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Investor distraction during the Swedish summer and stock market under-reaction to companies’ earnings releasesGuscott, Alyssa, Bach, My January 2011 (has links)
This paper investigates whether greater investor distraction on the Swedish stock market during the summer months of June, July and August leads to a more pronounced post earnings announcement drift (PEAD) effect, during the ten year period between 2000 and 2009. PEAD is an anomaly whereby the information contained in earnings announcements is not immediately or completely incorporated into stock prices, in the cases where the announcement contains an ‘earnings surprise’. The methodology involves using the standardised unexpected earnings (SUE) metric to measure the level of ‘earnings surprise’ and a buy and hold abnormal returns (BHAR) trading strategy to measure return. The study tests and confirms the existence of greater investor distraction during summer months on the Swedish market. For a holding period of 12 months, a BHAR trading strategy generates a greater abnormal return for summer months (11.3%) compared with the abnormal return for non-summer months (10.5%). These results are also interesting in a broader context, as they confirm the existence of the PEAD effect, one of the strongest counter-arguments to the efficient markets hypothesis (EMH); the foundation of many financial models used for stock market valuation. This is because, according to the EMH, in an efficient market it should not be possible to generate abnormal returns based on available information. However, it may be noted that these results do not take into account transaction costs. This means that while it can be demonstrated that there is greater investor distraction during the Swedish summer, in order to implement a successful trading strategy based on this finding, further testing would be required. Therefore, based on the findings of this paper, a number of areas for future research have been identified.
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Étude par éléments finis des effets de la distraction ostéogénique symphysaire sur l'articulation temporo-mandibulaireSavoldelli, Charles 12 July 2013 (has links) (PDF)
Les chirurgies de l'os mandibulaire peuvent modifier la position anatomique des disques et des condyles de l'articulation temporo-mandibulaire (ATM). Les modifications de contraintes qui en résultent peuvent être à l'origine d'une dislocation temporaire ou permanente du disque et peuvent provoquer des dysfonctionnements s'exprimant par des douleurs buccales et faciales. L'objectif de ce travail était de prévoir les modifications de contraintes dans l'articulation temporo-mandibulaire (ATM) après un protocole de distraction symphysaire mandibulaire (DS). Ce traitement chirurgical sert à traiter les encombrements dentaires de la mandibule.De manière à étudier l'impact d'une telle intervention au niveau de l'ATM, nous avons fait le choix de réaliser un modèle d'approche numérique de mastication par éléments finis. Les données géométriques ont été obtenues à partir de l'imagerie scanner et IRM d'un patient dont les composants de l'ATM ont été maillés. La chirurgie de distraction symphysaire a été réalisée sur le modèle avec un élargissement de 10 mm dans la région médiane de la mandibule. La géométrie et le maillage du cal osseux ont été reconstruits. Le cal osseux a été caractérisé par un module d'élasticité correspondant à l'os consolidé pour prédire l'effet biomécanique à long terme de la DS. Pour simuler une fermeture de la mâchoire, les conditions aux limites ont été appliquées au modèle sous la forme de vecteurs de force. Les champs de contraintes de von Mises dans les deux disques et condyles ont été analysés et comparés avant et après la DS. Contrairement aux approches habituellement menées, le modèle proposé est complet et ne contient pas de symétrie, de manière à mettre en évidence d'éventuelles asymétries dans la répartition des contraintes. La répartition des contraintes était proche dans les disques et sur les surfaces condyliennes dans les modèles avant et après distraction. Les résultats de cette étude suggèrent que les changements anatomiques des structures de l'ATM ne prédisposent pas à une fatigue des tissus. La DS n'exposerait donc pas au risque de dysfonction des ATM et de symptômes cliniques.
