Bakgrund: Deep brain stimulation (DBS) i kaudala zona incerta (Zi) har en tremorreducerande effekt vid den neurologiska sjukdomen essentiell tremor (ET). Stimulering av Zi har även positiva effekter på rösttremor, men individuella variationer förekommer. Tidigare har främst effekten mellan på- och avslagen stimulering undersökts. Inga studier har jämfört effekten på rösttremor vid ökande nivåer av stimuleringsstyrka.   Mål: Att undersöka effekt på rösttremor vid ökande unilateral stimuleringsstyrka av DBS i Zi hos deltagare med ET. Samt att undersöka prevalens och att se vilken rösttremorreducerande effekt deltagarnas kliniska inställningar har.   Metod: Trettioåtta deltagare med DBS Zi, bedömdes vid tre tillstånd: utan stimulering (DBS OFF), med kliniska inställningar (DBS ON) samt med ökande stimuleringsstyrka, 0,5-4,5V (DBS+). Rösttremor bedömdes utifrån inspelningar av uthållna vokalproduktioner i programmet “Visual Sort and Rate Method” (VISOR). Vid bedömning skattades förekomst och grad av rösttremor hos deltagarna genom att deltagarens egna inspelningar jämfördes med varandra i VISOR.   Resultat: DBS Zi hade på gruppnivå en positiv effekt på rösttremor vid såväl DBS ON som vid DBS+. De individuella skillnaderna var dock stora. Flest antal deltagare blev rösttremorfria vid DBS ON och vid stimuleringsnivåerna 1,5V, 2,0V, 3,5V och 4,5V. Prevalensen av rösttremor var 71% (27 deltagare).   Slutsats: DBS Zi har på gruppnivå en positiv effekt på rösttremor. De kliniska inställningarna är stimuleringsnivån som flest deltagare blir rösttremorfria vid. Den individuella variationen gör att man inte kan förutse om en individ kommer att få reducerad rösttremor av DBS Zi. / Tal- och rösteffekter av djup hjärnstimulering hos patienter med ärftlig tremor

Rigidity is one of the cardinal symptoms in Parkinson's disease, along with Bradykinesia, tremor and postural instability. Rigidity in PD has been understudied, but its pathophysiological basis remains unclear. Various types of neurophysiological and biomechanical approach have been developed in order to investigate the neural control of muscle tone. A common approach is to observe the sensitivity of muscle resistance in response to stretch velocity or displacement [Kamper, Rea, He]. A recent study on elbow flexors in patients with spasticity and rigidity showed a velocity dependent increase in reactive torque in both groups [Lee H, et al). Even though this Study shows a correlation between elbow flexors and velocity, it doesn't discuss the role of elbow extensors. We studied the rigidity response in the elbow of both arms to different speed movements in 12 patients suffering from Parkinson's disease ON or OFF medication. The purpose of this study was to look at both elbow flexion and extension and show that quantitative measures of rigidity and movement disorders in subjects with Parkinson's disease correlate with the currently used clinical evaluations and also find the correlation between velocity and both elbow extension and flexion at the same time. Elbow was flexed and extended by means of a robotic arm,under four different speeds. The resistance to movement was recorded with a torque sensor and EMG of two elbow muscles; Biceps and Triceps; was recorded while the subjects were attempting to relax. The patients were also examined by physicians and their elbow rigidity and muscle tone and Parkinson's disease stage was evaluated and a Universal score in the categories of UPDRS, MMSE, and CAPIT was assigned for each arm of each individual. In the end we will argue that there is a very strong correlation between speed and elbow Extension and Flexion, muscle activity and the rigidity presented in each arm. We will also present the correlation between the robotic torque measurement and the clinical scores given to each subject.

