Dynamics of airflow in a short inhalation

During a rapid inhalation, such as a sniff, the flow in the airways accelerates and decays quickly. The consequences for flow development and convective trans- port of an inhaled gas were investigated in a subject geometry extending from the nose to the bronchi. The progress of flow transition and the advance of an inhaled non-absorbed gas were determined using highly resolved simulations of a sniff 0.5 s long, 1 litre per second peak flow, 364 ml inhaled volume. In the nose, the distribution of airflow evolved through three phases: (i) an initial transient of about 50 ms, roughly the filling time for a nasal volume, (ii) quasi-equilibrium over the majority of the inhalation, and (iii) a terminating phase. Flow transition commenced in the supraglottic region within 20ms, resulting in large- amplitude fluctuations persisting throughout the inhalation; in the nose, fluctuations that arose nearer peak flow were of much reduced intensity and diminished in the flow decay phase. Measures of gas concentration showed non-uniform build-up and wash-out of the inhaled gas in the nose. At the carina, the form of the temporal concentration profile reflected both shear dispersion and airway filling defects owing to recirculation regions.Comment: 15 page

Characterization of the Airflow within an Average Geometry of the Healthy Human Nasal Cavity

This study’s objective was the generation of a standardized geometry of the healthy nasal cavity. An average geometry of the healthy nasal cavity was generated using a statistical shape model based on 25 symptom-free subjects. Airflow within the average geometry and these geometries was calculated using fluid simulations. Integral measures of the nasal resistance, wall shear stresses (WSS) and velocities were calculated as well as cross-sectional areas (CSA). Furthermore, individual WSS and static pressure distributions were mapped onto the average geometry. The average geometry featured an overall more regular shape that resulted in less resistance, reduced WSS and velocities compared to the median of the 25 geometries. Spatial distributions of WSS and pressure of the average geometry agreed well compared to the average distributions of all individual geometries. The minimal CSA of the average geometry was larger than the median of all individual geometries (83.4 vs. 74.7 mm²). The airflow observed within the average geometry of the healthy nasal cavity did not equal the average airflow of the individual geometries. While differences observed for integral measures were notable, the calculated values for the average geometry lay within the distributions of the individual parameters. Spatially resolved parameters differed less prominently

Using Beatboxing for Creative Rehabilitation After Laryngectomy:Experiences From a Public Engagement Project

Laryngectomy is the surgical removal of the larynx (voice box), usually performed in patients with advanced stages of throat cancer. The psychosocial impact of losing the voice is significant, affecting a person’s professional and social life in a devastating way, and a proportion of this patient group subsequently must overcome depression (22–30%) and social isolation (40%). The profound changes to anatomical structures involved in voicing and articulation, as a result of surgery, radiotherapy or chemotherapy (separately or in combination with one another), introduce challenges faced in speech rehabilitation and voice production that complicate social reintegration and quality of life. After laryngectomy, breathing, voicing, articulation and tongue movement are major components in restoring communication. Regular exercise of the chest, neck and oropharyngeal muscles, in particular, is important in controlling these components and keeping the involved structures supple. It is, however, a difficult task for a speech therapist to keep the patient engaged and motivated to practice these exercises. We have adopted a multidisciplinary approach to explore the use of basic beatboxing techniques to create a wide variety of exercises that are seen as fun and interactive and that maximize the use of the structures important in alaryngeal phonation. We herein report on our empirical work in developing patients’ skills, particularly relating to voiced and unvoiced consonants to improve intelligibility. In collaboration with a professional beatboxing performer, we produced instructional online video materials to support patients working on their own and/or with support from speech therapists. Although the present paper is focused predominantly on introducing the structure of the conducted workshops, the rationale for their design and the final public engagement performance, we also include feedback from participants to commence the critical discourse about whether this type of activity could lead to systematic underlying research and robustly assessed interventions in the future. Based on this exploratory work, we conclude that the innovative approach that we employed was found to be engaging, useful, informative and motivating. We conclude by offering our views regarding the limitations of our work and the implications for future empirical research

Olfactory Inputs Modulate Respiration-Related Activity In The Prefrontal Cortex And Fear Behavior

Voluntary control of respiration, especially via rhythmic nasal breathing, alleviates negative feelings such as fear and is used clinically to manage certain types of panic attacks. However, the neural substrates that link nasal breathing to fear circuits remains unknown. Here we show that during conditioned fear-induced freezing behavior, mice breathe at a steady rate (~4 Hz) which is strongly correlated with a predominant 4 Hz oscillation observed in the olfactory bulb and the prelimbic prefrontal cortex (plPFC), a structure critical for the expression of conditioned fear behaviors. We demonstrate anatomical and functional connectivity between the olfactory pathway and plPFC via circuit tracing and optogenetic approaches. Disrupting olfactory inputs significantly reduces the 4 Hz oscillation in the plPFC suggesting that respiration-related signals from the olfactory system play a role in entraining this fear-related signal. Surprisingly, we find that without olfactory inputs, freezing times are significantly prolonged. Collectively, our results indicate that olfactory inputs modulate rhythmic activity in fear circuits and suggest a neural pathway that may underlie the behavioral benefits of respiration-entrained olfactory signals

