MILWAUKEE, NOV. 9 -- A judge has given permission to a court-appointed psychiatrist to electronically scan the brain of Jeffrey L. Dahmer to help determine if he was criminally insane during his admitted slaying of 17 people.

Circuit Judge Laurence C. Gram Jr., who will preside over Dahmer's trial in January, signed an order late Friday approving a request by psychiatrist George B. Palermo to study Dahmer's brain.

Palermo, working for the prosecution, is one of several mental health specialists expected to examine Dahmer before the trial.

Palermo wrote in his request that "a complete psychological testing" should be done, along with electronic scans of the brain and a chromosome analysis to provide an objective medical-psychiatric report.

Dahmer, 31, has admitted killing 17 boys and young men, most of them in Wisconsin, in the past 13 years. He confessed to the killings after the dismembered remains of 11 people were found in his apartment in July.

The former candy factory worker and Army veteran told police he lured victims to his apartment to take nude pictures, have sex or watch videos. He then drugged them, strangled them, dismembered them, took photos of the bodies in various stages of mutilation and boiled some of their skulls to preserve them.

Dahmer has been charged with 16 of the murders -- 15 in Milwaukee and one in Ohio. He has pleaded innocent by reason of insanity.

Defense attorney Gerald Boyle has said Dahmer might forgo the guilt phase of the trial if evidence against him is overwhelming.

If the guilt phase is waived, the insanity phase would form the bulk of Dahmer's trial, meaning testimony primarily would come from mental health experts like Palermo.

Some specialists believe that chromosomes, which carry genes conveying hereditary characteristics, are similar among the criminally insane and could dictate a person's criminal behavior.

A CAT scan, which uses X-rays of soft tissues to form an image of the brain, will be used to analyze Dahmer's brain, Palermo said.