Balance deficit enhances anxiety and balance training decreases anxiety in vestibular mutant mice

Treatment of anxiety disorders by either pharmacological or behavioral means is applied with the intention to directly target the limbic system or high brain centers that down-regulate limbic activity. In spite of intense and long treatment, remission is not achieved in many patients, suggesting that their pathophysiology is not addressed by either of the above treatments. An alternative pathophysiology may be a disordered vestibular system, which may be studied in the context of comorbidity of balance and anxiety disorders. Here we studied whether mutant vestibular Headbanger (Hdb) mice demonstrate elevated anxiety and whether physical treatment of balance alleviates the behavioral symptoms of anxiety. Hdb and wildtype (Wt) mice were raised in either balance training or standard cages and were subjected repeatedly at 1-3 months of age to balance and anxiety-related tests. Results demonstrated progressive deterioration of balance performance and parallel elevation of anxiety in untrained Hdb as compared to untrained Wt mice. Training significantly improved balance performance of Hdb mice and in parallel, decreased the level of anxiety compared to untrained Hdb mice. These findings confirm that vestibular pathophysiology may be causally related to development of anxiety and suggest that in some clinical cases of anxiety, the appropriate treatment is physical rehabilitation of balance.