New litigation discovery rules dealing with a wide range of electronic communications are causing headaches for lawyers and their corporate clients. But the amendments to the Federal Rules of Civil Procedure, which took effect Friday, have also opened opportunities for companies such as Nexidia Inc., an Atlanta business that uses advanced phonetic-based technology to search audio recordings.

The new rules require litigants to tell opponents about the existence of electronic information — under definitions that go far beyond e-mails, word processing and databases to include information stored in any electronic medium.