This study examined the impact of several noise conditions on speech articulator movements during a sentence repetition task. Sixty participants in three age groups ranging from 20 to 70 repeated a sentence under five noise conditions. Lower lip movements during production of a target sentence were used to compute the spatiotemporal index (STI). It was hypothesized that STI would be lower (indicating greater stability) in the silent baseline condition. There were changes in speech production under several of the noise conditions. The duration for the 1-talker condition was significantly shorter when compared to the silent condition, which could be due to the impact of the 1-talker noise on the attention of the speaker. The peak velocity of a selected closing gesture increased in all of the noise conditions compared to silence. It could be speculated that the repetitive and predictable nature of the speaking task allowed participants to easily filter out the noise while automatically increasing the velocity of lip movements, and consequently, the rate of speech. The STI in the pink noise and 6-talker conditions was lower than in the silent condition, which may be interpreted to reflect a steadier manner of speech production. This could be due to the fact that in the 6-speaker noise condition, the overall effect was more similar to continuous noise, and thus potentially less distracting than hearing a single speaker talking. The count of velocity peaks was unexpectedly lower in the noise conditions compared to speech in silence, suggesting a smoother pattern of articulator movement. The repetitiveness of the task may not require a high level of self-monitoring, resulting in speech output that was more automatic in the noise conditions. With the presentation of noise during a speaking task, the intensity increased due to the Lombard effect in all of the noise conditions. People communicate in noisy environments every day, and an increased understanding of the effects of noise on speech would have value from both theoretical and clinical perspectives.



College and Department

David O. McKay School of Education; Communication Disorders



Date Submitted


Document Type





speech motor control, lip kinematics, noise