Examining a respiratory control model using an allometric analysis of speech breathing

1992 ◽  
Vol 92 (4) ◽  
pp. 2389-2389
Author(s):  
David M. Hogue ◽  
Robert J. Porter
2014 ◽  
Vol 14 (02) ◽  
pp. 1450014 ◽  
Author(s):  
SHYAN-LUNG LIN ◽  
NAI-REN GUO ◽  
TSUNG-CHI CHEN

There has been considerable research effort regarding ventilatory responses to breathing with an imposed external dead space, and inhalation of fixed levels of CO 2 by human subjects. A human respiratory control model incorporating the optimality hypothesis can successfully demonstrate ventilatory responses to both chemical stimuli and muscular exercise. In this study, to verify the model behavior of the optimal chemical–mechanical respiratory control model, we simulated the ventilatory control under dead space loading and CO 2 inhalation. The simulation was provided by a LabVIEW® based human respiratory control simulator and signal monitoring system. The dead space measurement was described with two distinct models, derived from Gray and Coon, and predicted behaviors with corresponding ventilatory responses were investigated and compared with experimental findings. While both dead space models produced satisfactory predictions on simulated optimal [Formula: see text] versus Pa CO 2, [Formula: see text] versus Pa CO 2, F versus PI CO 2, VT versus PI CO 2, VD-total versus VT, VD- total /VT versus VT, [Formula: see text] versus VT and [Formula: see text] versus VT relationships, Gray's model provided better correlation and more consistent results throughout most of the ventilatory responses. The study of relative behavior of respiratory signals and comparative relationship of the ventilator responses between dead space loading during rest and CO 2 inhalation will certainly provide valuable understanding of increases in central respiratory motor command output of human respiratory control, which is also associated with Dyspnea on exertion, and give potential clinical perspective to realize the impaired ability to excrete CO 2 in patients diagnosed with acute respiratory distress syndrome.


2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Casey O. Diekman ◽  
Peter J. Thomas ◽  
Christopher G. Wilson

2021 ◽  
pp. 026921552199247
Author(s):  
Jie Wang ◽  
Gaiyan Li ◽  
Shanshan Ding ◽  
Long Yu ◽  
Yan Wang ◽  
...  

Objective: The aim of the study was to investigate whether liuzijue qigong could improve the ability of respiratory control and comprehensive speech in patients with stroke dysarthria. Design: A randomized controlled trial. Setting: The research was carried out in the department of rehabilitation. Participants: Altogether, a total of 98 stroke patients with dysarthria participated in the study. Interventions: Patients were randomly divided into two groups (the experimental group: basic articulation + liuzijue qigong, 48 patients or the control group: basic articulation + traditional breathing training, 50 patients). All therapies were conducted once a day, five times a week for three weeks. Main measures: Primary outcome measure: Speech breathing level of the modified Frenchay Dysarthria Assessment. Secondary outcome measures: the modified Frenchay Dysarthria Assessment, maximum phonation time, maximal counting ability, /s/, /z/, s/z ratio, and the loudness level. All outcome measures were assessed twice (at baseline and after three weeks). Results: At three weeks, There were significant difference between the two groups in the change of speech breathing level (81% vs 66%, P = 0.011), the modified Frenchay Dysarthria Assessment (5.54 (4.68–6.40) vs 3.66 (2.92–4.40), P = 0.001), maximum phonation time (5.55 (4.92–6.18) vs 3.01(2.31–3.71), P < 0.01), maximal counting ability (3.08(2.45–3.71) vs 2.10 (1.53–2.67), P = 0.018), and /s/ (3.08 (2.39–3.78) vs 1.87 (1.23–2.51), P = 0.004), while no significant differences were found in the change of /z/ (3.08 (2.31–3.86) vs 2.10 (1.5–2.64), P = 0.08), s/ z ratio (1.26 (0.96–1.55) vs 1.03 (0.97–1.09), P = 0.714), and the change of loudness level (69% vs 60%, P = 0.562). Conclusions: Liuzijue qigong, combined with basic articulation training, could improve the respiratory control ability, as well as the comprehensive speech ability of stroke patients with dysarthria. Trial registration: ChiCTR-INR-16010215.


2017 ◽  
Vol 118 (4) ◽  
pp. 2194-2215 ◽  
Author(s):  
Casey O. Diekman ◽  
Peter J. Thomas ◽  
Christopher G. Wilson

How sensory information influences the dynamics of rhythm generation varies across systems, and general principles for understanding this aspect of motor control are lacking. Determining the origin of respiratory rhythm generation is challenging because the mechanisms in a central circuit considered in isolation may be different from those in the intact organism. We analyze a closed-loop respiratory control model incorporating a central pattern generator (CPG), the Butera-Rinzel-Smith (BRS) model, together with lung mechanics, oxygen handling, and chemosensory components. We show that 1) embedding the BRS model neuron in a control loop creates a bistable system; 2) although closed-loop and open-loop (isolated) CPG systems both support eupnea-like bursting activity, they do so via distinct mechanisms; 3) chemosensory feedback in the closed loop improves robustness to variable metabolic demand; 4) the BRS model conductances provide an autoresuscitation mechanism for recovery from transient interruption of chemosensory feedback; and 5) the in vitro brain stem CPG slice responds to hypoxia with transient bursting that is qualitatively similar to in silico autoresuscitation. Bistability of bursting and tonic spiking in the closed-loop system corresponds to coexistence of eupnea-like breathing, with normal minute ventilation and blood oxygen level and a tachypnea-like state, with pathologically reduced minute ventilation and critically low blood oxygen. Disruption of the normal breathing rhythm, through either imposition of hypoxia or interruption of chemosensory feedback, can push the system from the eupneic state into the tachypneic state. We use geometric singular perturbation theory to analyze the system dynamics at the boundary separating eupnea-like and tachypnea-like outcomes. NEW & NOTEWORTHY A common challenge facing rhythmic biological processes is the adaptive regulation of central pattern generator (CPG) activity in response to sensory feedback. We apply dynamical systems tools to understand several properties of a closed-loop respiratory control model, including the coexistence of normal and pathological breathing, robustness to changes in metabolic demand, spontaneous autoresuscitation in response to hypoxia, and the distinct mechanisms that underlie rhythmogenesis in the intact control circuit vs. the isolated, open-loop CPG.


Sign in / Sign up

Export Citation Format

Share Document