Thesis Projects

2011 - Optimisation of CT Scanning and Reconstruction for Improvement (K Eibenberger, Master Thesis)

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Johns Hopkins, USA

Location: Johns Hopkins School of Medicine, Baltimore, USA

Advisor at Johns Hopkins: John Carey, MD
FH-Advisor:
Thomas Haslwanter


 

The Master’s Thesis derives from the study held at the Johns Hopkins University School of Medicine, Department of Otolaryngology and Head and Neck Surgery, Baltimore, MD, USA. The project focuses on the novel approach of Cone Beam Computed Tomogaphy (CBCT) for the use of Inner and Middle Ear Imaging in the clinical environment.

   

2010 - Training of Smooth Pursuit Eye Movements - A qualitative survey (K Eibenberger, Bachelor Thesis)

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Johns Hopkins, USA

Location: FH OOe, Campus Linz

FH-Advisor: Thomas Haslwanter


Patients with impaired smooth pursuit eye movements have problems in tracking visual targets, experience unsteady gate, vertigo and in general show insecurity in their activities of daily living which seriously reduces quality of life. Adaptive changes of the smooth pursuit system have already been evidenced and theories about the reasons exist and are summed up within this thesis. The aim of this thesis is to document the realization of a clinical study to investigate subjective training effects of patients suffering from MS and vertigo after performing visual training and to show the development of the training stimulus.The visual training consists of a stimulus in form of an avi-file which was developed in Matlab and the Psychtoolbox 3 and which can be watched on every consumer PC or laptop. The subjects were training twice a day for 10 minutes and patients were asked to fill out two accredited questionnaires before their first and after the last training session to observe subjective changes of their perception of vertigo. At first, a pre-study was carried out to get feedback about the training stimulus, the procedure and the complexity of the questionnaires. For this part of the study, a homepage had to be designed and published where participants who were training for four weeks received the training materials and the necessary information about the project. After this first stage, the quantitative study was launched at the rehabilitation centre Buchenberg in Waidhofen/Ybbs, where stationary patients could train on laptops for their duration of stay (three weeks). Again, the same questionnaires as in the pre-study were used to measure potential changes. The study suggests that daily visual training leads to positive subjective changes in patient's overall perception of dizziness and vertigo, and further improvements of the training stimulus - like providing a moving text stimulus to overcome the problem of compliance - are presented.

   

2010 - Limits of Multi Slice Computer Tomography (R Penninger, Diploma Thesis)

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Johns Hopkins, USA

Location: Johns Hopkins School of Medicine in Baltimore, MD, USA (2010)

FH-Advisor: Thomas Haslwanter


Abstract: The gold standard for diagnosis of superior canal dehiscence (SCD) has been multi-slice CT. However, partial volume averaging and filtering may confound the ability to detect thin bone next to low-radio density brain and inner ear fluids. We correlated radiographic and surgical findings in SCD to determine if multi-slice CT overestimates the size of SCD and if a threshold radio density could be defined, below which actual dehiscence could be predicted. Participants were 34 humans with a clinical diagnosis of SCD syndrome who underwent middle fossa approach for SC plugging. High resolution Temporal bone CT scans were acquired axially with a Toshiba Aquilion scanner (step-mode, 120 kV, 300 mA, 1 s rotation, and 0.5 mm collimation). Reconstructions (512 X 512 pixels) from a field of view =24 cm were made in 0.2 mm increments in planes parallel, vertically orthogonal, and radially orthogonal to the SC. Dehiscence length and width measured from these reconstructions were compared to measurements made at microsurgery. Differences between radiographic and actual length and width were consistently larger than 0 (p < 0.001, one-sample t-test), indicating that CT tends to overestimate the size of SCD. Receiver operating characteristic analysis found that a threshold of -375 Hounsfield units predicted actual dehiscence. New CT modalities for resolving tiny structures in dense tissue have been found and the difference in resolution has been quantified.

   

2010 - Effects of Core Body Temperature on the Vestibulo-ocular Reflex in Mice (P Huebner, Diploma Thesis)

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Sydney, Australia

Location: Prince of Wales Neuroscience Center in Sydney, Australia (2010)

FH-Advisor: Thomas Haslwanter


Abstract:

The goal of this study was to determine if changes in core body temperature affects the properties of the vestibulo-ocular reflex (VOR). Previous studies investigating extracellular recordings of vestibular-nerve afferents in mice have shown significant changes in afferent discharge properties between different core body temperatures. In this study we show that core body temperature affects the VOR.
Vestibular evoked eye movements were measured in 9 mice maintained at core body temperatures of 26-28 deg C (T27), 31-33 deg C (T32) or 36-38 deg C (T37). The aVOR gain during sinusoidal rotations was ca. 13% lower at T32 than at T37. Lowering the core body temperature from T32 to T27 induced a gain increase of ca. 14%. The aVOR response during steps of acceleration was also affected by temperature, albeit by a lesser extent. The early acceleration response (GA-1020) was affected most when comparing the T27 to T32 data (gain decreased with temperature), and the T32 to T37 data (gain increased with temperature). The late acceleration response (GA-2040) was affected by temperature only when comparing the T32 to T37 data. The velocity response (GV) was strongly affected by temperature; however, the latency of the aVOR was not.