Yea-Ru Yang

Task-oriented progressive resistance strength training improves muscle strength and functional performance in individuals with stroke:

Objective: To examine the effectiveness of task-oriented progressive resistance strength training on lower extremity strength and functional performance in chronic stroke subjects. Design: Single-blind, randomized controlled trial. Setting: Medical centre and district hospital. Subjects: Forty-eight subjects at least one year post stroke. Interventions: Participants randomly allocated to two groups, control (n-/24) and experimental (n-/24). Subjects in the control group did not receive any rehabilitation training. Subjects in the experimental group were put on a four-week task-oriented progressive resistance strength training. Main measures: Lower extremity muscle strength, gait velocity, cadence, stride length, six-minute walk test, step test, and timed up and go test. Results: Muscle strength significantly improved in the experimental group for strong side muscle groups (ranged from 23.9% to 36.5%) and paretic side muscle groups (ranged from 10.1% to 77.9%). In the control group muscle strength changes ranged from 6.7% gain to 11.2% decline. The experimental group showed significant improvement in all selected measures of functional performance except for the step test. In the control group, the number of repetitions of the step test significantly decreased (-20.3%) with no change in other functional tests. There was a significant difference between groups for muscle strength and all functional measures. The strength gain was significantly associated with gain in the functional tests. Conclusions: The task-oriented progressive resistance strength training programme could improve lower extremity muscle strength in individuals with chronic stroke and could carry over into improvement in functional abilities.

Effects of an ankle-foot orthosis on balance performance in patients with hemiparesis of different durations

Objective: To examine the effects of an ankle-foot orthosis (AFO) on balance performance in patients with hemiparesis of short and long duration. Design: Within-subject random order of intervention, cross-sectional study design. Settings: Medical centres and district hospitals. Subjects: Forty-two subjects with hemiparesis of short duration (B=six months) and 61 subjects of long duration (=12 months). Measurements: The balance and gait ability of subjects were evaluated both with an AFO and without. The static and dynamic balance activities were evaluated by the Balance Master System, whereas the functional balance was assessed with the Berg Balance Scale. The speed and cadence were also measured during a 10-metre walk. Paired t-test was used to determine the effect of the AFO. Results: In subjects with hemiparesis of short duration, we found that subjects wearing an AFO showed significant improvements in (1) weight-bearing distribution during quiet standing (p / 0.042, 95% confidence interval (CI) 0.521, 7.325), (2) body sway during standing on foam surface with eyes open (p / 0.020, 95% CI 0.020, 0.680) and eyes closed (p / 0.041, 95% CI 0.023, 0.921), (3) movement velocity during limit of stability test (LOS) / toward the affected side (p / 0.037, 95% Cl / 0.978, / 0.042) and nonaffected side (p / 0.008, 95% CI / 2.223, / 0.377), (4) maximal excursion toward the affected side (p / 0.042, 95% CI / 19.546,=0.071), and (5) speed (p / 0.028, 95% CI / 0.204, / 0.017) and cadence (p / 0.021, 95% CI / 22.983, / 1.864). Such effects were not observed in subjects with hemiparesis of long duration. Conclusions: For the subjects with hemiparesis of short duration, the AFO improves the symmetry in quiet and dynamic standing balances. It also increases speed and cadence. However, its effectiveness is minimal for patients of long duration.

Gait Training—Induced Change in Corticomotor Excitability in Patients With Chronic Stroke

Background. Numerous studies have reported the effects of gait training on motor performance after stroke. However, there is limited information on treatment-induced changes in corticomotor excitability. Objectives. The purpose of the study was to investigate the effects of additional gait training on motor performance and corticomotor excitability and to demonstrate the relationship between motor improvement and corticomotor excitability change in patients with chronic stroke. Methods. Fourteen patients were randomly assigned to the experimental or control group. Participants in both groups participated in general physical therapy. Those in the experimental group received additional body weight− supported treadmill training for 4 weeks. All participants received baseline and posttreatment assessments. The outcome measures included assessment of the Berg Balance Scale (BBS) and gait parameters. Focal transcranial magnetic stimulation was used to measure the motor threshold, map size, and location of the amplitude-weighted center of gravity of the motor map for the tibialis anterior (TA) and abductor hallucis (AH) muscles. Results . After general physical therapy, we noted that the patients showed an improvement only in walking speed and cadence, and there were no significant changes in corticomotor excitability. After additional gait training, participants improved significantly on BBS score, walking speed, and step length. Moreover, the motor threshold for TA decreased significantly in the unaffected hemisphere. The map size for TA was increased in both hemispheres, whereas that for AH was increased only in the affected hemisphere. There were significant differences between the change scores of the groups in terms of walking speed, step length, and motor threshold for TA in the unaffected hemisphere and map size for AH in the affected hemisphere. Additionally, the changes in corticomotor excitability correlated with functional improvement. Conclusions . Additional gait training may improve balance and gait performance and may induce changes in corticomotor excitability.