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Tools for Designing Mobile Interaction with the Physical Environment in Outdoor LessonsEliasson, Johan January 2013 (has links)
Mobile technologies are increasingly being used to support students in outdoor learning activities. For instance, in a growing number of research projects, smartphones and positioning technologies are being used to support students in exploring the natural environment. However, previous research has identified challenges with the introduction of mobile technology into outdoor lessons. One fundamental challenge is that interaction with mobile technology in outdoor lessons may distract students from interacting with the physical environment. In this thesis this challenge is approached from the perspective of human-computer interaction, guided by the following research question: How can we design, evaluate, and reflect on mobile technology for interacting with the physical environment in outdoor lessons? The thesis presents four design cases on outdoor geometry and biology lessons, which act as probes for developing conceptual design tools. The design cases were developed through a concept-driven design approach and evaluated on field tests with primary school students. Future workshop and Interaction analysis were the main methods used. The results of the field tests suggest that mobile technology needs to be designed to orientate students in their interaction with the physical environment. In line with the concept-driven design approach, the thesis proposes three design tools. The design tools proposed are: Design guidelines that are specific enough for guiding the design of mobile technology for outdoor lessons, a Design model for designing and evaluating mobile technology for outdoor lessons, and Design concepts for reflecting on the placement of mobile technology in outdoor lessons. The design tools are proposed as tools for researchers and designers to take the challenge of distraction into account in designing mobile technology for outdoor lessons. / Mobilteknologi används allt oftare för att stödja elever i läraktiviteter utomhus. Till exempel, i ett växande antal forskningsprojekt, används mobiltelefoner och teknik för positionsbestämning som stöd för skolelever i att utforska naturen. Tidigare forskning har dock identifierat utmaningar med införandet av mobilteknologi i utomhuslektioner. En av de huvudsakliga utmaningarna är att interaktion med mobilteknologi i utomhuslektioner kan distrahera eleverna från att interagera med den fysiska omgivningen. Den här avhandlingen angriper den utmaningen ur ett människa-datorinteraktionsperspektiv, vägledd av följande frågeställning: Hur kan vi designa, utvärdera och reflektera över mobilteknologi för att interagera med den fysiska omgivningen i utomhuslektioner? I avhandlingen presenteras fyra designinterventioner bestående av utomhuslektioner i geometri och biologi, som låg till grund för att utveckla konceptuella designverktyg. Designverktygen utvecklades genom en koncept-driven designstrategi och utvärderades i fälttester med skolelever. Framtidsverkstad och Interaktionsanalys var de huvudsakliga metoder som användes. Resultaten från fälttesterna visar att mobilteknologin behöver utformas så att den kan orientera eleverna i interaktionen med den fysiska omgivningen. I linje med den koncept-drivna designstrategin, bidrar avhandlingen med tre designverktyg. De föreslagna designverktygen är: Designriktlinjer som är specifika nog för att vägleda utformningen av mobilteknologi för utomhuslektioner, en Designmodell för att utforma och utvärdera mobilteknologi för utomhuslektioner, och Designkoncept för att reflektera över hur mobilteknologi placeras och används i utomhuslektioner. Designverktygen föreslås som verktyg för att forskare och designers, som vill designa mobilteknologi för utomhuslektioner, ska kunna möta utmaningen i att mobilteknologin kan distrahera eleverna från att interagera med den fysiska omgivningen.
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Prédiction des habiletés et habitudes de conduite automobile sécuritaire chez les conducteurs âgés : apport de la neuropsychologie cliniqueHazel, Mylène 12 1900 (has links)
L’insécurité routière chez les conducteurs âgés est attribuable en partie, aux effets délétères du vieillissement normal sur le fonctionnement cognitif. Les méthodes d’évaluation neuropsychologique par les tests ayant montré une certaine efficacité dans le cas du dépistage des habiletés de conduite chez les conducteurs âgés atteints d’affections neurologiques pathologiques, la présente thèse vise à évaluer la pertinence de cette approche chez les conducteurs vieillissants de la population générale. Le principal objectif de cette thèse est ainsi d’obtenir une vue d’ensemble sur le rôle et la sensibilité des mesures neuropsychologiques dans la prédiction des habiletés et habitudes de conduite automobile sécuritaire chez les conducteurs âgés. Dans la même perspective, la thèse explore d’autre part le rôle de variables sociodémographiques et psychologiques.
