EMG Measurement of the fatigability of paraspinal muscles of patients with adolescent idiopathic scoliosis

• Author / Creator

  Richter, Alan D

• This thesis aimed to address two separate questions, 1) Are current exercise approaches to scoliosis based on a strong foundation in the literature? And 2) Do the paraspinal muscles of patients with adolescent idiopathic scoliosis (AIS) differ in endurance properties from controls? The first question was answered through a systematic review of the literature investigating functional muscle properties of the paraspinal muscles and reported a summary of findings as well as recommendations for future research. Results were reported according to 6 objectives: 1) To describe differences in paraspinal muscle functional properties in patients with AIS compared to healthy controls. 2) To describe differences in paraspinal muscle functional properties between concave and convex sides of spinal curvatures in patients with AIS compared to healthy controls. 3) To describe differences in paraspinal muscle functional properties within patients with AIS between concave/convex sides at the end vertebrae and apical vertebra of the spinal curves. 4) To describe differences in paraspinal muscle properties in patients with AIS with different curve types. 5) To describe the correlation between paraspinal muscle properties of patients with AIS with different curve characteristics (Cobb angle, apical translation, and progression). 6) To determine the ability of paraspinal muscle properties to predict curve progression in patients with AIS. The systematic review demonstrated a large amount of variation in methodology and heterogeneity in all outcomes. Some limited evidence supported findings, such as higher activity on the convex side of the curve, overall weakness in patients with scoliosis, and correlations between EMG activity at the lower end vertebrae and progression and prolonged latency and progression. However, due to poor reporting of methodology, small sample sizes, and heterogeneous samples, we concluded that not enough evidence exists to support many of the findings. Only one study was found on muscular endurance. We suggested ! ii! that future rigorous research should include sample sizes large enough to allow for sufficient power to detect differences, narrow ranges of Cobb angles, and have a sample size big enough to allow curve type subgroup comparisons. Based on this review, we concluded that while a number of exercise methodologies exist, these approaches are not yet based on a rationale related to knowledge of the muscle imbalances specific to idiopathic scoliosis. Exercise prescription may benefit from a stronger base of knowledge on muscle impairments in scoliosis. The second question was addressed through a matched case-control study. The endurance properties of the paraspinal muscles were compared between patients with AIS and controls. Subjects performed 6 side planks (3 on each side) as well as a Sorensen test. Subjects held each trial for as long as they could. EMG electrodes were placed at the apex, upper (UEV) and lower (LEV) end vertebrae, as well as, on the medial deltoid on each shoulder. Controls were matched for gender, age, BMI and EMG electrode placement sites. Groups were compared based on their task length as well as the slope of the median frequency of the EMG signal. No significant interactions involving groups were found, however, both groups performed better on convex (mostly right) sided planks than left sided planks. For the side planks, more fatigability was observed using EMG in the control group suggesting a possible difference in muscle activation strategy in patients with scoliosis. Only 14 subjects were tested for the Sorensen task and no group interactions were significant. Significantly more fatigue was noted at the LEV than at the UEV in both groups during the Sorensen test and at the UEV during side planks. This pilot study did not identify significant differences in endurance properties between the scoliosis and control groups. This inability to detect some possibly clinically important differences (effect sizes >0.4- 0.66) is partly due to a small sample size, as well as heterogeneity of curve types and severities in our sample. However, this study provides pilot data to guide future research in terms of task ! iii! selection, sample size estimation, and subject recruitment. This thesis demonstrates that more research is needed on paraspinal muscle impairments in patients with scoliosis to confirm the limited evidence of an association between such impairments and risk of progression.

• Subjects / Keywords

  • Paraspinal
  • Fatigability
  • EMG
  • Scoliosis
  • Muscle Properties

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3DN4018Z

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.