Investigating the Effectiveness of adding Transcranial Direct Current Stimulation (tDCS) to the Camperdown program on the Stuttering Severity index in Adults with Stuttering: A Randomized Double-Blind Clinical Trial
Objectives: The aim of this study is to investigate the effectiveness of tDCS stimulation along with conventional speech therapy in reducing the severity of stuttering in adults.
Design
The study is designed as a randomized clinical trial.
Settings and conduct
60 adults with stuttering from Golestan Hospital in Ahvaz will be randomly divided into two intervention and control groups. Both groups will be given conventional speech therapy, but the intervention group will also be given electrical stimulation with tDCS.In the control group, tDCS is provided in a sham and silent form. The duration of the intervention period is 8 sessions and a one-month follow-up period is considered for treatment follow-up.
Participants/Inclusion and exclusion criteria
Study inclusion and exclusion criteria: Adults with stuttering, age range 18 to 50 years, no metallic objects or abnormalities in the skull, Unwillingness to continue participating in the research.
Intervention groups
Intervention group: 30 adults with stuttering receiving speech therapy plus tDCS electrical stimulation
Control group: 30 adults with stuttering receiving speech therapy without tDCS electrical stimulation (sham tDCS)
Main outcome variables
Main outcomes: stuttering severity and stuttering-related quality of life.
General information
Reason for update
Acronym
IRCT registration information
IRCT registration number:IRCT20110928007657N5
Registration date:2026-03-17, 1404/12/26
Registration timing:prospective
Last update:2026-03-17, 1404/12/26
Update count:0
Registration date
2026-03-17, 1404/12/26
Registrant information
Name
Peyman Zamani
Name of organization / entity
Ahvaz Jundishapur University of Medical Sciences
Country
Iran (Islamic Republic of)
Phone
+98 61 3322 1002
Email address
zamanip@ajums.ac.ir
Recruitment status
recruiting
Funding source
Expected recruitment start date
2026-03-21, 1405/01/01
Expected recruitment end date
2026-09-21, 1405/06/30
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
Investigating the Effectiveness of adding Transcranial Direct Current Stimulation (tDCS) to the Camperdown program on the Stuttering Severity index in Adults with Stuttering: A Randomized Double-Blind Clinical Trial
Public title
Effectiveness of adding Transcranial Direct Current Stimulation (tDCS) to the Camperdown program on the Stuttering Severity index in Adults
Purpose
Treatment
Inclusion/Exclusion criteria
Inclusion criteria:
Having developmental stuttering
Having moderate to severe stuttering
being Right-handed
being Farsi-language
Not receiving stuttering-related treatment in the past month prior to the start of the intervention
Exclusion criteria:
Having skin lesions or bone defects in the skull area
Presence of other speech disorders with stuttering
Taking brain-stimulating drugs
Having metal implants in the skull
Age
From 18 years old to 50 years old
Gender
Both
Phase
N/A
Groups that have been masked
Participant
Outcome assessor
Data analyser
Sample size
Target sample size:
40
Randomization (investigator's opinion)
Randomized
Randomization description
Simple Randomized-block design
Randomization will be performed by using Randomized-block design method through WINPEPI software as well as applying 4-block for each group. This software create a sequence of random numbers that is used to assign participants to one of the groups. The person who is responsible to make a random list will be blinded to participants.
Blinding (investigator's opinion)
Double blinded
Blinding description
Blinding of participants is done using a sham method.
Assessor blinding: The assessor is unfamiliar with the name, gender, and grouping of the study subjects.
Blinding of the data analyst: The assessor is unfamiliar with the name, gender, and grouping of the study subjects.
Placebo
Not used
Assignment
Parallel
Other design features
Secondary Ids
empty
Ethics committees
1
Ethics committee
Name of ethics committee
Ethics committee of Ahvaz Jundishapur University of Medical Sciences
Street address
Golestan Ave., Golestan Hospital., School of Rehabilitation, Speech Therapy Department.
