Sensory aspects of Tourette syndrome.

Motor and vocal tics have long been recognised as the core features of Tourette syndrome (TS). However, patients' first-person accounts have consistently reported that these involuntary motor manifestations have specific sensory correlates. These sensory symptoms are often described as feelings of mounting inner tension ("premonitory urges") and are transiently relieved by tic expression. Multimodal hypersensitivity to external stimuli, perceived as triggers and/or exacerbating factors for specific tic symptoms, is also commonly reported by patients with TS. This article focuses on the rapidly expanding literature on the clinical and neurobiological aspects of the premonitory urge and multimodal hypersensitivity in patients with TS, with particular attention to pathophysiological mechanisms and possible treatment implications. These findings suggest that TS is a neurobehavioural condition characterised by intrinsic perceptual abnormalities involving the insula and sensorimotor areas, in addition to basal ganglia dysfunction. Further research will clarify the role of sensory symptoms in TS, as well as the effects of external sensory input on underlying motor abnormalities