Hen-Yu Lien

Hypoxic exercise training improves cardiac/muscular hemodynamics and is associated with modulated circulating progenitor cells in sedentary men

BACKGROUND Circulating progenitor cells (CPCs) improve cardiovascular function and organ perfusion by enhancing the capacities of endothelial repair and neovasculogenesis. This study investigates whether exercise regimens with/without hypoxia affect cardiac and muscular hemodynamics by modulating CPCs and angiogenic factors. METHODS Forty sedentary males were randomly divided into hypoxic (HT, n=20) and normoxic (NT, n=20) training groups. The subjects were trained on a bicycle ergometer at 60%VO(2max) under 15% (HT) or 21% (NT) O2 conditions for 30 min daily, five days weekly for five weeks. RESULTS After the five-week interventions, the HT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the HT regimen (i) enhanced cardiac output (Q(H)) and perfusion (Q(M))/oxygenation of vastus lateralis during exercise; (ii) increased levels of CD34(+)/KDR(+)/CD117(+), CD34(+)/KDR(+)/CD133(+), and CD34(+)/KDR(+)/CD31(+) cells in blood; (iii) promoted the proliferative capacity of these CPC subsets, and (iv) elevated plasma nitrite/nitrate, stromal cell-derived factor-1 (SDF-1), matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor-A (VEGF-A) concentrations. Despite the lack of changes in Q(H) and the number or proliferative capacity of CD34(+)/KDR(+)/CD117(+) or CD34(+)/KDR(+)/CD31(+) cells, the NT regimen elevated both Q(M) and plasma nitrite/nitrate levels and suppressed the shedding of endothelial cells (CD34(-)/KDR(+)/phosphatidylserine(+) cells). CONCLUSIONS The HT regimen improves cardiac and muscular hemodynamic adaptations, possibly by promoting the mobilization/function of CPCs and the production of angiogenic factors.

Predicting Clinically Significant Changes in Motor and Functional Outcomes After Robot-Assisted Stroke Rehabilitation

OBJECTIVE To investigate the predictors of minimal clinically important changes on outcome measures after robot-assisted therapy (RT). DESIGN Observational cohort study. SETTING Outpatient rehabilitation clinics. PARTICIPANTS A cohort of outpatients with stroke (N=55). INTERVENTIONS Patients with stroke received RT for 90 to 105min/d, 5d/wk, for 4 weeks. MAIN OUTCOME MEASURES Outcome measures, including the Fugl-Meyer Assessment (FMA) and Motor Activity Log (MAL), were measured before and after the intervention. Potential predictors include age, sex, side of lesion, time since stroke onset, finger extension, Box and Block Test (BBT) score, and FMA distal score. RESULTS Statistical analysis showed that the BBT score (odds ratio[OR]=1.06; P=.04) was a significant predictor of clinically important changes in the FMA. Being a woman (OR=3.9; P=.05) and BBT score (OR=1.07; P=.02) were the 2 significant predictors of clinically significant changes in the MAL amount of use subscale. The BBT score was the significant predictor of an increased probability of achieving clinically important changes in the MAL quality of movement subscale (OR=1.07; P=.02). The R(2) values for the 3 logistic regression models were low (.114-.272). CONCLUSIONS The results revealed that patients with stroke who had greater manual dexterity measured by the BBT appear to have a higher probability of achieving clinically significant motor and functional outcomes after RT. Further studies are needed to evaluate other potential predictors to improve the models and validate the findings.

Decrease of hypertonia after continuous passive motion treatment in individuals with spinal cord injury

Objective: To examine the effect of ankle continuous passive motion on the reflex excitability and overall hypertonia of calf muscles in individuals with chronic spinal cord injury and without physical disabilities. Design: Two-way repeated measure experimental design. Setting: Inpatient rehabilitation department in general hospital. Subjects: The spinal cord injury group comprised eight individuals with chronic complete spinal cord injury and the control group comprised eight healthy people without physical disabilities. An additional eight healthy people were recruited as the sham group. Interventions: Each subject received 60 min of continuous passive motion on the ankle joint. Main measures: The H-reflex of the soleus muscle was elicited by tibia nerve stimulation just before, immediately after, and 10 min after continuous passive motion. The Modified Ashworth Scale (MAS) score at the ankle joint was recorded for the spinal cord injury group just before and 10 min after continuous passive motion therapy. Results. After 60 min of continuous passive motion of the ankle joint, the H-reflex amplitude at the soleus muscle was depressed in individuals with and without spinal cord injury (77.46 ± 32.64%, P = 0.047 and 51.76 ± 26.74% of initial, P<0.0001, respectively). This depression persisted up to 10 min after continuous passive motion only in individuals without spinal cord injury. In individuals with spinal cord injury, the median of MAS scores decreased from 2 to 1.25 after continuous passive motion. Conclusion: Sixty minutes of continuous passive motion of the ankle joint decreased reflex excitability and overall hypertonia in people with or without spinal cord injury. The depression of overall hypertonia persisted longer than the reflex excitability in people with spinal cord injury.

