Explorative Study for Treating Persistent Developmental Stuttering With Ramipril

  • days left to enroll
  • participants needed
  • sponsor
    HaEmek Medical Center, Israel
Updated on 17 February 2021


Persistent developmental stuttering (PDS) is diagnosed when developmental stuttering persists beyond adolescence. Most stutterers experience vast improvement in stuttering during childhood and it generally disappears within five years. A minority of stutterers continue stuttering over age 18, often accompanied by social and personal difficulties.

Following a report of a 75 year old woman, with severe Persistent developmental stuttering , who experienced significant improvement in her stuttering since treated by Ramipril for hypertension, we scrutinized the literature, and discovered that there is a physiological basis for this surprising reaction. Ace inhibitors, such as Ramipril, might in fact be successful for treating Persistent developmental stuttering .

In theory, it seems that ACE inhibitors, such as Ramipril could improve stuttering by reducing striatum dopamine levels.

  1. Stuttering is associated with high striatum dopamine levels
  2. Angiotensin receptors are present in the striatum
  3. Angiotensin causes elevated striatum dopamine levels
  4. ACE inhibitors penetrate the blood brain barrier and reduce brain angiotensin II levels.

Methods The study will begin as a pilot study in which 10 stuttering patients will be recruited for 12 weeks on open label Ramipril 1.25mg/d.

If there is improvement in at least 2 of the stuttering patients, we will continue to the main study.

Efficacy Evaluation:

  1. The MINI Neuropsychiatric interview will be used to rule out major neuropsychiatric conditions
  2. Stuttering evaluation
  3. Stuttering Severity instrument Version 4 (SSI-4) (Riley 2009)
  4. SLD :Percentage of stuttered syllables (Yairi 2015)
  5. The Subjective Screening of Stuttering (SSS)
  6. Speech Situation Checklist (Brutten 1975,1981)
  7. Leibowitz Social Anxiety Scale (Leibowitz 1987)

The efficacy evaluation will be performed by speech therapists. All evaluations will be will be recorded on video

Safety evaluation:

  1. Blood pressure: The average of three consecutive measures. Blood pressure will be measure in both arms on the first meeting, and thereafter on the arm with the highest measurements.
  2. Orthostatic hypotension will be defined as a drop of 20mmHg systolic or 10mmHg diastolic, one and three minutes after standing from sitting position.
  3. Creatinine clearance will be calculated by the MDRD method (Levy 2006) GFR, in mL/min per 1.73 m2 = 186.3 x SCr (exp[-1.154]) x Age (exp[-0.203]) x (0.742 if female) x (1.21 if black)

Condition Persistent Developmental Stuttering
Treatment Ramipril 2.5 MG
Clinical Study IdentifierNCT04173949
SponsorHaEmek Medical Center, Israel
Last Modified on17 February 2021


Yes No Not Sure

Inclusion Criteria

Inclusion Criteria
Age 18 or above
Developmental stuttering of 10 points severity at least (SSI-4)
Agree not to have any speech or emotional therapy during the trial

Exclusion Criteria

Systolic blood pressure < 110mmHg
Estimated creatinine clearance < 50ml/min
Baseline potassium > 5meq/ml
Any sign of psychopathology by the MINI international neuropsychiatric interview
Any psychotropic medications or substances in the past month
History of angioedema or cough with any ACE inhibitor
Aliskerin use in diabetes patients
Current medication include ACE inhibitors or ARBS
Pregnancy, or pregnancy plans during the study
Less than 3% stuttered syllables
Subjects with cluttering-stuttering when the cluttering is prominent
Clear my responses

How to participate?

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What happens next?
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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