Effects of unilateral vocal cord paralysis on objective voice measures obtained by Praat

Abstract

Unilateral vocal cord paralysis (VCP) affects the objective properties of voice by diminished neurologic control and degenerative changes in laryngeal tissue. The goal of this study was to compare the acoustic parameters of VCP patients with control volunteers using the software Praat. Acoustic analysis results of 18 unilateral VCP patients were compared with age and sex matched 72 normal adult volunteers. Comparison of acoustic analysis results of male and female VCP patients with their age and sex matched control groups revealed statistically significant difference in jitter, shimmer, and noise-to-harmonics ratio values (P < 0.01) in both groups. There were no differences in mean fundamental frequency and intensity values. We conclude that these differences were in accordance with the results obtained by commercially available voice analysis programs. This study reflects the first results obtained with Praat software in VCP patients. Using the software Praat, is free and easy, that supports the clinician to rely on objective scientific data.

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“…Automated acoustic analysis of voice is increasingly used in voice clinics for collection of objective non-invasive voice data, documenting and quantifying dysphonia changes and the outcomes of therapeutic and/or phonosurgical treatment of voice problems [17,[25][26][27][28][29], as well as for screening laryngeal disorders [9,10,30,31]. One of the most important factors determining reliability and practical utility of screening and categorization of voice disorders is voice recordings of acceptable quality.…”

Vagus nerve stimulation paired with tones for tinnitus suppression: Effects on voice and hearing

“…Harmonic‐to‐noise ratio (HNR) or its inverse, the noise‐to‐harmonic ratio (NHR), assesses the presence of noise in a voice sample which is related to voice quality; specifically, a lower NHR or a higher HNR indicate superior voice quality 66 . The mathematical equation governing this metric is shown below: where the autocorrelation of the normalized lag (numerator) is divided by 1 minus the normalized lag (denominator) then the logarithm to the base 10 of this ratio is taken.…”

Modificações vocais acústicas produzidas pela fonação reversa

“…As medidas, obtidas através do software Praat (versão 4.6.10) (21) , utilizado em diversos estudos (16,17,22,23,24) , foram: frequência fundamental (f 0 ); frequência mínima; frequência máxima; Jitter (local); Jitter (local, absoluto); Jitter (rap); Jitter (ppq5); Jitter (ddp); Shimmer (local); Shimmer (local, dB); Shimmer (apq3); Shimmer (apq5); Shimmer (apq11); Shimmer (dda); relação ruído/harmônico (NHR); relação harmônico/ruído (HNR). Tais medidas englobam todas as oferecidas pelo programa, sendo importantes na análise pelo fato de fornecerem subsídios sobre os níveis de aperiodicidade, de estabilidade, de ruído, e de frequência do sinal vocal.…”