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Cardiac rehabilitation (CR) is a highly recommended secondary prevention measure for patients with diagnosed cardiovascular disease. Unfortunately, participation rates are low due to enrollment and adherence issues. As such, new CR delivery strategies are of interest, as to improve overall CR delivery. The goal of the study was to obtain a better understanding of the short-term progression of functional capacity throughout multidisciplinary CR, measured as the change in walking distance between baseline six-minute walking test (6MWT) and four consecutive follow-up tests. One-hundred-and-twenty-nine patients diagnosed with cardiovascular disease participated in the study, of which 89 patients who completed the whole study protocol were included in the statistical analysis. A one-way repeated measures ANOVA was conducted to determine whether there was a significant change in mean 6MWT distance (6MWD) throughout CR. A three-way-mixed ANOVA was performed to determine the influence of categorical variables on the progression in 6MWD between groups. Significant differences in mean 6MWD between consecutive measurements were observed. Two subgroups were identified based on the change in distance between baseline and end-of-study. Patients who increased most showed a linear progression. In the other group progression leveled off halfway through rehabilitation. Moreover, the improvement during the initial phase of CR seemed to be indicative for overall progression. The current study adds to the understanding of the short-term progression in exercise capacity of patients diagnosed with cardiovascular disease throughout a CR program. The results are not only of interest for CR in general, but could be particularly relevant in the setting of home-based CR. HDC is supported by a doctoral fellowship by the Research Foundation, Flanders (FWO), Belgium (grant number: 1S53616N). SVH acknowledges the financial support of imec. SVH's research received funding from the Flemish Government (AI Research Program). SVH, JFMT and CV's research is supported by Agentschap Innoveren en Ondernemen (VLAIO) (150466), OSA+. The funding organizations did not make a contribution to the creation of this manuscript. Acknowledgments: This research is part of the Limburg Clinical Research Center (LCRC) UHasselt-ZOL-Jessa, supported by the foundation Limburg Sterk Merk, province of Limburg, Flemish government, Hasselt University, Jessa Hospital and Ziekenhuis Oost-Limburg. We would like to thank the engineers from Holst center/imec the Netherlands for their technical support. We thank the physiotherapists of the cardiac rehabilitation center, Ziekenhuis Oost-Limburg, for their support and guidance during the study. We furthermore thank all the participants of this study. De Canniere, H (corresponding author), Hasselt Univ, Fac Med & Life Sci, Mobile Hlth Unit, B-3500 Hasselt, Belgium ; Ziekenhuis Oost Limburg, Future Hlth Dept, B-3600 Genk, Belgium. helene.decanniere@uhasselt.be; Christophe.smeets@uhasselt.be; Melanie.schoutteten@uhasselt.be; carolina.varon@esat.kuleuven.be; johnfredy.moralestellez@esat.kuleuven.be; chris.vanhoof@imec.be; sabine.vanhuffel@esat.kuleuven.be; Willemijn.groenendaal@imec.nl; pieter.vandervoort@zol.be

Background. Respiratory sinus arrhythmia (RSA) is a form of cardiorespiratory coupling. Its quantification has been suggested as a biomarker to diagnose different diseases. Two state-of-the-art methods, based on subspace projections and entropy, are used to estimate the RSA strength and are evaluated in this paper. Their computation requires the selection of a model order, and their performance is strongly related to the temporal and spectral characteristics of the cardiorespiratory signals. Objective. To evaluate the robustness of the RSA estimates to the selection of model order, delays, changes of phase and irregular heartbeats as well as to give recommendations for their interpretation on each case. Approach. Simulations were used to evaluate the model order selection when calculating the RSA estimates introduced before, as well as three different scenarios that can occur in signals acquired in non-controlled environments and/or from patient populations: the presence of irregular heartbeats; the occurrence of delays between heart rate variability (HRV) and respiratory signals; and the changes over time of the phase between HRV and respiratory signals. Main results. It was found that using a single model order for all the calculations suffices to characterize RSA correctly. In addition, the RSA estimation in signals containing more than 5 irregular heartbeats in a period of 5 min might be misleading. Regarding the delays between HRV and respiratory signals, both estimates are robust. For the last scenario, the two approaches tolerate phase changes up to 54°, as long as this lasts less than one fifth of the recording duration. Significance. Guidelines are given to compute the RSA estimates in non-controlled environments and patient populations.