Protective effects of treadmill training on infarction in rats.

This study was undertaken to determine the protective effects of treadmill training on brain ischemic lesions caused by middle cerebral artery (MCA) occlusion in male rats. Rats were divided into four groups: control, 1-week treadmill pre-training, 2-week treadmill pre-training, and 4-week treadmill pre-training. Cerebral infarction was induced by MCA occlusion for 60 min, followed by reperfusion. After 24 h, rats were killed and brain slices were then stained to assess lesion size. Treadmill training at least for 2 weeks can reduce the infarction size and edema caused by MCA occlusion (P<0.01). The present study provides evidence that treadmill training reduces ischemic brain damage in an animal model of cerebral ischemia.

Gait outcomes after additional backward walking training in patients with stroke: a randomized controlled trial

Objective: To examine the effectiveness of additional backward walking training on gait outcome of patients post stroke. Design: Randomized controlled trial. Setting: Medical centre. Subjects: Twenty-five subjects with stroke, who were lower extremity Brunnstrom motor recovery stage at 3 or 4 and were able to walk 11 m with or without a walking aid or orthosis, randomly allocated to two groups, control (n = 12) and experimental (n = 13). Interventions: Subjects in both groups participated in 40 min of conventional training programme three times a week for three weeks. Subjects in experimental group received additional 30 min of backward walking training for three weeks at a frequency of three times per week. Main measures: Gait was measured using the Stride Analyzer. Gait parameters of interest were walking speed, cadence, stride length, gait cycle and symmetry index. Measures were made at baseline before commencement of training (pre-training) and at the end of the three-week training period (post-training). Results: After a three-week training period, subjects in experimental group showed more improvement than those in control group for walking speed (change score: 8.609 ± 6.95 versus 3.659 ± 2.92, p-value = 0.032), stride length (change score: 0.0909 ± 0.076 versus 0.00649 ± 0.078, p-value = 0.006), and symmetry index (change score: 44.079 ± 53.29 versus 5.309 ± 13.91, p-value = 0.018). Conclusions: This study demonstrated that asymmetric gait pattern in patients post stroke could be improved from receiving additional backward walking therapy.

Early and late treadmill training after focal brain ischemia in rats.

Treadmill training is increasingly recognized as an effective means to promote rhythmical vigorous walking and also as a useful method of task-related training. The present study endeavored to investigate the effects of early and late treadmill training after ligation of the middle cerebral artery. Forty male Sprague-Dawley rats were subjected to 60 min right middle cerebral artery occlusion (MCAO). All rats were randomly assigned to one of four groups: 24 h group, 2 week no training group, early training group (training started 24 h post MCAO), and late training group (training started 1 week post MCAO). Infarct volume was measured morphometrically. A five-point neurological evaluation scale was used to assess the neurological status of rats. Rats sacrificed 24 h post MCAO had the largest infarct volume (177.8+/-14.3 mm(3)) and the highest neurological score [2(1-4)]. Early treadmill training was found to have significant effects in reducing brain infarct volume and in improving neurologic function when compared with spontaneous recovery. However, the same effects cannot be found in late training. Based on the present findings, we would encourage early treadmill training for ischemic brain recovery.

rTMS Combined With Task-Oriented Training to Improve Symmetry of Interhemispheric Corticomotor Excitability and Gait Performance After Stroke: A Randomized Trial

Background. The model of interhemispheric competition after stroke has been established for the upper but not for the lower extremity. Repetitive transcranial magnetic stimulation (rTMS) of the brain has been shown to modulate cortical excitability. Objective. The purpose of this study was to investigate the effects of rTMS followed by task-oriented training on cortical excitability and walking performance in individuals with chronic stroke. Methods. A total of 24 patients with average Fugl-Meyer lower limb scores of 17.88 ± 5.27 and average walking speeds of 63.81 ± 18.25 cm/s were randomized into an experimental group and a control group. Participants received rTMS (experimental group) or sham rTMS (control group) followed by task-oriented training (30 minutes) for 10 sessions over 2 weeks. Repetitive TMS was applied at a 1-Hz frequency over the leg area of the motor cortex of the unaffected hemisphere for 10 minutes. Outcomes, including motor-evoked potential (MEP), lower-extremity Fugl-Meyer score, and gait performance, were measured before and after training. Results. Decreased interhemispheric asymmetry of the amplitude of the MEP was noted after rTMS and task-oriented training. Improvement in spatial asymmetry of gait was comparable with increased symmetry in interhemispheric excitability. Motor control and walking ability were also significantly improved after rTMS and task-oriented training. Conclusions. rTMS enhances the effect of task-oriented training in those with chronic stroke, especially by increasing gait spatial symmetry and corticomotor excitability symmetry.

