Effects of a circumferentially vented mask on breathing patterns of women as measured by respiratory kinematic techniques

Phonation Demonstrates Goal Dependence Under Unique Vocal Intensity and Aerobic Workload Conditions

Purpose This study investigated whether metabolic respiratory requirements (treadmill workload) affected glottal valving in phonation, based on aerodynamic measures, when a sound pressure level (vocal SPL) is dictated as a target goal. Consistent with a theory of action, we hypothesized that adjustments in glottal valving as measured by laryngeal airway resistance would be dependent upon vocal SPL level, even as workload increased, and loud vocal SPL would interfere more with respiratory homeostasis than spontaneous vocal SPL. Method Thirty-two women enrolled who were ages 18-35 years. A repeated-measures design was used with random assignment of workload and vocal SPL conditions. Aerodynamic and acoustic data were collected during phonation, as were gas volume and concentration data. Analyses were performed with generalized estimating equations. Results Laryngeal airway resistance at a low workload significantly increased when vocal SPL changed from spontaneous to loud. At a loud vocal SPL, laryngeal airway resistance decreased when workload changed from rest to either low or high. Regarding the respiratory system response, minute ventilation increased at a loud vocal SPL when workload changed from rest to either low or high. End-tidal CO₂ increased under low and high workloads relative to rest at loud and spontaneous vocal SPLs. Conclusions Mostly consistent with a theory of action, in which motor control is goal dependent (i.e., vocal SPL targets), speakers can achieve a loud vocal SPL despite increases in workload requirements. In contrast, laryngeal airway resistance stays relatively low when vocal SPL occurs spontaneously, suggesting glottal adjustments are made to improve gas exchange as metabolic respiratory requirements become prioritized. Metabolic respiratory requirements appear to be overcome by the overlay of motor control for voicing when a loud vocal SPL is targeted. The implication of goal-dependent phonation for clinicians is that real-world conditions (i.e., loud vocal SPL) matter in vocal testing and voice therapy.

Respiratory kinematic and airflow differences between reflex and voluntary cough in healthy young adults

Background: Cough is a defensive behavior that can be initiated in response to a stimulus in the airway (reflexively), or on command (voluntarily). There is evidence to suggest that physiological differences exist between reflex and voluntary cough; however, the output (mechanistic and airflow) differences between the cough types are not fully understood. Therefore, the aims of this study were to determine the lung volume, respiratory kinematic, and airflow differences between reflex and voluntary cough in healthy young adults.

Methods: Twenty-five participants (14 female; 18–29 years) were recruited for this study. Participants were evaluated using respiratory inductance plethysmography calibrated with spirometry. Experimental procedures included: (1) respiratory calibration, (2) three voluntary sequential cough trials, and (3) three reflex cough trials induced with 200 μM capsaicin.

Results: Lung volume initiation (LVI; p = 0.003) and lung volume excursion (LVE; p < 0.001) were significantly greater for voluntary cough compared to reflex cough. The rib cage and abdomen significantly influenced LVI for voluntary cough (p < 0.001); however, only the rib cage significantly impacted LVI for reflex cough (p < 0.001). LVI significantly influenced peak expiratory flow rate (PEFR) for voluntary cough (p = 0.029), but not reflex cough (p = 0.610).

Discussion: Production of a reflex cough results in significant mechanistic and airflow differences compared to voluntary cough. These findings suggest that detection of a tussigenic stimulus modifies motor aspects of the reflex cough behavior. Further understanding of the differences between reflex and voluntary cough in older adults and in persons with dystussia (cough dysfunction) will be essential to facilitate the development of successful cough treatment paradigms.

Nasal and oral inspiration during natural speech breathing

PURPOSE

The purpose of this study was to determine the typical pattern for inspiration during speech breathing in healthy adults, as well as the factors that might influence it.

METHOD

Ten healthy adults, 18–45 years of age, performed a variety of speaking tasks while nasal ram pressure, audio, and video recordings were obtained. Inspirations were categorized as nasal-only, oral-only, simultaneous nasal and oral, or alternating nasal and oral inspiration. The method was validated using nasal airflow, oral airflow, audio, and video recordings for 2 participants.

RESULTS

The predominant pattern was simultaneous nasal and oral inspirations for all speaking tasks. This pattern was not affected either by the nature of the speaking task or by the phonetic context surrounding the inspiration. The validation procedure confirmed that nearly all inspirations during counting and paragraph reading were simultaneous nasal and oral inspirations, whereas for sentence reading, the predominant pattern was alternating nasal and oral inspirations across the 3 phonetic contexts.

