ARTICULATORY STABILITY OF NON-SENSE LABIODENTAL SEQUENCES IN PERSONS WITH STUTTERING

Abstract

The study aimed at understanding the articulatory stability differences fornonsense labiodental sequences in persons with stuttering and age, gender matched typical adults. Group 1 consisted of 5 [3M,2F] Persons with Stuttering (PsWS) in the age range of 18-30 years who were diagnosed to have stuttering from a qualified Speech-Language Pathologist using Stuttering Severity Instrument. Group 2 consisted of age, gender matched typical adults. Articulograph AG501 captured the articulatory movements of Lower Lip (LL) and Jaw in the superior-inferior dimension (Z dimension). Bisyllabic labiodental sequences such as /fafa/ (unvoiced), /vava/ (voiced) and /fava/ (mixed) were used as the study stimuli. Participants were instructed to repeat the target bisyllabic nonsense labiodental sequences in their habitual speaking rate and loudness. A derived kinematic measure called ?Spatiotemporal Index? (STI) was used to analyze the articulatory stability of LL and Jaw. Additionally, the articulatory stability was also compared with the total number of behavioral disfluencies of participants for voiced and combined (voiced-unvoiced) Kannada reading passages. Comparison of mean STI scores of LL and Jaw within each of these groups revealed no significant differences between the stimuli types. Interestingly, PsWS showed greater articulatory instability of LL and Jaw for unvoiced labiodental sequences. Even though between group comparisons of STI scores were insignificant, PsWS showed greater mean STI scores than age, gender matched typical adults. Behavioral disfluencies of combined reading passage correlated positively with the articulatory stability of Jaw for the mixed (/fava/) stimuli. The obtained findings werediscussed with respect to the discoordination hypothesis and the possible implications for future research.