PROCESSING OF PATHOLOGICAL CHANGES IN SPEECH CAUSED BY DYSARTHRIA T. Orzechowski 1 , A. Izworski 2 , R. Tadeusiewicz 3 K. Chmurzyńska 4 , P. Radkowski 5 , I. Gatkowska 6 1 necrot@o2.pl 2 izwa@agh.edu.pl 3 rtad@agh.edu.pl 4 kchm@ernie.icslab.agh.edu.pl 5 nuada@ernie.icslab.agh.edu.pl 6 iza_gatkowska@poczta.onet.pl 1234 Department of Automatics, AGH University of Science and Technology, Krakow, Poland 5 Computer Linguistic, Jagiellonian University, Krakow, Poland ABSTRACT Computer analysis of voice isolated sounds may lead to identification of parameters correlated with neurological diseases. This paper presents results of preliminary research of voice pathological changes caused by dysarthria. The selection of linguistic material was characterized according to the place and manner of articulation in the phonetic system of Polish. Results of clinical examination allowed to determine simple markers of neurodegenerative diseases, which will serve as a basis for construction of objective examination model. 1. INTRODUCTION The study presented in this publication is the first from the planned complex, interdisciplinary studies. The examination was carried out on patients of CM-UJ clinic in Krakow who suffered from neurodegenerative disease with the damage of the extrapiramidal system with dysarthria-type changes in speech. Control examinations of healthy persons have also been carried out. The elements which realization was tested had been chosen based on the linguistic knowledge in the scope of phonetics as well as experience resulting from long-term practice as a speech pathologist. The linguistic material was selected in such a way as to pinpoint voice changes typical for patients with dysarthria. 2. VOICE PHYSIOLOGY Voice and speech production requires close cooperation of numerous organs which from the phoniatric point of view may be divided into organs: • lungs, bronchi, trachea: (producing expiration air stream necessary for phonation); • larynx: (amplifying the initial tone); • root of the tongue, throat, nasal cavity, oral cavity: (forming tone quality and forming speech sounds). 3. VOICE DISORDERS Apart from typical changes caused by neurodegenarative disease (e.g. shivering of the body, limbs, muscle stiffness) changes in the voice may also be observed. There is high correlation of neurodegenerative diseases and voice pathologies, approximately 75% of cases, as shown in [4]. Thus it may be concluded that voice constitutes one of the more crucial components of neurological diagnosis. Patients suffering from neurodegenerative diseases (as patients examined by the authors) show dysarthria-type speech alternations. Dysarthria is a group phonation and articulation disorder which results from damage to the movement control systems of the central or peripheral nervous system responsible for the speech apparatus. The distortions occur although the speech plan is preserved [3]. Other definitions characterize dysarthria as abnormal production of articulated speech sounds resulting from disturbances to nervous mechanisms of voice production, modulation, intensity, timbre and resonance [2]. Nowadays dysarthria is described as a group of motor speech impairment result from a disruption of muscular control due to lesions of either the central or peripheral, or both, nervous systems (Communication Independence for the Neurologically Impaired CINI – 1994). Due to the dominating symptom of disorder [3] 6 types of dysarthria have been specified. In our study, patients suffered from hypokinetic and hyperkinetic types. Parkinson disease and Parkinson syndrome (damage to the extrapiramidal system; speech impairment related to slowness) are accompanied by hypokinetic dysarthria-type changes in speech. Its most important characteristics in relation to isolated sounds are: distortions, loudness Proceedings of 2005 International Symposium on Intelligent Signal Processing and Communication Systems December 13-16, 2005 Hong Kong 0-7803-9266-3/05/$20.00 ©2005 IEEE. - 49 -