Envelope modulation spectral (EMS) analyses of solo reading and choral reading conditions suggest changes in speech rhythm in adults who stutter

Abstract

PurposeA longstanding finding in persons who stutter is that stuttering frequency significantly reduces during choral reading when compared to the solo reading condition. Here, we tested the hypothesis that this decrease in stuttering frequency may be because speech of the normal speaker dictates the speech rhythm of a person who stutters. We used an automated, sensitive acoustic technique—Envelope Modulation Spectral (EMS) analysis— that allowed us to document speech rhythm. MethodSeventeen adults who stutter (AWS) read sentences under two conditions: solo reading and choral reading. Percentage of syllables stuttered (%SS), the rate of speech, and speech rhythm were calculated from the recorded sentences from AWS. Further, AWS speech rhythm during solo reading was compared with typical adults. EMS was extracted for the full signal and seven-octave bands. From the extracted envelope six predictor variables (peak frequency, peak amplitude, energy in the spectrum 3–6 Hz, energy in the spectrum from 0 to 4 Hz, energy in the spectrum from 4 to 10 Hz, and the ratio of energy below4 Hz/above 4 Hz) were computed. ResultsSignificant decrease in stuttering frequency and rate of speech was noticed in choral reading when compared to the solo reading condition. Further, analysis of EMS results suggested the statistically significant difference between two reading conditions (for peak frequency and peak amplitude), and between two groups for all predictor variables. ConclusionOverall, current results highlight that decreases in stuttering during the choral reading is characterized by a decrease in rate and changes in some aspects of speech rhythm in Kannada speaking AWS.