Evaluating instability on phonation in Parkinson?s disease and aging speech - Andrés Gómez Rodellar; Daniel Palacios Alonso; José Manuel Ferrández Vicente; Jiri Mekyska; Agustin Alvarez Marquina; Pedro Gómez Vilda (From Bioinspired Systems And Biomedical Applications To Machine Learning: 8th International Work-Conference On The Interplay Between Natural And Artificial Computation, Iwinac 2019, Almería, Spain, June 3?7, 2019)