Dr. Sandeep Kapoor, Dr. Khristina Eroshevich and Stern are charged with conspiring to illegally provide Smith with controlled substances before her death. The three have pleaded not guilty to the drug charges. Their lawyers maintain they are blameless in the death of a strong willed woman who directed her own course of medical treatment.
It was unknown what information Birkhead could add to the story of Smith's death. Defense attorney Adam Braun said that an audio recording of authorities interviewing Birkhead was turned over to him recently. He said he had not had time to study it and would ask to delay Birkhead's testimony.
Birkhead has been raising Smith's now three-year-old daughter, Dannielynn.
Also on the witness list for Wednesday are the bodyguard who tried unsuccessfully to revive Smith when she was found unresponsive in her bed at a Florida casino hotel on Feb. 8, 2007, and a toxicologist who analyzed the drugs in Smith's body.
Her death at age 39 was ruled an accidental overdose
Tuesday's single witness, California Department of Justice investigator Danny Santiago, painted a portrait of Smith in her final days as being ill, confused and isolated in a hotel room with a cornucopia of prescription drugs.
He offered evidence he collected from Florida authorities and others about the drugs she was given and the many fake names that were used to get them for her. He said some were in the name of her lawyer-boyfriend, Howard K. Stern.
Prosecutors allege Smith was victimized by her boyfriend and doctors who provided her with a lethal amount of prescription drugs. However, when Deputy District Attorney Renee Rose suggested they might have caused her death, Superior Court Judge Robert J. Perry stopped her line of questioning.
"There is not a murder charge," Perry said. "The cause of death is not an issue."
Smith's autopsy concluded she died of "acute combined drug intoxication," and the drugs involved were chloral hydrate combined with Benadryl, clonazepam, diazepam and lorazepam. Clonazepam and Soma, both muscle relaxants, and the sedative diazepam were among medications found in her hotel suite.
On Tuesday, Rose played a video of Smith's appearance on the 2004 American Music Awards in which the flashy blond introduced Kanye West, calling him "a freakin' genius" in a performance noted for her slurring words. Some thought she was drunk but Stern's attorney said she had taken the medication diazepam for a seizure she had suffered.
"Video is video," Sadow said later outside court. "We're not running from it. It's what she was on that day. It just depends on the context of why she was that day. We all have bad days.
"She had medical problems," he said. "If she's on medication for that, that would explain her activity."
The preliminary hearing is to result in a determination by the judge of whether there is enough evidence for the three defendants to stand trial. Stern is named in all 11 counts of the complaint. The doctors each face six counts, including conspiracy, and if convicted could be sentenced to as much as five years, eight months in prison. It was not clear what sentence Stern might face if convicted.