Axial tics in Tourette syndrome and chronic tic disorders

BackgroundTics are the hallmark of Tourette syndrome (TS) and chronic tic disorders (CTD). Although typically involving the face, especially at onset, tics may involve any muscle under voluntary control, including axial muscles of the neck (causing head movements), shoulders and trunk (thorax and abdomen). We aimed to characterize these tics and provide a clinical frame for their associations and complications. Materials and methods We reviewed video recordings and clinical history of 196 patients with TS or CTD according to DSM-5. Results Any axial tic was identified in 75% of patients. Tic distribution were head (n = 113, 57.6%), shoulder (n = 91, 46.4%), and trunk (n = 63, 32.2%). There were no differences in sex, age at onset or at evaluation between patients with and without axial tics. The most common axial tics by anatomical distribution were head turning, bilateral synchronous shoulder elevation and trunk jerks; however, tic phenomenology was quite variable. A greater severity of tics (P = 0.018) was associated with axial tics in the multivariate regression analysis. Head/neck tics associated with simple phonic tics (P = 0.002); whereas shoulder and trunk tics associated with complex motor tics (P < 0.05) in a bivariate analysis. Neck pain, breathing interference, sleep limitation and radiculopathy, secondary to axial tics were complications observed in a proportion of these cases. Conclusions Axial tics are commonly observed in patients with TS/CTD with variable phenomenology. They associate with greater tic severity, phonic tics and complex motor tics. They may result in neck pain, breathing interference, sleeping problems and cervical spine injuries.