Lombard’s effect’s implication in intensity, fundamental frequency and stability on the voice of individuals with Parkinson’s disease

Abstract

SummaryParkinson’s disease affects the central nervous system resulting in voice quality alterations. It is typically resistant to drug therapy and often persists despite extensive behavioural speech and language therapy. Previous findings show that masking noise will produce a consistent increase in voice intensity in most normal individuals (Lombard’s effect). Aim: we evaluated Lombard’s effect’s implication in intensity, fundamental frequency and stability on the voice of individuals with Parkinson’s disease (N=17). Material and methods: through acoustic analysis, we evaluated intensity alterations and fundamental frequency, before and after white masking noise 40, 70 and 90 dBSL intensities, as well as variations during each vocalization and compared with a control group (N=16). Results: voice intensity varied according to masking intensity, tending to non-linear increases in both groups and gender. Fundamental frequency varied, tending to non-linear increase in both groups and gender. Improvement stability occurred in fundamental frequency and vocal intensity. Conclusion: Lombard’s effect increased intensity, fundamental frequency and improves voice stability on these patients. Study: clinical and experimental.