The project's aim was to develop a dedicated workstation in order to process multiple channels of electrophysiological signals in real-time during sleep. In ESPIS we were aiming to define both an architecture and an environment for EEG signal interpretation in medicine based on computer science gold standards (Unix, XWindow, Motif). The design takes advantage of the development environment, processing and graphics resources, and networking capabilities of high-performance UNIX workstations. Signal processing and pattern recognition analysis are provided by parallel processing on a specific developed acquisition architecture (DSP) based on transputers. The main result is a high performance prototype demonstrating signal interpretation during sleep which has already been tested in a medical environment (3 clinical centres and 1 research centre). The overall specifications allow this biomedical device to be extended to other types of medical signals.