Impact of Muscle Tension Dysphonia on Tone Height and Fundamental Frequency Movements in Vietnamese Tones

Abstract

There has been no published study on how voice disorders affect lexical tones in Vietnamese. In this study, we investigated a number of tonal parameters in the Northern Vietnamese dialect in 42 female teachers with muscle tension dysphonia and compared them with 30 control speakers. Speech samples included tone syllables in isolation and in a reading passage. Computerized Speech Lab 4300B was used to measure fundamental frequency. Mean tonal fundamental frequency was evaluated for group and age effects. Parameters representing pitch movement (time, size, and speed of a movement) for tone 2 and tone 5 were compared between the two groups. The results showed that there was a significant effect of muscle tension dysphonia on Vietnamese tones: mean fundamental frequency was decreased in the high tones. Rise size and rise speed of fundamental frequency change were reduced in tone 5 phonated by the muscle tension dysphonia participants. There was a significant effect of age, with decreased tonal fundamental frequency in participants older than 45 years. We concluded that an interaction existed between tonal characteristics in Vietnamese and muscle tension dysphonia. Data on pitch movement may reflect tonal pitch control mechanisms in this voice disorder.