Effects of increasing sound pressure level on lip and jaw movement parameters and consistency in young adults

Abstract

Purpose: Examination of movement parameters and consistency has been used to infer underlying neural control of movement. However, there has been no systematic investigation of whether the way individuals are asked (or cued) to increase loudness alters articulation. This study examined whether different cues to elicit louder speech induce different lip and jaw movement parameters or consistency.

Method: Thirty healthy young adults produced two sentences (a) at comfortable loudness, (b) while targeting 10 dB SPL above comfortable loudness on a sound level meter, (c) at twice their perceived comfortable loudness, and (d) while multitalker noise was played in the background. Lip and jaw kinematics and acoustic measurements were taken.

Results: Each of the loud conditions resulted in a similar amount of SPL increase, about 10 dB. Speech rate was slower in the background noise condition. Changes to movement parameters and consistency (relative to comfortable) were different in the targeting condition as compared to the other loud conditions.

Conclusions: The cues elicited different task demands, and therefore, different movement patterns were used by the speakers to achieve the target of increased loudness. Based on these results, cueing should be considered when eliciting increased vocal loudness in both clinical and research situations.

Figure 1

Segmentation and measurement points for the lip and jaw kinematic traces. Trace of lower lip + jaw from female speaker during comfortable condition. Top: SHORT sentence; Bottom: EMBED sentence. Lines A and B are the segmentation points. Point C is peak closure for the first “b” in “Bob”; point D is the peak opening for the vowel in “Bob”; point E is the peak closure for the second “b” in “Bob.” Point F is peak opening velocity for the vowel in “Bob”; point G is peak closing velocity for the second “b” in “Bob.”

Figure 2

Means for opening displacement (ODISP) articulator by condition interaction, LL = lower lip, JW = jaw, and UL = upper lip. Bars represent means; lines show standard errors. Asterisks indicate significantly different from COMF within articulator; carrots indicate significantly different from lower lip within condition.

Figure 3

Means for the closing displacement (CDISP) articulator by condition interaction, LL = lower lip, JW = jaw, and UL = upper lip. Bars represent means; lines show standard errors. Asterisks indicate significantly different from COMF within articulator; carrots indicate significantly different from lower lip within condition.

Figure 4

Means for the opening velocity (OVEL) articulator by condition interaction, LL = lower lip, JW = jaw, and UL = upper lip. Bars represent means; lines show standard errors. Asterisks indicate significantly different from COMF within articulator; carrots indicate significantly different from lower lip within condition.

Figure 5

Means for the closing velocity (CVEL) articulator by condition interaction, LL = lower lip, JW = jaw, and UL = upper lip. Bars represent means; lines show standard errors. Asterisks indicate significantly different from COMF within articulator; carrots indicate significantly different from lower lip within condition.