Perceptive and acoustic analysis of neurological voice: a preliminary study

Introduction: Object of our study were neurogenic dysphonias, characterized by a disorder in the coordination of respiration with speech and articulation. The important time variations of frequency and intensity of vocal signal do not allow the applicability of the common indexes shimmer and jitter and of the I parameter of G.I.R.B.A.S, scale is the only one that considers them. The aim of the study is to analyze whether there are other perceptive and acoustic parameters that allow to differentiate neurological voices. Materials and methods: 30 subjects aged 22-84 years (mean age 66 years) have been studied: 14 subjects were affected by Amyotrophic Lateral Sclerosis, 11 subjects by Parkinson disease and 5 subjects by Spasmodic Dysphonia. Their voices have been analyzed with a perceptive and an acoustic analysis, for large periods. Data have been compared through Mann-Whittney Test. Results: Statistically significant differences have been found for the I parameter of the G.I.R.B.A.S. scale, and for acoustic parameters used in subjects with Spasmodic Dysphonia. Conclusions: The results of this study suggest the importance of quantitative acoustic analysis for large periods in neurogenic voice disorders and that G.I.R.B.A.S. scale can be an useful instrument for differential diagnosis.