About 25% had unsatisfactory fluency. There are no reported studies of stuttering modification therapies. I haven't found any other published studies of fluency shaping therapies. return to table of contents return to Stuttering Home Page Subject: Computers And Electronic Devices For Stuttering AUDITORY FEEDBACK FOR IMMEDIATE FLUENCY The four main types of auditory feedback are: - Delayed auditory feedback (DAF) delays your voice to your headphones a small fraction of a second (typically 50 milliseconds). - Frequency-altered auditory feedback.