Laryngeal Aerodynamics in Healthy Older Adults and Adults With Parkinson's Disease.

Purpose: The present study compared laryngeal aerodynamic function of healthy older adults (HOA) to adults with Parkinson's disease (PD) while speaking at a comfortable and increased vocal intensity.

Method: Laryngeal aerodynamic measures (subglottal pressure, peak-to-peak flow, minimum flow, and open quotient [OQ]) were compared between HOAs and individuals with PD who had a diagnosis of hypophonia. Increased vocal intensity was elicited via monaurally presented multitalker background noise.

The effect of increased vocal intensity on interarticulator timing in speakers with Parkinson’s disease: a preliminary analysis.

Purpose: The purpose of the current study was to investigate the effect of increased vocal intensity on interarticulator timing in individuals with Parkinson's disease (PD).

Methods: Ten individuals with mild to moderate hypophonia, secondary to PD, were selected for study. Over an 8-week treatment period, multi-talker babble noise was presented monaurally to the individuals with PD during everyday communication contexts to elicit increased vocal intensity (Lombard effect).

Increased vocal intensity due to the Lombard effect in speakers with Parkinson's disease: simultaneous laryngeal and respiratory strategies.

Purpose: The objective of the present study was to investigate whether speakers with hypophonia, secondary to Parkinson's disease (PD), would increases their vocal intensity when speaking in a noisy environment (Lombard effect). The other objective was to examine the underlying laryngeal and respiratory strategies used to increase vocal intensity.

Methods: Thirty-three participants with PD were included for study.

Changes in acoustic characteristics of the voice across the life span: measures from individuals 4-93 years of age.

Purpose: The purpose of the present investigation was to examine acoustic voice changes across the life span. Previous voice production investigations used small numbers of participants, had limited age ranges, and produced contradictory results.

Method: Voice recordings were made from 192 male and female participants 4-93 years of age.

Perceptual evaluation of hypernasality compared to HONC measures: the role of experience.

Objectives: Nasality ratings from experienced and inexperienced listeners were compared to accelerometric measures using the Horii Oral Nasal Coupling (HONC) Index to determine if one group's ratings are more closely related to the HONC Index measures. The reliability of listener ratings was studied to determine if experienced listeners had better reliability than inexperienced listeners. The influence of phonetic content was analyzed to learn if ratings of sentences with stop consonants yielded higher correlations with HONC scores than sentences containing glides.

The control of aerodynamics, acoustics, and perceptual characteristics during speech production.

One of the most important areas of study in speech motor control is the identification of control variables, the variables controlled by the nervous system during motor tasks. The current study examined two hypotheses regarding control variables in speech production: (1) pressure and resistance in the vocal tract are controlled, and (2) perceptual and acoustic accuracy are controlled. Aerodynamic and acoustic data were collected on 20 subjects in three conditions, normally (NT), with an open air pressure bleed tube in place (TWB), and with a closed bleed tube in place (TNB).

Respiratory and laryngeal responses to an oral air pressure bleed during speech.

Researchers have hypothesized that the respiratory and laryngeal speech subsystems would respond to an air pressure bleed, but these responses have not been empirically studied. The present study examined the nature of the responses of the respiratory and laryngeal subsystems to an air pressure bleed in order to provide information relevant to the nature of motor control for speech. Participants produced a syllable train consisting of 7 syllables of [pa] 10 times with and without an air pressure bleed in place.