The Effects of Auditory Masking on the Anxiety Level, Frequency of Dysfluency, and Selected Vocal Characteristic of Stutterers

Abstract
This study tested and compared two different explanations of the effects of auditory masking on stuttering: masking minimizes the individual’s auditory feedback of his stuttering so that he is less anxious about the dysfluency and consequently stutters less; or masking causes the stutterer to increase his vocal intensity and reduce his speech rate, and these changes create the reduction in stuttering. Twelve stutterers with normal hearing read aloud in masking and no-masking (control) conditions. Measures of palmar sweat anxiety, the frequency of stuttering, reading time, and vocal intensity were obtained for each subject in both of these situations. Significantly less stuttering and more vocal intensity were noted concomitantly in the masking as compared to the control condition. The between-condition differences in reading time and measured anxiety were small and rather unreliable. These results were interpreted as supporting the “modified vocalization” explanation of the masking effect, but as detracting from the “reduced anxiety over stuttering” hypothesis.