Association Between Postural Balance and Muscle Activity of the Lumbar and Lower Limb Muscles in Female With or Without Adolescent Idiopathic Scoliosis (AIS) During Standing Balance Tasks With Upper Limb Movement

Summary

Adolescent idiopathic scoliosis (AIS) is the most common type of three-dimensional deformity of the spine in adolescence with a clear female predominance at a prevalence rate of 3.5% in Hong Kong. AIS increases the risk of spinal degeneration, back pain, and cardiorespiratory dysfunction. These impairments caused by AIS can be related to the abnormal lateral deviation, axial rotation, and reduction of sagittal curves of the spine. AIS has been associated with asymmetrical muscle activity and impaired postural balance performance. AIS who had convex side of the major curves to the right demonstrated an increase in right side thoracic and lumbar erector spinae muscle activity during pelvic anterior, posterior, and left tilting on an unstable sitting board as measured by electromyography (EMG).

Postural balance is defined as the act of maintaining, achieving and restoring a state of balance during any posture or activity. The ability of maintaining postural balance in AIS is influenced by multiple factors including spinal deformities, asymmetrical muscle activities, alteration in sensory input, central integration or motor response. Previous studies have investigated the motor response in young adults. They were found to depend more on ankle strategy than hip strategy during a balance perturbation on a movable platform. Increased lateral gastrocnemius muscle activity was also observed when centre of gravity falls forward during an EMG measurement in quiet stance. In a study of low back pain patients, training regime involving single rapid arm movement in flexion and extension was found to promote the activation of the transversus abdominis muscle and improved the feedforward postural adjustment. There are limited studies to investigate the association between somatosensory input and motor response particularly lower limb muscle activity and upper limb movement on balance control in AIS. Recent evidence also suggested that AIS tend to overestimate the severity of their spinal deformity but their perception of their body schema and spinal curvature can be improved by enhancing motor skills. Therefore, training of postural balance that involved enhancing motor skills and stimulating somatosensory system will have the potential to improve motor response as well as improve self-perceived body schema in AIS.

Conditions

• Adolescent Idiopathic Scoliosis

Interventions

DIAGNOSTIC_TEST

Proprioceptive-stabilometric assessment machine (ProKin 252, TecnoBody®, Italy)

Proprioceptive-stabilometric assessment machine (ProKin 252, TecnoBody®, Italy) Balance performance of subjects will be tested on the proprioceptive-stabilometric assessment machine. Noraxon wireless TELEmyo Direct Transmission System (TELEmyo DTS) with product code of 580 (Noraxon, USA Inc., USA) The sampling frequency will be of 1000Hz and bandwidth of 10-500Hz. Bipolar silver chloride electrodes of 15mm diameter will be used for EMG signals collection, the interelectrode distance will be fixed at 20mm. Normalization procedure will be done by asking subjects to perform isometric maximum voluntary contractions (MVC). The MVC will be measured by Lafayette hand-held dynamometer connected to flat stirrup. MVC will be tested as listed below. The sEMG signals during each experiment will be normalized to the sEMG at isometric MVC and expressed as percentages of the maximum sEMG activity (%EMG\_max) for comparison with normalization signal processing program in Noraxon System.

Sponsors & Collaborators

• Tung Wah College

  lead OTHER

Eligibility

Min Age

10 Years

Max Age

16 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2021-10-15

Primary Completion

2021-12-31

Completion

2022-05-30

Countries

• Hong Kong

Study Locations