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EEG signal processing and interpretation during sleep

Objective

The overall objectives of the project have not changed since the first audit (selection of the project) namely to demonstrate sleep signal interpretation results and their impact on clinical decision via a prototype system. it is based on workstation, and will be used by physicians, nurses, end-users. For this reason user-interface, computer architecture (real time analysis) and clinical validation (reference library) are the main points of the project which will be developed.
Research is being carried out in order to develop a dedicated workstat automatic analysis and interpretation of the electroencephalographic (EEG) signa a prototype of a universal system for digital signal processing.

The major achi project so far:
the design of the system architecture;
the conception and manufa version) of a high performance digital signal processing (DSP) board based on a (T800);
the implementation of the low level signal analysis procedures on the DS creation of a first prototype (workstation) able to carry out electrophysiologic and real time monitoring;
the test of the prototype in clinical environment;
the sleep parameters and spectral parameters needed;
the specification of transient characteristics during sleep;
the creation of the first step in building a sleep
The objectives of the previous year were mostly after a "state of the art" sleep analysis study, to develop the hardware of the device and the acquisition software (digital processing algorithms) in order to confirm the validity of both the methodology and the architecture used. Specification of sleep analysis criteria set and creation of a reference library in "classical sleep" were also carried out and are now in good progress.

Technical approach

During this period work was performed and we demonstrated (during the technical audit) a prototype able to acquire and monitor electrophysiological signals. This prototype is running in two sleep units (FORENAP and MAX PLANCK sleep units) for testing and will be used by the last clinical partner at the beginning of 1993.

The device architecture concerning electrophysiological signals acquisition and analysis has now been validated.

The proposed system has modular structure. it is built with the main following elements:

a) a Unix workstation
b) an EEG signal acquisition and processing sub-system (DSP)
c) a data mass storage unit
d) a high resolution graphic unit

Each sub-system can be adapted according to the needs of the ultimate use.

The system is able to record and process in real time up to 32 electrophysiological signals.

During the recording the signals are displayed continuously (monitoring) on a high resolution screen with the same look as on a polygraph (paper device). At the same time these signals are processed in order to display continuous curves (results extracted from the signals,..) or to do automatic sleep scoring. This can help users during the night recording to monitor the patients.

In order to do this prototype a DSP (Digital Signal Processing) board plugged into a UNIX Workstation manufactured by our industrial partner has been built. The DSP board is based on parallel processors issued from EEC programmes: the transputers. This technical approach enables great modularity of the power of the board. Coprocessing boards based on transputers and connected to the acquisitions board through the transputer links can be added. As far as the software is concerned, only slight changes are needed. In the near future, the T800 will be replaced by the new T9000 without modifying the software running on the board.

Today this board is available in an industrial version.

Coordinator

Fornap
Address
Pavillon 4
68250 Rouffach
France

Participants (3)

CENTRO DE ESTUDOS EGAS MONIZ
Portugal
Address
Hopital De Santa Maria
1699 Lisboa
Max-Planck-Gesellschaft zur Förderung der Wissenschaften eV
Germany
Address
Kraepelinstraße 2-16
80804 München
Telmat Informatique SA
France
Address
6 Rue De L'industrie Zone Industrielle
68360 Soultz