Reduced Sensory Attenuation Scales with Tic Severity in Tourette Syndrome

Patients with Tourette syndrome (TS) often describe tics as reactions to uncomfortable somatic sensations (premonitory urges), suggesting a breakdown in how the brain filters internally generated sensory information. This filtering capacity is indexed by sensory attenuation (SA), a mechanism relying on sensorimotor predictions to dampen the perceived intensity of self-produced inputs. However, objective behavioral evidence of such impairment in TS remains lacking.

The aims were to determine whether patients with TS exhibit reduced SA and to evaluate whether the magnitude of this impairment correlates with the severity of the symptoms related to the syndrome.

Thirty adults with TS and 30 healthy controls performed a force-matching task. Participants reproduced a target force in a direct condition (directly with their finger) and in an indirect condition (controlling force via a button). TS patients underwent a comprehensive clinical assessment, including the Yale Global Tic Severity Scale (YGTSS).

Compared with controls, patients with TS exhibited reduced SA, evidenced by lower force overestimation during direct force reproduction, whereas no group differences were observed in the indirect condition. This reduction was associated with greater tic severity and accounted for additional variance in YGTSS total tic scores beyond medication load, obsessive-compulsive symptoms, and premonitory urge severity.

These findings provide the first direct behavioral evidence of reduced SA in adults with TS. The observed association with tic severity suggests that SA may represent a clinically relevant behavioral marker of altered sensorimotor predictive processing in TS. © 2026 International Parkinson and Movement Disorder Society.