(CNN) -- The man accused of killing six people in an Arizona shooting rampage can receive medical treatment for another four months, a federal judge ruled Monday after reviewing a report from a psychologist that found "measurable progress" in the suspect's condition.
The medical treatment plan for Jared Loughner -- aimed at improving his mental state, so he would be competent to stand trial -- was set to expire on Wednesday.
On Monday, U.S. District Judge Larry Burns decided to extend that treatment until at least June 7, Ninth Circuit court spokesman David Madden said.
Loughner, 23, allegedly killed six people and wounded 13 others during a January 2011 meet-and-greet event for then-U.S. Rep. Gabrielle Giffords outside a Tucson supermarket. Giffords, who was shot in the head, stepped down from her position in Congress last month in order to focus on her recovery.
Prosecutors have said that Loughner suffers from schizophrenia, and his mental condition has been central to much of the related court proceedings since the mass shooting.
Burns led Monday's hearing from San Diego, where he is based. He is overseeing the case in part because one of the shooter's victims was Arizona-based federal Judge John Roll.
Prosecutors and defense attorneys participated from Tucson in Monday's session by videoconference, according to Madden.
The judge reviewed a report prepared by Dr. Christina Pietz, Loughner's psychologist, indicating the suspect had made what Burns termed "measurable progress" toward competency.
Burns made his decision to extend Loughner's treatment based on that report, said the court spokesman. Neither the defense nor the prosecution presented any additional evidence.
Pietz will notify Burns if she determines Loughner is competent before June 7.
Loughner was declared incompetent to stand trial last May after an initial evaluation term at a federal mental hospital in Springfield, Missouri, where he is now.
In July, bizarre and suicidal actions by Loughner while in custody pushed a federal appeals panel to allow authorities to force the defendant to take anti-psychotic medication.
Prosecutors said then that Loughner had been deteriorating: He displayed screaming and crying fits that lasted hours, harmed himself and made claims that the radio was inserting thoughts into his head, they said.
His attorneys have consistently fought court rulings that Loughner continue his treatment at the Missouri hospital.
In November, defense attorney Ellis Johnston argued before a different federal judge that the side effects of the psychotropic drugs he has been receiving during his court-ordered treatment may interfere with Loughner's ability to work with his attorneys.
But Assistant U.S. Attorney Christina Cabanillas said then that Loughner "could revert to being a danger to himself" if the medication were halted.
"It is his mental illness that is the cause of the danger in the hospital setting," Cabanillas told the court.