Bill Cosby’s lawyers said they will demand "competency and memory tests" from 13 women accusing the entertainer of sexual assault.

His defence team will say prosecutors are rounding up women to build a stale case at a pretrial hearing at Montgomery County Court in Pennsylvania.

Cosby’s lawyers have warned they will challenge sexual misconduct claims dating as far as the 1960s by arguing the case is reminiscent of the casting couch era – when sexual favours were traded in the entertainment industry.

The defence will also seek competency hearings from any woman called to testify.

The fact that even the most fervently held memories can actually be tainted – or altogether false – is supported by a vast existing and growing body of science, Cosby’s lawyers said.

His team has downplayed the charges as stories of a night spent partying with a famous celebrity.

Cosby, now 79 and claims he is blind, remains free on a $1m bail.

He is charged with drugging and molesting a former Temple University employee in 2004. He has pleaded not guilty.

In the deposition, Cosby defended himself against the allegations by saying she did not ask him to stop.

I don’t hear her say anything. And I don’t feel her say anything, he said.

And so I continue and I go into the area that is somewhere between permission and rejection.

His lawyers have argued his debilitated memory prevents Cosby from defending himself against vague accusations that stretch back to the 1960s.

Prosecutors hope to have 13 of about 60 known women accusers testify to show a pattern of prior bad acts.

Their goal is to convince the court of a signature crime pattern which, if proven, allows the women to testify.

The defence argues some of the women took alcohol and drugs knowingly and some women don’t even know when they met Cosby.

The testimony of the 13 others, if consented by the judge, could bolster a case that turns on the question of consent.

Cosby, who has repeatedly denied any wrongdoing, became the first black actor to star in a primetime TV show more than fifty years ago.

It has been more than 20 years since his top-ranked homage to black family life, The Cosby Show, stopped filming.

His trial has been scheduled for June 2017.

(c) Sky News 2016: Cosby lawyers demand ‘memory tests’ from ‘casting couch’ accusers