CONCLUSIONS

Healthy adults inspire through both the nose and mouth during natural speech breathing. This pattern of inspiration is likely beneficial in reducing pathway resistance while preserving some of the benefits of nasal breathing.

Ventilation and speech characteristics during submaximal aerobic exercise

PURPOSE

This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks.

METHOD

Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO(2) max). Measures of ventilation, oxygen consumption, heart rate, perceived dyspnea, syllables per phrase, articulation rate, and inappropriate linguistic pause placements were obtained at baseline and throughout the experimental tasks.

RESULTS

Ventilation was significantly lower during the speaking tasks compared with the nonspeaking tasks. Oxygen consumption, however, did not significantly differ between speaking and nonspeaking tasks. The perception of dyspnea was significantly higher during the speaking tasks compared with the nonspeaking tasks. All speech parameters were significantly altered over time at both task intensities.

CONCLUSIONS

It is speculated that decreased ventilation without a reduction in oxygen consumption implies that utilization of oxygen by the working muscles was increased during the speaking tasks to meet the metabolic needs. A greater ability to utilize oxygen from inspired air is found in individuals who are at higher fitness levels, and therefore these findings may have implications for individuals who must complete simultaneous speech and exercise for occupational purposes (e.g., fitness/military drill instructors, singers performing choreography).

Heart-rate and blood-pressure variability during psychophysiological tasks involving speech: influence of respiration

Changes in heart-rate and systolic arterial pressure variability (HRV and SAPV) indexes have been used in psychophysiology to assess autonomic activation, including during tasks involving speech. The current article clearly demonstrates in a sample of 25 adult subjects that the erratic and broadband respiratory patterns during such tasks violate the usual assumption that respiration is limited to the high-frequency band (0.15-0.4 Hz). For these tasks, interindividual differences and rest-task changes in HRV and SAPV in the low-frequency band (0.04-0.15 Hz) can be explained, to a large extent, by variations in the respiratory volume signal. This makes the use of HRV and SAPV as markers of autonomic function during these tasks highly questionable. Furthermore, a number of subjects with long respiratory period at rest were identified, whose presence in the sample can bias the estimation of baseline rest values.

Effect of facemask use on respiratory patterns of women in speech and singing

PURPOSE

Research into respiratory behavior during singing and speech makes extensive use of standard respiratory and vented pneumotachograph facemasks. This study investigated whether the use of such facemasks would affect respiratory behavior in terms of lung volume (excursion, at initiation and at termination) or duration (of inspiration and of expiration) during speech or singing.

METHOD

The respiratory patterns of 6 females were recorded using uniaxial surface magnetometry during 4 tasks: quiet breathing, a /pa/ syllabic train, reading ("The Rainbow Passage"), and singing a Christmas carol ("Silent night"). Each task was performed in 4 facemask conditions: wearing no facemask, wearing a facemask rim only, wearing a standard respiratory facemask, and wearing a vented pneumotachograph facemask.

RESULTS

No significant effect was found for any of the facemask conditions on lung volume or duration measures during any tasks.

CONCLUSION

The results confirm earlier studies that the vented pneumotachograph facemask does not affect breathing behavior in speech research studies and extends the finding to the study of breathing behavior in singing and to the use of a standard respiratory facemask.

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. Acoustic, aerodynamic, and respiratory kinematic data were collected. In the bleed condition, peak intraoral air pressure and average oral airflow during the [a] were lower, lung and rib cage volume excursions were longer, and rib cage volume terminations were more negative. This study provides empirical data demonstrating a clear interaction among the speech subsystems. Both active and passive mechanisms are suggested by the subsystems' responses.

Influence of continuous speaking on ventilation

This study was conducted to explore the influence of speaking on ventilation. Twenty healthy young men were studied during periods of quiet breathing and prolonged speaking using noninvasive methods to measure chest wall surface motions and expired gas composition. Results indicated that all subjects ventilated more during speaking than during quiet breathing, usually by augmenting both tidal volume and breathing frequency. Ventilation did not change across repeated speaking trials. Quiet breathing was altered from its usual behavior following speaking, often for several minutes. Speaking-related increases in ventilation were found to be strongly correlated with lung volume expenditures per syllable. These findings have clinical implications for the respiratory care practitioner and the speech-language pathologist.