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

Abstract

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 H 2 O, ranging from ±1.70 to ±3.74 cm H 2 O 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.