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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Investigating the Lidcombe Program of early stuttering intervention for preschool age children when parental verbal contingencies for fluent and stuttered moments are removed.
Scientific title
Is the Lidcombe Program of early stuttering intervention for preschool age children at least as effective and efficient as current practice when parental verbal contingencies for fluent and stuttered moments are removed?
Secondary ID [1] 281940 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Developmental stuttering in preschool children. 288344 0
Condition category
Condition code
Public Health 288697 288697 0 0
Health service research

Study type
Description of intervention(s) / exposure
The Lidcombe Program (LP) is currently the most efficacious treatment for the early intervention of stuttering. Components of LP as described in the treatment manual (Packman et al, 2011) consist of parent verbal contingencies (PVCs), measurement of stuttering, weekly visits with a speech pathologist, treatment in structured and unstructured conversations.

Despite being primarily described as an operant treatment, it is not known whether the operant verbal contingencies are the active agent in the program. During treatment, parents are taught how to provide verbal contingencies directly following stutter-free and stuttered speech. There are three contingencies for stutter-free speech: 1. Acknowledgement 2. Praise, and 3. Request for self-evaluation of stutter-free speech; and two contingencies for instances of stuttered speech: 1. Acknowledgement 2. Request for self-correction of the unambiguous stutter. In order to provide these responses successfully, the parent is taught by the clinician to provide PVCs in ‘structured’ tasks and ‘unstructured’ conversations. The parent is also taught how to rate the child’s stuttering severity, how to recognise types of stutters and given advice on how to alter treatment when necessary to maintain stutter-free speech as much as possible. Despite the proven efficacy of LP, little is known about which components are essential for the outcome. Initial critics of LP expressed concerns that PVCs may be harmful to the child, however these claims have since been disproven. The role of PVCs from the parent’s perspective has been investigated in many studies. While themes regarding the use of PVCs in these studies are generally positive, each study has revealed participants that have struggled with the use of PVCs. These studies show that some parents have difficulty delivering PVCs, and some children respond negatively to PVCs. Other smaller studies have displayed that children decreased stuttering whether or not the parent was taught to use PVCs (Harrison et al, 2004). In another preliminary study comparing LP with a Demands and Capacities approach (containing no direct contingencies for stuttering) nil difference was found between both groups after 12 weeks of therapy (Franken, Schalk & Boelens, 2005). Further, in a small study of three parent/child pairs, Carr-Swift et al (2011), showed that parent compliance with delivery of PVCs may not always reflect correct practice.

In the current study, the number, frequency and duration of clinic visits and intervention is not expected to be different across both treatment arms. Lidcombe Program clinic visits are usually between 45 and 60 minutes in duration. Investigators anticipate that while the removal of one component may reduce the duration of individual clinic visits, this will not be known until the study has reached completion. Determining the role of PVCs may help to reduce the load for parents in their delivery of the program and if PVCs are shown to slow progress, their removal may possibly make therapy more efficient and lead to better provision of services.

Provided participants meet criteria for the study and are able to commit to study protocols, children and their parents will be seen for treatment weekly until the child displays no stuttering or very little stuttering. This varies for every child and may be dependent on other factors such as the severity of the child's stutter. Once near normal fluency is achieved, there is a period of programmed maintenance of fluency, with a gradual reduction in clinic visits as required to maintain fluency for approximately one year. In this study, the final data point will be at 18 months after the first clinic visit. It is presumed that most children will have completed therapy at this time.
Intervention code [1] 286499 0
Treatment: Other
Comparator / control treatment
The Lidcombe program of early stuttering intervention.
Control group

Primary outcome [1] 288842 0
The first primary outcome measure will be
the mean percentage of syllables stuttered taken from two 10-minute audio recordings of the child talking in the home or other non-treatment environment.
Timepoint [1] 288842 0
Audio recordings will be taken at 4 data points:
1. Pre treatment
2. When the child is at near-zero levels of stuttering (Stage 2 of the Lidcombe Program)
3. 9 months post randomisation
4.18 months post randomization.
Secondary outcome [1] 301123 0
Parent reported Severity Ratings of the child’s typical and worst severity of stuttering for the week at each data point.
Timepoint [1] 301123 0
Data points will be at:
1. Pre treatment
2. When the child is at near-zero levels of stuttering (Stage 2 of the Lidcombe Program)
3. 9 months post randomisation
4.18 months post randomization.
Secondary outcome [2] 330483 0
The number of weeks and number of sessions to achieve near zero stuttering (Stage 2 of the Lidcombe Program).
Timepoint [2] 330483 0
This will be measured from the first therapy session, to the date at which each child has reached three weeks in a row of near-zero levels of stuttering.

