Effects of physiological aging on selected acoustic characteristics of voice.

The relationship between age-related changes in body physiology and certain acoustic characteristics of voice was studied in a sample of 48 men representing three chronological age groupings (25-35, 45-55, and 65-75) and two levels of physical condition (good and poor). A fundamental frequency analysis program (SEARP) was used to measure mean fundamental frequency, jitter, shimmer, and phonation range from samples of connected speech and sustained vowel production. Subjects in good physical condition produced maximum duration vowel phonation with significantly less jitter and shimmer and had larger phonation ranges than did subjects of similar chronological ages who were in poor physical condition. These differences were most apparent in the productions of the elderly subjects. While chronological aging is undoubtedly a contributor to such changes in the acoustic characteristics of voice, these results suggest that age-related changes in body physiology, or physiological aging, also must be considered.