Is abnormal vestibulomotor responses related to idiopathic scoliosis onset or severity?

Results from several studies have suggested that brainstem dysfunction occurs more often in adolescent with idiopathic scoliosis compared to healthy individuals. The vestibular nuclei occupy a prominent position in the brainstem. Because the lateral vestibulospinal tract controls axial muscles, alteration in the brainstem during body growth (i.e., preadolescent and adolescent period) may translate in abnormal trunk activation and thus cause permanent spinal deformities. We conceive that vestibular dysfunction may be observed only in AIS patients with severe spine deviation. Consequently, adolescent with severe idiopathic scoliosis (AIS) would exhibit abnormal vestibulomotor responses compared to healthy age-matched individuals and AIS patients with mild spine deformation. If this hypothesis is confirmed, it will suggest that abnormal vestibulomotor response may contribute to curve progression. On the other hand, if AIS patients with mild severity also show abnormal vestibulomotor response, it will indicate that impaired vestibulomotor may be related to scoliosis onset but is not necessarily related to curve progression. It is expected, however, that regardless of curve severity, not all patients would have abnormal vestibulomotor responses. For instance, in some cases, gene defects may lead to malformation of the semicircular canals or alteration of the vestibular cortical network and cause scoliosis or curve progression.