Have disfluency-type measures contributed to the understanding and treatment of developmental stuttering?

PURPOSE

This article critically reviews evidence to determine whether the use of disfluency typologies, such as syllable repetitions or prolongations, has assisted the understanding or treatment of developmental stuttering. Consideration is given to whether there is a need for a fundamental shift in the basis for constructing measures of stuttering behavior.

METHOD

The history of using specific types of disfluencies to assess stuttering, including more recent developments such as counts of stuttering-like disfluencies, is reviewed. The focus is on studies that have investigated the validity and reliability of these perceptually based assessment methods.

CONCLUSION

The evidence from use of disfluency-type measures shows that the behavioral difference between stuttering and normally fluent speakers is solely related to the amount of observable stuttering; the differences are only partially realized within disfluency-type measures. Indeed, because disfluency-type measures show poor reliability and conflate stuttered and nonstuttered speech, they have only limited heuristic value for research and provide no obvious benefits for clinicians. At best, they should be regarded as imprecise descriptors of observable stuttering and not a fundamental measure of stuttering. A recommended solution to the problematic history of verbal-based definitions of stuttering behavior is continued development and investigation of exemplar-based definition and measurement.