Verbal Contingencies in the Lidcombe Program: A Noninferiority Trial

Area of Science:

• Speech-Language Pathology
• Child Psychology
• Clinical Intervention Research

Background:

• The Lidcombe Program is a leading early stuttering intervention.
• Its effectiveness is attributed to parent verbal response contingent stimulation.
• This study aimed to isolate the effect of these specific verbal contingencies.

Purpose of the Study:

• To test the assumption that parent verbal response contingent stimulation is essential for the Lidcombe Program's efficacy.
• To determine if removing these specific verbal contingencies impacts treatment outcomes for early stuttering.

Main Methods:

• A parallel, open-label, noninferiority randomized controlled trial.
• Seventy-four children with early stuttering were randomized.
• The experimental group omitted the five Lidcombe Program verbal contingencies from parent instruction.

Main Results:

• Noninferiority for stuttering severity (percentage syllables stuttered) was inconclusive at 18 months.
• The primary outcome measure did not definitively show the intervention without verbal contingencies was worse.
• Overall outcomes appeared similar between the group receiving the full Lidcombe Program and the group with modified parent verbal responses.

Conclusions:

• The contribution of verbal contingencies to the Lidcombe Program's effect remains uncertain due to inconclusive noninferiority findings.
• Outcomes suggest that modified parent verbal responses may yield similar results to the standard Lidcombe Program.
• Further research is needed to clarify the role of specific verbal contingencies and inform clinical practice.