NEW YORK -- A woman and her convict son have been charged in the beating death of her daughter -- a crime authorities say the mother kept secret for two decades by hiding the girl's body in her home.

Madelyn Carmichael, 60, pleaded not guilty Thursday to second-degree murder at a special hearing at Brooklyn Hospital.Handcuffed to her bed and hooked up to an oxygen machine, Carmichael never spoke during the 10-minute hearing, but slowly shook her head as prosecutor Frank Urzi detailed the charges.

She has been hospitalized with chest pains since fainting as she watched detectives retrieve the body of 3-year-old Latanisha Carmichael from a sealed trunk stashed in a locked closet in her Brooklyn apartment Nov. 5.

Justice Betsy Barros ordered a psychiatric exam of Carmichael after her lawyer, Joshua Horowitz, said his client told him she hears voices and sees visions.

Gregory Carmichael, 37, already serving time for robbery, pleaded not guilty to the same charge in state Supreme Court. Afterward, defense attorney Jeff Adler said his client "didn't hit this girl, and he had absolutely nothing to do with her death."

If convicted, each faces a maximum sentence of 25 years to life in prison.

Prosecutors say, in 1979, Carmichael and Gregory, then 17, beat Latanisha unconscious in front of a teenage daughter named Sabrina. Afterward, Carmichael was unable to revive Latanisha, authorities said.

The pair allegedly beat Sabrina to make her keep quiet and stashed Latanisha's body in a trunk, which was later moved to another apartment.

The death went undetected until several weeks ago when Latanisha's twin brother, Andre, who had been sent into foster care in the 1980s, sought to renew a relationship with his mother.

Andre, now 23, contacted an aunt, who startled him by asking if he was in touch with his twin. He didn't recall having one. He confronted Sabrina, who broke down and told him she believed his twin was dead and the body was still in their mother's apartment.