200 Section - Brain–Muscle Activation Coupling During Self-Correction in Adolescents with Idiopathic Scoliosis Under Dual-Task Conditions

Objectives : We investigated how adolescents with idiopathic scoliosis (AIS) engage prefrontal cortical networks and coordinate trunk musculature when actively correcting their posture while simultaneously performing a cognitive task. A key aim was to determine whether these neuromotor control patterns differ between the two most common 3D curve classifications: Rigo type A (single curve) and type B (double curve).

Design: In this cross-sectional study, 30 AIS patients (15 Rigo A, 15 Rigo B) and 22 matched healthy controls performed postural tasks (habitual vs. corrected sitting/standing) under single- and dual-task conditions (Stroop test). We used fNIRS to quantify prefrontal cortex hemodynamics and high-density surface EMG to assess activation of paraspinal and abdominal muscles. Asymmetry indices (convex/concave RMS ratios) and cortical beta values were compared across groups and conditions, and their correlations were examined.

Results: Under dual-task load, both AIS subtypes showed increased compensatory muscle activity in the lower back and lateral trunk compared to controls. However, their cortical-motor strategies diverged: Rigo A patients exhibited suppressed frontopolar activity alongside elevated muscle co-contraction during corrected postures. In contrast, Rigo B patients demonstrated reduced prefrontal recruitment when maintaining a corrected stance, suggesting a more automated postural mode, yet preserved the ability to modulate cortical activity in response to varying cognitive demands. Correlation analyses revealed stronger and more disorganized brain-muscle coupling in Rigo A than in Rigo B.

Conclusion: Our findings demonstrate distinct cortical and muscular control phenotypes in AIS during cognitively loaded postural correction. Rigo A individuals appear to adopt a less efficient, high-cost compensatory strategy, while Rigo B individuals may possess a greater capacity for adaptive neuromuscular optimization. This suggests that rehabilitative dual-task training in AIS should be personalized according to curve-specific control deficits.