Turkish Version of the Stuttering Severity Instrument-Version 4 (SSI-4)

Objectives: The Stuttering Severity Instrument-4 (SSI-4) is a reliable and valid norm-referenced tool used to assess stuttering severity by comparing an individual's speech characteristics to a standardized sample. This study aimed to evaluate the validity and reliability of the SSI-4 for Turkish-speaking adults who stutter. The relationship between the frequency, duration, and physical concomitant behaviors in the SSI-4 and domains of Clinical Use of Self-Reports (CUSR) was also investigated. Materials and Methods: The study included 40 adults who stutter (M/F = 29/11; age range = 18–39, M = 25.8, SD =6). The Turkish translation of SSI-4 was administered to all participants, and the recordings were evaluated by three speech and language therapists. Reliability analysis comprised inter-rater reliability, intra-rater reliability, and test-retest reliability of the Clinical Use of Self-Report (CUSR). Additionally, the correlation between the CUSR and the three main parameters of the SSI-4 was calculated. Results: The SSI-4 demonstrated strong consistency with high inter-rater and intra-rater reliability coefficients (> .90) for the CUSR items. In addition, its test-retest reliability was also found to be high (> .90). However, no strong correlation was found between the CUSR and the SSI-4 parameters such as frequency, duration, and physical concomitants. Conclusion: The study confirms that the Turkish version of SSI-4 is a valid and reliable tool for assessing stuttering severity in Turkish-speaking adults.