Parkinson’s Disease and Aging: Analysis of Their Effect in Phonation and Articulation of Speech

Parkinson’s disease (PD) is a neurological disorder that affects the communication ability of patients. There is interest in the research community to study acoustic measures that provide objective information to model PD speech. Although there are several studies in the literature that consider different characteristics of Parkinson’s speech like phonation and articulation, there are no studies including the aging process as another possible source of impairments in speech. The aim of this work is to analyze the vowel articulation and phonation of Parkinson’s patients compared with respect to two groups of healthy people: (1) young speakers with ages ranging from 22 to 50 years and (2) people with ages matched with respect to the Parkinson’s patients. Each participant repeated the sustained phonation of the five Spanish vowels three times and those utterances per speaker are modeled by using phonation and articulation features. Feature selection is applied to eliminate redundant information in the features space, and the automatic discrimination of the three groups of speakers is performed using a multi-class Support Vector Machine (SVM) following a one vs. all strategy, speaker independent. The results are compared to those obtained using a cognitive-inspired classifier which is based on neural networks (NN). The results indicate that the phonation and articulation capabilities of young speakers clearly differ from those exhibited by the elderly speakers (with and without PD). To the best of our knowledge, this is the first paper introducing experimental evidence to support the fact that age matching is necessary to perform more accurate and robust evaluations of pathological speech signals, especially considering diseases suffered by elderly people, like Parkinson’s. Additionally, the comparison among groups of speakers at different ages is necessary in order to understand the natural change in speech due to the aging process.