L’article 1 évalue la validité prédictive de sept tests des fonctions visuo-attentionnelles et de la mémoire de travail en regard des habiletés de détection périphérique chez 50 conducteurs âgés de 62 à 83 ans. L’étude sur simulateur de conduite comprend une condition de conduite simple et une condition plus soutenue incluant une distraction téléphonique de type « mains-libres ». Selon les résultats, certains tests cognitifs prédisent bien les temps de détection. En outre, la validité prédictive des tests est plus importante dans la situation de conduite plus exigeante. Cela dit, les résultats de l’article 2 révèlent que le recours aux stratégies d’évitement des situations exigeantes est plus prononcé chez les individus qui présentent des faiblesses à certains des tests neuropsychologiques proposés. Les résultats indiquent en outre que l’utilisation des stratégies d’évitement routier est plus fréquente chez les conducteurs ayant tendance à déprécier leurs habiletés de conduite générales, à exprimer une moindre perception de contrôle ainsi qu’une attitude défavorable à l’endroit des situations de conduite complexes ou risquées. Les stratégies d’évitement se révèlent donc comme des réponses autorégulatrices proportionnelles aux limitations cognitives et aux perceptions individuelles.
Dans les deux études, l’âge ne permet pas d’expliquer les différences individuelles, ceci ni en termes d’habiletés de détection périphérique ni de tendances autorégulatrices. Le rôle du genre est cependant plus nuancé.
Ainsi, le principal apport de la présente thèse réside dans la constatation que si d’une part, certaines limitations neuropsychologiques sont associées à une réduction des habiletés de détection périphérique, ces mêmes limitations s’accompagnent aussi de mesures autorégulatrices qui peuvent contribuer à réduire le risque routier. Il appert conséquemment que les méthodes de dépistage de l’insécurité routière chez les conducteurs âgés se basant sur l’évaluation des limitations cognitives et attentionnelles doivent également rechercher et évaluer la teneur de leurs comportements routiers autorégulateurs. Dans le contexte de vieillissement de la population, des interventions pourront également miser sur le renforcement de ces comportements. / The increase of crash rates in elderly population can be attributed in some part to the effects of normal aging on cognitive functioning. In the other hand, older drivers are likely to adopt self-regulated driving behaviours, such as driving habits to restrict their exposure to less complex situations. Neuropsychological assessments have shown some efficacy in the field of fitness-to-drive screening of older drivers suffering from neurological disorders. This thesis aims to assess the relevance of clinical neuropsychology in screening methods considering older drivers population. The main goal is thus to study the contribution and the sensitivity of neuropsychological testing in the prediction of skills and habits of safe driving among older drivers. In the same vein, the thesis investigates the role of other socio-demographic and psychological variables.
To this end, article 1 evaluates the predictive validity of seven tests of visuo-attentional functions and working memory efficiency in relation to peripheral detection task performances in 50 drivers aged from 62 to 83 years in a simulated car driving environment. The driving simulation consisted of a simple driving condition and a condition including a "hands-free" cell phone distraction task. The results indicate that some neuropsychological tests, as opposed to age, are good predictors of detection performances. In addition, the predictive validity of the tests is more important in the most challenging driving condition. The Corsi Block Tapping test, assessing visuospatial working memory, is revealed as on of the best predictor of detection skills.
Article 2 was carried from previous neuropsychological testing and self-administered questionnaires related to avoidance driving behaviours, drivers perceptions and attitudes. The results indicate that individuals who show higher difficulties in tests assessing visuospatial working memory, processing speed, and divided and selective attention capacities are significantly more likely to adopt avoidance driving strategies. The results also demonstrate that driving avoidance is higher among drivers who tend to depreciate their general driving skills, to express a lower perception of control and an unfavourable attitude towards risky driving. Avoidance strategies are thus proven to be self-regulatory responses which are proportionate to cognitive limitations and individual perceptions.
In summary, this thesis demonstrates that peripheral detection performances of older drivers in a simulated car study, are well reflected in neuropsychological testing assessing working memory and other attentional abilities. Since detection skills are crucial for driving safety, an indirect link can be established between neuropsychological measures and road safety among older drivers. It also seems that those drivers, who have greater cognitive limitations, are more likely to avoid challenging driving situations, thereby balancing their crash risk. It is concluded that fitness-to-drive assessments based on neuropsychological screening need to be complemented with the assessment of self-regulatory behaviors. In the context of an aging population, new interventions should focus on strengthening self-regulatory behaviors of older drivers.
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Impulsivity in college students with and without ADHD /Miller, Jessica A. January 2010 (has links) (PDF)
Thesis (Au.D.)--James Madison University, 2010. / Includes bibliographical references.
