A rating scale for Gilles de la Tourette's syndrome: description, reliability, and validity data.

We developed a rating scale for tic disorders that uses only objective criteria and accommodates the variety of tic manifestations. Using short videotaped recordings with the examiner out of the taping room, we measured five tic variables: number of body areas affected, frequency of motor tics and vocalizations, and severity of motor tics and vocalizations. The rating scale fulfilled tests for inter-rater reliability and temporal stability, and correlated well with scales used to assess global changes over prolonged periods. It objectively detected improvement in tics with neuroleptics, the one pharmacotherapy accepted to abate tics in most patients.