Unsteady-State Pressure and Flow Characteristics of the Human Nose: Pre- and Post-Nasal Turbinectomy

This research obtained quantitative data for pressure drop across the human nose during breathing. Quantitative and visual analyses of the transition between laminar and turbulent flow was also conducted. Controlling the flow of water through 2X scale models; pre- and post-turbinectomy, yielded a pressure versus flow rate curve, which demonstrated the transition between linear and quadratic flow. A hysteresis was observed which is concurrent with clinical observations. These findings suggest that the assumption of quasi-steady flow is invalid

A Preliminary Investigation of Velopharyngeal Timing in Normally Developing Preschool Children and Those with Speech Sound Disorders

As children acquire speech and language, they also begin to develop speech motor control. A widely accepted theoretical model for explaining speech acquisition and motor modifications necessary for appropriate speech is the Directions Into Velocities of Articulators (DIVA)model.This model posits that individuals plan and produce speech (feedforward system). If errors in speech are identified, they are modified since the DIVA Model includes a feedback system that is sensitive to such perturbations made during speech production (feedback system). This feedback system functions to make positive changes to one’s motor programming for speech. Literature suggests that children gain stability of articulators as they mature, but children with speech sound disorders (SSDs) achieve stability of articulators, e.g. jaw and lips, at a later age than their typically developing peers which may suggest a breakdown in their feedforward system. However, to our knowledge, no previous studies have analyzed velopharyngeal timing differences in children with SSDs in comparison to their typically developing peers. There is some limited evidence that suggests children with language delays present with delays in velopharyngeal development, which caused the researchers of the study to question the possibility of velopharyngeal timing differences in children with SSDs of unknown etiology. The findings of the current study indicate more variability in velopharyngeal timing for children with SSDs; however, comparison with children who had typically developing speech did not always show statistically significant differences. The trend of variability in velopharyngeal timing that was identified should be further examined with larger subject groups

Nasal flow at High Inspiration Pressures

This project develops and utilizes a system that replicates nasal breathing in order to visually document flow distributions and patterns under a wide range of breathing conditions. It is our hope that this approach and data will prove helpful in future medical research of nasal delivery systems. Our results show that there is a distinct change in flow pattern as pressure increases. This study also demonstrates that a turbinectomy also will change flow patterns and should be accounted for when designing nasal delivery systems

Understanding English Phonology: A Beginner's Guide

The purpose of this research is to provide understanding of English phonology to the learners who are new with English phonology. The method used in this research is literature review. This discussion explores the study of English sounds, known as English phonology. It covers important topics for beginners, such as understanding the basic units of sounds (phonemes) and their variations (allophones). The chat also introduces processes like assimilation, dissimilation, and deletion that affect how sounds change in spoken English. Additionally, it explains vowel and consonant reduction, which impact how certain sounds are pronounced. Lastly, the chat provides an overview of classifying consonant and vowel sounds based on their characteristics. By learning about these aspects, beginners can improve their pronunciation, understand different sound patterns, and enhance their overall communication skills in English

QUANTIFICATION OF PRETERM INFANT FEEDING COORDINATION: AN ALGORITHMIC APPROACH

Oral feeding competency is a primary requirement for preterm infant hospital release. Currently there is no widely accepted method to objectively measure oral feeding. Feeding consists primarily of the integration of three individual feeding events: sucking, breathing, and swallowing, and the objective of feeding coordination is to minimize aspiration. The purpose of this work was to quantify the infant feeding process from signals obtained during bottle feeding and ultimately develop a measure of feeding coordination. Sucking was measured using a pressure transducer embedded within a modified silicone bottle block. Breathing was measured using a thermistor embedded within nasal cannula, and swallowing was measured through the use of several different piezoelectric sensors. In addition to feeding signals, electrocardiogram (ECG) signals were obtained as an indicator of overall infant behavioral state during feeding. Event detection algorithms for the individual feeding signals were developed and validated, then used for the development of a measurement of feeding coordination. The final suck event detection algorithm was the result of an iterative process that depended on the validity of the signal model. As the model adapted to better represent the data, the accuracy and specificity of the algorithm improved. For the breath signal, however, the primary barrier to effective event detection was significant baseline drift. The frequency components of the baseline drift overlapped significantly with the breath event frequency components, so a time domain solution was developed. Several methods were tested, and it was found that the acceleration vector of the signal provided the most robust representation of the underlying breath signal while minimizing baseline drift. Swallow signal event detection was not possible due to a lack of available data resulting from problems with the consistency of the obtained signal. A robust method was developed for the batch processing of heart rate variability analysis. Finally a method of coordination analysis was developed based on the event detection algorithm outputs. Coordination was measured by determining the percentage of feeding time that consisted of overlapping suck and breath activity