Outi Väisänen

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We present the four key areas of research-preprocessing, the volume conductor, the forward problem, and the inverse problem-that affect the performance of EEG and MEG source imaging. In each key area we identify prominent approaches and methodologies that have open issues warranting further investigation within the community, challenges associated with(More)
Aerobic spore-forming bacteria were found dominant in the microflora of food packaging paper and board. Twenty-five strains of bacteria belonging to the genusBacillus were isolated from these paper and board machines, papermaking chemicals, and final products of papermaking. Nineteen strains were analyzed for production of α-amylase, α-glucosidase,(More)
A solid-phase enzyme-linked immunosorbent assay (ELISA) for detection of mumps and parainfluenza type 1 antibodies (immunoglobulin G [IgG] and IgM classes) is described and compared with the conventional complement fixation (CF) test. A highly positive correlation was found between mumps IgG ELISA and the mumps CF test, whereas parainfluenza type 1 IgG(More)
In this paper, we introduce a new modelling related parameter called region of interest sensitivity ratio (ROISR), which describes how well the sensitivity of an electroencephalography (EEG) measurement is concentrated within the region of interest (ROI), i.e. how specific the measurement is to the sources in ROI. We demonstrate the use of the concept by(More)
We have developed a multielectrode lead technique to improve the signal-to-noise ratio (SNR) of scalp-recorded electroencephalography (EEG) signals generated deep in the brain. The basis of the method lies in optimization of the measurement sensitivity distribution of the multielectrode lead. We claim that two factors improve the SNR in a multielectrode(More)
BACKGROUND The electroencephalography (EEG) is an attractive and a simple technique to measure the brain activity. It is attractive due its excellent temporal resolution and simple due to its non-invasiveness and sensor design. However, the spatial resolution of EEG is reduced due to the low conducting skull. In this paper, we compute the potential(More)
i ABSTRACT Electroencephalography (EEG) is a convenient technique for studying the function of the brain non‐invasively from the surface of the scalp. The greatest advantages of EEG are its temporal resolution on a millisecond scale and its affordability compared to other non‐ invasive techniques employed to register brain activity. The development in(More)
—The electroencephalogram (EEG) generated by cere-bral cortex can be recorded far away from the cortex, analogous to the electrocardiogram (ECG) that can be recorded far from the heart. ECG is often seen as an artifact in EEG recordings. In this paper we demonstrate that the burst suppression pattern of EEG, which is generated by the cerebral cortex, can be(More)
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