Superior Court Judge Ronald S. Harris said in a hearing that the 69-year-old actor is in “incurable neurocognitive decline” from which he is unlikely to recover.
The former adult film star could be declared fit for trial in the future if his condition improves, according to the LA County Deputy DA, but it's not expected.
The accusations include over 30 counts of sexual assault involving 21 women and girls dating back more than two decades.
The porn actor has been charged with 28 counts of sexual violence in Los Angeles County.
The Los Angeles County District Attorney's office said the adult industry star could be sentenced to up to 90 years in prison.
The 65-year-old allegedly groped, sucked and penetrated the young woman all in one day.
The adult film legend allegedly violated the Adult Video News event's "zero tolerance harassment policy."