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To assess the applicability of magnetic resonance spectroscopy (MRS) for long-term follow-up of neurological diseases a longitudinal 1H-MRS study at 3 T was carried out on ten patients having relapsing-remitting multiple sclerosis (MS) who, after baseline examination, received interferon-β (IFN) lb. At 8–20 examinations within up to 34 months absolute(More)
A semi-parametric approach for the quantitative analysis of magnetic resonance (MR) spectra is proposed and an uncertainty analysis is given. Single resonances are described by parametric models or by parametrized in vitro spectra and the baseline is determined nonparametrically by regularization. By viewing baseline estimation in a reproducing kernel(More)
Standard analyses of neurophysiologically evoked response data rely on signal averaging across many epochs associated with specific events. The amplitudes and latencies of these averaged events are subsequently interpreted in the context of the given perceptual, motor, or cognitive tasks. Can such critical timing properties of event-related responses be(More)
The variability of electric and magnetic signals from the heart during the depolarization phase is investigated. A signal processing method is developed, which provides estimates for the beat-to-beat variability of the QRS-complex. The method is based on the decomposition of the depolarization signal into bandpass signals by means of the Morlet wavelet(More)
The phase of the complex output of a narrow band Gaussian filter is taken to define the latency of the auditory evoked response M100 recorded by magnetoencephalography. It is demonstrated that this definition is consistent with the conventional peak latency. Moreover, it provides a tool for reducing the number of averages needed for a reliable estimation of(More)
For quantitative analysis of in vivo MR spectra, a state-of-the-art time domain method was compared with a recently reported time domain frequency domain method which uses wavelets for background characterization. The comparison was made on the basis of results for simulated test problems that were constructed by combining measured and simulated MRS data at(More)
− We consider the task of uncertainty evaluation in the context of dynamic measurements. We assume that the relation between the time-dependent value of the measurand and the available output signal of an employed sensor is governed by a linear time-invariant system. Estimation of the measurand is done by applying a digital filter to the sensor’s output(More)
DC-magnetoencephalography (DC-MEG) technique has been refined and allows to record cortical activity in the infraslow frequency range less than 0.1 Hz noninvasively. Important questions however, remained, especially, how specific these infraslow activations can be recorded and whether different activations, for example, motor versus acoustic, can be(More)
The compensation of LTI systems and the evaluation of the according uncertainty is of growing interest in metrology. Uncertainty evaluation in metrology ought to follow specific guidelines, and recently two corresponding uncertainty evaluation schemes have been proposed for FIR and IIR filtering. We employ these schemes to compare an FIR and an IIR approach(More)
− Knowledge of the transfer function of a force transducer is required in order to determine a transient force from the transducer’s output signal. We describe a linear least-squares fit method for system identification to estimate the transfer function from sinusoidal force calibration measurements, and we consider the evaluation of uncertainty associated(More)