There is increasing interest in electroencephalogram (EEG)-based brain-computer interface (BCI) as a tool for rehabilitation of upper limb motor functions in hemiplegic stroke patients. This type of ...BCI often exploits mu and beta oscillations in EEG recorded over the sensorimotor areas, and their event-related desynchronization (ERD) following motor imagery is believed to represent increased sensorimotor cortex excitability. However, it remains unclear whether the sensorimotor cortex excitability is actually correlated with ERD. Thus we assessed the association of ERD with primary motor cortex (M1) excitability during motor imagery of right wrist movement. M1 excitability was tested by motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) with transcranial magnetic stimulation (TMS). Twenty healthy participants were recruited. The participants performed 7 s of rest followed by 5 s of motor imagery and received online visual feedback of the ERD magnitude of the contralateral hand M1 while performing the motor imagery task. TMS was applied to the right hand M1 when ERD exceeded predetermined thresholds during motor imagery. MEP amplitudes, SICI, and ICF were recorded from the agonist muscle of the imagined hand movement. Results showed that the large ERD during wrist motor imagery was associated with significantly increased MEP amplitudes and reduced SICI but no significant changes in ICF. Thus ERD magnitude during wrist motor imagery represents M1 excitability. This study provides electrophysiological evidence that a motor imagery task involving ERD may induce changes in corticospinal excitability similar to changes accompanying actual movements.
Because recovery from upper limb paralysis after stroke is challenging, compensatory approaches have been the main focus of upper limb rehabilitation. However, based on fundamental and clinical ...research indicating that the brain has a far greater potential for plastic change than previously thought, functional restorative approaches have become increasingly common. Among such interventions, constraint-induced movement therapy, task-specific training, robotic therapy, neuromuscular electrical stimulation (NMES), mental practice, mirror therapy, and bilateral arm training are recommended in recently published stroke guidelines. For severe upper limb paralysis, however, no effective therapy has yet been established. Against this background, there is growing interest in applying brain–machine interface (BMI) technologies to upper limb rehabilitation. Increasing numbers of randomized controlled trials have demonstrated the effectiveness of BMI neurorehabilitation, and several meta-analyses have shown medium to large effect sizes with BMI therapy. Subgroup analyses indicate higher intervention effects in the subacute group than the chronic group, when using movement attempts as the BMI-training trigger task rather than using motor imagery, and using NMES as the external device compared with using other devices. The Keio BMI team has developed an electroencephalography-based neurorehabilitation system and has published clinical and basic studies demonstrating its effectiveness and neurophysiological mechanisms. For its wider clinical application, the positioning of BMI therapy in upper limb rehabilitation needs to be clarified, BMI needs to be commercialized as an easy-to-use and cost-effective medical device, and training systems for rehabilitation professionals need to be developed. A technological breakthrough enabling selective modulation of neural circuits is also needed.
Unilateral spatial neglect (USN) may lead to poor functional rehabilitation outcomes. However, studies investigating the rehabilitation outcomes of right-sided USN are lacking. We aimed to ...investigate (1) the clinical impacts of USN, including right-sided USN, for stroke patients in sub-acute rehabilitation, and (2) evaluate the differences in clinical characteristics and rehabilitation outcomes between right- and left-sided USN patients. We retrospectively screened the medical records of 297 inpatients at the Tokyo-Bay Rehabilitation Hospital who experienced a cerebrovascular accident with supratentorial lesions between January 1st, 2014 and December 31st, 2016. We performed independent multiple regression analysis in patients with left and right hemisphere damage. The Behavioral Inattention Test was a significant independent variable for predicting the motor, cognitive, and total functional independence measure (FIM), compared to the Stroke Impairment Assessment Set and Mini-Mental State Examination. USN affects motor FIM recovery more than cognitive FIM recovery regardless of the damaged hemisphere. Our study results confirm that both right- and left-sided USN influence the functional recovery of stroke patients. USN occurs, slightly less frequently, following a left hemisphere stroke. However, USN negatively affected rehabilitation outcomes, regardless of the neglected side. Therefore, USN treatment is necessary for patients with left and right hemisphere damage.
