Macrostructural Cerebellar Neuroplasticity Correlates With Motor Recovery After Stroke.

BACKGROUND: Motor recovery varies across post-stroke individuals, some of whom require a better rehabilitation strategy. We hypothesized that macrostructural neuroplasticity of the motor control network including the cerebellum might underlie individual differences in motor recovery. Objectives. To gain insight into the macrostructural neuroplasticity after stroke, we examined 52 post-stroke individuals using both the Fugl-Meyer assessment and structural magnetic resonance imaging. METHODS: We performed voxel-based lesion symptom mapping and cross-sectional voxel-based morphometry to correlate the motor scores with the lesion location and the gray matter volume (GMV), respectively. Longitudinal data were available at ~8 and/or 15 weeks after admission from 43 individuals with supratentorial lesions. We performed a longitudinal VBM analysis followed by a multiple regression analysis to correlate between the changes of the motor assessment scores and those of GMV overtime. RESULTS: We found a cross-sectional correlation of residual motor functioning with GMV in the ipsilesional cerebellum and contralesional parietal cortex. Longitudinally, we found increases in GMV in the ipsilesional supplementary motor area, and the ipsilesional superior and inferior cerebellar zones, along with a GMV decrease in the ipsilesional thalamus. The motor recovery was correlated with the GMV changes in the superior and inferior cerebellar zones. The regaining of upper-limb motor functioning was correlated with the GMV changes of both superior and inferior cerebellum while that of lower-limb motor functioning with the GMV increase of the inferior cerebellum only. CONCLUSIONS: The present findings support the hypothesis that macrostructural cerebellar neuroplasticity is correlated with individual differences in motor recovery after stroke.

Relationship between weight bearing ratio in sitting and physical function assessment in healthy adults.

[Purpose] The weight-bearing ratio in sitting is a simple quantitative assessment using a body weight scale. Bilateral total weight bearing ratio in sitting is related to the ability to stand up, transfer, and walk; however, it has not been examined in the performance test on just one side. Therefore, this study aimed to investigate the relationship between weight bearing ratio in sitting and performance tests on one side. [Participants and Methods] Thirty-two healthy adults were recruited (27.47 ± 4.06 years). Weight-bearing ratio in sitting, knee extensor muscle strength, lateral reach test, and one-leg stand-up test were measured. Correlation analysis between the measurement results was performed on the pivot and non-pivot sides and the total. [Results] Correlation analysis of the weight-bearing ratio in sitting showed a significant positive correlation (pivot/non-pivot/total) with knee extensor muscle strength (r=0.54/0.44/0.50), lateral reach test (r=0.42/0.44/0.48), and one-leg stand up test (r=0.44/0.52/0.51). [Conclusion] Weight-bearing ratio in sitting, both pivot, non-pivot, and total, reflected results of the performance tests. Weight bearing ratio in sitting would be a highly useful quantitative assessment for a wide range of individuals, from those with unstable standing to those with relatively high function.

Effects of unilateral neck muscle vibration on standing postural orientation and spatial perception in healthy subjects based on stimulus duration and simultaneous stimulation of trunk muscles.

Neck muscle vibration (NMV) influences proprioceptive sensations and modulates standing postural orientation and spatial perception. However, the effects of NMV in healthy participants would vary based on the influence of stimulus duration and combination with trunk muscle vibration. Therefore, this study with a cross-over design clarified these effects. Twenty-four healthy participants (mean age, 25.7±3.7 years) were enrolled. To assess standing postural orientation, standing center-of-pressure (COP) measurements were recorded on a COP platform, starting with closed eyes and then with open eyes. The mean mediolateral (ML) and anteroposterior (AP) position [mm] of COP and other parameters were calculated. To assess spatial perception, subjective straight ahead (SSA) measurements were recorded, wherein participants were instructed to point and project the position of the manubrium of sternum on the touch panel using their right index finger with their eyes closed. Measurements were taken before and after four conditions: no vibration (control), left NMV for 30 s, left NMV for 10 min, and left NMV and left lumbar back vibration for 10 min. Vibratory stimulation was performed with the eyes closed at 80 Hz. The measurements under the four conditions were conducted with random cross-over and 5-min resting period between the conditions. COP and SSA values were subtracted before and after each condition for standardized variation and compared. NMV combined with trunk muscle vibration for 10 min resulted in significant deviations of the ML-COP toward the stimulation side and AP-COP toward the anterior side compared to the control condition with closed eyes. SSA showed no significant differences. These findings suggest that NMV-induced nervous system modulation would be amplified by proprioceptive sensory input to trunk muscles. Therefore, this method could provide a new option for clinical trials on postural orientation using NMV. SSA based on proprioceptive sensation may not be biased without visual illusions.

