Treatment of a vocal tic by differential reinforcement.

The purpose of this study was to investigate the effectiveness of differential reinforcement of the absence of a chronic vocal tic in a 9-year-old male. This procedure was used after problems in the application of a simplified habit reversal procedure were encountered, and when it became evident that a reinforcement procedure was more acceptable to the patient. Once differential reinforcement was implemented, a substantial decrease (to near zero frequency) in coughing and throat clearing resulted. The reduction of coughing and throat clearing was seen within and outside the treatment session. Treatment effects were maintained after fading the reinforcement and throughout posttreatment (50 weeks).