Electroglottographic Analysis in Individuals with Chronic Laryngitis during Speech Task

Abstract

Electroglottography (EGG) is a method to monitor the vibrations of the vocal folds by measuring the varying impedance to a weak alternating current through the tissues of the neck. Non-invasive measures of vocal fold activity are useful for describing normal and disordered voice production. Measures of open, closed and speed quotient from glottal airflow and electroglottographic (EGG) waveforms have been used to describe timing events associated with vocal fold vibration. There are very few studies in western context and no Indian studies were done using speech task. The aim of the present study was to analyze the laryngeal behavior of individuals with chronic laryngitis using electroglottograph on reading voiced passage and to compare with normal individuals. 10 adults with chronic laryngitis and 10 age and gender matched normal adults in the age range of 30 – 40 years participated in the present study. All the recorded samples were analyzed for contact quotient (CQ), open quotient (OQ) and speed quotient (SQ). Results indicated that there was significant statistical difference between normal and abnormal group on all the three EGG quotients for voiced passage reading task. These results also suggested that the closed duration during vocal fold vibratory pattern was longer in individuals with chronic laryngitis and open duration was reduced thereby reducing the speed quotient which indicates the asymmetry of vocal fold vibration during reading passage task in these individuals. It also suggest that connected speech context, as in passage reading, can give better representation, due to the fact that passage is more representative to one’s daily speech characteristics than sustained phonation. The laryngeal measures obtained from connected speech context offer a more accurate representation in differentiating normal versus pathological voices. Implications of the findings are discussed and topics for further exploration are identified