In the neurointensive care unit (NICU) there is a need for a single bedside monitor for continuously monitoring the function of the patient's central nervous system. This dissertation describes the ...development of a system of hardware and software for continuously and automatically monitoring the ongoing neurological condition of patients in the NICU. The system samples several electrophysiological waveforms at regular intervals along with routinely monitored physiological parameters. The electrophysiological data consists of brainstem auditory, somatosensory and visual evoked potentials and epochs of the electroencephalogram (EEG). The system applies peak detection and spectral analysis to extract salient parameters from the raw waveforms. These parameters are assembled into a state vector representing the patient's neurophysiological state. The parameters include the latencies and amplitudes of the significant peaks in the brainstem auditory, somatosensory and visual evoked potentials, the spectral pole positions, peak frequencies and energy distributions of the EEG and such physiological parameters as heart rate, blood pressure and intracranial pressure. A display summarizing the history of the patient's state is provided for visual review. The results are also made available on the network for review and further analysis on the local network. A web-based interface makes review possible anywhere within the hospital's secure intranet during and after monitoring. Experimental data from six intensive care patients show that certain regions of the state space correspond with particular pathologies and this may have diagnostic value in particular patients. Experimental data from angioplasty and stent patients suggest that the electrophysiological changes correspond with the induced physiological changes in the central nervous system as they occur in real time. If these results are extrapolated to NICU patients, it implies that further analysis of the state space dynamics may be of prognostic value in these patients. In particular, the results suggest that continuous multimodality electrophysiological monitoring of this type may potentially contribute to the quality of care of stroke patients with hemorrhagic and edematous brain injuries during the critical period during which tissue shifts and possible herniation may give rise to pressure on the brainstem and other structures, with associated morbidity or mortality.
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Provider: - Institution: National Library of the Netherlands - Koninklijke Bibliotheek - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction ...under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: National Library of the Netherlands - Koninklijke Bibliotheek - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction ...under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: National Library of the Netherlands - Koninklijke Bibliotheek - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction ...under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
The usefulness of the neural network method of Matsuoka et al. 1995 for separating a mixture of two signals is investigated. The method appears to be very effective at separating signals which have ...been combined synthetically, but much less effective at separating a mixture of two real voices recorded with a pair of microphones. The algorithm was applied to specific examples to determine how critical it is that they be temporally aligned and that there be no spatial spread of the sources. The results indicate that the algorithm is very sensitive to temporal misalignment of voice mixture signals, whilst the spatial spread of the voice sources is less significant. This suggests that adaptive alignment of the mixture signals before signal separation may be beneficial.
An interface is presented which provides a quadriplegic person with C2-level injury with the ability to access any standard keyboard-input computer software. A colour coded image of a standard ...keyboard is presented on the screen of the interface. The user selects the keys in quasi direct access mode by sequentially fixating one of four flashing light emitting diodes (LED's) arranged around the edge of the screen, each associated with one colour of the keyboard image. The selected key is detected by a real-time analysis of the visual evoked potential (VEP) elicited by the flashing LED's.
A VEP-based computer interface for C2-ouadriplegics Cilliers, P.J.; Van Der Kouwe, A.J.W.
Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Societ,
1993
Conference Proceeding
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