PROPRIO-OCULO-VESTIBULAR ABNORMALITIES IN SCOLIOSIS

Introduction The Proprio-oculo-vestibular system is involved in scoliosis. In Congress ZORAB, Oxford 2006, we showed correlations between morphological semicircular canals (SCC) anomalies and vestibular dysfunctions associated with oculomotor anomalies. We will describe a set of specific anomalies in adolescent idiopathic scoliosis (AIS) in favour of an altered perception of space. Methods The study included 95 patients with AIS: 57 had thoracolumbar scoliosis, 24 thoracic scoliosis, and 14 lumbar deformation. Patients were submitted to a set of tests: (1) three-dimensional vestibular evaluation with semicircular canal-specific horizontal and vertical stimulations; (2) measurement of the static ocular torsion; (3) ocular smooth pursuits analyses with a new automatised programme; and (4) posturographic recording (static and dynamic tests). The tests were done before and after treatment (vestibular training and oculomotor training). Results In AIS, the vestibular and oculomotor results highlighted lateralised signs following a specific pattern: in the case of a right thoracic and right thoracic/left lombar scoliosis we found a right head tilt (head to shoulder), a left horizontal vestibular predominance associated with a posterior vertical predominance, a pronounced exocylotorsion on left eye, and specific abnormal horizontal and vertical smooth pursuits. All these signs were not found in mirror in cases of inversed deformation nor in cases of lumbar scoliosis. Conclusions We propose that in some AIS, the proprio-oculo-vestibular system is altered and induces anomalies in space perception with consequences on the descending direct vestibulospinal output and consequences on the cognitive top-down influence. Our results suggest that the most common deformation (right thoracic/left lombar) is organised on a predeterminate brain level.