Immediate effects of AAF devices on the characteristics of stuttering: a clinical analysis

The present study investigated the immediate effects of altered auditory feedback (AAF) and one Inactive Condition (AAF parameters set to 0) on clinical attributes of stuttering during scripted and spontaneous speech. Two commercially available, portable AAF devices were used to create the combined delayed auditory feedback (DAF) and frequency altered feedback (FAF) effects. Thirty adults, who stutter, aged 18-68 years (M=36.5; SD=15.2), participated in this investigation. Each subject produced four sets of 5-min of oral reading, three sets of 5-min monologs as well as 10-min dialogs. These speech samples were analyzed to detect changes in descriptive features of stuttering (frequency, duration, speech/articulatory rate, core behaviors) across the various speech samples and within two SSI-4 (Riley, 2009) based severity ratings. A statistically significant difference was found in the frequency of stuttered syllables (%SS) during both Active Device conditions (p=.000) for all speech samples. The most sizable reductions in %SS occurred within scripted speech. In the analysis of stuttering type, it was found that blocks were reduced significantly (Device A: p=.017; Device B: p=.049). To evaluate the impact on severe and mild stuttering, participants were grouped into two SSI-4 based categories; mild and moderate-severe. During the Inactive Condition those participants within the moderate-severe group (p=.024) showed a statistically significant reduction in overall disfluencies. This result indicates, that active AAF parameters alone may not be the sole cause of a fluency-enhancement when using a technical speech aid.

The reader will learn and be able to describe: (1) currently available scientific evidence on the use of altered auditory feedback (AAF) during scripted and spontaneous speech, (2) which characteristics of stuttering are impacted by an AAF device (frequency, duration, core behaviors, speech & articulatory rate, stuttering severity), (3) the effects of an Inactive Condition on people who stutter (PWS) falling into two severity groups, and (4) how the examined participants perceived the use of AAF devices.