Unfolding Laryngeal Neuromotor Activity in Parkinson’s Disease by Phonation Inversion

Neuromotor disorders are a group of neurodegenerative alterations involving the neuromuscular system. Among them, Parkinson’s disease (PD) is the one with fastest growing rates. Speech is one of the activities affected by PD, producing strong negative impact on the personal wellbeing of affected people. The present study aimed to characterize PD speech by using a neuromechanical model of phonation by speech inversion methods to estimate the differential activity of the thyroarytenoid and cricothyroid articulations (dNA) under the control of two independent direct neuromotor pathways. The dNA amplitude distributions from persons with PD and age-matched healthy control subjects (HCs) were compared with respect to a mid-age normative database (RSPs). Results show that for the male group 75% of PD and 100% of HC participants were labelled as misaligned to normative. Within the female group misalignments with respect to normative were of 75% in both cases. Regarding the normative participants, 12.5% (males) and 25% (females) were misaligned with respect to their average distributions. This methodology could help in characterizing and explaining neurodegenerative phonation alterations.