Objective: This study aims to investigate the relationship between background noise and a speech scaling task in individuals with Parkinson’s disease to better understand speech motor control processes.

Background: Individuals with PD frequently experience deficits in speech loudness, quality, and intelligibility [1]. These difficulties are often associated with decreased quality of life and social isolation [2]. Speech scaling tasks require participants to produce a habitual loudness level and to then produce utterances that are ratios of the habitual production (i.e. 2x louder, 4x quieter, etc.). Despite the documented link between PD and decreased speech loudness, it is unclear how a speech intensity scaling task is affected when speaking in the context of background noise, which is an ecologically valid context.

Method: The results from 7 individuals with PD and 16 neurologically healthy controls are presented as preliminary findings. Participants were fitted with a microphone and instructed to repeat a sentence at habitual loudness, 2x, 4x, and max loudness. These productions were accompanied by randomized background noise (5dB increments from 60-90dB) played through field speakers. All audio files were analyzed using Praat [3].

Results: To examine the speech scaling task, a linear regression analysis was performed on each participant’s data using the speech intensity response values and the corresponding values related to each of the four instruction levels (habitual, 2x, 4x, max loudness). These slope values were then used for all analysis. Two-way repeated measures ANOVA with background noise levels as within-subjects factor indicate a significant main effect of group (F (1,21) = 5.811, p = .025) with PD participants producing an overall reduced slope of the speech scaling task. There was no significant group x background noise condition effect (F (1,6) = 2.001, p=.070) however pairwise comparisons suggest that the louder background noise conditions may be driving this result.

Conclusion: Preliminary results indicate possible differences between the speech scaling of individuals with PD and controls, specifically in the 60, 65 and 70dB noise conditions. Further investigation is required to determine precisely how speech scaling differs between these groups and comparisons with older healthy controls will be presented. Results from this study could help to better understand speech motor control processes in PD.

References: [1] Atalar, M. S., Oguz, O., & Genc, G. (2023). Hypokinetic dysarthria in Parkinson’s disease: A narrative review. The Medical Bulletin of Sisli Etfal Hospital. 57(2), 163–170. https://doi.org/10.14744/SEMB.2023.29560

[2] Miller, N., Noble, E., Jones, D., & Burn, D. (2006). Life with communication changes in Parkinson’s disease. Age and Ageing, 35(3), 235–239. https://doi.org/10.1093/ageing/afj053

[3] Boersma, P., & Weenink, D. (2011). Praat: Doing phonetics by computer [Computer program]. Version 5.2.26. Retrieved from: http://www.praat.org/

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MDS Abstracts - https://www.mdsabstracts.org/abstract/speaking-in-noise-examination-of-speech-motor-control-in-parkinsons-disease/