Otolith dysfunction as a possible cause for the development of idiopathic scoliosis

BACKGROUND: To investigate whether otolith system, as a major contributor to muscles for postural control, might play a role in the pathogenesis of idiopathic scoliosis (IS). METHODS: Cervical vestibular-evoked myogenic potentials (VEMP) testing was applied to investigate the otolith function in patients with IS. Twenty-nine healthy patients (mean age 13.5±2.5 y, 4 males) were included. In all but 2 patients, the major curve deviation was to the right and the mean angle deviation was 49.7±21.6 degrees. Nineteen age-matched individuals (10 males) served as controls. RESULTS: The P13 (first positive wave) latencies were comparable in both groups. Patients with IS had significantly longer N23 (first negative wave) latencies than controls. A high correlation between the age and N23 latencies on the right was found in IS patients. A link between the scoliosis angle and VEMP latencies could not be demonstrated.The VEMP amplitudes were higher in patients than in controls, whereas the amplitude asymmetry ratio was similar in both groups. CONCLUSIONS: This work brings further evidence for vestibular abnormalities in patients with IS. Prospective studies are needed to elucidate a possible causative relationship between otolith dysfunction and the development of scoliosis. LEVEL OF EVIDENCE: III.