Listener perception of respiratory-induced voice tremor

Purpose: The purpose of this study was to determine the relation of respiratory oscillation to the perception of voice tremor. Method: Forced oscillation of the respiratory system was used to simulate variations in alveolar pressure such as are characteristic of voice tremor of respiratory origin. Five healthy men served as speakers, and 6 clinically experienced women served as listeners. Speakers produced utterances while forced sinusoidal pressure changes were applied to the surface of the respiratory system. Utterances included vowels and sentences produced using usual loudness, pitch, quality, and rate, and vowels produced using different loudness, pitch, and quality. Perceptual tasks included detection threshold for voice tremor and pair comparison judgments in which listeners identified the sample with the greater magnitude of voice tremor. Results: The mean detection threshold for voice tremor was 1.37 cmH ₂ O (SD = 0.47) for vowel utterances and 2.16 cmH ₂ O (SD = 1.52) for sentence utterances. Tremor magnitude was judged to be different for vowel and sentence utterances, but not for different vowels. Results revealed differential effects for loudness, pitch, and quality. Conclusions: These findings offer implications for the evaluation and management of voice tremor of respiratory causation.