Sit-to-stand Training With Interactive Feedback in Chronic Stroke

Effects of Sit-to-stand Training With Interactive Feedback on Muscle Contraction Sequences and Weight Bearing Symmetry in Individuals With Chronic Stroke

The major problems of people with chronic stroke include muscle weakness, sensory alteration, and inter-muscular coordination impairment. Inter-muscular coordination impairment caused altered muscle contraction sequences and weight-bearing asymmetry during functional activities. Sit-to-stand (STS) training is often used to improve functional activities among post-stroke subjects. However, the improvement may come from compensatory movements. Using compensatory movement may cause muscle weakness in the affected side and increase fall risk. This study will develop a novel STS training system with interactive visual and audio feedback emphasizing weight transferring and weight bearing. The present study aims to investigate the effects of sit-to-stand training with interactive visual and audio feedback on muscle contraction sequences and weight bearing symmetry in individuals with chronic stroke.

This is a prospective randomized single-blinded controlled trial with pre- and post-measurements. 20 individuals will be recruited, and randomly assigned to experimental or control group. Statistical data analysis will be done by SPSS 24.0. Baseline characteristics will be analyzed using independent t-test or Chi-square test. Repeated measures two-way analysis of variance (ANOVA) with Tukey's post-hoc analysis will be used for time-by-group comparisons. The significant level is set at 0.05.

Interactive feedback, Muscle contraction sequence, Weight bearing symmetry, Sit-to-stand training, Chronic stroke

The interactive interface of visual and auditory feedback system was designed using LabVIEW and integrated force plates for training. Signals from the pressure detectors of the seat and two force plates on the floor will be converted to the indication of the body weight distribution (indicated by the size of the two circles of both legs, larger circle represented the more weight beard on the leg) and the movement path of the overall center of pressure (indicated by a mobile solid dot).

30 minutes per session, 3 sessions per week, for a total of 3 weeks. The visual and auditory feedback signals will be given throughout the sit-to-stand movement. As the size of circle representing the weight bearing gets more even, and the mobile dot indicating the overall center of pressure moves forward and approaches the midline, the auditory cues will get louder to indicate proximity to the target. It allows the participants to adjust and relearn the correct weight shifting and symmetry. The intensity will be adjusted based on different chair heights (e.g. 115%, 100%, 80% of lower leg length), various seat materials, and supported level of thigh (progressing from one-third of the length between the greater trochanter of the femur and the knee joint line to full support). The training program will be progressed according to the abilities of the participants.

30 minutes per session, 3 sessions per week, for a total of 3 weeks. All settings will be the same as the experimental group, except for the feedback. In the control group, the verbal cues will be given by the physical therapist and a mirror will be placed in front of the participant for visual feedback. During the sit-to-stand movement, participants will be asked to try to maintain the alignment in the midline.

Use the surface electromyography to evaluate the "onset" time (% MT, EMG activities ≥ 2 SD of the baseline for ≥100 ms) of different muscles recruited during sit to stand (rectus femoris, biceps femoris, gluteus maximus, tibialis anterior, gastrocnemius, and soleus)

Use the surface electromyography to evaluate the "peak force" time (% MT, maximal EMG activities) of different muscles recruited during sit to stand (rectus femoris, biceps femoris, gluteus maximus, tibialis anterior, gastrocnemius, and soleus)

Use the surface electromyography to evaluate the "offset" time (% MT, EMG activities < 2 SD of the baseline for ≥100 ms) of different muscles recruited during sit to stand (rectus femoris, biceps femoris, gluteus maximus, tibialis anterior, gastrocnemius, and soleus)

Use the force plates to evaluate the "cumulative vertical force " (% of body weight), and calculate with the "asymmetry ratio" = |1-affected side/less affected side|

Use the force plates to evaluate the total length (cm) of the moving pathway of the overall center of pressure in X or Y axis individually

Use the surface electromyography to evaluate the "movement time" (MT, sec), using the "offset time of the last activated muscle" - "onset time of the first activated muscle"

Use the GAITRite® system to evaluate gait speed (m/s) in comfortable speed (with/ without assisted device), and calculate with the "asymmetry ratio" = |1-affected side/less affected side|

Use the GAITRite® system to evaluate step length (m) in comfortable speed (with/ without assisted device), and calculate with the "asymmetry ratio" = |1-affected side/less affected side|

Use the GAITRite® system to evaluate step time (sec) in comfortable speed (with/ without assisted device), and calculate with the "asymmetry ratio" = |1-affected side/less affected side|

Inclusion Criteria: Diagnosis of stroke ≥ 6 months Mini-mental state examination (MMSE) ≥ 24 points Brunnstrom lower limb recovery stage: ≥ stage 3 Be able to independently perform STS for at least 10 times Single STS >1.7 seconds Be able to walk ≥10 meters independently Exclusion Criteria: Any other musculoskeletal, neurological and cardiovascular diseases Have visual or language impairments