Vestibulomotor coherence in adolescents with idiopathic scoliosis

Adolescence idiopathic scoliosis (AIS) is a 3D deformity of the spine that occurs during growth. It affects 2–3 % of adolescents, and the prevalence is ∼10 times higher in girls compared to boys. There is growing evidence that alteration in the processing of vestibular signals results in asymmetrical activity in the vestibulospinal pathway. Since the latest modulates back muscles activity, an asymmetrical functioning of the vestibulospinal pathway could be related to AIS. To assess the symmetry of the vestibular pathway, we calculated coherence between vestibular evoked activity and postural response. Nineteen adolescent girls (4 with AIS and 15 with no AIS) participated in this study. Participants received stochastic electrical vestibular stimulation (EVS; frequency spectrum: 0–25Hz, amplitude±3mA, DS5 stimulator, Digitimer Ltd) while standing upright on a force platform (model OPTIMA, Advanced Mechanical Technology, Inc.), arms alongside, eyes closed, and head immobilized ∼18° tilted upward (Laerdal Medical). Binaural or monaural (left and right) EVS induced changes in ground reaction forces along the anteroposterior (AP) and medio-lateral (ML) axis. Vestibulomotor coherence between EVS and ML or AP forces was calculated. Compared to controls, adolescents with AIS showed a greater asymmetry in vestibulomotor coherence along the ML axis when comparing right and left monaural EVS. Although the EVS should mainly evoke changes in ML axis, vestibulomotor coherence was observed between EVS and forces along the AP axis only in the AIS group. The results suggest An asymmetrical vestibulomotor transformation in the adolescents with idiopathic scoliosis is suggested.