Stuttering, Developmental
Conditions
Keywords
transcranial direct current stimulation, MRI, Speech, fluency, tDCS
Brief summary
Research studies in stuttering have shown that activity patterns in certain brain areas differ in people who stutter compared to people who do not stutter when speaking. The purpose of this study is to investigate how mild, non-invasive brain stimulation applied consecutively for five days affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people who stutter.
Interventions
DEVICEAnodal tDCS
20 minutes of 2mA anodal stimulation.
BEHAVIORALFluency training
Speaking along with a metronome and/or speaking along with another person (choral speech) for 20 minutes
DEVICESham tDCS
For sham stimulation, current is ramped up and back down over 30 seconds.
Sponsors
University of Michigan
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
A researcher who is not involved in any aspect of the study will randomize participants into the sham and active study arms using a minimization procedure. Allocation concealment will be achieved by assigning a unique 6-digit random code per participant, which will be provided to the researcher. The code is used to deliver stimulation. The participants and the researchers who deliver stimulation, assess outcomes, and analyze data will be masked to trial arm.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* history of persistent developmental stuttering * stuttering severity ranging from mild to very severe, specifically Stuttering Severity Instrument (SSI) total score of 20 (mild) or higher and stuttering rates of 3% or higher * scores within 1 standard deviation of the norm on the standardized tests for the study
Exclusion criteria
* received any treatment for stuttering within the past year * other neurological conditions such as Tourette's syndrome or post-traumatic stress disorder * taking any medications/drugs that affect brain function * history of past or current mental illness for example, schizophrenia that may affect brain development and function * history of serious medical or neurological illness such as epilepsy and Parkinson's disease * history of closed head injury (e.g., concussion) * history of reading disorders * hearing loss * taking any medication, prescription or non-prescription with any psychotropic effects at the time of the study * metal or electronic implants such as cochlear implants, and pacemakers
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in Brain Activation as Assessed by fMRI Images | Baseline, 1 week (post), 4 weeks (follow up) | Investigators will use the fMRI images taken from before and after tDCS to determine if the treatment intervention contributed to any changes within brain regions associated with speech production. This will be measured by Blood-Oxygen-Level-Dependent (BOLD) signal change (arbitrary units). Images from scans are preprocessed. Changes in BOLD signal are modeled for contrasts within a group for \[post-pre\] and \[follow up-pre\] (e.g., active group reading condition post visit MINUS active group reading pre visit). Results are reported for reading condition. |
| Change in Percentage of Stuttered Syllables Produced During Speech Sample | Baseline, 1 week (post), 4 weeks (follow up) | Investigators will calculate the percentage of stuttered syllables (out of total syllables) in a speech sample. Decreased stuttered syllables represents better outcomes (greater reduction in stuttering). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Baseline, 1 week (post), 4 weeks (follow up) | The OASES is a standardized assessment of the functional impact of stuttering on a person's life. There are 4 sub-tests: general information about speech, your reactions to stuttering, communication in daily situations, quality of life. Each one has a score from 1 to 5 with regard to impact (1 least, 5 most negative impact). These are combined to give a total impact score between 1 and 5, with 5 representing the highest negative impact on person's life. The change on the total impact score will be used. Changes are shown in the table below by comparison between the measurements at the three points in time. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Changes From Baseline on Rhythm Judgement Task | Baseline, 1 week, 4 weeks | Investigators will compare performance accuracy on a computerized rhythm judgement task from before and after tDCS to assess effects of tDCS. Improved accuracy reflects better performance. |
| Changes From Baseline on Tapping Tasks | Baseline, 1 week, 4 weeks | Investigators will compare performance on computerized tapping tasks from before and after tDCS to assess effects of tDCS. |
| Changes From Baseline on Self-rated Measure of Speech Fluency | Baseline, 1 week, 4 weeks | Investigators will compare participant scores on a self-rated measure of speech fluency (1 = NO STUTTERING; 9 = EXTREMELY SEVERE STUTTERING) from before and after tDCS to assess effects of tDCS. Lower scores indicate improvement. |
Countries
United States
Participant flow
Pre-assignment details
Participants were required to meet a certain stuttering severity status. Four participants who were enrolled did not meet the pre-assignment criteria and were thus not assigned to an arm.
Participants by arm
| Arm | Count |
|---|---|
| Active tDCS and Fluency Training Participants will receive anodal tDCS at 2milliampere (mA) intensity for 20 minutes during speech fluency training (5 consecutive days).
Anodal tDCS: 20 minutes of 2mA anodal stimulation.
Fluency training: Speaking along with a metronome and/or speaking along with another person (choral speech) for 20 minutes | 12 |
| Sham tDCS and Fluency Training Participants will receive sham tDCS. Sham stimulation will involve 30 seconds of stimulation at the beginning of the 20 minutes of speech fluency training (5 consecutive days).