Effects of Exercise Intensity on Spatial Memory Performance and Hippocampal Synaptic Plasticity in Transient Brain Ischemic Rats

Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO) procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed), low-intensity exercise (Low-Ex), or high-intensity exercise (High-Ex) group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF), synapsin-I, postsynaptic density protein 95 (PSD-95), and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be considered during exercise training.

Balance outcomes after additional sit-to-stand training in subjects with stroke: a randomized controlled trial

Objective: To determine the effectiveness of sit-to-stand training in individuals with stroke. Design: Randomized controlled trial. Setting: Rehabilitation medical centre. Participants: Thirty-two subjects with stroke were randomly assigned to the control and experimental groups (n = 16 for each group). Interventions: Subjects in both groups received 30 minutes of general physical therapy three times a week for four weeks. Subjects in the experimental group received additional sit-to-stand training for 15 minutes each time. The total amount of therapy received was 45 minutes in the experimental group and 30 minutes in the control group each time. Main outcome measures: The weight-bearing distribution during quiet standing, the directional control and maximal excursion during limits of stability test, the scores of Berg Balance Scale and the extensor muscle strength of lower extremity were assessed before and after completing the 12 treatment sessions. Results: Our data showed significant improvements in directional control anteriorly in the experimental group (from 47.4 (36.6)% to 62.6 (26.1)%) compared with the control group (from 68.7 (16.7)% to 62.8 (29.7)%) (P = 0.028). A significant improvement in affected hip extensor strength was noted in the experimental group (from 19.3 (9.8)% to 22.6 (8.4)%) compared with the control group (from 24.4 (9.0)% to 22.8 (7.2)%) (P = 0.006). Significant improvements were noted only in the experimental group after treatment, including bilateral extensors, except the affected plantar flexors, the weight distribution in standing, the maximal excursion (Panterior = 0.049; Paffected = 0.023) and the directional control (Paffected = 0.013; Pnon-affected = 0.025). Conclusions: Additional sit-to-stand training is encouraged due to effects on dynamic balance and extensor muscles strength in subjects with stroke.

Intermittent Hypoxia after Transient Focal Ischemia Induces Hippocampal Neurogenesis and c-Fos Expression and Reverses Spatial Memory Deficits in Rats

Background Memory impairment is a frequent complication of brain ischemia. Neurogenesis is implicated in learning and memory and is regulated by the transcription factor c-Fos. Preconditioning intermittent hypoxia (IH) attenuates ischemia-related memory impairments, but it is not known whether post-ischemia IH intervention has a similar effect. We investigated the effects of post-ischemia IH on hippocampal neurogenesis and c-Fos expression as well as spatial learning and memory in rats. Methodology/Principal Findings Focal cerebral ischemia was induced in some rats by middle cerebral artery occlusion (MCAO), while other rats received sham MCAO surgery. Beginning a week later, half of the rats of each group received IH interventions (12% oxygen concentration, 4 hrs/d, for 7 d) and half received sham IH sessions. An additional group of rats received MCAO, IH, and injections of the neurogenesis-impairing agent 3′-AZT. Spatial learning and memory was measured in the Morris water maze, and hippocampal neurogenesis and c-Fos expression were examined. Hypoxia-inducible factor 1α (HIF-1α) and phosphorylated mitogen-activated protein kinase (pMAPK) were considered as possible mediators of IH-induced changes in neurogenesis and c-Fos expression. IH intervention following MCAO resulted in recovered spatial memory, increased hippocampal neurogenesis, and increased expression of c-Fos in newborn hippocampal cells. These effects were blocked by 3′-AZT. IH intervention following MCAO also was associated with increased hippocampal pMAPK and HIF-1α expression. Conclusions/Significance IH intervention following MCAO rescued ischemia-induced spatial learning and memory impairments, likely by inducing hippocampal neurogenesis and c-Fos expression through mediators including pMAPK and HIF-1α