Investigation of Integrated Behavior Therapy for Selective Mutism: A Replicated Single-Case Study Design

  •  Allison Siroky    
  •  John Carlson    
  •  Aimee Kotrba    


Selective Mutism (SM) is a rare but potentially debilitating disorder characterized by a lack of speech in certain settings where speaking is expected. This study examined the effectiveness of a shortened version (12 sessions over 18 weeks) of Integrated Behavior Therapy for Selective Mutism (IBTSM; Bergman, 2013) in increasing speech and relieving anxiety for two four-year-old males with SM via a replicated single-case design. Treatment effectiveness, integrity, and acceptability were measured at baseline, throughout treatment, and at a three-month follow-up. Treatment integrity was excellent for both cases. SM severity ratings decreased from baseline to end-of-treatment, and again at follow-up, for each case. Verbal communication increased at end-of-treatment and follow-up, and significant decreases in social anxiety were seen across both cases by the three-month follow-up. Parents rated the shortened IBTSM as highly acceptable, effective, and efficient. Future studies should explore the effectiveness of varying lengths of IBTSM.

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