Fluency training: Speaking along with a metronome and/or speaking along with another person (choral speech) for 20 minutes
Sham tDCS: For sham stimulation, current is ramped up and back down over 30 seconds. | 11 |
| Total | 23 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Completed Study Follow up | Could not complete study due to COVID-19 research pause | 2 | 1 |
| Randomized | Withdrawal by Subject | 0 | 2 |
Baseline characteristics
| Characteristic | Active tDCS and Fluency Training | Sham tDCS and Fluency Training | Total |
|---|---|---|---|
| Age, Continuous | 27.43 years STANDARD_DEVIATION 8.14 | 23.31 years STANDARD_DEVIATION 2.87 | 25.46 years STANDARD_DEVIATION 6.54 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants | 0 Participants | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 11 Participants | 11 Participants | 22 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Overall Assessment of Speaker's Experience of Stuttering | 2.48 score on a scale STANDARD_DEVIATION 0.58 | 2.67 score on a scale STANDARD_DEVIATION 0.68 | 2.57 score on a scale STANDARD_DEVIATION 0.64 |
| Race (NIH/OMB) American Indian or Alaska Native | 1 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) Asian | 2 Participants | 1 Participants | 3 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants | 1 Participants | 3 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 7 Participants | 8 Participants | 15 Participants |
| Sex: Female, Male Female | 2 Participants | 1 Participants | 3 Participants |
| Sex: Female, Male Male | 10 Participants | 10 Participants | 20 Participants |
| Stuttering Severity | 5.66 percent STANDARD_DEVIATION 3.23 | 9.72 percent STANDARD_DEVIATION 8.88 | 7.69 percent STANDARD_DEVIATION 6.06 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 12 | 0 / 11 |
| other Total, other adverse events | 12 / 12 | 10 / 11 |
| serious Total, serious adverse events | 0 / 12 | 0 / 11 |
Outcome results
Primary
Change in Percentage of Stuttered Syllables Produced During Speech Sample
Investigators will calculate the percentage of stuttered syllables (out of total syllables) in a speech sample. Decreased stuttered syllables represents better outcomes (greater reduction in stuttering).
Time frame: Baseline, 1 week (post), 4 weeks (follow up)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS and Fluency Training | Change in Percentage of Stuttered Syllables Produced During Speech Sample | % Change follow up | -1.03 percent change in stuttered syllables | Standard Deviation 4.17 |
| Active tDCS and Fluency Training | Change in Percentage of Stuttered Syllables Produced During Speech Sample | % Change post | -1.82 percent change in stuttered syllables | Standard Deviation 2.22 |
| Sham tDCS and Fluency Training | Change in Percentage of Stuttered Syllables Produced During Speech Sample | % Change post | 1.06 percent change in stuttered syllables | Standard Deviation 2.02 |
| Sham tDCS and Fluency Training | Change in Percentage of Stuttered Syllables Produced During Speech Sample | % Change follow up | 3.46 percent change in stuttered syllables | Standard Deviation 5.47 |
Comparison: Analyses conduced with a mixed ANOVA, with between-subjects factor of group (active, sham) and two within-subjects factors: time (post, follow up) and speech task (reading, conversation).p-value: 0.936ANOVA
Primary
Changes in Brain Activation as Assessed by fMRI Images
Investigators will use the fMRI images taken from before and after tDCS to determine if the treatment intervention contributed to any changes within brain regions associated with speech production. This will be measured by Blood-Oxygen-Level-Dependent (BOLD) signal change (arbitrary units). Images from scans are preprocessed. Changes in BOLD signal are modeled for contrasts within a group for \[post-pre\] and \[follow up-pre\] (e.g., active group reading condition post visit MINUS active group reading pre visit). Results are reported for reading condition.
