Unscheduled Telephone Calls to Measure Percent Syllables Stuttered During Clinical Trials

Abstract

Researchers have used unscheduled telephone calls for many years during clinical trials to measure adult stuttering severity before and after treatment. Because variability is a hallmark of stuttering severity with adults, it is questionable whether an unscheduled telephone call is truly representative of their everyday speech. The authors studied the speech of 9 men and 1 woman for a 12-hr day during different speaking activities. On that day and 1 week prior to that day, participants received an unscheduled 10-min telephone call from a person unknown to them. The authors compared the percent syllables stuttered (%SS) for the unscheduled telephone call on the day to the %SS of the unscheduled telephone call 1 week prior to the day and to the %SS during the entire day. No significant differences were found, and all confidence intervals with t tests included 0. The concordance correlation test also showed a strong positive correlation between %SS scores for the entire day and for the unscheduled 10-min telephone call. The authors conclude that there is no reason to doubt that 10-min unscheduled telephone calls are a representative speech sample for %SS during clinical trials of stuttering treatments.