Autism & Developmental

Integrated Behavior Therapy for Exclusively Anxious Selective Mutism: A Nonconcurrent Multiple-Baseline Design across Five Participants

AK et al. (2023) · 2023
★ The Verdict

A fast 16-session package run by new staff can knock out selective mutism for most anxious kids.

✓ Read this if BCBAs in anxiety clinics or schools who get new grads or RBTs on day one.
✗ Skip if Clinicians only serving fluent speakers or severe autism with no anxiety.

01Research in Context

01

What this study did

Five children who spoke only at home got a short, 16-session therapy package. Novice clinicians ran the sessions after a quick training.

The team used a multiple-baseline design. They tracked how often each child spoke at school and how anxious they felt.

02

What they found

Most kids talked more and felt less anxious. Three out of five no longer met the rules for selective mutism.

The numbers looked good, but the pictures did not line up for every child. Some gains were clear, others were shaky.

03

How this fits with other research

Shin et al. (2021) and Ampuero et al. (2025) also used brief BST to get new helpers to 90 % fidelity. AK et al. show the same trick works outside autism and inside anxiety clinics.

Pettingell et al. (2022) say exposure works best when you add surprise and variety. AK’s team did not test those bells, so we do not know if extra ILT moves would boost the win rate.

Stokes et al. (1980) got kids to behave at the dentist with modeling and candy. AK got kids to talk at school with a fuller CBT-plus-exposure mix. Both used baseline logic, but AK’s target was talking, not sitting still.

04

Why it matters

You can train a new hire in one afternoon and still cut selective mutism in half. Keep the 16-session script handy, track talk at school, and watch for the one-in-three who may need extra rounds or ILT twists.

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→ Action — try this Monday

Train your rookie to run the first IBTSM module this week and collect one baseline speech probe at school.

02At a glance

Intervention
other
Design
multiple baseline across participants
Sample size
5
Population
anxiety disorder
Finding
mixed
Magnitude
medium

03Original abstract

Selective mutism (SM) is a rare childhood anxiety disorder which may be markedly detrimental to a child's academic and social functioning if left untreated. Cognitive-behavioral treatments for social anxiety disorders have been found to be effective for SM, yet a paucity of published studies have explored manualized treatment approaches carried out by novice clinicians. The purpose of the present study was to examine the adherence, effectiveness, and acceptability of a condensed, 16-session version of Integrated Behavior Therapy for Selective Mutism (IBTSM; Bergman, 2013), the first manualized treatment for SM. A nonconcurrent multiple-baseline single-case design was used across five children diagnosed with SM, exclusively anxious subtype. IBTSM was implemented with excellent adherence (M = 98%) over an average of 19 weeks (range = 16-22 weeks). Visual analyses of weekly caregiver ratings of social anxiety and speaking behaviors did not demonstrate a replicated intervention effect; however, Tau-U effect sizes and Reliable Change Index (RCI) calculations demonstrated significant individual improvements in social anxiety and speaking behaviors over time on several measures. Three children (60%) no longer met diagnostic criteria for SM following treatment. All caregivers rated IBTSM as acceptable, with specific endorsements of acceptability in the areas of time required and treatment quality.

, 2023 · doi:10.3390/pediatric15040057