Anxiety affects vestibulospinal function of labyrinthine-defective patients during horizontal optokinetic stimulation

Comorbidity of vestibular and anxiety disorders wassuggested by epidemiological studies and, recently, newinsights into potential neural circuits which subserve bothbalance control and emotions, appear to support thishypothesis. In particular, disorienting visual surroundings,such as those generated by full-field moving scenes, equallydisrupt postural control of patients with vestibular or panicdisorders. In the present study, behaviour of body sway wasassessed in response to an optokinetic stimulation by meansof static posturography in 20 patients with vestibularneuritis (10 patients with normal affect and 10 with generalizedanxiety disorders, as diagnosed according to theAmerican Psychiatric Association criteria), and 20 normalsubjects who served as controls. Optokinetic responses andvestibulo-spinal function during a full-field, bi-directionalhorizontal optokinetic stimulation, were recorded simultaneously.Labyrinthine-defective patients with low and highlevel of anxiety showed a common pattern of asymmetricoptokinetic reflexes. On the contrary, body sway was foundto be increased more by eye closure and optokinetic stimulationtowards the defective labyrinth in patients affectedby high level of anxiety as compared to those with normalaffect and controls. These data confirm the combined effectof anxiety and labyrinthine dysfunction on vestibulo-spinalfunction which is disclosed by both visual suppression anddisorienting visual contexts.