Effects of Soft Palate Implants on Acoustic Characteristics of Voice and Articulation

Abstract

To evaluate the effects of soft palate implants on voice and articulation. Prospective case series. Male subjects (n=23) diagnosed with mild obstructive sleep apnea and/or habitual snoring underwent acoustic analysis with the Multidimensional Voice Program (Kay Multi-Speech Model 3700 Advanced Version; Kay Elemetrics [KayPentax], Lincoln Park, NJ) before and 8 weeks after insertion of palatal implants to determine the effects of soft palate implants on voice and articulation. Sustained vowels (/a/e/u/o/i/) and phonetically balanced carrier sentences were used for acoustic analyses. Parameters measured were fundamental frequency (F0), jitter, shimmer, noise-to-harmonics ratio, Voice Turbulence Index, Soft Phonation Index, degree of voiceless, degree of voice breaks and peak amplitude variation, first formant (F1) and second formant (F2) frequencies, and voice onset time (VOT). F1 and F2 for each vowel were determined using linear predictive analysis on a spectrogram. VOT was measured for the palatal consonant /k/ and the dental consonant /t/ on a wideband spectrogram from a carrier sentence segment that contained a syllable with a stop consonant. No statistically significant difference was detected in F0, F1, F2, or other MDVP parameters before and after implantation. Average VOT values measured for /t/ were not significantly different. On the other hand, average VOT values of /k/ were found to be significantly shorter. Implant insertion had no significant effect on MDVP parameters, F0, F1, or F2. On the other hand, articulation as a function of velar region seemed to be affected because VOT values of velar /k/ were changed.