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Smart Car Technologies: A Comprehensive Study of the State of the Art with Analysis and TrendsJanuary 2015 (has links)
abstract: Driving is already a complex task that demands a varying level of cognitive and physical load. With the advancement in technology, the car has become a place for media consumption, a communications center and an interconnected workplace. The number of features in a car has also increased. As a result, the user interaction inside the car has become overcrowded and more complex. This has increased the amount of distraction while driving and has also increased the number of accidents due to distracted driving. This thesis focuses on the critical analysis of today’s in-car environment covering two main aspects, Multi Modal Interaction (MMI), and Advanced Driver Assistance Systems (ADAS), to minimize the distraction. It also provides deep market research on future trends in the smart car technology. After careful analysis, it was observed that an infotainment screen cluttered with lots of small icons, a center stack with a plethora of small buttons and a poor Voice Recognition (VR) results in high cognitive load, and these are the reasons for the increased driver distraction. Though the VR has become a standard technology, the current state of technology is focused on features oriented design and a sales driven approach. Most of the automotive manufacturers are focusing on making the VR better but attaining perfection in VR is not the answer as there are inherent challenges and limitations in respect to the in-car environment and cognitive load. Accordingly, the research proposed a novel in-car interaction design solution: Multi-Modal Interaction (MMI). The MMI is a new term when used in the context of vehicles, but it is widely used in human-human interaction. The approach offers a non-intrusive alternative to the driver to interact with the features in the car. With the focus on user-centered design, the MMI and ADAS can potentially help to reduce the distraction. To support the discussion, an experiment was conducted to benchmark a minimalist UI design. An engineering based method was used to test and measure distraction of four different UIs with varying numbers of icons and screen sizes. Lastly, in order to compete with the market, the basic features that are provided by all the other competitors cannot be eliminated, but the hard work can be done to improve the HCaI and to make driving safer. / Dissertation/Thesis / Date collected about reaction time in the experiment_Excel / Masters Thesis Computer Science 2015
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Análise da estabilidade funcional de um distrator osteogênico osseosuportado utilizando o método dos elementos finitos / Functional Stability Analysis of an Endosseous Distractor Osteogenesis Using the Finite Elements MethodArantes, Margareth Gomes Rosa 19 September 2007 (has links)
The distraction osteogenesis is a surgical technique used in the dentistry for the transversal
discrepancies correction of the jaw, having as basic principle the intrinsic capacity of some
tissue development when submitted to the stress caused by slow and continuous traction. To
obtain the osteogenesis success, the distractors osteogenesis symphysianic have to
minimize any bone parts displacement. This work had the purpose to evaluate the stability of
a distractor symphysis through three-dimensional models of finite elements where different
setting positions and different amounts of setting screws are evaluated. The stability was
evaluated through the determination of vertical displacements in the load direction in the
range of 20 up to 140 N. Additionally; the results of an experimental analysis had been used
to adjust the numerical models of finite elements. It was observed that, for the load profile
applied, the stability is not a function of setting screws number. The stiffness of the distractor
at cut region was the cause of the differences between fixations. In the distractor lower
position setting the displacements levels had been lesser, indicating a better distractor
stability. / A distração osteogênica é uma técnica cirúrgica utilizada na Odontologia para a correção de
discrepâncias transversais da mandíbula, tendo como princípio fundamental a capacidade
intrínseca de alguns tecidos vivos de se desenvolverem quando submetidos à tensão
provocada por tração lenta e contínua. Para se conseguir sucesso na osteosíntese, os
distratores osteogênicos sinfiseanos têm que minimizar qualquer tipo de movimento entre os
segmentos ósseos obtidos com o corte. Este trabalho tem por finalidade avaliar a
estabilidade de um tipo de distrator da sínfise mentoniana através de modelos
tridimensionais de elementos finitos onde são avaliadas diferentes posições de fixação e
diferentes quantidades de parafusos de fixação. A estabilidade foi avaliada através da
determinação dos deslocamentos verticais na direção do carregamento variando as cargas
de 20 a 140 N. Paralelamente, foram utilizados os resultados de uma análise experimental
para ajustar os modelos numéricos de elementos finitos. A análise indicou que, para o tipo
