Basic Telephone Fluency System
The Basic Fluency System provides two or three types of altered auditory feedback (AAF).
Delayed auditory feedback (DAF) immediately reduces stuttering about 70% at normal speaking rates without training, mental effort, or abnormal-sounding or abnormally slow speech. 55% carryover fluency after removing the device, without speech therapy. With speech therapy, DAF can induce a slower speaking rate with stretched vowels to make even severe stutterers nearly 100% fluent.
Pitch-shifting frequency-shifted auditory feedback (FAF) immediately reduces stuttering about 70% at normal speaking rates and induces speech motor changes in stutterers. Only Casa Futura Technologies stuttering treatment devices have octave-scale FAF downshifting (pitch shifting). Combining DAF and FAF increases effectiveness.