Enhanced Physiological Awareness and Inhibitory Dysfunction in Tourette Syndrome

Background: Most individuals with Tourette syndrome (TS) report that their motor and phonic tics are commonly preceded by specific sensory phenomena. These premonitory sensations are likely to play a critical role not only in the subjective experience of TS, but also in the success of behavioral therapy for tics, which, in turn, may be related to inhibitory functioning. Objectives: In this study, we investigated whether TS is associated with broader alterations in the awareness of internal physiological sensations, and whether changes in physiological awareness may be linked to inhibitory dysfunction. Method: Awareness of bodily sensations and inhibitory functioning were investigated in 18 adult patients with “pure” TS (mild-to-moderate tic severity, no comorbid conditions) compared with 18 healthy controls. Relationships between the aforementioned factors, tic severity and awareness of premonitory sensations were also explored. Results: TS was associated with significantly higher scores on the Private Body Consciousness (PBC) scale and impaired performance on both traditional and emotional Stroop tests. Inhibitory functioning was negatively related to scores on both the PBC and Premonitory Urge for Tics Scale. Complex relationships were apparent between inhibitory functioning and tic severity. Conclusions: Patients with TS exhibit increased private body consciousness and deficits in the inhibition of neutral and affect-related stimuli. Furthermore, aspects of inhibitory functioning appear to relate to level of physiological awareness, the experience of premonitory sensations, and tic severity. These findings highlight complex interactions between neuropsychological and neurophysiological mechanisms in TS that could affect both tic severity and the success of behavioral treatments.