Introduction: Adolescent idiopathic scoliosis is characterized by a threedimensional deviation of the vertebral column and its etiopathogenesis is unknown. Various factors cause idiopathic scoliosis, and among these a prominent role has been attributed to the vestibular system. Various studies have proposed that alteration of the vestibular or reticular formation must be implied in the generation of spine curvature (e.g., Manzoni & Miele, 2002).
Objectives: The aim of this study is to determine whether asymmetrical activity of the vestibulospinal or the reticulospinal tracts is associated to idiopathic scoliosis and its severity.
Methods: In order to quantify the response of the vestibulospinal and reticulospinal tracts, we will employ the galvanic vestibular stimulation (GVS) technique (Lund & Broberg, 1983; Britton et al., 1993). In a standing position, galvanic vestibular stimulation elicits muscles responses by stimulating only the vestibular afferences. For instance, during GVS, Ardic et al. (2000) have observed modulation in the responses of the paraspinal muscles.
Expected Results: If our hypotheses are validated the idiopathic scoliosis patients with severe curvature will demonstrate asymmetrical vestibulomotor responses. For example, we expect to observe a smaller left paraspinal muscle inhibition and greater right paraspinal activation during galvanic vestibular stimulation with the anode on the left mastoid process compared with the anode on the right mastoid process (or vice versa).
Conclusion: These results would provide evidence that asymmetrical vestibulomotor responses can increase the likelihood of developing severe curvature.
Significance: Results could help in the decision-making process and identify the mechanisms related to curve progression.