Treatment of Exercise-induced Laryngeal Obstruction : Exploring modalities in short and long term

Background: Exercise-induced laryngeal obstruction (EILO) is an umbrella term describing inappropriate and transient closure of laryngeal structures during exercise, causing breathlessness and/or noisy respiration (stridor). EILO is a relatively prevalent entity, affecting adolescents or young adults in all activity levels. The condition has been reported to have a considerable functional impact, particularly as a limitation of physical activity in an effort to minimize the occurrence and severity of inspiratory symptoms. Objective visualization of the laryngeal obstruction and determining the level of obstruction within the larynx (supraglottic and/or glottic) during ongoing exercise is considered gold-standard for diagnosing EILO and seems of importance for subsequent treatment planning. Treatment options are based on weak evidence, with evaluation of different modalities mainly based on subjective outcomes. Information about the diagnosis and breathing advice (IBA) seems to be fundamental elements. Small studies and case reports suggests effect from speech therapy, biofeedback, inspiratory muscle training (IMT) and surgical supraglottoplasty. Robust treatment algorithms and follow-up streams are yet to be established. Aims: The overall aim of the thesis was to explore improvement of symptoms and laryngeal obstruction in EILO patients treated with IMT and supraglottoplasty in short- and long term. Study #I: To investigate laryngeal response pattern(s) during inspiratory muscle training (IMT) in healthy subjects using laryngoscopic evaluation and imaging. Study #II: To expand our knowledge and to explore possible effects from inspiratory muscle training in patients diagnosed with EILO. Study #III: To investigate the efficacy and safety of laser supraglottoplasty for patients with supraglottic EILO, using continuous laryngoscopy exercise (CLE) tests before and after surgery. Study #IV: To assess changes of self-reported symptoms and laryngeal outcomes shortly after IMT, and to compare self-reported symptoms with a control group 4-6 years later. Methods: Study design: An explorative approach with combined descriptive and quasi-experimental observational design. Study #I: cross-sectional study, Study #II: prospective pre-post study Study #III: retrospective pre-post study. Study #IV: follow-up study. Subjects and study procedures: Study #I: Twenty healthy volunteers examined with laryngoscopy during inspiratory muscle training (IMT). The laryngeal movements were retrospectively assessed from video files. Study# II and #III: EILO patients examined with continuous laryngoscopy exercise (CLE)-test before and after a treatment; six-week training program with IMT or supraglottoplasty. Outcome data were self-reported symptom scores and laryngeal obstruction (by CLE-scores from video recordings). Study #IV: Two groups were retrospectively identified from the EILO-register; one group receiving IBA only at diagnosis, and the other additionally receiving six weeks of IMT (IBA+IMT). Laryngeal outcome was assessed shortly after IMT, and the two groups’ self-reported symptoms were compared with a new questionnaire 4-6 years later. Results: Study #I: IMT facilitated laryngeal abduction in the investigated healthy subjects and application of medium intensity resistance seemed superior to higher resistance in opening of the laryngeal aperture. Study #II: IMT was safe and the perceived symptoms and laryngeal obstruction improved in subgroups of EILO after IMT, with improvement mainly observed at the glottic level. Study #III: Supraglottoplasty improved symptoms and reduced laryngeal obstruction in the investigated patients with predominantly supraglottic EILO and appeared safe in highly selected severe cases. Notably, supraglottoplasty might improve also glottic obstruction in patients with combined supraglottic and glottic obstruction. Study #IV: The response rate after 4-6 years was 40 % in the IBA-group and 55% in IBA+IMT-group. After 2-4 weeks, 23/32 in the IBA+IMT-group reported symptom improvements, associated mainly with glottic changes, contrasting unchanged laryngeal scores in 9/32 without symptom improvements. After 4-6 years, self-reported exercise-related symptoms and activity had decreased to similar levels in both groups. Full symptom resolution was reported by 8/55. Conclusion: Self-reported symptoms and laryngeal obstruction as observed and rated in CLE-tests can improve in EILO patients treated with IBA, IMT or supraglottoplasty. Heterogeneous responses to treatment were observed and substantiates that EILO is a heterogeneous condition, thus it is unlikely that one mode of treatment will work in all. Individual treatment and follow-up based on laryngeal findings seems essential. Future controlled studies with longer follow-up time are needed to establish effects from the treatment modalities applied in EILO patients. This work provides hypotheses that may serve as a basis in doing so.Doktorgradsavhandlin

Frictional Fluid Dynamics and Plug Formation in Multiphase Millifluidic Flow

We study experimentally the flow and patterning of a granular suspension displaced by air inside a narrow tube. The invading air-liquid interface accumulates a plug of granular material that clogs the tube due to friction with the confining walls. The gas percolates through the static plug once the gas pressure exceeds the pore capillary entry pressure of the packed grains, and a moving accumulation front is reestablished at the far side of the plug. The process repeats, such that the advancing interface leaves a trail of plugs in its wake. Further, we show that the system undergoes a fluidization transition—and complete evacuation of the granular suspension—when the liquid withdrawal rate increases beyond a critical value. An analytical model of the stability condition for the granular accumulation predicts the flow regime

