Determining the reliability of the Persian version of stuttering severity instrument-fourth edition for adults

Stuttering Severity Instrument-Fourth Edition (named hereafter SSI-4) is one of the most wildly recognized and reliable measures of stuttering severities to date. This instrument has been used for describing some aspects of stuttering and also for measuring treatment outcomes. Considering the importance of outcome measurement in evidence- based practice and the paucity of reliable instruments to make such estimates in Iran، it was decided to determine the reliability of SSI-4 through this study.

After being translated in to Persian according to IQOLA protocol، the reliability of instrument was evaluated in a sample of 35 adults who stutter. 5 experienced raters scored each subject''s stuttering severity using SSI-4.

Inter- and intra-rater reliability was determined using Cronbach''s alpha coefficient، Intra-class correlation coefficient (ICC)، and one way ANOVA. ICC values ranged from 0. 93 to 0. 98 for inter-rater reliability and from 0. 85 to 0. 98 for intra-rater reliability. One way ANOVA with repeated measures did not provide any evidence of mean difference between the severity scores obtained from weekly assessments.

Regarding to the high reliability of SSI-4 reported in this study، it can be concluded that the Persian version of SSI-4 is an appropriate instrument for evaluating stuttering severity in adults who stutter. However، the point that has to be made here is that SSI-4 address only one aspect of stuttering، namely its severity، and cannot cover all complicacies of the disorder.