Hauptaufgabe der Vulkanseismologie ist die qualitative and quantitative Beschreibung einer oder mehrerer unbekannter seismischer Quellen, die sich in einer unbekannten Tiefe unter dem Vulkan befinden. Auch wenn viele Vulkane der Erde ähnliche Signalcharakteristiken aufweisen, war es bis heute nicht möglich, für Vulkane ein seismisches Standard-Quellmodell zu finden, analog dem Double- Couple in der Erdbebenseismologie. Kontinuierlich tätige Vulkane, wie z.B. Stromboli (Italien), stellen für den Vulkanseismologen ein ideales natürliches Feldlabor dar, diese Fragestellung zu untersuchen. Die vorliegende Arbeit untersucht auf Stromboli registrierte Explosionsbeben und vulkanischen Tremor in einem breiten Frequenzband und behandelt die Frage nach der Lage und dem Mechanismus der seismischen Quelle(n). Seismische und Infraschallmessungen von strombolischen Explosionsbeben zeigen, dass sich eine Hochfrequenz-Phase mit einer Geschwindigkeit von etwa 330 m/s fortbewegt. Die seismische Quelle kann durch eine Explosion am oberen Ende der Magmasäule erklärt werden, die durch aufsteigende Gasblasen verursacht wird. Sowohl die seismische P-Welle, als auch die Luftwelle werden zum gleichen Zeitpunkt an ein und demselben Ort generiert. Die verschiedenen Laufwege und Geschwindigkeiten der seismischen und der Luftwelle resultieren in einem Laufzeitunterschied dt, der zur Bestimmung des Magmenstandes und der Schallgeschwindigkeit in der Eruptionss¨aule im Schlotinnern genutzt werden kann. In Kraternähe installierte Stationen zeigen, dass Infraschall- und seismische Messungen des kurzperiodischen Tremors (> 1 Hz) den gleichen Frequenzgehalt und ähnliche Fluktuationen der seismischen Energie aufweisen. Daher wird der kurzperiodische vulkanische Tremor auf Stromboli durch das kontinuierliche Aufsteigen und Platzen kleiner Gasblasen im oberen Teil der Magmasäule verursacht. Das Spektrum des auf Stromboli registrierten langperiodischen Tremors besteht hauptsächlich aus drei Maxima bei 4.8 s, 6 s und 10 s, deren Spektralamplitude mit der jeweiligen Wettersituation variieren. Sie werden daher nicht von einer lokalen vulkanischen Quelle erzeugt, sondern durch Meeresmikroseismik (MMS). Der Durchzug eines lokalen Tiefdruckgebietes scheint die Ursache für Spektralenergie bei 4.8 s and 10 s, die jeweils die Doppelte bzw. die Primäre Frequenz der MMS darstellen. Als Ursache des spektralen Maximums bei 6 s könnte ein Tief nahe der Britischen Inseln in Frage kommen. Seismische Daten, die von dem ersten auf Stromboli installierten Breitband- Array registriert wurden, zeigten überraschend einfache Wellenformen, die einen anfänglich kontraktierenden Quellmechanismus anzeigen. Die Analyse der Partikelbewegung und die Anwendung seismischer Arraytechniken ermöglichten eine Lokalisierung der seismischen Quelle in Oberflächennähe. Die Anwendung verschiedener Inversionsmethoden gestattete es, Eruptionsparameter und Charakteristiken der seismischen Quelle während der Strombolieruption am 5. April 2003 abzuschätzen. Als Ergebnis kann festgehalten werden, dass der paroxystische Ausbruch durch eine langsame Überschiebungsdislokation mit einer Momentenmagnitude von Mw = 3.0 verursacht wurde, ausgelöst durch einen vorher durch Dike-Intrusion verursachten Bruch. Während des Paroxysmus konnte in den seismischen Signalen mindestens eine Blow-out Phase mit einer Momentenmagnitude von Mw = 3.7 identifiziert werden. Diese kann durch einen vertikalen linearen Vektordipol, zwei schwächere horizontale lineare Dipole in entgegengesetzter Richtung, zuzüglich einer Vertikalkraft repräsentiert werden. Seismische Messungen, die während kontrollierter und reproduzierbarer Blowout Experimente unter Verwendung von einem in einer Basaltschmelze eingeschlossenen Gasvolumen durchgeführt wurden, ergaben folgende Ergebnisse: Monochromatische Signale sind Anzeiger für einen Blow-out in einem duktilen Regime, wohingegen ein breitbandigerer Frequenzgehalt auf einen Sprödbruch hinweist. Je grösser die Länge des Schmelztiegels ist, desto schwächer sind die seismischen Signale. Ein grösser Gasdruck bewirkt eine stärkere Fragmentation des Magmas, aber keine höhere Austrittsgeschwindigkeit des Magmapropfens und auch keine grössere seismische Amplitude. Auch wenn die langperiodischen Signale, wie beispielsweise Tilt, im Labor nicht simuliert werden konnten, sind die Blow-out Experimente überraschend gut in der Lage, die am Vulkan Stromboli registrierten kurzperiodischen seismischen Signale zu reproduzieren. / The main purpose of volcano-seismology concerns