Staff Sgt. Robert Bales, charged with killing 16 Afghan civilians last year, will undergo a sanity-board hearing at Joint Base Lewis-McChord that will include an examination of whether he was affected by post-traumatic stress disorder and traumatic brain injury.

The review of Bales by Army doctors will start Sunday and could last three to seven days, said a defense attorney, John Henry Browne. Such reviews are aimed at discerning a defendant’s mental state at the time of the crime and competency to stand trial.

The Ohio native and father of two from Lake Tappsis accused of murdering Afghan villagers, mostly women and children, during pre-dawn raids on March 11, 2011.

Bales, who was on his fourth combat deployment, slipped away from his base in southern Afghanistan to attack two nearby villages and returned in bloodstained clothes, according to testimony at a pretrial hearing last year.

Bales has not entered a plea. The Army is seeking the death penalty.

Prosecutors and defense attorneys sparred over the terms of a sanity-board hearing, with defense attorneys last spring saying their client would refuse to participate.

Prosecutors said that if Bales opted out of the sanity- board review then he should be prohibited from raising a mental-health defense.

After a pretrial hearing that ended in November, an Army judge ordered Bales to participate in the sanity- board hearing.

But the judge, Col. Jeffrey Nance, in a written order, did grant a key defense request, according to Emma Scanlan, an attorney representing Bales.

The judge ruled that the board’s conclusions, including a summary of the findings, would only be made available to prosecutors if Bales raises mental health as part of his defense.

“They’re not going to get that information, which is why our client is agreeing to participate,’’ Scanlan said.

Defense attorneys also had requested to be present at the sanity-board hearing, but that request was not granted, according to Scanlan.

The Associated Press and Seattle Times reporter Hal Bernton contributed to this story.