de cargas aplicadas, a estabilidade não depende do número de parafusos de fixação e sim
da rigidez do distrator na região do corte. Na posição de fixação inferior do distrator os níveis
de deslocamentos foram menores, indicando uma melhor estabilidade do distrator. / Mestre em Engenharia Mecânica
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Evaluation of drivers\' behavior performing a curve under mental workload / Avaliação do comportamento dos condutores para realizar uma curva sob distração mentalFábio Sartori Vieira 20 April 2016 (has links)
Driving under distraction may lead drivers to wrong actions that can result in serious accidents. The objective of this thesis was to apply a driving simulator to verify variations in drivers\' behavior while driving. Behavior to drive on a curve was measured by variation in drivers\' speed profile in a virtualized highway. The comparison was performed between two identical simulations, one involving drivers distracted with a mental workload, and other in which they were full aware of driving task. 54 volunteer drivers took part in this study, which was divided into 4 stages. 17 drivers performed the distraction test known as PASAT, and results showed that distracted drivers did not recognize the beginning of the curve and drove through it at speeds higher than those when they were fully aware. Moreover, driving performance was increased when drivers were aware of driving, thereby hitting high speeds in tangents, but perceiving curves in advance to reduce acceleration. This study confirms that driving simulators are beneficial in discovering drivers\' behavior exposed to activities that could be highly risky if driving in real situations. / A distração durante a atividade de direção pode levar o condutor de veículos automotores a cometer falhas, que podem ocasionar até mesmo acidentes graves. Este estudo aborda a utilização de simuladores de direção para verificar variações no comportamento de motoristas ao realizar a atividade de direção, distraídos ou com plena atenção na condução do veículo. O comportamento é medido pela variação no perfil de velocidade dos condutores para desenvolver uma curva considerada perigosa em uma rodovia simulada em ambiente virtual. A variação de velocidade deste perfil é comparada entre duas simulações idênticas, onde em uma delas os condutores estão distraídos com um teste que proporciona estresse mental e, na outra, estão com plena atenção à direção. 54 condutores fizeram parte deste estudo dividido em 3 etapas. 17 participantes realizaram o teste de distração conhecido como PASAT, e a análise dos resultados mostram que, distraídos, os condutores não perceberam o início da curva e desenvolveram velocidades maiores durante seu trajeto. Além disso, quando estavam com plena atenção à atividade de direção, o desempenho dos condutores foi melhor, atingindo velocidades maiores nas tangentes, mas percebendo as curvas antecipadamente e reduzindo suas velocidades antes de iniciar esses trechos.
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Avaliação de pontos cefalométricos no alongamento ósseo do terço médio da face com a utilização de dispositivo externo rígido em portadores craniossinostose sindrômica / Evaluation of cephalometric points in the midface bone lengthening with the use of rigid external device in syndromic craniosynostosis patientsDaniel Santos Corrêa Lima 10 April 2008 (has links)
A distração osteogênica tem sido extensamente empregada na correção da grave hipoplasia do terço médio da face de portadores de craniossinostose sindrômica. Contudo, poucos estudos têm apresentado os resultados da distração do terço médio da face através de avaliação cefalométrica. O objetivo do presente estudo foi o de avaliar os resultados obtidos com o avanço ósseo do terço médio da face após osteotomia tipo Le Fort III ou frontofacial em monobloco seguida da utilização de dispositivo rígido externo de distração (RED), em portadores de craniossinostose sindrômica, em termos de quantidade de alongamento ósseo, estabilidade esquelética e crescimento facial. Onze pacientes submetidos aos procedimentos de distração, de fevereiro de 2002 a janeiro de 2006, na unidade de cirurgia plástica do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, foram avaliados retrospectivamente. Seis pacientes eram portadores da síndrome de Crouzon, quatro da síndrome de Apert, e um da síndrome de Saethre-Chotzen. Onze pacientes foram submetidos ao procedimento de alongamento ósseo do terço médio da face através do uso de dispositivo externo rígido (RED), após osteotomias tipo Le Fort III (N = 4) ou frontofacial monobloco (N = 7). Foram avaliadas retrospectivamente três telerradiografias de face em norma lateral de cada paciente (T1- préoperatório; T2 - pós-operatório recente, logo após a remoção do distrator; T3 - pós-operatório tardio, obtida com um intervalo mínimo de 12 meses após cirurgia). Três cefalogramas foram obtidos de cada paciente, através da direta sobreposição das três telerradiografias, tomado como referência reparos anatômicos do crânio e da porção anterior da fossa craniana. Desta forma, os três traçados cefalométricos foram obtidos