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Approval date
2025-12-06, 1404/09/15
Ethics committee reference number
IR.AJUMS.REC.1404.491
Health conditions studied
1
Description of health condition studied
Stuttering
ICD-10 code
ICD-10 code description
لکنت
Primary outcomes
1
Description
Stuttering Severity
Timepoint
Before of intervention, After intervention, one month for follow up
Method of measurement
Questionnary of Stuttering Severity Scale
2
Description
Quality of Life
Timepoint
Before of intervention, After intervention, one month for follow up
Method of measurement
Overall Assessment of the Speakers Experiences of Stuttering
Secondary outcomes
empty
Intervention groups
1
Description
Intervention group:Electrical stimulation is provided using the Segal Stim AT-12 device from Pharmed Tajhiz Company, in tDCS mode. An electroencephalography cap will be used to identify the location of the stimulation, so the brain areas are designated on it with the international 10-20 system. Stimulation is performed by passing a current of 2 mA and a resolution of 0.1 mA between two 5 cm x 7 cm electrodes for 20 minutes.Simultaneously with the device's stimulation, a speech therapy program is presented at a slow and drawn-out pace.
Category
Treatment - Devices
2
Description
Control group: In the control group, the device's electrical current will increase to 2 mA for 15 seconds and then immediately turn off. Simultaneously with the device's stimulation, a speech therapy program is presented at a slow and drawn-out pace.
Category
Treatment - Devices
Recruitment centers
1
Recruitment center
Name of recruitment center
Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences
Full name of responsible person
Peyman Zamani
Street address
Golestan Ave., Golestan Hos., Ahvaz Jundishapur University of Medical Siences, School of Rehabilitation, Speech Therapy Department.
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Phone
+98 61 3322 1002
Email
zamanipdrst@gmail.com
Sponsors / Funding sources
1
Sponsor
Name of organization / entity
Ahvaz University of Medical Sciences
Full name of responsible person
Dr. Abdollah Rafiei
Street address
Golestan Blvd., Ahvaz Jundishapur University of Medical Sciences, School of rehabilitation.
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Phone
+98 61 3374 3701
Email
zamanip@ajums.ac.ir
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
Yes
Title of funding source
Ahvaz University of Medical Sciences
Proportion provided by this source
100
Public or private sector
Public
Domestic or foreign origin
Domestic
Category of foreign source of funding
empty
Country of origin
Type of organization providing the funding
Academic
Person responsible for general inquiries
Contact
Name of organization / entity
Ahvaz University of Medical Sciences
Full name of responsible person
Peyman Zamani
Position
Associate professor
Latest degree
Ph.D.
Other areas of specialty/work
Speech therapy
Street address
Golestan Blvd., Golestan Hos., School of Rehabilitation, Speech Therapy Department.
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Phone
009833743105
Email
zamanipdrst@gmail.com
Person responsible for scientific inquiries
Contact
Name of organization / entity
Ahvaz University of Medical Sciences
Full name of responsible person
Peyman Zamani
Position
Associate professor
Latest degree
Ph.D.
Other areas of specialty/work
Speech therapy
Street address
Golestan Blvd., Golestan Hos., School of Rehabilitation, Speech Therapy Department
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Phone
009833743105
Email
zamanip@ajums.ac.ir
Person responsible for updating data
Contact
Name of organization / entity
Ahvaz University of Medical Sciences
Full name of responsible person
Peyman Zamani
Position
Associate professor
Latest degree
Ph.D.
Other areas of specialty/work
Speech therapy
Street address
Golestan Blvd., Golestan Hos., School of Rehabilitation, Speech Therapy Department
City
Ahvaz
Province
Khouzestan
Postal code
6135733133
Phone
009833743105
Email
zamanipdrst@gmail.com
Sharing plan
Deidentified Individual Participant Data Set (IPD)
Yes - There is a plan to make this available
Study Protocol
Yes - There is a plan to make this available
Statistical Analysis Plan
Yes - There is a plan to make this available
Informed Consent Form
Yes - There is a plan to make this available
Clinical Study Report
Yes - There is a plan to make this available
Analytic Code
Not applicable
Data Dictionary
Not applicable
Title and more details about the data/document
Publishing an article, participating in a speech therapy scientific conference
When the data will become available and for how long
Access period starts 12 months after results are published.
To whom data/document is available
The data will be available to researchers working in academic and scientific institutions.
Under which criteria data/document could be used
-
From where data/document is obtainable
Peyman Zamani 09166176780
What processes are involved for a request to access data/document