Brain‐computer interfaces (BCIs) can provide sensory feedback of ongoing brain oscillations, enabling stroke survivors to modulate their sensorimotor rhythms purposefully. A number of recent clinical ...studies indicate that repeated use of such BCIs might trigger neurological recovery and hence improvement in motor function. Here, we provide a first meta‐analysis evaluating the clinical effectiveness of BCI‐based post‐stroke motor rehabilitation. Trials were identified using MEDLINE, CENTRAL, PEDro and by inspection of references in several review articles. We selected randomized controlled trials that used BCIs for post‐stroke motor rehabilitation and provided motor impairment scores before and after the intervention. A random‐effects inverse variance method was used to calculate the summary effect size. We initially identified 524 articles and, after removing duplicates, we screened titles and s of 473 articles. We found 26 articles corresponding to BCI clinical trials, of these, there were nine studies that involved a total of 235 post‐stroke survivors that fulfilled the inclusion criterion (randomized controlled trials that examined motor performance as an outcome measure) for the meta‐analysis. Motor improvements, mostly quantified by the upper limb Fugl‐Meyer Assessment (FMA‐UE), exceeded the minimal clinically important difference (MCID=5.25) in six BCI studies, while such improvement was reached only in three control groups. Overall, the BCI training was associated with a standardized mean difference of 0.79 (95% CI: 0.37 to 1.20) in FMA‐UE compared to control conditions, which is in the range of medium to large summary effect size. In addition, several studies indicated BCI‐induced functional and structural neuroplasticity at a subclinical level. This suggests that BCI technology could be an effective intervention for post‐stroke upper limb rehabilitation. However, more studies with larger sample size are required to increase the reliability of these results.
The direct cortico-motoneuronal connection is believed to be essential for the control of dexterous hand movements, such as precision grip in primates. It was reported, however, that even after ...lesion of the corticospinal tract (CST) at the C4–C5 segment, precision grip largely recovered within 1–3 mo, suggesting that the recovery depends on transmission through intercalated neurons rostral to the lesion, such as the propriospinal neurons (PNs) in the midcervical segments. To obtain direct evidence for the contribution of PNs to recovery after CST lesion, we applied a pathway-selective and reversible blocking method using double viral vectors to the PNs in six monkeys after CST lesions at C4–C5. In four monkeys that showed nearly full or partial recovery, transient blockade of PN transmission after recovery caused partial impairment of precision grip. In the other two monkeys, CST lesions were made under continuous blockade of PN transmission that outlasted the entire period of postoperative observation (3–4.5 mo). In these monkeys, precision grip recovery was not achieved. These results provide evidence for causal contribution of the PNs to recovery of hand dexterity after CST lesions; PN transmission is necessary for promoting the initial stage recovery; however, their contribution is only partial once the recovery is achieved.
A retrospective cohort study OBJECTIVE: To establish a logarithmic model to predict functional independence after spinal cord injury.
The National Hospital Organization, Murayama Medical Center, ...Japan.
Thirty-one adults with a traumatic spinal cord injury (SCI) were enrolled. The Spinal Cord Independence Measure (SCIM) III scores obtained at month 1 and 3 after admission were used to construct a simple logarithmic model to predict SCIM III scores. The validity of the predicted scores was evaluated using a linear mixed model, and agreement between the predicted and measured scores were assessed using the Bland-Altman analysis.
In the linear mixed model, the fixed effect slope 95% CI and the intercept 95% CI were 1.18 0.78, 1.58 and -1.75 -10.3, 6.83, respectively. The scatter plot showed non-linear correlation between the predicted and actual SCIM III scores. This non-linearity became inconspicuous when Sphincter Management scores were omitted. The fixed effect slope and the intercept were 1.12 0.89, 1.36 and -1.64 -4.95, 1.68, respectively. A significant fixed or proportional bias was not identified on the Bland-Altman analysis of the total SCIM III score, with most scores lying between an upper limit of +15.3 and a lower limit of -19.3.
The logarithmic model provided an accurate prediction of the functional independence score of individuals with SCI in our cohort which included various neurological levels and severity of the injury. Along with its simplicity, our prediction model could be useful in daily practice.
