The effects of age and pitch level on electroglottographic measures during sustained phonation

The aim of the present study was to use electroglottography (EGG) to explore the effects of age and pitch level on sustained vowel phonation. Thirty female individuals (10 young, 10 middle-aged, and 10 older speakers) without voice disorders or training in singing participated in this study. Eight EGG parameters were measured during sustained vowel production with a high, mid, or low pitch: fundamental frequency, contact quotient, contacting-time quotient, decontacting-time quotient, speed quotient with a midslope criterion (SQ-mid), jitter, shimmer, and the harmonics-to-noise ratio. Age was found to be a significant factor in fundamental frequency, contact quotient, contacting-time quotient, decontacting-time quotient, and SQ-mid. With increasing age, the mean fundamental frequency decreased while the contact quotient increased. The middle-aged and older speakers had more asymmetrical vocal fold vibratory patterns than the young speakers. As for pitch level, the high pitch had a significantly less decontacting-time quotient and greater SQ-mid than low and mid pitches. The lack of significant interaction between age and pitch level indicates that the effects of age and pitch level could be additive. Finally, the discriminant analyses show that contact quotient is an important factor in predicting the age of a voice.