But although Los Angeles Superior Court Judge David Cowan ruled that the public has a right to view the proceedings in a trial that will revolve around the mental competency of the 92-year-old billionaire, Cowan said some testimony could be shielded from the public.

Attorneys for Redstone, the controlling shareholder of Viacom Inc (>> Viacom, Inc.) and CBS Corp (>> CBS Corporation), had asked the judge to keep part of the trial behind closed doors to protect Redstone's right to medical privacy.

Redstone's ex-girlfriend, Manuela Herzer, filed a lawsuit asking to be reinstated as the person in charge of Redstone's healthcare if he becomes unable to make decisions on his own. Herzer argues that Redstone lacked the mental competency to remove her from his advance healthcare directive last October.

Viacom and CBS shareholders have closely followed the lawsuit for what it could reveal about Redstone's condition.

Lawyers for Redstone argue that Herzer is seeking financial gain after Redstone revoked a part of his estate plan that would have given her a $70 million inheritance.

At Wednesday's court hearing, in saying that the public has a right to view the proceedings, the judge also said it would not be practical to conduct part of the trial in private.

Cowan added, however, that he wanted to have a "dignified" trial. He said either side could request to shield specific testimony from the public during the proceedings.

Cowan also said he would carefully examine Redstone's medical records and limit the information entered as evidence.

"Just because there is a trial doesn't necessarily mean that all of his medical records have to end up on the Internet," Cowan said.

The judge deferred a decision on Herzer's request for Redstone to appear as a witness. Her attorneys previously said they would not call him to testify.

Pierce O'Donnell, an attorney for Herzer, on Wednesday said he wants to call Redstone because his lawyers "are not answering the most important questions."

Those questions are: "What did he know? When did he know it? Who told him? And when did he act on the information" in October? O'Donnell told reporters.

Redstone's attorneys say he was fully aware of his actions when he named Viacom's chief executive, Philippe Dauman, as his designated healthcare agent. Earlier this month, Redstone made another change, naming his daughter, Shari, as his healthcare agent instead of Dauman.

The case is set to go to trial May 6 unless the two sides reach a settlement. Earlier settlement talks fell apart.

(Reporting by Lisa Richwine; Editing by Leslie Adler)

By Lisa Richwine

Stocks treated in this article : CBS Corporation, Viacom, Inc.