I. Introduction
The health condition of the human voice can significantly affect the quality of life of an individual [1]. The current practice to detect voice disorders accurately consists of a meticulous laryngeal examination procedure called "laryngeal endoscopy" [2], [3]. Performing this procedure is significantly expensive, as it requires physical intrusion in the patient’s body and an expert operator to perform the medical evaluation. A non-intrusive approach to detect voice disorder consists of analyzing the patient’s voice directly. Clinically, voice is considered as a multi-dimensional measurement tool and it can be used to identify the reason, severity, and prognosis of a disease, as well as to develop a therapeutic program for the cure [4]. Abnormalities in the respiratory system may lead to a voice problem and reduce mean airflow rate (MAFR). These phenomena can be further diagnosed to identify the clinical reason behind it [4], e.g.: vocal fold paralysis causes high MAFR whereas spastic dysphonia results lower MAFR [4]. Through patients phonating the vowels /a:/, /i:/ and /u:/, an expert can estimate the deviation from the optimum which can be useful for therapy modeling [4]. Although this method is non-intrusive, it still requires an experienced operator to give the diagnosis. In contrast, automated pathological voice diagnosis can be used as an inexpensive pre-screening tool to identify the disease remotely [2], [3].