Use of differential reinforcement of low rates of behavior to decrease repetitive speech in an autistic adolescent.

A differential reinforcement of low rates of behavior (DRL) schedule was successful in reducing repetitive speech in an autistic adolescent. Over a period of 18 months, the rate of repetitions was gradually reduced from a mean of 4.7 to less than 0.3 repetitions per min. Tokens were awarded for maintaining rates of repetitive speech below each of nine successive criterion levels. A reversal phase in which the token economy was no longer in effect resulted in a return to baseline repetition rates. Subsequent reintroduction of the contingencies saw a return to previous low levels of responding which were maintained at a 6-month and 14-month follow-up.