Effects of Neuroacoustic Stimulation on Two Study Cases of Parkinson's Disease Dysarthria

The first prevailing Neuromotor Disorder (ND) is Parkinson's Disease (PD) with steadily increasing incidence rates, lacking a definitive cure. Nevertheless, dopaminergic medication and rehabilitation may improve the living conditions of people affected by PD. Neuroacoustical stimulation is a non-invasive, which may improve some motor symptoms associated to PD, as Hypokinetic Dysartrhia (HD). The aim of this research is to extend previous findings in phonation features before and after neuroacoustical binaural stimulation using two-tone combinations. The study evaluated two study cases (one male and one female) from a database collected on smartphone terminals, consisting in utterances of sequences of vowels peripheral to the vowel triangle. The longitudinal evolution of the participants under an ongoing weekly neuroacoustical stimulation stood on the energy and FO profiles, the Vowel Space Area, Formant Centralization Ratio, Vowel Articulation Index, and Dynamic Formant Spans. The two cases comprised four recordings, and the comparisons were referred to the first recording. The results reported mixed behavior on the traits studied. The male case showed improvements with respect to phonation quality and tremor, whereas the female case showed improvements with respect to vowel space features, energy and fundamental frequency dispersion.