A recent opinion by the U.S. Patent and Trademark Office Board of Patent Appeals will change patent lawyers’ actions in so-called “interference cases,” or disputes about who invented something first, and potentially affect the outcome of cases, lawyers say.

The memorandum and opinion in a patent interference case is a “strong admonition” for lawyers to avoid objections to the form or phrasing of questions, and not to question witnesses about how their affidavit testimony was prepared, said David Dykeman, an intellectual property shareholder in Greenberg Traurig’s Boston office. Paolo Pevarello v. Nancy C. Lan, Patent Interference No. 105,394 (USPTO Bd. of Patent App. & Inferences).