Movement patterns of the functional reach test do not reflect physical function in healthy young and older participants.

The relationship of the Functional Reach Test (FRT) value with the Center of Pressure Excursion (COPE) and physical function remains unclear, and would be influenced by different population characteristics and movement patterns used in the FRT. Therefore, we explored the relationship between the FRT value and the COPE and physical function in healthy young and older individuals classified according to movement patterns. In 21 healthy young participants (42 sides) and 20 older participants (40 sides), three-dimensional motion analysis was performed during the FRT and physical function assessments. The participants were assigned to two clusters after performing a motion analysis during the FRT. Kinematic and kinetic parameters during the FRT and physical function assessment results were compared between the clusters for both groups. Correlation analysis was performed to investigate the relationships of the FRT value with COPE and physical function parameters in each cluster, in young and older individuals separately. The results showed that the hip strategies could be divided into two groups according to the degree of use (Small Hip Strategy, SHS Group; Large Hip Strategy, LHS Group). In the older SHS group, the FRT values were significantly correlated with the COPE (r = 0.75), toe grip strength (r = 0.62), and the five-times sit-to-stand test time (r = -0.52). In the older LHS group and in both groups of young individuals, there were no significant correlations of the FRT value with any parameters. The FRT value reflects the COPE and physical function only in older individuals using the SHS. This could explain previous discrepant results. As there is no simple relationship between the FRT value and physical function, it is important to include movement strategy assessment when using the FRT in clinical evaluations.

The immediate effect of the Honda Walking Assist Device on foot and ankle function in hemiplegic stroke patients.

[Purpose] We evaluated the reliability of the measurement function of the Honda Walking Assist Device and investigated the effect of the device on walking improvements, and foot and ankle function, in hemiplegic stroke patients. [Participants and Methods] We recruited 16 hemiplegic stroke patients who performed 10-meter walk tests, twice without assistance and once with device assistance. Based on the rate of change of velocity, we divided the participants into two groups and compared the walking parameters, the toe grip strength, the cross tests, and the maximum step width. Two examiners assessed the 10-meter walk test results, and the authors calculated the intraclass correlation coefficients for walking speed, stride length, cadence, flexion, extension, and scissor angles. [Results] The intraclass correlation coefficients were greater than 0.70 for all the walking parameters we measured. The device increased hip joint movement but did not alter the maximum walking speed of the stroke patients. The patients in the group with a greater change in velocity displayed lower toe grip strength and decreased maximum step width and used orthoses more commonly. [Conclusion] The walking measurement function of the device was reliable. The immediate effect of the device in stroke patients may be influenced by the level of paralysis and the presence of an orthosis.

Difference in the electromyographic onset of the deep and superficial multifidus during shoulder movement while standing.

Based on the current literature, it remains unclear whether electromyographic onset of the deep fibers of the multifidus (DM) is dependent on the direction of shoulder movement and the position of the center of foot pressure (CFP). In the present study, we re-examined the electromyographic onset of the DM during shoulder flexion and extension and investigated the influence of the CFP position before arm movement. Intramuscular and surface electrodes recorded the electromyographic onset of the DM, superficial fibers of the multifidus (SM), rectus abdominis, and anterior and posterior deltoid. Eleven healthy participants performed rapid, unilateral shoulder flexion and extension in response to audio stimuli at three CFP positions: quiet standing, extreme forward leaning, and extreme backward leaning. It was found that the electromyographic onset of the DM and SM relative to the deltoid was dependent on the direction of arm movement. Additionally, of all electromyographic onsets recorded, only that of the DM occurred earlier in the extreme forward leaning position than in the extreme backward leaning position during shoulder flexion. These results suggest that the electromyographic onset of DM was influenced by the biomechanical disturbance such as shoulder movement and CFP position.