By Dr. Carles Escara
One adult who stuttered was tested in an appropriately-controlled single-case time-series (A-B-A) study. On each of six consecutive working days, the stuttering adult was instructed to read aloud during three different experimental phases: Baseline, Test, and Post-test, while wearing a Forbrain headset. During the Test phase, the device was turned on, whereas it was off during Baseline and Post-test phases. This way the transient effects of Forbrain could be analyzed.
Six quantitative measures of voice quality were retrieved from the participant’s voice recordings during his readings over each phase of the experiment. Data were statistically analyzed through the single-case d-statistic. A clear transient effect of Forbrain, when turned on, was observed on voice quality, supported by significant differences between Baseline and Test, and Test and Post-test in the tilt of the trendline of the long-term average spectrum (tLTAS) of the voice. The present single-case study supports the effectiveness of Forbrain in modifying the voice during stuttering, supporting its role as an AAF device.