Estimating Subglottal Pressure From Neck-Surface Acceleration During Normal Voice Production

Purpose

The purpose of this study was to evaluate the potential for estimating subglottal air pressure using a neck-surface accelerometer and to compare the accuracy of predicting subglottal air pressure relative to predicting acoustic sound pressure level (SPL).

Method

Indirect estimates of subglottal pressure (P_sg′) were obtained from 10 vocally healthy speakers during loud-to-soft repetitions of 3 different /p/–vowel gestures (/pa/, /pi/, /pu/) at 3 pitch levels in the modal register. Intraoral air pressure, neck-surface acceleration, and radiated acoustic pressure were recorded, and the root-mean-square amplitude of the acceleration signal was correlated with P_sg′ and SPL.

Results

The coefficient of determination between accelerometer level and P_sg′ was high when data were pooled from all vowel and pitch contexts for each participant (r ² = .68–.93). These relationships were stronger than corresponding relationships between accelerometer level and SPL (r ² = .46–.81). The average 95% prediction interval for estimating P_sg′ using accelerometer level was ±2.53 cm H₂O, ranging from ±1.70 to ±3.74 cm H₂O across participants.

Conclusions

Accelerometer signal amplitude correlated more strongly with P_sg′ than with SPL. Future work is warranted to investigate the robustness of the relationship in nonmodal voice qualities, individuals with voice disorders, and accelerometer-based ambulatory monitoring of subglottal pressure.

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