LOS ANGELES -- A judge is scheduled to consider whether a mental evaluation of media mogul Sumner Redstone should be conducted in response to claims by his ex-girlfriend.

The hearing Monday afternoon in Los Angeles Superior Court has been prompted by a recent filing by Redstone's former companion, Manuela Herzer, who contends his signature was forged on a recent document.

Redstone controls CBS Corp. and Viacom Inc.

His attorney, Gabrielle Vidal, has stated in court filings that she witnessed Redstone sign the disputed document and a court-ordered evaluation of the 92-year-old is unnecessary.

Herzer dated Redstone and until recently was in charge of making medical decisions for him. That ended in October, when Herzer was kicked out of Redstone's house.

She contends a November agreement allowing her to retrieve her belongings was forged, and Redstone lacks the ability to make meaningful decisions.

Vidal has called Herzer a liar who is misrepresenting Redstone's condition to try to remain a factor in his life. Redstone recently underwent a brain scan, which found no signs of stroke or other impairment, court filings state.

Herzer denies she is motivated by the billionaire's money, saying he has already paid her tens of millions of dollars and she is merely trying to ensure he gets the care he needs.

Redstone controls CBS and Viacom through National Amusements Inc., which holds nearly 80 per cent of the voting stock in both media companies. He hasn't joined an investor conference call since November 2014.