no mesmo papel acetato, o qual foi digitalizado. Utilizando o programa de computação gráfica de domínio público Image J, várias mensurações foram realizadas com a intenção de determinar a extensão do avanço sofrido pelos segmentos ósseos na direção do vetor do movimento esquelético, assim como de seus componentes horizontal e vertical, tomando como referência pontos A e orbitário. Pacientes foram ainda divididos em dois grupos (G 1 - pacientes submetidos à osteotomia tipo Le Fort III; G 2 - pacientes submetidos à osteotomia frontofacial em monobloco), e os dados obtidos a partir mensurações de ambos os grupos foram comparados. Avanço significativo do terço médio da face foi obtido com os procedimentos. O componente horizontal do movimento esquelético predominou ao componente vertical. A taxa de reposicionamento posterior horizontal tardio (perda de resultado) foi mínima. Quando comparados os dois procedimentos, foi observada uma diferença significativa entre os grupos Le Fort III e monobloco. A quantidade de avanço obtido foi maior no grupo monobloco que no grupo Le Fort III. Em termos perda de resultado, o grupo Le Fort III foi mais estável que o grupo monobloco. Foi observada uma evidente alteração vertical no posicionamento dos pontos de referência no pós-operatório tardio, se comparado ao pós-operatório recente, evidenciando crescimento na vertical da face, ao contrário do que ocorre na direção horizontal, onde existiu um pequeno reposicionamento posterior e nenhuma evidência de crescimento. / Distraction osteogenesis has been applied extensively to correct the severe midface hipoplasia in syndromic craniosynostosis patients. However few studies have reported midface distraction outcomes through cephalometric evaluation. The purpose of the present study was to evaluate outcomes with midface distraction after Le Fort III and frontofacial monobloc osteotomy using a rigid external device (RED) in patients with syndromic craniosynostosis, in terms of quantity of bone lengthening, skeletal stability and facial growth. Eleven patients underwent to midface distraction from February of 2002 to January of 2006 at the plastic surgery unit of The \'Hospital das Clínicas\' of the Medical School of The University of São Paulo were retrospectively evaluated. Six patients had Crouzon, four had Apert, and one had Saethre-Chotzen syndrome. The patients were submit to bone lengthening procedure of the midface using a rigid external device (RED) after osteotomy type Le Fort III (n=4) and frontofacial monobloc osteotomy (n=7). Three teleradiography were retrospectively evaluated of each patient (T1 - before surgery; T2- after surgery, rigth after distractor removal; T3 - after surgery, obtained with a minimal interval of 12 months after surgery). The three lateral cephalograms were obtained from each patient by direct teleradiography superimposition taken as references the anatomic repairs in the cranium and anterior skull base. This way the three cephalometric tracings were obtained in the same acetate paper which was digitalized. Utilizing a public domain program Image J, various mensurations were accomplished with intension of determine the extent of advancement suffered by the bone segments in the direction of vector skeletal movement and its horizontal and vertical components as well, as taken as references point A and orbitale. Patients still were divided between two groups (G 1- patients submitted to an osteotomy type Le Fort III; G 2- patients submitted to monobloc frontofacial osteotomy), and the data obtained from mensurations from both groups were compared. Significant midface advancement was achieved with the procedures. The horizontal component of the movement was predominant if compared to vertical. The rate of horizontal relapse was minimal. When compared the two procedures was noted a significant difference between Le Fort III and monobloc groups. The advancement rate was greater in monobloc than Le Fort III group. In terms of relapse Le Fort III group was more stable than monobloc group. In vertical direction was noted an evident altered position of the reference points at late postoperative period if compared with recent postoperative period given evidence of facial vertical direction growth, contrary from what occurred in horizontal direction where existed a small relapse and no growth.
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Treatment of craniosynostosesSalokorpi, N. (Niina) 31 October 2017 (has links)
Abstract
This work evaluated the safety and effectiveness of operative techniques used in cranioplastic surgery and outcomes of these surgical methods.
In study I the feasibility of endocranial fixation in frontal remodeling surgery for metopic and coronal synostosis was established. Good to excellent aesthetic results were seen in 96% of cases evaluated by a surgeon at the time of follow-up. Three patients out of 27 had complications requiring revisions. No mortality or permanent morbidity, nor complications related to endocranial placement of the plates were seen. Thus it was verified that placing resorbable material intracranially reduces the aesthetic impact without hindering the final result.
