Originally created 01/23/04

Expert argues damage to brain



Humans, even serial-homicide suspect Reinaldo Rivera, are not at the mercy of their genetic or biological makeup, a Medical College of Georgia expert said.

Despite what a defense expert claimed earlier, Mr. Rivera does not have significant brain damage that would diminish his ability to control himself, said David Hess, the chairman of the Department of Neurology at MCG.

Testifying as a rebuttal witness in the rape and murder trial in Richmond County Superior Court, Dr. Hess said he also examined Mr. Rivera and had him undergo an MRI. He did find some shrinking of the brain on the MRI but "it wasn't impressive," Dr. Hess said. "I didn't think it was clinically significant."

His opinion contradicts defense expert and neuropsychiatrist Dr. Thomas Sachy, who said the atrophy was "absolutely not normal" and added to his findings that Mr. Rivera has a dysfunctional brain. Dr. Sachy noted on a positron emission tomography scan, or PET scan, that the frontal lobes showed low activity. This is the area that should enforce impulse control and socially appropriate behavior, Dr. Sachy said, and it was not doing so in Mr. Rivera's case.

Dr. Sachy was interpreting a PET scan done at MCG. The physician who first read the scan, however, did not agree. Hadyn Williams, the chief of nuclear medicine at MCG, said he did not see anything on those images.

"I thought they were normal," he said.

That could also be the case with the severely disturbed, defense attorney Jacque Hawk argued.

"It would be possible for a person to be totally disabled (with a personality disorder) and you would have a normal PET scan?" Mr. Hawk asked.

"Yes," Dr. Williams said.

Dr. Hess said his exam also did not show frontal lobe damage and even if it was there, patients with that damage don't fit the mold of the "predatory" Mr. Rivera.

"They can't plan anything," Dr. Hess said of the frontal lobe patients. "They can't seduce anybody," as Mr. Rivera claimed he did.

Dr. Hess did agree, under cross-examination, with research that showed that most anti-social personality disorder patients show significant signs by ages 12-15, as Mr. Rivera said he did. But that didn't mean it was inevitable that he would become what he turned out to be, Dr. Hess said.

"You're getting to biological determinism, that people don't have a choice in the matter," Dr. Hess said. "I don't think that's been shown."

Reach Tom Corwin at (706) 823-3213 or tom.corwin@augustachronicle.com.