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OBJECTIVES The authors aimed at investigating the occurrence of depression and the level of quality of life in patients with amyotrophic lateral sclerosis (ALS), an incurable neurodegenerative disease leading to progressive motor paralysis. They further wished to elucidate correlates of depression and quality of life, such as physical impairment, time since(More)
Successional phases describe changes in ecological communities that proceed in steps rather than continuously. Despite their importance for the understanding of ecosystem development, there still exists no reliable definition of phases and no quantitative measure of phase transitions. In order to obtain these data, we investigated primary succession in an(More)
OBJECTIVE In navigated orthopedic surgery, accurate registration of bones is of major interest. Usually, this registration is performed using landmarks positioned directly on the bone surface. These landmarks must be exposed during surgery. Our goal is to avoid the exposure of bone surface for the sole purpose of registration by using an intraoperative(More)
We developed a fast and robust algorithm to register intraoperative three dimensional ultrasound data of the spine with preoperative CT data. We compared different gradient based and evolutionary optimization strategies for solving the registration problem. The iRprop, a fast gradient based optimization algorithm, quickly and reliably led to higher(More)
We studied the effects of transcranial magnetic stimulation (TMS) on slow cortical potentials (SCPs) of the brain elicited during performance of a feedback and reward task. Ten healthy participants were trained to self-regulate their SCP amplitude using visual feedback and reward for increased or decreased amplitudes. Subjects participated in 27 runs (each(More)
For many navigated surgical procedures, the precise registration of preoperative data sets with bones of the patient is an important requisite. Conventional navigation systems use paired point registration based on anatomical landmarks or fiducial markers. This approach increases the invasiveness, since landmarks must be exposed and fiducial markers must be(More)
Zusammenfassung. Ein zentrales Problem in der bildgestützten, na-vigierten Chirurgie ist die exakte Registrierung präoperativer CT/MR-Daten im Koordinatensystem des Operationssaales. Um die Nachteile einer landmarkenbasierten Registrierung zu umgehen, dient bei unse-rem Ansatz 3-dimensionaler, intraoperativer Ultraschall zur Registrie-rung. Ein(More)
An algorithm for the registration of bones in three-dimensional CT-and ultrasound-datasets, based on surface-volume-matching, is tested in vitro with respect to its accuracy. A point-registration based on fiducial markers is used as a reference for the measurements. The comparison of ultrasound-und point-registration shows maximal deviations of up to 1.7 mm(More)