Tertiary disease prevention for dementia focuses on improving the quality of life of the patient. The quality of life of people with dementia (PwD) and their caregivers is hampered by the presence of behavioral and psychological symptoms of dementia (BPSD), such as anxiety and depression. Non-pharmacological interventions have proved useful in dealing with these symptoms. However, while most PwD exhibit BPSD, their manifestation (in frequency, intensity and type) varies widely among patients, thus the need to personalize the intervention and its assessment. Traditionally, instruments to measure behavioral symptoms of dementia, such as NPI-NH and CMAI, are used to evaluate these interventions. We propose the use of activity trackers as a complement to monitor behavioral symptoms in dementia research. To illustrate this approach we describe a nine week Cognitive Stimulation Therapy conducted with the assistance of a social robot, in which the ten participants wore an activity tracker. We describe how data gathered from these wearables complements the assessment of traditional behavior assessment instruments with the advantage that this assessment can be conducted continuously and thus be used to tailor the intervention to each PwD.

El autismo es un trastorno del desarrollo neurológico que se caracteriza por deficiencias en la comunicación, la interacción social y por presentar comportamientos de conducta repetitivos o rutinarios. Los niños con autismo experimentan variaciones emocionales y problemas para auto-regular sus emociones. Estos comportamientos desafiantes se pueden exhibir en forma de agresiones, desobediencia o autolesiones. Los comportamientos desafiantes son comunes en niños con autismo que, sin una intervención adecuada, pueden persistir a largo plazo y poner en riesgo sus oportunidades educativas y sociales. La práctica de ejercicios de respiración y los sistemas de bio-retroalimentación pueden ayudar a reducir los comportamientos desafiantes mediante la reducción de la frecuencia cardiaca y respiratoria de los individuos que los presentan. En esta tesis nos enfocaremos en estudiar la respiración como una estrategia para apoyar a los niños con autismo en la reducción de su frecuencia respiratoria y cardiaca. Para ello, se diseño y desarrolló Respiración Etérea, un holograma interactivo de bio-retroalimentación que promueve la práctica de respiración en niños con autismo. Respiración Etérea cuenta con una narrativa la cual guía al niño a través de una historia mientras realiza ejercicios de respiración. Para evaluar la efectividad de Respiración Etérea se realizó un estudio en sitio donde participaron 20 niños con autismo. Todos los niños practicaron ejercicios de respiración utilizando Respiración Etérea yuna guía de papel. Los resultados indican que Respiración Etérea promueve respiraciones 1.74 veces más largas, y reduce de mejor manera la frecuencia cardiaca y respiratoria de los niños con autismo en comparación con la guía de papel. Los resultados de uso de Respiración Etérea indican que es atractiva, novedosa y útil en el contexto terapéutico de niños con autismo, y con el potencial de apoyar la auto-regulación de emociones y la generalización de habilidades. Estos resultados implican que Respiración Etérea es más eficiente como guía que las prácticas tradicionales en el desarrollo de ejercicios de respiración en niños con autismo. Autism is a neurodevelopmental disorder characterized by deficiencies in communication, social interaction and by presenting repetitive or routine behavior behaviors. Children with autism experience emotional variations and problems to self regulate their emotions. These challenging behaviors can be exhibited in the form of aggression, disobedience or self-harm. Challenging behaviors are children with autism who, without adequate intervention, can persist in the long term and put their educational and social opportunities at risk. The practice of breathing exercises and bio-feedback systems can help reduce challenging behaviors by reducing the heart and respiratory rate of the individuals who present them. In this thesis we focus on studying breathing as a strategy to help children with autism in reducing their respiratory and cardiac frequency. For this, Ethereal Respiration was designed and studied, an interactive bio-feedback hologram that promotes the practice of breathing in children with autism. Ethereal Breathing has a narrative which guides the child through a story by performing breathing exercises. To assess the effectiveness of Ethereal Breathing, a study was conducted at the site where 20 children with autism participated. All the children practiced breathing exercises using Ethereal Breathing and a paper guide. The results indicate that Ethereal Breathing promotes 1.74 times longer breaths, and reduction in a better way than the heart and respiratory rate of children with autism compared to the paper guide. The results of the use of Ethereal Breathing indicate that it is attractive, novel and useful in the therapeutic context of children with autism, and with the potential to support the self-regulation of emotions and the generalization of abilities. These results imply that Ethereal Breathing is more efficient than traditional activities in the development of exercises in children with autism.

In order to explore and analyze the effect of an ablation performed on the anterior corneal surface, it is useful to calculate the refractive power maps of the original and the treated corneas. The optical characteristics of the anterior corneal surfaces are typically simulated with different models, according to different degrees of simplification. To predict which ablation would improve the refractive power of such cornea, which is directly related with the spherical aberration associated with the shape of the anterior corneal surface, it is important to analyze those simplifications. Such information is displayed in a refractive power map, which yields the true refractive power of the corneal surface, point by point, expressing this power in diopters. The aim of the present work is twofold: different corneal models are simulated so as to compare the spherical aberration produced by each one. On the other hand, simulations are made in such a way that permits to foresee how the visual performance of an eye can be achieved by modifying the anterior surface of its cornea through the corresponding power maps.