the qualitative and quantitative description of one or more unknown seismic source(s) located at some unknown depth beneath a volcano. Even if many different volcanoes show similar seismic signal characteristics, up to now it was not possible to find a standard seismic source model for volcanoes, as the double-couple in earthquake seismology. Volcanoes with a continuous activity, like Stromboli (Italy), represent for the volcano seismologist a perfect natural laboratory to address this question. This thesis treats the study of explosion-quakes and volcanic tremor recorded on Stromboli in a broadband frequency range, and discusses the location and the possible mechanisms of the seismic source(s). Seismic and infrasonic recordings of explosion-quake from Stromboli showed that the high-frequency phase propagates with a velocity of approximately 330 m/s. The seismic source can be explained as an explosion at the top of the magma column generated by rising gas bubbles. The seismic P-wave and the air-wave are both generated in the same point at the same time. The different path lengths and velocities for the seismic wave and the air-wave result in a difference in arrival times dt, that could be used to deduce the magma level and sound speed in the eruption column inside the conduit. Stations installed near the active crater reveal that infrasonic and seismic recordings of the short-period tremor (> 1 Hz) share the same spectral content and show similar energy fluctuations. Therefore, the short-period volcanic tremor at Stromboli originates from the continuous out-bursting of small gas bubbles in the upper part of the magmatic column. The spectrum of the long-period tremor recorded at Stromboli consists of three main peaks with periods at 4.8 s, 6 s and 10 s, and amplitudes varying with the regional meteorological situation. Hence, they are not generated by a close volcanic source but rather by ocean microseisms (OMS). The passage of a local cyclone seems to be the seismic source for spectral energy at 4.8 s and 10 s, which represent the Double Frequency and the Primary Frequency of the OMS, respectively. Concerning the 6 s peak, a cyclone near the British Isles could act as a seismic source. Seismic data from the first broadband array deployed on Stromboli showed surprisingly simple waveforms, indicating an initially contracting source mechanism. The analysis of particle motion and the application of seismic array techniques allowed the location of a seismic source in the shallow part of the volcano. Eruption parameters and seismic source characteristics of the April 5, 2003 Stromboli eruption have been estimated using different inversion approaches. The paroxysm was triggered by a shallow slow thrust-faulting dislocation event with a moment magnitude of Mw = 3.0 and possibly associated with a crack that formed previously by dike extrusion. At least one blow-out phase during the paroxysmal explosion could be identified from seismic signals with an equivalent moment magnitude of Mw = 3.7. It can be represented by a vertical linear vector dipole and two weaker horizontal linear dipoles in opposite direction, plus a vertical force. Seismic measurements performed during controlled and reproducible blow-out experiments with a gas volume entrapped in basaltic melt revealed the following: Monochromatic seismic signals suggest a blow-out in a more ductile regime, whereas broader frequency content indicates rupture in a more brittle environment. The longer the crucible, the weaker the seismic signals. An increase in pressure results in a stronger fragmentation, but not in a higher ejection velocity of the plug neither in a higher seismic amplitude. Even if the very long period observations like the tilt signal could not be simulated in the laboratory, the blow-out experiments simulate very well the short-period seismic signals recorded at Stromboli volcano.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 53-54. / by Bruce Edward Bates. / B.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 65. / by Mark Howard Sloan. / B.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaf 60. / by Susan Russell Stapleton. / B.S.