Changes in linguistic variables during operant, laboratory control of stuttering in children

Response contingent stimulation (RCS) is known to reduce stuttering in many cases. Time-out (TO) from speaking after stuttering is a particularly effe ctive form of RCS. However, the mechanism underlying the TO effect is unkno wn. The demonstrated value of operant methods in the clinical control of st uttering in young children warrants renewed interest in exploring why pausi ng for a short time after stuttering would reduce the frequency of stutteri ng. In this study, selected linguistic measures were made for two school-ag e boys whose stuttering reduced during TO in a laboratory study. One boy sh owed a clear reduction in verbal output, accompanied by a reduction in lexi cal diversity, but the other boy showed no changes in linguistic measures. This finding is of interest because, in a previous acoustic analysis of the same speech samples, the first boy showed no changes in acoustic speech me asures of duration while the second boy did show changes in acoustic speech measures of duration. This raises the possibility that people who stutter may change their verbal output in response to TO, but in different ways. Al though the present data do not establish a causal relationship between alte rations in verbal output and reductions in stuttering, they raise the need for further research that might explain why TO might control stuttering.