Effect of aerobic interval training on erythrocyte rheological and hemodynamic functions in heart failure patients with anemia

BACKGROUND Anemia disturbs hemorheological/hemodynamic properties, whereas aerobic interval training (AIT) achieves a superior aerobic fitness in patients with heart failure (HF). This study investigated whether AIT influences functional capacity by modulating hemorheological/hemodynamic functions in HF patients with/without anemia. METHODS Sixty HF patients were divided into non-anemic (HF-NA, hemoglobin >/= 12 g/dL in women/ >/= 13 g/dL in men; n=30) and anemic (HF-A, hemoglobin<11 g/dL in women/<12 g/dL in men; n=30) groups, and 30 normal counterparts were enrolled as a control group. These HF patients performed AIT (3-minute intervals at 40% and 80%VO(2peak)) on a bicycle ergometer for 30 min/day, 3 days/week for 12 weeks. Erythrocyte rheological and central/peripheral hemodynamic characteristics were determined by slit-flow ektacytometer and bioreactance-based device/near infrared spectrometer, respectively. RESULTS In both HF-NA and HF-A groups, the AIT regimen 1) reduced blood senescent/spherical erythrocyte counts, 2) diminished the values of critical shear stresses for disaggregation and half-maximal deformation of erythrocytes, 3) enhanced cardiac output during exercise, 4) heightened VO(2peak) and O2 uptake efficiency slope (OUES), and 5) decreased plasma myeloperoxidase and interleukin-6 levels. However, AIT increased the amounts of blood distributed to the frontal cerebral lobe and vastus lateralis muscle during exercise in HF-NA group but not in HF-A group. Additionally, HF-A group exhibited fewer the enhancements of VO(2peak) and OUES caused by AIT than HF-NA group did. CONCLUSION AIT improves aerobic capacity and efficiency by depressing aggregability and enhancing deformability of erythrocytes in patients with HF. However, anemic comorbidity attenuates the adaptations of cerebral/muscular hemodynamic responses to exercise following this regimen.

Increases of quadriceps inter-muscular cross-correlation and coherence during exhausting stepping exercise.

The aim of this study was to examine the change of the intermuscular cross-correlation and coherence of the rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL) during exhausting stepping exercise. Eleven healthy adults repeated the stepping exercise up to their individual endurance limits (RPE score reached 20), and the cross-correlation and coherence were assessed by surface electromyography (EMG) recordings. The coefficient and time lag of cross-correlation and the coherence areas in the alpha (8–12 Hz), beta (15–30 Hz), gamma (30–60 Hz) and high-gamma (60–150 Hz) bands among the three muscle pairs (RF-VM, RF-VL and VM-VL) were calculated. As muscle fatigue, RF-VM and VM-VL showed increases of coefficients and the shortening of time lags. RF-VM and RF-VL showed increases of beta-band coherence in the ascent and descent phases, respectively. The increased intermuscular cross-correlation and beta-band coherence may be a compensatory strategy for maintaining the coordination of knee synergistic muscles during fatigue due to the fatigue-related disturbance of the corticospinal transmission. Therefore, the intermuscular cross-correlation and beta-band coherence may be a potential index for assessing muscle fatigue and monitoring the central control of motor function during dynamic fatiguing exercise.

Bimanual gliding control for indoor power wheelchair driving

Power wheelchairs are essential for many individuals with mobility impairment. The objective of this study was to investigate the effectiveness of bimanual gliding (BG) and conventional joystick (CJ) control in an indoor environment, with application to (1) wheelchair driving performance (i.e., practice time, completion time, and driving deviation) and (2) muscle activity of the upper limbs. This study included 22 participants (11 experienced manual wheelchair users and 11 novice manual wheelchair users). Experienced wheelchair users who used the BG strategy needed less time to practice and complete the task. Muscle activity of the upper limbs was focused on the triceps brachii, with relatively less use of the wrist muscles while applying the BG strategy. In novice wheelchair users, wrist muscles were less involved when using the BG control compared with the CJ control. The findings imply that it is feasible to modify manual wheelchairs using BG and motors, which can serve as an alternative option for wheelchair users.