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2017 / This study presents the development of a potentially new biomarker for three different movement disorders: Huntington’s Disease (HD), Parkinson’s Disease (PD) and Essential Tremors (ET). A Leap Motion® gaming device was used to record the trajectories of subjects’ forefinger as they trace simple patterns in the air. The patterns used were stepfunction, triangle and circle. The recorded signals were analysed using transform functions and Fourier analysis. Both analysis types yielded features from which differences between the four categories studied: PD, HD, ET and control subjects, were sought and displayed in both graphical and numerical forms. The X-axis and Y-axis of the signals were separately analysed and yielded different results. For the step-function pattern, no distinct differences between the four categories were found from the transfer function analysis whereas the Y-axis of the signal could distinguish between the categories. For the triangle pattern, the X-axis features provided a discrimination between the categories while the Y-axis feature did not. For the circle pattern, neither X-axis nor Y-axis features were able to distinguish between the categories. A Fourier analysis showed a better discrimination ability for both X- and Y- axis. This study is a preliminary one and all results indicate that more subjects of all categories are needed to develop a bio-marker for the diseases studied and that a higher order transfer function analysis is required. However, the methodology outlined in this work, comprising of both the experimental system and the analysis showed a potential to produce a biomarker for movement disorders. / MT2018

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a resting tremor combined with varying degrees of rigidity and bradykinesia. Introduced in the 1950s, thalamotomy is used as a surgical procedure to improve brain function in patients and serves as an effective treatment method for the PD tremor where connections within the thalamus are cut. In 1987, deep brain stimulation (DBS), chronic electrical stimulation of deep neural structures using electrodes, was introduced as a clinical treatment for medically refractory tremor in patients with PD. Though thalamotomy has historically been the primary treatment method for PD, an increasing number of patients have chosen to undergo DBS as it has become increasingly touted as an alternative to ablative therapies. The proposed study examines the advantages and disadvantages of both treatment methods to improve cardinal features in highly-skilled, career-oriented PD patients who actively use motor functions in their work. As an alternative to a simple finger-tapping test used for normal PD patients, a more complex strength-dexterity (S-D) test would be performed on 50 skilled patients to evaluate and compare the effectiveness of tremor suppression between both surgeries. The goal of this experiment is to determine which treatment produces the most short-term benefits for the patient to continue with his or her career with minimal future management required. The results of this study will help determine the preferred treatment method when taking into consideration other external factors such as cost, continual management, and preference for short-term vs. long-term results.

<p>Ogg Vorbis is a rather new audio format with some similarities with other more known formats such as MP3 and WMA. It is generally accepted to have a better audio quality than most competing formats and it is in contrast to many of its competitors totally licence and royalty free. </p><p>The goal with this thesis is to port the existing fixed point decoder Tremor, which is written in C, to Motorola's DSP56002. The DSP has a very limited amount of memory so some optimizations has to be made to be able to run Tremor successfully. </p><p>The report presents the necessary steps taken to port Tremor to the DSP and the difficulties of this process. It also describes the memory and CPU usage of the DSP when running Tremor and other results of the port. </p><p>A description as well as examples and workarounds of bugs found in the compiler g56k is attached to this report.</p>

Dichoptic presentation of vernier stimuli, i.e., one segment to each eye, yielded three times higher thresholds than binocular presentation, mainly due to uncorrelated movements of both eyes. Thresholds allow one to calculate an upper estimate for the amplitudes of uncorrelated eye movements during fixation. This estimate matches the best results from direct eye position recording, with the calculated mean amplitude of eye tremor corresponding to roughly one photoreceptor diameter. The combined amplitude of both correlated and uncorrelated eye movements was also measured by delaying one segment of the vernier relative to its partner under monocular or dichoptic conditions.