Vocal Loading and Environmental Humidity Effects in Older Adults

The goal of this study was to investigate the effects of a vocal loading challenge that combined prolonged speaking, in child-directed voice within a noisy environment, in older adults. An additional goal was to determine whether increased environmental humidity would attenuate the negative effects of this vocal loading challenge.

Method: Thirteen healthy subjects (five males and eight females; >65 years) completed a vocal loading challenge. The challenge involved 45 minutes of child-directed speech in the presence of 65 dB multitalker babble background noise. Subjects completed this challenge in both low humidity and moderate humidity in counterbalanced order. Vocal function was assessed before and after the challenge using phonation threshold pressure (PTP), cepstral peak prominence (CPP), low/high spectral ratio (LHR), perceived phonatory effort (PPE), and perceived vocal tiredness.

Results: Negative changes were observed in the aging larynx following the 45-minute vocal loading challenge. Measures of PTP, PPE, and perceived vocal tiredness demonstrated statistically significant loading effects. Increased ambient humidity significantly alleviated the negative changes observed in PPE and perceived vocal tiredness. Increased humidity significantly improved CPP measures both before and after the vocal loading challenge.

Conclusions: This study furthers our understanding of how older adults respond to a vocal loading challenge of prolonged nonhabitual speech in a noisy environment. Our data suggest that the aging voice is negatively affected by prolonged loud speaking and that humidification may be beneficial in reducing some of these negative effects.