Protocol - Stuttering

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The Stuttering Severity Instrument–Fourth Edition (SSI-4) is an interviewer-administered test that records a sample of the respondent's speech. The Computerized Scoring of the Stuttering Severity (Version 2; CSSS-2.0) software is provided to facilitate the calculation of frequency and duration of stuttering dysfluencies. The software automatically produces a record of the percentage of syllables stuttered (frequency) and the duration of the three longest stuttering events.

Specific Instructions

The Stuttering Severity Instrument–Fourth Edition (SSI-4) is a proprietary protocol, and administration requires a licensing agreement from Pro-Ed. Researchers should complete and return an application to testquestion@pro-ed.com.

The Expert Review Panel recommends that the researcher develop a profile to capture the clinical characteristics of stuttering for each person.


Limited Availability


Summary of the Stuttering Severity Instrument–Fourth Edition

Respondents are asked to describe their job or school and read a short passage (or describe pictures if they cannot read). The examiner records the speech and scores the respondent on stuttering frequency, stuttering duration, and physical concomitants across four categories.

Scoring Instructions

Frequency is expressed in percentage of syllables stuttered and is converted to scale scores of 2–18. Duration is timed to the nearest tenth of a second and is converted to scale scores of 2–18. The four types of physical concomitants are scored and converted to scale scores of 0–20. A total score is obtained from the frequency and duration of stuttering dysfluencies, the score of physical concomitants, and the estimation of speech naturalness. This total score is ranked according to age-specific population norms and is used to assign a verbal descriptor of stuttering severity, ranging from very mild to very severe.

Stuttering Severity Instrument–Fourth Edition (SSI-4). Copyright © 2009 Pro-Ed, Incorporated. All Rights Reserved.

Personnel and Training Required

The Stuttering Severity Instrument–Fourth Edition (SSI-4) can be administered by trained research assistants. Examiners should have formal training in the ethical administration, scoring, and interpretation of clinical assessments. Additionally, investigators are encouraged to have quality control procedures in place to maintain consistency across examiners.

Equipment Needs

The interviewer will need a copy of the Stuttering Severity Instrument–Fourth Edition (SSI-4) test record and a frequency computation form as well as audio recording equipment to record the speech sample. The interviewer will also need the Computerized Scoring of Stuttering Severity (CSSS-2.0) software to score the recorded speech sample.

Requirement CategoryRequired
Major equipment No
Specialized training No
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual Yes
Mode of Administration

Interviewer-administered questionnaire


Child, Adolescent, Adult


Children, adolescents, and adults ages 2 years and older

Selection Rationale

The Stuttering Severity Instrument–Fourth Edition (SSI-4) was selected because it is a widely used, validated protocol that can be easily administered and includes normed data to assist scoring.


Chinese, English

Logical Observation Identifiers Names and Codes (LOINC) Stuttering proto 62996-4 LOINC
Human Phenotype Ontology Stuttering HP:0025268 HPO
Derived Variables


Process and Review

The Expert Review Panel #7 (ERP 7) reviewed the measures in the Speech and Hearing domain.

Guidance from ERP 7 includes the following:

  • Minor changes to Specific Instructions

Protocol Name from Source

The Stuttering Severity Instrument-Fourth Edition (SSI-4)


Riley, G. D. (2009). Stuttering Severity Instrument–Fourth Edition (SSI-4). Austin, TX: Pro-Ed, Inc.

The Stuttering Severity Instrument–Fourth Edition (SSI-4) is a proprietary instrument and can be obtained through:

Pro-Ed, Inc.
Attn: Customer Service

8700 Shoal Creek Boulevard
Austin, Texas 78757
Telephone: 800-897-3202
E-mail: info@proedinc.com

General References

Kang, C., Riazuddin, S., Mundorff, J., Krasnewich, D., Friedman, P., Mullikin, J. C., & Drayna, D. (2010). Mutations in the lysosomal enzyme-targeting pathway and persistent stuttering. New England Journal of Medicine, 362, 677–685.

Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX200901000000 Protocol 200901 - proprietary. Check DCW for more
contact. show less
Speech, Language and Hearing
Measure Name


Release Date

October 8, 2010


This measure assesses the severity of the respondent's stuttering.


This measure is used to quantify stuttering.


Stuttering, Stuttering Severity Instrument, SSI-4, recorded speech sample, speech and hearing

Measure Protocols
Protocol ID Protocol Name
200901 Stuttering

Rice, M.L. & Tager-Flusberg, H. (2016) Language Phenotypes. In V. Jagaroo and S.L. Santangelo (eds.) Neurophenotypes, Innovations in Cognitive Neuroscience. Springer. 2016 January; doi: 10.1007/978-1-4614-3846-5_12