Key inclusion criteria
1. Aged between 3 years old until 5 years, 11 months old.
2. Stuttering for longer than 6 months
3. Child stutters more than 2% syllables stuttered on pooled data from beyond clinic recordings
4. Able to attend clinic weekly
5. Functional English for both parent and child (i.e. child usually speaks English at home)
Minimum age
36 Months
Maximum age
72 Months
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Child has had stuttering therapy previously
2. Parent has implemented the Lidcombe Program with other sibling/s
3. Parental report, or clinician observation of child ADHD, intellectual disability, moderate to severe speech and/or language difficulties or any other complicating factor.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be selected on the basis of inclusion and exclusion criteria in order of entry to waiting lists at each of the four sites.
Participant allocation to either control or experimental groups will be by randomisation schedule provided by a statistician. Clinicians will request randomisation for each participant after assessment and before the first therapy visit, from a research assistant at the Australian Stuttering Research Centre.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Block randomisation, stratified to +/- 5% Syllables Stuttered
and clinician.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
One intervention group will receive a modified version of the Lidcombe Program of Early Stuttering Intervention whilst the control group receives the original version of the Lidcombe Program of Early Stuttering Intervention.
Phase 2
Type of endpoint(s)
Statistical methods / analysis
A non- intention to treat analyses (to avoid Type I error risk) with 2 sided 95% confidence interval, as recommended by Piaggio et al. (2006) as suitable for a non-inferiority design. For 80% power and 5% level of significance 82 children in total will be recruited to show non-inferiority to within 2 additional treatment sessions for the experimental group. These calculations were provided by a bio-statistician based on previous studies related to removal of verbal contingencies.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 6361 0
2141 - Lidcombe
Recruitment postcode(s) [2] 6362 0
2109 - Macquarie University
Recruitment postcode(s) [3] 6363 0
2132 - Croydon
Recruitment postcode(s) [4] 6364 0
3052 - Parkville

Funding & Sponsors
Funding source category [1] 286719 0
Government body
Name [1] 286719 0
Address [1] 286719 0
Level 1
16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 286719 0
Primary sponsor type
Australian Stuttering Research Centre, The University of Sydney
The Australian Stuttering Research Centre,
The University of Sydney, C42
PO Box 170, Lidcombe NSW 1825

Secondary sponsor category [1] 285543 0
Name [1] 285543 0
Murdoch Childrens Research Institute
Address [1] 285543 0
Flemington Road
Country [1] 285543 0
Secondary sponsor category [2] 285544 0
Name [2] 285544 0
Macquarie University
Address [2] 285544 0
The Macquarie University Speech and Hearing Clinic
The Australian Hearing Hub
University Avenue
Macquarie Park NSW 2113
Country [2] 285544 0

Ethics approval
Ethics application status
Ethics committee name [1] 288788 0
The University of Sydney Human Research Ethics Committee
Ethics committee address [1] 288788 0
Level 6, Jane Foss Russell Building - G02
The University of Sydney
Ethics committee country [1] 288788 0
Date submitted for ethics approval [1] 288788 0
Approval date [1] 288788 0
Ethics approval number [1] 288788 0
Ethics committee name [2] 288789 0
Macquarie University Ethics Review Committee (Human Research) (EC00124)
Ethics committee address [2] 288789 0
Macquarie University
Balaclava Rd,
North Ryde NSW 2109
Ethics committee country [2] 288789 0
Date submitted for ethics approval [2] 288789 0
Approval date [2] 288789 0
Ethics approval number [2] 288789 0
Ref: 5201200585 - External Approval
Ethics committee name [3] 288790 0
Royal Children's Hospital HREC
Ethics committee address [3] 288790 0
50 Flemington Road,
Melbourne VIC 3052
Ethics committee country [3] 288790 0
Date submitted for ethics approval [3] 288790 0
Approval date [3] 288790 0
Ethics approval number [3] 288790 0
Ethics committee name [4] 290152 0
RPAH Sydney Local Health District HREC
Ethics committee address [4] 290152 0
Research Development Office
Royal Prince Alfred Hospital
Missenden Road,
Camperdown, NSW 2050
Ethics committee country [4] 290152 0
Date submitted for ethics approval [4] 290152 0
Approval date [4] 290152 0
Ethics approval number [4] 290152 0

Brief summary
The study aims to develop and improve the Lidcombe Program, a treatment designed specifically for stuttering in preschool children. The aim of this project is to find out if all components of the Lidcombe Program are necessary to achieve stutter-free speech. We hope the information gained from this project will help speech pathologists provide improved treatment outcomes for children who stutter.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 37782 0
Prof Mark Onslow
Address 37782 0
Australian Stuttering Research Centre
Faculty of Health Sciences
The University of Sydney
PO Box 170
Lidcombe NSW 1825
Country 37782 0
Phone 37782 0
+61 2 9351 9061
Fax 37782 0
+61 2 9351 9392
Email 37782 0
Contact person for public queries
Name 37783 0
Mrs Michelle Donaghy
Address 37783 0
Australian Stuttering Research Centre
Faculty of Health Sciences
The University of Sydney
PO Box 170
Lidcombe NSW 1825
Country 37783 0
Phone 37783 0
+61 2 9351 9061
Fax 37783 0
+61 2 9351 9392
Email 37783 0
Contact person for scientific queries
Name 37784 0
Dr Susan O'Brian
Address 37784 0
Australian Stuttering Research Centre
Faculty of Health Sciences
The University of Sydney
PO Box 170
Lidcombe NSW 1825
Country 37784 0
Phone 37784 0
+61 2 9351 9061
Fax 37784 0
+61 2 9351 9392
Email 37784 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary