The Grammar of the Tic in Gilles de La Tourette's Syndrome

Psychodynamic theorists would predict that the verbal tics characterizing Gilles de la Tourette's syndrome should exhibit primitive syntax but complex semantics, while neurological considerations lead to an opposite expectation. A phrase structure grammar describing the tics and finite state grammars describing both the tics and the strings of tics observed in a patient suffering from the disease are presented. Zero- and one-limited grammars fail to describe adequately both tics and tic strings. However, a two-limited finite state grammar is presented which successfully generates the tics. Tics seem to vary in form independently of lexical environment.