An investigation into the causal factors of the Kråknes landslide

On the 3rd of June 2020, a landslide measuring 600 meters long and 160 meters wide initiated along the shoreline at Kråknes, in Alta municipality in Troms and Finnmark County. The landslide was comprised of a series of smaller slides, which destroyed eight houses and a caravan in the process. Fortunately, no human lives were lost in the event. Due to the widespread presence of sensitive clays along the Norwegian coast, numerous areas are at the potential risk of landslides. As these landslides pose a risk to human life and infrastructure, a better understanding of what promotes instability and triggers these types of landslides is necessary. The goal of this thesis is to determine the causal factors responsible for the slope failure at Kråknes. To do this, hydrometeorology, ground conditions and human activity were analyzed in combination with slope stability modeling. The array of data used in this thesis comprises meteorological reports and models, field observations, unmanned aerial vehicle surveys, LiDAR- and bathymetry data, and a consultant geotechnical survey. The results indicate that the initial stability at Kråknes was low. Signs of quick- and sensitive clay were observed during fieldwork, and were also detected during the geotechnical survey. The layered stratigraphy of the ground conditions, with permeable- and non-permeable layers are interpreted to have intensified the leaching process of the marine clay and promoted the development of excess pore pressure. With the added load of the cabin building in 2015, it is suspected that the average stability at Kråknes was lowered enough to be triggered by an abrupt snowmelt event in the second half of May. As a result, the formation of a tension crack on the 2nd of June is interpreted to be the initiation of a progressive flake-type failure that spread north overnight to where the slide initiated below Kråknesveien 416 on the 3rd of June. The slope stability modeling supported the expected negative effects higher groundwater levels, excess pore pressure and external loading from the cabin building might have had. However, some model results regarding the dimension of the failure surface and factor of safety did not reflect reality

Comparison of relative biological effectiveness in passive scattering- and pencil beam scanning proton therapy of pediatric cancer

Masteroppgave i fysikkPHYS399MAMN-PHY

An Energy Efficient Localization Strategy for Outdoor Objects based on Intelligent Light-Intensity Sampling

A simple and low cost strategy for implementing pervasive objects that identify and track their own geographical location is proposed. The strategy, which is not reliant on any GIS infrastructure such as GPS, is realized using an electronic artifact with a built in clock, a light sensor, or low-cost digital camera, persistent storage such as flash and sufficient computational circuitry to make elementary trigonometric computations. The object monitors the lighting conditions and thereby detects and tracks the sunrise and sunset times. By the means of a simple celestial model an estimate of the geographical position of the object can be made. An intelligent light sampling method is proposed allowing the object to sleep most of the time and hence save battery power. The strategy is energy efficient and the speed of convergence can be adjusted as a function of the energy consumed. Objects employing the method can therefore operate for long times without recharging their batteries. The strategy has applications in mobile sensor networks where nodes need to log geographical information, sensing equipment such as floating buoyancies, or pervasive technologies in need of geo-spatial information such as digital cameras, mobile devices, etc

Towards calibration-free geo-localization of stationary outdoor webcams

This study proposes two strategies for determining the approximate geographical location of outdoor webcams based on time-series comprising regularly sampled images. The strategies require an accurate account of universal time and the date to be known, then the intensity of the images are used to estimate the sunrise and sunset times. Given accurate sunrise and sunset times a celestial model can be used to extract the latitude and longitude of the webcam. Webcams vary in quality, dynamic pixel depth and sensitivity to light. Two strategies are therefore proposed for avoiding the need to perform calibration. The first technique involves normalizing and noise-damping the image intensity measurements. The second technique employs a self-normalizing brightness ratio. The brightness ratio is computed from the overall brightness of the upper part of the image in relation to the bottom part. During day the sky is much brighter than the ground, while at night the sky is much darker than the ground if the ground is lit up. Experiments demonstrate that the intensity normalization strategy is the most robust and it is capable of determining the geographical location of webcams with an accuracy of approximately 2 degrees

Unsupervised and Fast Continent Classification of Digital Image Collections using Time

Advances in storage capacity means that digital cameras can store huge collections of digital photographs. Typically such images are given non-descriptive filenames names such as a unique identifier, often an integer. Consequently it is time-consuming and difficult to browse and retrieve images from large collections especially on small consumer electronics devices. A strategy for classifying images into geographical regions is presented which allows images to be coarsely sorted into the continent where they were taken. The strategy employs patterns in the time-stamps of images to identify events such as holiday and individual days, and to estimate the approximate longitude where the photographs were taken. Experimental evaluations demonstrate that the continent is correctly estimated for 89 % of the images in arbitrary collections and that the longitude is estimated with a mean error of 27.5 degrees. The strategy is relatively straightforward to implement, also in hardware, and computationally inexpensive

A Configurable Photo Browser Framework for Large Image Collections

Image collections are growing at an exponential rate due to the wide availability of inexpensive digital cameras and storage. Current browsers organize photos mostly chronologically, or according to manual tags. For very large collections acquired over several years it can be difficult to locate a particular set of images – even for the owner. Although our visual memory is powerful, it is not always easy to recall all of one’s images. Moreover, it can be very time consuming to find particular images in other peoples image collections. This paper presents a prototype image browser and a plug-in pattern that allows classifiers to be implemented and easily integrated with the image browser such that the user can control the characteristics of the images that are browsed and irrelevant photos are filtered out. The filters can both be content based and based on meta-information. The current version is only employs meta-information which means that large image collections can be indexed efficiently

On the Truthfulness of Petal Graphs for Visualisation of Data

A petal graph is an aesthetically attractive and applauded tool for visualising parameter sets. For instance, petal graphs are often used by Norwegian policy makers and decision makers in higher education as the Ministry of Education and Research relies on petal graphs in their reports. This study argues that petal graphs are prone to misinterpretation. It is challenging to interpret a petal graph in general, it is hard to compare two or more petal graphs and this study demonstrates that the physical characteristics of petal graphs can be incorrect in terms of the parameters on display. This study concludes that the use of petal graphs should be abolished and that other visualisation techniques to be used instead. Several alternatives are suggested