Prosecutors want 13 more women to testify against Bill Cosby in sex assault case.

Prosecutors in the US have said they want 13 other women who have accused Bill Cosby of molesting them to testify at his upcoming sex assault trial.

The criminal case against the 79-year-old actor involves a single 2004 encounter at his home near Philadelphia with former Temple University employee Andrea Constand.

But prosecutors can introduce evidence of other acts, even though no charges were brought in those cases, to show a pattern of behaviour.

Prosecutors said they had reviewed accusations made against Cosby by about 50 women and concluded 13 should be allowed to testify.
The defence is expected to oppose such testimony.

Ms Constand told police that Cosby drugged and molested her. Legal experts have said a judge might allow as evidence similar allegations against Cosby in which drugs or alcohol were involved.

Lawyers for Cosby disclosed in a letter provided before Tuesday's hearing that Cosby is blind, and as a result, he may need special accommodations at his trial, Judge Steven O'Neill said.

Cosby was arrested in December after the investigation into the allegation Ms Constand first brought in 2005 was reopened, following disclosure of the entertainer's testimony in a civil lawsuit and a stream of new allegations by women going back decades.

Cosby looked noticeably healthier as he walked into court for the pre-trial hearing. He clutched an aide's arm but did not have the wooden cane he has used at past hearings.

Cosby's eyes appeared less milky and he seemed more engaged and animated as he spoke with his legal team.

A trial date has not yet been set, though the judge indicated that he wanted one to start before June.

Lead defence lawyer Brian McMonagle said at the hearing that he has other trials booked until June.

But the judge said Mr McMonagle might have to review his schedule and look for an earlier date.