Dynamic measures of voice stability in young and old adults

This paper examines age-related differences in voice quality between 15 young and 15 old speakers, using electroglottographic (EGG) recordings of three elicitation types: sustained vowels, hVd word lists, and readings of the Rainbow Passage. For each elicitation type, fundamental frequency (F0), contact quotient (Qx), and their standard deviations are analysed. Results found, for all three elicitations, that Qx was significantly lower for older speakers. F0 was higher for the older speakers, but this was only significant for the hVd word lists. Sustained vowels were used to examine the effect of target pitch and loudness on F0 and Qx. Both Qx and F0 were raised with increased target loudness. The hVd word lists were used to examine the phonetic effects of different vowels. Lip rounded vowels had higher Qx than non-lip rounded vowels. Readings of the Rainbow Passage encompassed prosodic and phonetic variations in F0 and Qx, in addition to voice quality. F0 and Qx contours of the hVd word lists and the vowel/ei/taken from the Rainbow Passage were analysed using the discrete cosine transform. The hVd frame produced coarticulation effects on the Qx contour, but no such effects were evident for the vowel /ei/. The study concluded that using multiple elicitation types is beneficial in the study of the effect of age on the voice, and that analysing contour tracks for F0 and Qx will allow further examination of how prosodic and phonetic effects interact with age-related changes in voice quality.