Beyond tics: movement disorders in patients with Tourette syndrome

Tics are the hallmark of Tourette syndrome (TS). However, TS patients may have a particular vulnerability to develop other movement disorders (MDs), such as dystonia, chorea, stereotypy, and other hyperkinetic disorders that may be wrongly attributed to tics.

We studied a cohort of 201 patients with motor and phonic tics associated with TS to determine if they have additional, co-existent, MDs.

There were 67 (33.3%) patients with comorbid non-tic MDs. Phenomenology-wise, piano-playing movements resembling chorea or myoclonus, were the most common non-tic movement, observed in 11% of cases, followed by stereotypies (8.0%), tremor, dystonia and parkinsonism, 5.0% each. Drug-induced was the most common etiology (6.0%), followed by functional movement disorders (5.0%) and tardive phenomena (5.0%). No clear etiology was identified in most patients. Piano-playing movements, were associated with a younger age at onset (P = 0.004) and younger age at presentation (P < 0.001). Patients with drug-induced movements and tardive phenomena had a lower frequency of craniofacial tics. FMDs, and idiopathic MDS showed no specific associations with TS. Tic severity was not a predictor of any co-existent MD.

About a third of patients with TS present with comorbid MDs which should be differentiated and distinguished from tics as their etiopathogenesis and treatment may be different.