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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Neurogenic stuttering: Characteristics and treatment
Scientific title
Acquired stuttering following neurological conditions: Using etiology, speech characteristics and co-occurring disorders to tailor treatment approaches
Secondary ID [1] 304340 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Neurogenic stuttering 322099 0
Parkinson's disease 322743 0
Traumatic Brain Injury 322744 0
Stroke 322745 0
Condition category
Condition code
Neurological 320334 320334 0 0
Parkinson's disease
Injuries and Accidents 320335 320335 0 0
Other injuries and accidents
Stroke 320336 320336 0 0
Stroke 320337 320337 0 0

Study type
Description of intervention(s) / exposure
There are three parts to this study.
Part 1:
Part 1 is the behavioural characteristics part of the study. It focuses on gathering comprehensive case history and completing thorough assessment of speech and language. All participants will complete this part. By taking a full case-history, we will obtain information that supports us to understand how dysfluencies have developed in each participant. Neurogenic stuttering commonly co-occurs with other speech and language impairments such as dysarthria and aphasia. It is important to conduct thorough assessment to identify whether neurogenic stuttering is the only issue. In part 1, information will be gathered regarding how long the participant has had neurogenic stuttering for, and any treatments that have been attempted. This will provide information pertaining to changes in characteristics of their stuttering that have occurred without treatment. Case histories, review of health information and language and speech assessments will guide treatment decisions.
Language and speech assessment will include:
• assessment for dysarthria and apraxia including oral motor assessment and speech intelligibility assessment
• assessment for aphasia using the Comprehensive Aphasia Test (Swinburn et al., 2004)
• assessment of speech fluency using the SSI-4: Stuttering Severity Instrument – Fourth Edition (Riley, 2009) by collecting speech samples during different speech tasks including conversation, reading and monologue. Fluency-inducing techniques such as singing and rhythmic speech will be trialled during this assessment
• assessment of self-perceptions of individuals’ dysfluencies using the OASES: Overall Assessment of the Speaker’s Experience of Stuttering (Yaruss & Quesal, 2010)
• assessment of level of communicative participation using the CPIB: Communicative Participation Item Bank (Baylor et al., 2009)
We know that the behavioural characteristics that clients with neurogenic stuttering present with are highly variable. Therefore the population is very heterogeneous, and it is important to use participants as their own baseline control rather than comparing across participants in initial treatment studies. We will collect baseline data from each participant following the best practice multiple-baseline single-case methodology.
Two baseline sessions will be conducted two weeks apart during part 1. A third baseline will be taken after two weeks of intensive treatment during part 2 of the study. Analysis will compare the impact of stuttering on participants at baselines and following treatment via the OASES. CPIB will give a measure of the impact of therapy on communicative participation of the person with neurogenic stuttering in their life.
Part 2:
Those participants who have been identified during the behavioural characteristics part of the study as having acquired neurogenic stuttering and who wish to undergo speech therapy for their dysfluencies, will be given the opportunity to do so in part 2 of the study (the treatment phase). There is no previous research documenting, describing, and assessing speech language therapy treatment focusing on neurogenic stuttering. Part 2 of this study begins to rectify this lack of research.
Therapy will be based on the comprehensive stuttering programme. Fluency techniques including prolonged speech, pacing, and gentle onset will be trialled and a technique chosen to concentrate on based on effectiveness and participant preference. Therapy will be provided by qualified and experienced Speech Language Therapists or by Speech Language Therapy students. Any students engaged in providing therapy for this study will be supervised during their involvement. Therapy will be provided in face-to-face, individual sessions at the University of Canterbury Speech and Hearing Clinic.
Treatment will focus on reduction of severity and frequency of stutter-like dysfluencies (as measured with the SSI-4), as well as on minimising the impact of dysfluencies on communicative participation (as measured with the CPIB) and quality of life (as measured with the OASES).
Therapy sessions will be recorded audio visually, meaning they can be audited by an independent third party. If a participant prefers, recordings can be audio only. Recording of the sessions allows transcription of speech, identifying and recording non-verbal communication and conducting inter-rater reliability rating.
While individual circumstances will dictate the dosage of therapy, the aim will be to provide 20 sessions to each participant, in line with the evidence from studies on aphasia. Intensity of treatment will be dependent on factors such as fatigue and participant availability.
Ideally, therapy sessions will be offered as an intensive two-week block of ten sessions, followed by up to ten weekly follow-up sessions, but individual circumstances, including physical well-being and whanau support available dictate a need for flexibility. Each session will include discussion of communication achievements and obstacles faced, and establishment of a speech-fluency baseline in conversation and in other measures such as reading or sentence repetition. This will be followed by a period of practicing use of fluency-enhancing technique. Following completion of the treatment block, further long-term follow-up will be provided at six and 12 months.
Analysis will look at percentage of syllables stuttered at baseline (taken during part 1 of the study) and following treatment to establish effectiveness. Similarly during part 1, each participant will provide their own baseline for the impact stuttering has on them via the Overall Assessment of the Speaker’s Experience of Stuttering (OASES). By repeating this measure in part 2, following therapy, we will be able to see the impact of therapy on participation of the person with neurogenic stuttering in their life.
Adherence to intervention will be monitored through session attendance and discussion at each session about use of fluency techniques since the previous session.
Part 3:
Part 3 is the imaging phase. Eligible participants (those diagnosed with neurogenic stuttering) will be offered an opportunity to participate in part 3. This will involve undergoing brain scans to ascertain any neural correlates associated with onset of neurogenic stuttering at baseline, and any neuroplastic changes associated with therapy for acquired neurogenic stuttering for those participants completing part 2 of the study. This will include structural and functional scans, T1 weighted, T2 weighted, DTI and fMRI scans. Where brain scans have previously been conducted, this study will require participants wanting to take participate in part 3, to undergo a new brain scan pre-treatment. A brain scan will be conducted post-treatment, within one week of the end of the 12 week treatment period where possible. All brain scan results will be provided to participants’ usual doctor to form part of their clinical record. By conducting pre- and post-treatment scans on a subset of participants, we will gather information not only on the aetiology of neurogenic stuttering, but also on any changes that occur as a result of treatment.
All sessions, including treatment, assessment, and brain scan sessions, will be no more than one hour in length. Clinical judgement will be used to evaluate the appropriate intensity of sessions and frequency of breaks for individual participants.
Intervention code [1] 320693 0
Diagnosis / Prognosis
Intervention code [2] 320694 0
Treatment: Other
Comparator / control treatment
No control group - all participants will have a period of no treatment of approximately two weeks between first and second speech samples being obtained, prior to starting treatment.
Control group