Study II found that posterior cranial vault distraction procedures produced a mean increase of 25% in intracranial volume. This proved to be an effective technique for treating a variety of craniosynostosis with significant shortage of intracranial volume. 3D photogrammetric imaging was found to be a suitable non-ionizing method for evaluation of cranial volume increase following distraction. In study III a new tool was developed and successfully used for the intraoperative guidance of distractor device placement to ensure congruent vectors and thus reduced complications of these surgical procedures.
In study IV long-term functional and aesthetic outcomes of the surgical treatment for sagittal synostoses in patients reaching adulthood was examined. The mean follow-up time was 26.5 years and the patients were 18 to 41 years old at the time of follow-up. The patients treated for sagittal synostosis were equally satisfied with their facial appearance as were their age and gender matched controls. Independent panels found patients’ appearance to be slightly less attractive, but the difference was less than 10 mm on a 100 mm Visual Analogue Scale, representing a low clinical significance. Patients’ socioeconomic situation such as education, housing, employment and marital status equaled controls with similar frequencies of headaches, mental problems or health issues as the controls. / Tiivistelmä
Tässä tutkimuksessa selvitettiin kallon saumojen ennenaikaisen luutumisen (kraniosynostoosi) leikkausmenetelmien tehokkuutta ja turvallisuutta sekä pitkäaikaisia tuloksia.
Leikkausmenetelmä, jossa epämuotoinen kallo uudelleenmuotoillaan ja luiset osat kiinnitetään toisiinsa kallon sisäpuolelle asennettavilla ja kudokseen hajoavilla levyillä oli tehokas ja luotettava (N=27). Jälkitarkastuksessa tulos arvioitiin erinomaiseksi tai hyväksi 96 %:lla tapauksista. Leikkaushoitoa vaativia ongelmia tai komplikaatioita esiintyi kolmella, mutta pysyvää haittaa ei jäänyt. Komplikaatiot eivät johtuneet levyjen sijainnista kallon sisällä.
Saumojen ennenaikaisesta luutumisesta johtuvaa kallon tilavuuden alenemaa hoidettiin venytyshoidolla (N=30). Menetelmällä saavutettiin keskimäärin 25 %:n lisääntyminen tilavuudessa, ja se soveltuukin erityisen hyvin potilaille, joilla tarvitaan suuri tilavuuden lisääntyminen. Leikkaustekniikkaan ei liittynyt isoja komplikaatioita. Tulosta arvioitiin osalla potilaista kolmiulotteisella valokuvauksella, joka perinteisistä seurantamenetelmistä poiketen ei altista ionisoivalle säteilylle, ja se osoittautui käyttökelpoiseksi seurantamenetelmäksi.
Venytyshoitoa varten kallon pintaan kiinnitettävät pidennyslaitteet tulee asettaa yhdensuuntaisesti, ja se on teknisesti haasteellista. Työssä kehitettiin kirurginen instrumentti, jolla venyttimet voidaan luotettavammin asetella samansuuntaisiksi. Uusi tekniikka ehkäisee mekaanisia ongelmia, joita muuten voisi ilmetä erisuuntaisten venyttimien välillä pidennyksen edetessä.
Lapsuudessa venekallon johdosta leikattujen potilaiden (N=40) pitkäaikaiset hoitotulokset sekä selviytyminen elämässä 26.5 vuoden seuranta-ajan jälkeen olivat hyviä. Heidän taloudellinen ja sosiaalinen tilanne (koulutus, asumismuoto, työllistyminen, siviilisääty ym.) ei eronnut ikä- ja sukupuolivakioitujen vertailuhenkilöiden (N=40) tilanteesta. Yleisessä terveydentilassa, päänsärkyjen esiintymisessä ja mielenterveysongelmissa ei ollut eroa. Potilaiden tyytyväisyys omaan ulkonäköönsä oli samankaltainen kuin vertailuhenkilöillä. Ulkopuolisen asiantuntijapaneelin tekemän arvion perusteella potilaiden kasvojen ulkonäkö oli vähemmän miellyttävä kuin vertailuhenkilöillä, mutta ero oli vähäinen (<10 % ero visual analogue scale, VAS, asteikolla). Asiantuntijapaneeli teki arvionsa tietämättä onko arvioitava henkilö potilas vai vertailuhenkilö.
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