Time frame: Baseline, 1 week (post), 4 weeks (follow up)
Population: One subject assigned to the sham condition did not want to participate in the MRI but participated in every other aspect of the study. Additionally, 2 subjects assigned to active and 1 assigned to sham did not complete follow up MRI due to pandemic research pause. The MRI data from one subject in the active arm was corrupted and therefore not analyzable and was excluded from MRI results. Therefore \[post-pre\] includes 11 active and 10 sham, whereas \[follow up-pre\] includes 9 active and 9 sham.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left supplementary motor area (SMA) (post-pre) | 1.39 Percent signal change | Standard Deviation 0.45 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left SMA (fol-pre) | 1.03 Percent signal change | Standard Deviation 0.49 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right SMA (post-pre) | -0.45 Percent signal change | Standard Deviation 0.48 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right SMA (fol-pre) | 0.86 Percent signal change | Standard Deviation 0.54 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left superior temporal gyrus (STG) (post-pre) | 1.43 Percent signal change | Standard Deviation 0.74 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left STG (fol-pre) | 0.09 Percent signal change | Standard Deviation 0.53 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right STG (post-pre) | -0.63 Percent signal change | Standard Deviation 0.97 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right STG (fol-pre) | 0.3 Percent signal change | Standard Deviation 1.07 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left putamen (post-pre) | 1.37 Percent signal change | Standard Deviation 0.66 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left putamen (fol-pre) | 2.42 Percent signal change | Standard Deviation 0.71 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right putamen (post-pre) | -1.01 Percent signal change | Standard Deviation 0.65 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right putamen (fol-pre) | 0.89 Percent signal change | Standard Deviation 0.69 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left inferior frontal gyrus (IFG) (post-pre) | 1.6 Percent signal change | Standard Deviation 0.94 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left IFG (fol-pre) | 0.23 Percent signal change | Standard Deviation 0.96 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right IFG (post-pre) | -0.48 Percent signal change | Standard Deviation 0.8 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right IFG (fol-pre) | -0.2 Percent signal change | Standard Deviation 0.8 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left premotor cortex (PMC) (post-pre) | 1.33 Percent signal change | Standard Deviation 0.91 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left PMC (fol-pre) | 0.68 Percent signal change | Standard Deviation 0.96 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right PMC (post-pre) | 0.31 Percent signal change | Standard Deviation 0.72 |
| Active tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right PMC (fol-pre) | 1.32 Percent signal change | Standard Deviation 1.01 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left PMC (fol-pre) | 0.62 Percent signal change | Standard Deviation 1.11 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left supplementary motor area (SMA) (post-pre) | 0.81 Percent signal change | Standard Deviation 0.47 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right putamen (post-pre) | -0.74 Percent signal change | Standard Deviation 0.67 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left SMA (fol-pre) | 0.9 Percent signal change | Standard Deviation 0.54 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right IFG (fol-pre) | -0.2 Percent signal change | Standard Deviation 0.8 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right SMA (post-pre) | 0.49 Percent signal change | Standard Deviation 0.52 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right putamen (fol-pre) | 0.06 Percent signal change | Standard Deviation 0.86 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right SMA (fol-pre) | 0.09 Percent signal change | Standard Deviation 0.35 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right PMC (fol-pre) | 1.01 Percent signal change | Standard Deviation 1.17 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left superior temporal gyrus (STG) (post-pre) | 0.79 Percent signal change | Standard Deviation 0.75 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left inferior frontal gyrus (IFG) (post-pre) | -0.33 Percent signal change | Standard Deviation 0.97 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left STG (fol-pre) | 0.57 Percent signal change | Standard Deviation 0.85 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left premotor cortex (PMC) (post-pre) | -0.15 Percent signal change | Standard Deviation 1.67 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right STG (post-pre) | 1.56 Percent signal change | Standard Deviation 1.39 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left IFG (fol-pre) | 0.14 Percent signal change | Standard Deviation 0.74 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right STG (fol-pre) | 0.83 Percent signal change | Standard Deviation 1.17 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right PMC (post-pre) | 1.2 Percent signal change | Standard Deviation 0.93 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left putamen (post-pre) | -0.31 Percent signal change | Standard Deviation 0.58 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | right IFG (post-pre) | 0.11 Percent signal change | Standard Deviation 0.65 |
| Sham tDCS and Fluency Training | Changes in Brain Activation as Assessed by fMRI Images | left putamen (fol-pre) | -0.22 Percent signal change | Standard Deviation 0.59 |
p-value: <0.001t-test, 2 sided
Secondary
Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES)
The OASES is a standardized assessment of the functional impact of stuttering on a person's life. There are 4 sub-tests: general information about speech, your reactions to stuttering, communication in daily situations, quality of life. Each one has a score from 1 to 5 with regard to impact (1 least, 5 most negative impact). These are combined to give a total impact score between 1 and 5, with 5 representing the highest negative impact on person's life. The change on the total impact score will be used. Changes are shown in the table below by comparison between the measurements at the three points in time.
Time frame: Baseline, 1 week (post), 4 weeks (follow up)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Pre | 2.48 score on a scale | Standard Deviation 0.61 |
| Active tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Post | 2.34 score on a scale | Standard Deviation 0.55 |
| Active tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Follow up | 2.35 score on a scale | Standard Deviation 0.57 |
| Sham tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Pre | 2.67 score on a scale | Standard Deviation 0.75 |
| Sham tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Post | 2.56 score on a scale | Standard Deviation 0.78 |
| Sham tDCS and Fluency Training | Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) | Follow up | 2.59 score on a scale | Standard Deviation 0.88 |
p-value: 0.619ANOVA
Other Pre-specified
Changes From Baseline on Rhythm Judgement Task
Investigators will compare performance accuracy on a computerized rhythm judgement task from before and after tDCS to assess effects of tDCS. Improved accuracy reflects better performance.
Time frame: Baseline, 1 week, 4 weeks
Other Pre-specified
Changes From Baseline on Self-rated Measure of Speech Fluency
Investigators will compare participant scores on a self-rated measure of speech fluency (1 = NO STUTTERING; 9 = EXTREMELY SEVERE STUTTERING) from before and after tDCS to assess effects of tDCS. Lower scores indicate improvement.
Time frame: Baseline, 1 week, 4 weeks
Other Pre-specified
Changes From Baseline on Tapping Tasks
Investigators will compare performance on computerized tapping tasks from before and after tDCS to assess effects of tDCS.
Time frame: Baseline, 1 week, 4 weeks