Primary outcome [1] 327690 0
Changes to frequency of dysfluencies as measured by Stuttering Severity Index - Edition 4.
Timepoint [1] 327690 0
During 20th hour of therapy.
Primary outcome [2] 327691 0
Changes to the impact of dysfluencies on communicative participation as measured by the Communicative Participation Item Bank.
Timepoint [2] 327691 0
During 20th hour of therapy.
Primary outcome [3] 327692 0
Changes to quality of life as measured by the Overall Assessment of the Speaker's Experience of Stuttering.
Timepoint [3] 327692 0
During 20th hour of therapy.
Secondary outcome [1] 396243 0
Neuroplastic changes associated with therapy for neurogenic stuttering completed during part 2 identified through fMRI.
Timepoint [1] 396243 0
Within seven days of concluding 20 hours of therapy.

Key inclusion criteria
Diagnosis of neurological condition (e.g. Parkinson’s disease or Traumatic Brain Injury) and presenting with stuttering dysfluencies.
Ability to provide informed consent.
Ability to participate in assessment sessions, treatment sessions (if participant opts to undergo treatment), and undergo MRI scanning (if participant opts to participate in study arm 3).

Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Receiving other therapy for stuttering precludes from participation in arm 2 of the study.

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Because of the lack of previous research, and the therefore exploratory nature of this study, each individual participant will provide new information that is both clinically and scientifically useful. Due to the heterogeneity in conditions that lead to an onset of acquired stuttering, we aim to recruit a total of 50 participants to allow moving beyond single-case studies to group-level studies.

For each participant, baselines will be taken during arm 1. These baselines consist of calculations of percentage syllables stuttered (two baselines during arm 1), and scores on the OASES and CPIB. Further data on percentage syllables stuttered will be collected in each therapy session. OASES and CPIB will be re-administered at the completion of arm 2. For each participant, their scores will be compared across time to establish statistical significance (repeated measures design). Percentage syllables stuttered will be compared for each participant for clinical significance also. For previous dysfluency studies, clinical significance has been set at 1.5% syllables stuttered.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 23737 0
New Zealand
State/province [1] 23737 0

