Sensory experience as a trigger in Gilles de la Tourette's syndrome.

The case to be reported presented with multiple motor tics. During the course of therapy, directed along behavioural lines, a model of the nature of the movements emerged which was later found to be strikingly similar to that described by Bliss (1980). The patient (J) complained of a "horrible" sensation, similar to an "itch", which always preceded the tic movements and which could be removed by movement. Occasionally, by supreme effort, the "itch" would be resisted and movement avoided. These sensations could thus be viewed as a trigger for the movements. The implications of such an analysis for current conceptualisations of, and intervention with, motor tics are discussed.