The effects of aging on acoustic parameters of voice.

BACKGROUND/AIMS: There are no studies of the phonatory parameters of elderly Iranian speakers. The purpose of this study was to obtain normative acoustic data for a group of elderly Iranian male and female speakers over 70 years of age. Four selected acoustic parameters [fundamental frequency (F0), jitter, shimmer, and harmonics-to-noise ratio] were obtained and compared to a group of young and middle-aged speakers.

METHODS

Subjects were 21 Iranian elderly men and 20 Iranian elderly women. The age range for both male (mean ± SD: 77.09 ± 5.84) and female subjects (77.55 ± 4.34) was 70-90 years. The control group consisted of 40 Iranian young and middle-aged adults who were 20-49 years old (20 men and 20 women). The age range for the females was 23-40 years (30 ± 4.76) and for the males it was 21-49 years (30.1 ± 8.51). Each subject phonated 5/a/vowels with constant pitch and loudness for at least 5 s. The mid 3-second portion of the tokens was analyzed using the Dr. Speech 4.3u software (subprogram: Vocal Assessment; Dr. Speech, Tiger Electronics, Seattle, Wash., USA).

RESULTS

F0 was greater for elderly males than for young and middle-aged males. Conversely, F0 was greater for young and middle-aged females than for elderly females. Average shimmer was significantly higher in elderly males than in elderly females. Likewise, jitter was significantly higher in elderly males than in elderly females. Both shimmer and jitter were significantly greater in elderly speakers than in the young and middle-aged speakers. In addition, the harmonics-to-noise ratio was significantly greater for young and middle-aged males and females than for elderly males and females.

CONCLUSIONS

The results of this study indicate that elderly Iranian speakers had significantly greater vocal instability than young and middle-aged Iranian adults, as measured by the selected acoustic parameters. As the elderly population in Iran and the world continues to increase rapidly, studies of this kind are needed for researchers, educators, and practitioners to better understand the effects of aging on all aspects of human speech-language communication. Voice is an important factor for communication, and its change with age alters the communication process.