Funding & Sponsors
Funding source category [1] 308712 0
Name [1] 308712 0
University of Canterbury
Address [1] 308712 0
School of Psychology, Speech and Hearing
Arts Road
Christchurch 8041
Country [1] 308712 0
New Zealand
Primary sponsor type
University of Canterbury
20 Kirkwood Avenue
Upper Riccarton
Christchurch 8041
New Zealand
Secondary sponsor category [1] 309602 0
Name [1] 309602 0
Address [1] 309602 0
Country [1] 309602 0

Ethics approval
Ethics application status
Ethics committee name [1] 308636 0
Northern B Health and Disabilities Ethics Committees
Ethics committee address [1] 308636 0
Ministry of Health
Health and Disabilities Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 308636 0
New Zealand
Date submitted for ethics approval [1] 308636 0
Approval date [1] 308636 0
Ethics approval number [1] 308636 0

Brief summary
The hypotheses of this study are: In a group of people with acquired neurogenic stuttering with different underlying etiologies, speech characteristics and co-occuring disorders, is a treatment approach to their stuttering based on the comprehensive stuttering programme, more effective than no treatment? Does that treatment approach lead to neural changes identifiable on structural MRI scans and to normalising of functional brain activity during speech?

Norman et al. (2018), concluded that the clinical work field urgently needs guidance, support and evidence-based best practice in this area.

Part 1: Identifying characteristics of neurogenic stuttering and associated conditions following various neurological disorders will increase our understanding of the occurrence and presentation of neurogenic stuttering. This allows timely intervention to minimise the impact on communicative participation of such deficits.

Part 2: This study will contribute knowledge around effective treatments for neurogenic stuttering which are specific to presenting behavioural characteristics. This will provide an evidence base for clinicians working with this population, to assist them in selecting the most efficacious treatments. At this point in time there are no guide-lines or evidence-base for treatment of neurogenic stuttering. Health outcomes will be improved where clinicians have an accurate knowledge of the efficacious treatments and the potential for improvement. Part 2 will look at both effect of treatment on stuttering, and effect of treatment on the participant's experience of their stutter.

Part 3: This study will add to the knowledge-base of which parts of the brain can be involved in neurogenic stuttering. This will be achieved through analysis of medical records, and performing pre- and post-treatment MRI scans. Post-treatment scans will be analysed to establish the degree of neuroplasticity that may be present in this population.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 111386 0
Mrs Nicole Renaud
Address 111386 0
c/- University of Canterbury Speech-Language Neuroscience Lab
Private Bag 4800
Christchurch 8140
Country 111386 0
New Zealand
Phone 111386 0
+64 02041442741
Fax 111386 0
Email 111386 0
Contact person for public queries
Name 111387 0
Mrs Nicole Renaud
Address 111387 0
c/- University of Canterbury Speech-Language Neuroscience Lab
Private Bag 4800
Christchurch 8140
Country 111387 0
New Zealand
Phone 111387 0
+64 02041442741
Fax 111387 0
Email 111387 0
Contact person for scientific queries
Name 111388 0
Mrs Nicole Renaud
Address 111388 0
c/- University of Canterbury Speech-Language Neuroscience Lab
Private Bag 4800
Christchurch 8140
Country 111388 0
New Zealand
Phone 111388 0
+64 02041442741
Fax 111388 0
Email 111388 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
All individual participant data collected during the study, after de-identification
When will data be available (start and end dates)?
Immediately following publication for 10 years
Available to whom?
On a case-by-case basis at the discretion of the Primary Sponsor
Available for what types of analyses?
Any analyses
How or where can data be obtained?
Access subject to approval by Principle Investigator contactable at
What supporting documents are/will be available?
Study protocol
Statistical analysis plan
Clinical study report
Ethical approval
How or where can supporting documents be obtained?
Type [1] 11834 0
Study protocol
Citation [1] 11834 0
Link [1] 11834 0
Email [1] 11834 0
Other [1] 11834 0
Attachment [1] 11834 0
Type [2] 11835 0
Statistical analysis plan
Citation [2] 11835 0
Link [2] 11835 0
Email [2] 11835 0
Other [2] 11835 0
Attachment [2] 11835 0
Type [3] 11836 0
Clinical study report
Citation [3] 11836 0
Link [3] 11836 0
Email [3] 11836 0
Other [3] 11836 0
Attachment [3] 11836 0
Type [4] 11837 0
Ethical approval
Citation [4] 11837 0
Link [4] 11837 0
Email [4] 11837 0
Other [4] 11837 0
Attachment [4] 11837 0
Summary results
No Results