohort study included 422 patients with acute stroke. The WMH severity from magnetic resonance images was evaluated using the Fazekas scale. Age, type of stroke, Fazekas scale, Brunnstrom motor recovery stage, Motricity Index, and Mini-Mental State Examination were used as independent variables. Multivariable logistic regression analysis was conducted on the factors of independent walking at discharge and 6 months after onset, respectively. RESULTS: Multivariable analysis revealed that the Fazekas scale is not a predictive factor of independent walking at discharge (odds ratio [OR] = 0.89, 95% confidence intervals [CI] = 0.65-1.22), but at 6 months (OR = 0.54, 95% CI = 0.34-0.86). CONCLUSION: The WMH severity was a predictive factor of independent walking in patients with acute stroke after 6 months. WMH is a factor that should be considered to improve the accuracy of predicting long-term walking function in patients with stroke.

Longitudinal changes in physical activity accumulation patterns during 1-year follow-up in stroke survivors.

PURPOSE: Few studies have reported changes in the accumulation patterns of physical activity over a year after stroke. This study characterized the longitudinal changes in physical activity levels and their accumulation patterns for a 1-year follow-up period in stroke survivors. MATERIALS AND METHODS: In this single-center, prospective, longitudinal observational study, 47 stroke survivors were assessed at rehabilitation discharge and at 6 and 12 months post-discharge. Physical activity was evaluated, and measures included the number of steps, walking duration, total number of bouts per day, and intensity (light, moderate-to-vigorous) and spread (short, medium, and long bouts). RESULTS: There were no significant main or interaction effects of time on any physical activity variables. Light physical activity accounted for 90% of all walking bouts and 70% of walking duration. Regarding moderate-to-vigorous physical activity (MVPA), 85% of walking bouts and 35% of walking duration were accumulated in short and medium bouts. The number of long-bout MVPA was three per day. CONCLUSIONS: Physical activity levels and accumulation patterns were highly stable throughout the 12-month follow-up period. Accumulating light physical activity and intermittent MVPA is important for maintaining physical activity levels in stroke survivors. These findings will promote a better understanding of disability and rehabilitation practice.IMPLICATIONS FOR REHABILITATIONPhysical activity levels and accumulation patterns were highly stable throughout the 12-month follow-up period.The accumulation of moderate-to-vigorous physical activity in long bouts might be challenging for stroke survivors.Accumulating light physical activity and intermittent moderate-to-vigorous physical activity may be acceptable for stroke survivors.

Gait training using a wearable robotic hip device for incomplete spinal cord injury: A preliminary study.

CONTEXT/OBJECTIVE: To explore changes in gait functions for patients with chronic spinal cord injury (SCI) before and after standard rehabilitation and rehabilitation with a wearable hip device, explore the utility of robot-assisted gait training (RAGT), and evaluate the safety and dose of RAGT. DESIGN: Single-arm, open-label, observational study. SETTING: A rehabilitation hospital. PARTICIPANTS: Twelve patients with SCI. INTERVENTIONS: Standard rehabilitation after admission in the first phase. RAGT for two weeks in the second phase. OUTCOME MEASURES: Self-selected walking speed (SWS), step length, cadence, and the 6-minute walking distance were the primary outcomes. Walking Index for SCI score, lower extremity motor score, and spasticity were measured. Walking abilities were compared between the two periods using a generalized linear mixed model (GLMM). Correlations between assessments and changes in walking abilities during each period were analyzed. RESULTS: After standard rehabilitation for 66.1 ± 36.9 days, a period of 17.6 ± 3.3 days of RAGT was safely performed. SWS increased during both periods. GLMM showed that the increase in cadence was influenced by standard rehabilitation, whereas the limited step length increase was influenced by RAGT. During RAGT, the increase in step length was related to an increase in hip flexor function. CONCLUSIONS: Gait speed in patients with SCI increased after rehabilitation, including RAGT, in the short-term. This increase was associated with improved muscle function in hip flexion at the start of RAGT.Trial Registration: This study was registered with the UMIN Clinical Trials Registry (UMIN-CTR; UMIN000042025).

Differences in motor unit firing properties of the vastus lateralis muscle during postural and voluntary tasks.

The firing properties of the motor units are usually affected by the motor task. However, it has not been clarified whether the firing properties of the motor units of a specific muscle are different between postural and voluntary tasks. Therefore, this study investigated whether the recruitment and rate coding of the motor units differ between these two motor tasks. Thirteen healthy volunteers performed trapezoidal muscle contraction with a target value of 15% maximum electromyography (EMG) activity by voluntary left knee extension in the sitting position (voluntary task) and postural maintenance in the semi-squatting position (postural task) with a knee flexion angle of 30°. We obtained four channels of surface EMG activity during each task from left vastus lateralis muscle. We extracted the firing properties of individual motor units using the EMG decomposition algorithm. The recruitment threshold and motor unit action potential amplitude were significantly lower in the postural task than in the voluntary task, and conversely, the mean firing rate was significantly higher. These results were explained by the preferential recruitment of motor units with higher recruitment threshold and amplitude in the voluntary task, while motor units with lower recruitment threshold and higher firing rate were preferentially recruited in the postural task. Preferential activation of fatigue-resistant motor units in the postural task is a reasonable strategy as it allows for sustained postural maintenance. We provide the first evidence that motor unit firing properties are clearly different between postural and voluntary tasks, even at the same muscle activity level.

Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Modulates Cognitive Function Related to Motor Execution During Sequential Task: A Randomized Control Study.

In daily life, we perform a variety of sequential tasks while making cognitive decisions to achieve behavioral goals. If transcranial direct current electrical stimulation (tDCS) can be used to modulate cognitive functions involved in motor execution, it may provide a new rehabilitation method. In the present study, we constructed a new task in which cognitive decisions are reflected in motor actions and investigated whether the performance of the task can be improved by tDCS of the left dorsolateral prefrontal cortex (DLPFC). Forty healthy participants were randomly assigned to a real or sham tDCS group. The anode electrode was placed at F3 (left DLPFC), and the cathode electrode was positioned in the contralateral supraorbital area. Participants underwent one session of tDCS (1.5 mA, 20 min) and a sequential non-dominant hand task was performed for nine trials before and after tDCS. The task consisted of S1 (a manual dexterity task) and S2 (a manual dexterity task requiring a decision). The results showed the S2 trajectory length was significantly shorter after real tDCS than after sham tDCS (p = 0.017), though the S1 trajectory length was not significant. These results suggest that a single tDCS session of the left DLPFC can improve the performance of cognitive tasks complementary to motor execution, but not on dexterity tasks. By elucidating the modulating effect of tDCS on cognitive functions related to motor execution, these results may be used to improve the performance of rehabilitation patients in the future.

Interindividual differences in upper limb muscle synergies during baseball throwing motion in male college baseball players.

Throwing is a fundamental human motor behavior that has evolved to aid hunting and defense against predators. In modern humans, accurate throwing is an important skill required in many sports. However, the spatiotemporal coordination of muscles during baseball throwing has not been fully elucidated. We herein aimed to identify the muscle synergies involved in baseball throwing and determine whether their spatiotemporal patterns are shared among individuals. Ten college baseball players participated in this study. Electromyographic activity was recorded from 13 ipsilateral upper limb muscles during throwing using full effort. Non-negative matrix factorization was used to extract the motor module composition and temporal activation patterns during baseball throwing, followed by k-means analysis to cluster the extracted motor modules based on their similarity. Four motor modules were extracted for each player. These were classified into four clusters (Clusters 1-4), each reaching the peak activity sequentially from the early cocking phase to ball release. Spatiotemporal interindividual similarity in the muscle synergy cluster comprising the muscles activated during the transition from early cocking to late cocking (Cluster 2) was significantly lower than that in the other clusters. There was no individual-specific muscle synergy. These results suggest that the skilled baseball throwing motion acquired through years of practice may consist of four basic muscle synergies that are common among individuals with some differences in their spatiotemporal patterns.

Asymmetry of Interhemispheric Connectivity during Rapid Movements of Right and Left Hands: A TMS-EEG Study.

The interhemispheric signal propagation (ISP) obtained by electroencephalography during transcranial magnetic stimulation (TMS) allows for the assessment of the interhemispheric connectivity involved in inhibitory processes. To investigate the functional asymmetry of hemispheres during rapid movement, we compared ISP in the left and right hemispheres during rapid hand movements. In 11 healthy right-handed adults, we delivered TMS to the M1 and recorded ISP from the M1 to the contralateral hemisphere. We found that ISP from the left to right hemisphere during right-hand rapid movement was higher than ISP from the right to left hemisphere during the left-hand rapid movement. These results indicate that the left M1 strongly inhibits the right M1, and that the left hemisphere is dominant for rapid movements as well as sequential movements.

Weight Change during the Early Phase of Convalescent Rehabilitation after Stroke as a Predictor of Functional Recovery: A Retrospective Cohort Study.

It has been reported that weight gain at discharge compared with admission is associated with improved activities of daily living in convalescent rehabilitation (CR) patients with low body mass index. Here, we investigated whether weight maintenance or gain during the early phase of CR after stroke correlates with a better functional recovery in patients with a wide range of BMI values. We conducted this retrospective cohort study in a CR ward of our hospital and included adult stroke patients admitted to the ward from January 2014 to December 2018. After ~1 month of hospitalization, the patients were classified into weight loss and weight maintenance or gain (WMG) groups based on the Global Leadership Initiative on Malnutrition criteria for weight. We adopted the motor functional independence measure (FIM) gain as the primary outcome. The motor FIM gain tended to be greater in the WMG group but without statistical significance. However, multiple regression analysis showed that WMG was significantly and positively associated with motor FIM gain. In conclusion, weight maintenance or gain in patients during the early phase of CR after stroke may be considered as a predictor of their functional recovery, and nutritional management to prevent weight loss immediately after the start of rehabilitation would contribute to this.