DIGITAL ARCHIVAL AND EXCHANGE OF EVENTS IN A SIMPLE FORMAT FOR POLYGRAPHIC RECORDINGS WITH APPLICATION IN EVENT-RELATED POTENTIAL STUDIES

This paper describes a simple method of event encoding as an extension to a previously defined standard format, the European Data Format (ED F). The specification ensures full backward compatibility with the exi sting definition. By using this extension, the format can be used to s tore both continuous recordings and selected epochs of recordings. The encoding is performed in a channel of event-codes or in a pseudo-chan nel for annotations. Standardisation of event encoding is discussed. D ecoding of events or annotations from the extended format is implement ed at the application level. Existing programs that do not support the new encoding scheme still operate correctly and can simply ignore the new channels in processing 'extended' data files. The event encoding is also compatible with EDF's capability to encode channels of differe nt sampling frequency. (C) 1998 Elsevier Science Ireland Ltd. All righ ts reserved.