Effect of Adding HUBER® 360 Feedback-Based Versus Home-Based Balance Training to Individualized Conservative Scoliosis Exercises on Postural Balance in Adolescent Idiopathic Scoliosis: A Prospective Randomized Controlled Trial With 12-Week Follow-Up
Effect of Adding HUBER® 360 Feedback-Based Versus Home-Based Balance Training to Individualized Conservative Scoliosis Exercises on Postural Balance in Adolescent Idiopathic Scoliosis: A Prospective Randomized Controlled Trial With 12-Week Follow-Up
Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis occurring during the growth period and is associated with significant alterations in postural balance compared with healthy peers. Prior research has shown that adding sensorimotor or balance-focused training to scoliosis-specific exercises may produce greater improvements in postural control and overall balance function than scoliosis-specific exercises alone. However, no study has previously investigated the effects of feedback-based balance training using a multi-axial platform with real-time biofeedback (the HUBER® 360 Evolution system) in this population.
The aim of this study is to evaluate the effect of adding HUBER® 360-based feedback balance training to individualized conservative scoliosis exercises on postural balance, postural symmetry, and health-related quality of life in adolescents with AIS.
The intervention protocol consists of 12 sessions delivered over 4 weeks, three sessions per week. Each session comprises 40 minutes of individualized conservative scoliosis exercises (identical between arms) followed by 30 minutes of balance training that differs between arms: HUBER® 360-based feedback balance training delivered in the clinic in the intervention arm, and a structured home-based balance exercise program performed independently after physiotherapist instruction in the active comparator arm.
Outcomes are assessed at three time points: T0 (baseline, week 0), T1 (immediately post-intervention, week 4), and T2 (12-week follow-up, week 16 from baseline). The primary outcome is the Stability Index measured by the TecnoBody ProKin stabilometric platform. Pre-specified key secondary outcomes include mediolateral standard deviation of the center of pressure, Romberg area ratio, Limits of Stability, the Scoliosis Research Society-22 Patient Questionnaire (SRS-22) total score, and single-leg stance time. Additional exploratory outcomes include further static, dynamic, and proprioceptive balance parameters from the TecnoBody ProKin platform; postural asymmetry parameters from the DIERS Formetric 4D rasterstereography system; and SRS-22 subdomain scores.
Background
Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity, with a global prevalence of approximately 1-3% in adolescents aged 10-18 years. AIS is associated with paraspinal proprioceptive impairment, altered sensory reweighting, and biomechanical asymmetry of the trunk, all of which can disturb static and dynamic postural control. Conservative scoliosis-specific exercises are recommended by the 2016 SOSORT (International Society on Scoliosis Orthopaedic and Rehabilitation Treatment) guidelines as the first-line conservative treatment for mild-to-moderate AIS curves.
Recent randomized trials have suggested that adding sensorimotor or balance-focused training to scoliosis-specific exercises produces greater improvements in postural control and trunk symmetry than scoliosis-specific exercises alone. However, conventional balance training relies on therapist-mediated external feedback and does not provide quantitative real-time information on postural sway or weight distribution. Motor learning research indicates that augmented (device-based) visual feedback accelerates motor control acquisition, particularly when intrinsic proprioceptive feedback is impaired. The HUBER® 360 Evolution (LPG Systems, Valence, France) is a multi-axial neuromuscular training platform with force sensors in its handles and an integrated screen that delivers real-time visual biofeedback on applied force and weight distribution. Although its clinical efficacy has been demonstrated in chronic non-specific low back pain and other musculoskeletal populations, its effect in AIS has not previously been investigated in a controlled study.
Study Design
This is a prospective, two-arm, parallel-group, randomized controlled trial conducted at a single tertiary rehabilitation center.The a priori sample size required to detect a Group × Time interaction in the primary outcome at α = 0.05 and 80% power was calculated using G*Power as 50 participants (25 per arm); 72 participants are enrolled to allow for attrition during follow-up.
Interventions
The intervention protocol consists of 12 clinic-based sessions delivered over 4 weeks, three sessions per week. Each session comprises 40 minutes of individualized conservative scoliosis exercises (identical between arms) followed by a 30-minute balance training component that differs between arms.
The individualized conservative scoliosis exercise program is informed by the general principles outlined in the 2016 SOSORT guidelines (three-dimensional auto-correction, adaptation to activities of daily living, stabilization of the corrected posture, and patient education) and is tailored to each patient based on curve pattern, apex location, and clinical examination findings. The program is delivered by physiotherapists experienced in scoliosis rehabilitation but who are not formally certified in any specific Physiotherapeutic Scoliosis-Specific Exercise (PSSE) school.
Intervention arm: 40 minutes of individualized conservative scoliosis exercises followed by 30 minutes of HUBER® 360-based feedback balance training, both delivered under physiotherapist supervision in the clinic.
Active comparator arm: 40 minutes of individualized conservative scoliosis exercises delivered in the clinic under physiotherapist supervision, plus a 30-minute structured home-based balance exercise program performed by the participant independently after detailed instruction by a physiotherapist. The home-based balance program is performed three times per week for 4 weeks (matching the frequency and total exposure of the intervention arm) and includes bilateral and unilateral stance exercises, balance tasks with eyes open and closed, exercises on different surfaces, and controlled weight-shifting tasks, organized according to a progressive difficulty principle. No device-based or real-time biofeedback is used.
Outcome Assessment
Outcomes are assessed at three pre-specified time points: T0 (baseline, week 0), T1 (immediately after the 4-week intervention, week 4), and T2 (12-week follow-up, week 16 from baseline). All assessments use validated, device-based, automated measurement systems where applicable, minimizing observer bias.
The primary outcome is the change in the Stability Index, a measure of overall postural control performance during a multi-axial dynamic balance task on the TecnoBody ProKin PK252 stabilometric platform (TecnoBody S.r.l., Dalmine, Italy), where lower values indicate better postural stability. This parameter is conceptually comparable to the Overall Stability Index (OSI) reported by the Biodex Balance System, which was used as the reference source for the a priori sample size calculation.
Pre-specified key secondary outcomes are: change in mediolateral standard deviation of the center of pressure; change in Romberg area ratio (eyes-closed to eyes-open sway area); change in Limits of Stability (LOS); change in the Scoliosis Research Society-22 Patient Questionnaire (SRS-22) total score; and change in single-leg stance time.
Pre-specified exploratory outcomes include the remaining TecnoBody ProKin static, dynamic, and proprioceptive parameters; postural and spinal alignment parameters measured by the DIERS Formetric 4D rasterstereographic surface topography system (DIERS International GmbH, Wiesbaden, Germany); and SRS-22 subdomain scores (function/activity, pain, self-image, mental health).
Inclusion Criteria:
Exclusion Criteria: