Alpermann, A., Huber, W., Natke, U., & Willmes, K. (2012) Construct validity of modified time-interval analysis in measuring stuttering and trained speaking patterns. Journal of Fluency Disorders, 37, 42-53.
Purpose: The aim of the present study was to examine the construct validity of modified time-interval analysis. This measure allows judgments on stuttered and fluent speech as well as trained speaking patterns and might be valuable for outcome studies.
Method: Construct validity was investigated in an intervention study with two treatment groups (24 clients received stuttering modification treatment, 30 clients received fluency modification treatment) and a control group (38 stuttering adults). All participants were interviewed during surprise phone calls before and after treatment; the speech samples were analyzed by means of modified time-interval analysis and stuttering frequency counts. Results: The outcomes confirmed prior hypotheses for the most part. First, the amount of trained speaking patterns after therapy was significantly higher in both treatment groups than in the control group. Secondly, longitudinal changes in the treatment groups met prior expectations based on differing treatment goals and exceeded the changes in the control group. Modified time-interval analysis was sufficiently sensitive to detect changes of speech fluency, but underestimated spontaneous fluent speech when trained speaking patterns were applied.
Conclusion: The present study supports construct validity of modified time-interval analysis in measuring stuttering and trained speaking patterns, but also reveals a lack of accuracy.