Deficits in sensory organization for postural stability in children with Tourette syndrome

Tourette syndrome (TS) is a childhood-onset developmental disorder characterized by involuntary motor and vocal tics. Previous studies have indicated that children with TS demonstrate postural control anomalies when standing. The aim of this study was to compare postural stability under normal and altered sensory conditions in children with TS and healthy control (HC) children. A convenience sample of twelve children with TS (9 boys and 3 girls; 9.4 ± 1.1 yr) and 12 HC age- and gender-matched children (9.2 ± 1.1 yr) participated in this study. The Sensory Organization Test (SOT) was used to assess postural stability under six altered sensory conditions (1. normal vision, fixed support; 2. eyes closed, fixed support; 3. vision sway-referenced, fixed support; 4. normal vision, support sway-referenced; 5. eyes closed, support surface sway-referenced; 6. both vision and support surface sway-referenced) using the SMART Balance Master® 8.2 (NeuroCom® International, Inc, Clackamas, OR, USA). The results showed significant differences between the two groups in conditions 5 and 6 (p=0.003 and 0.002, respectively). The mean composite equilibrium score in children with TS was significantly lower than that of HC children (p<0.000). The results suggested that children with TS had greater difficulty in maintaining postural stability, especially when vestibular information was challenged. The results of this study provide supporting evidence for possible deficits in impaired access to vestibular information and sensorimotor integration of postural control in children with TS.

Early and anticipatory postural adjustments in healthy subjects under stable and unstable sitting conditions

Clinicians frequently incorporate unstable sitting devices into training plans for improving proximal postural muscle control; however, the effect of unstable sitting conditions on postural adjustments during dynamic activities has not been fully explored. The aim of this study was to characterize early postural adjustments (EPAs) and anticipatory postural adjustments (APAs) under stable and unstable sitting conditions. Using a cross-sectional laboratory study design, 13 healthy college student volunteers used their dominant hand to reach forward and push a target under stable and unstable sitting conditions; subjects sat on an air-filled rubber cushion for the unstable condition. EPAs and APAs were quantified by recording muscle activation of the trunk and lower extremity muscles using electromyography (EMG). The center of pressure (COP) was measured using a force plate. The resulting EMG integral of the ipsilateral gastrocnemius muscle was larger during the EPA phase and smaller during the APA phase under unstable conditions (p = 0.014 and p = 0.041, respectively). COP amplitude in the anterior-posterior direction, path length, and velocity, was larger during the APA phase (p = 0.035, p = 0.023, and 0.023, respectively). This suggests greater distal muscle activation during EPAs in unstable sitting conditions, specifically in the ipsilateral gastrocnemius muscle. In addition, APAs adjusted by reducing the activity of the ipsilateral gastrocnemius muscle and increasing the anterior-posterior shift in the COP to compensate for the expected additional perturbation due to an unstable surface.

Postural alignment in children with bilateral spastic cerebral palsy using a bimanual interface for powered wheelchair control.

OBJECTIVE To examine postural alignment in children with bilateral spastic cerebral palsy while driving a powered wheelchair using both a unilateral joystick and an innovative bimanual interface. DESIGN Cross-sectional study. SUBJECTS A total of 20 children with bilateral spastic cerebral palsy (mean age 9.0 years (standard deviation 2.1); 11 with diplegia, 9 with quadriplegia) and 14 typically developing children (mean age 7.7 years (standard deviation 2.9)). METHODS All children drove the powered wheelchair in both the unilateral and bimanual conditions. The Seated Postural Control Measure quantified the postural alignment of subjects while driving the powered wheelchair. Statistical analysis was carried out using repeated measures analysis of variance and Spearmans rank correlation coefficient. RESULTS As expected, typically developing children had better postural alignment in both driving conditions than children with cerebral palsy. Children with cerebral palsy demonstrated more symmetrical postural alignment while using the bimanual interface than when using the unilateral joystick. In addition, the severity of cerebral palsy correlated moderately with postural symmetry in both conditions. CONCLUSION The results suggest that this innovative bimanual interface might be beneficial for promoting symmetrical postural alignment in some children with bilateral spastic cerebral palsy.