A perception bias of the gravitational vertical is confirmed in Adolescent Idiopathic Scoliosis.

Purpose Adolescent Idiopathic Scoliosis (AIS) is the most frequent spine deformity in adolescence. The cause of AIS remains unknown. Several studies show that AIS can be associated with a perception bias of gravitational vertical. In particularly, AIS patients with a right thoracic convexity exhibit deviation of the Subjective Postural Vertical. The origin of this disturbance could be located in trunk proprioceptive graciveptors. We wanted to verify this result with a population of lumbar and thoracolumbar AIS with left convexity. Methods It was a multicenter, cross-sectional case-control study. Thirty adolescents with left lumbar or thoraco-lumbar AIS (age 14.3 ± 1.7 years; Cobb angle 27.6° ± 6.1°) and 30 controls matched for age (14.0 ± 1.5 years), were compared for Subjective Visual Vertical (SVV) measured in static and dynamic (optokinetic stimulation) conditions, and Subjective Postural Vertical (SPV). Results For SVV, there was no difference in the two groups, for static and dynamic conditions. The SPV was significantly different between the two groups (p Conclusion Our study confirms a significant directional bias in the orientation of SPV in left lumbar or thoraco-lumbar AIS. This confirmation paves the way to a new physiopathological model focused on trunk proprioception. Level of evidence III.