Unlike clinical conditions, such as gait apraxia, which permanently affects ability to walk, few neurological disorders cause episodic gait dysfunction. Of these, FoG, mainly observed in parkinsonism, is the most frequent. Less-common disorders include psychogenic disorders, paroxysmal dyskinesias, and episodic ataxias. Episodic gait abnormalities induced by tics (e.g., tripping, “blocking” of gait, and hip movements) have been also reported. Our patient fulfilled criteria for diagnosis of TS. Phenomenological aspects of her gait dysfunction could resemble FoG, from which, however, differed for the absence of alternate trembling of the legs, increase in cadence with decrease in step length, and subjective feeling of feet being glued to the floor. On the contrary, she complained of an urge to stop. The need to move her legs as if to hit or move something with her foot could suggest an OCB. The interpretation of gait arrests as tics was based on the feeling of inner tension, consisting with a typical premonitory urge,[5, 6] that she experienced when she tried to suppress them, and the relief of this sensation after she stopped again, when gait arrests could manifest repeatedly in clusters. There were no features suggestive of alternative phenomenological diagnoses, such as psychogenic gait abnormality or stereotypies.
Notably, risperidone therapy (level of evidence A, according to European Society for the Study of Tourette syndrome [ESSTS] guidelines)was effective on all symptoms, including gait dysfunction.