Chronic and severe upper-limb motor deficits can result from damage to the corticospinal tract. However, it remains unclear what their characteristics are and whether only corticospinal tract damage ...determines their characteristics. This study aimed to investigate the clinical characteristics and neural bases of chronic and severe upper-limb motor deficits. Motor deficits, including spasticity, of 45 patients with brain lesions were assessed using clinical scales. Regarding their scores, we conducted a principal component analysis that statistically extracted the clinical characteristics as two principal components. Using these principal components, we investigated the neural bases underlying their characteristics through lesion analyses of lesion volume, lesion sites, corticospinal tract, or other regional white-matter integrity. Principal component analysis showed that the clinical characteristics of chronic and severe upper-limb motor deficits could be described as a comprehensive severity and a trade-off relationship between proximal motor functions and wrist/finger spasticity. Lesion analyses revealed that the comprehensive severity was correlated with corticospinal tract integrity, and the trade-off relationship was associated with the integrity of other regional white matter located anterior to the posterior internal capsule, such as the anterior internal capsule. This study indicates that the severity of chronic and severe upper-limb motor deficits can be determined according to the corticospinal tract integrity, and such motor deficits may be further characterized by the integrity of other white matter, where the corticoreticular pathway can pass through, by forming a trade-off relationship where patients have higher proximal motor functions but more severe wrist/finger spasticity, and vice versa.
We aimed to investigate whether a newly defined distance in the lower limb can capture the characteristics of hemiplegic gait compared to healthy controls. Three-dimensional gait analyses were ...performed on 42 patients with chronic stroke and 10 age-matched controls. Pelvis-toe distance (PTD) was calculated as the absolute distance between an anterior superior iliac spine marker and a toe marker during gait normalized by PTD in the bipedal stance. The shortening peak during the swing phase was then quantified as PTDmin. The sagittal clearance angle, the frontal compensatory angle, gait speed, and the observational gait scale were also collected. PTDmin in the stroke group showed less shortening on the affected side and excessive shortening on the non-affected side compared to controls. PTDmin on the affected side correlated negatively with the sagittal clearance peak angle and positively with the frontal compensatory peak angle in the stroke group. PTDmin in stroke patients showed moderate to high correlations with gait speed and observational gait scale. PTDmin adequately reflected gait quality without being affected by apparent improvements due to frontal compensatory patterns. Our results showed that various impairments and compensations were included in the inability to shorten PTD, which can provide new perspectives on gait rehabilitation in stroke patients.
Background and Purpose:
Limited research has been conducted with the aim of understanding which upper extremity movements are difficult for persons with severe chronic stroke. The purpose of this ...study was to test the structure of the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) using Rasch analysis in persons with chronic stroke with moderate to severe deficits and to determine the item difficulty hierarchy.
Methods:
This was a secondary analysis of data from previous randomized, controlled trials, or clinical trials. The participants were 101 persons with chronic stroke with moderate to severe hemiparesis (time after onset of stroke, 1375.3 ± 1157.9 days; the 33-item FMA-UE, 31.1 ± 12.8). Principal component analysis and infit statistics were used to evaluate dimensionality. Rasch analysis using a rating scale model was performed, and item difficulty was determined.
Results:
Six misfit items were removed. The results showed that the 27-item FMA-UE was unidimensional. Rasch analysis showed that the movements performed within synergies were among the easiest items. Shoulder and elbow movements were among the easiest items, whereas forearm and wrist movements were among the moderately to most difficult items. Hand items spanned various difficulty levels.
Discussion and Conclusions:
The FMA-UE is a valid assessment tool of upper extremity motor function in persons with chronic stroke with moderate to severe deficits. The results showed that item difficulty was consistent with the stepwise recovery course proposed by Fugl-Meyer. The movements that are difficult for patients with moderate to severe chronic paresis were determined, which would enable comparison of each movement using a measure of motion difficulty in future studies.
To examine the inter-rater reliability of the thumb localizing test (TLT) and its validity against quantitative measures of proprioception. The TLT was assessed by two raters in a standardized manner ...in 40 individuals with hemiparetic stroke. Inter-rater reliability was examined with weighted Kappa. For the quantitative measures, a bimanual matching task in a planar robotic device was performed. Without vision, each participant moved the unaffected hand to the perceived mirrored location of the affected hand, which was passively moved by the robot. Three measures were taken after 54 trials: Variability, trial-to-trial variability of the mirrored-matched locations; Area, the ratio of the area enclosed by the active hand relative to the passive hand; and Shift, systematic shifts between the passive and active hands. The correlation between the TLT and each robotic measure was examined with Spearman's rank correlation coefficient. The overall weighted kappa of the TLT was 0.84 (P<0.001). The TLT correlated highly with Area (r = -0.71, P<0.001) and moderately with Variability (r = 0.40, P = 0.011). No significant correlation was found between the TLT and Shift. The TLT had a high inter-rater reliability, and was validated against quantitative measures of proprioception reflecting the perceived area of movement and variability of the limb location.
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