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Experts share differing opinions on Pittsburgh synagogue gunman’s brain scans

Dave Klug

Three UPMC brain imaging experts testified Tuesday that convicted synagogue shooter Robert Bowers’ brain scans seemed largely normal but were ultimately inconclusive. Expert witnesses called by the defense later in the day argued that the same scans showed evidence of brain abnormalities potentially indicative of schizophrenia and epilepsy.

Bowers’ lawyers called the imaging experts to the stand in support of their argument that Bowers suffers from psychotic and delusional thoughts. They claim those thoughts led him to attack the Tree of Life synagogue in 2018.

The arguments were made during the ongoing penalty phase of Bowers’ trial as his defense team aims to help their client avoid the death penalty. He was convicted June 16 of federal murder and hate crimes charges stemming from the shooting that left 11 Jewish worshipers dead.

Though the defense has argued that Bowers has schizophrenia and epilepsy, they have not yet called any witnesses who said they diagnosed Bowers.

Neurologist Dr. Vijayalakshmi Rajasekaran specializes in epilepsy and reviewed Bowers’ EEG results in 2021. She explained that an EEG measures electrical activity in the brain, and although her analysis found some general slowing across the brain, she didn’t observe any seizure activity or abnormalities indicating epilepsy during the scan.

Rajasekaran noted that it’s common not to capture a seizure during an EEG. She said the scan can suggest potential seizure tendencies, but it alone can’t definitively tell whether or not a patient has epilepsy.

The medical history included with Bowers’ MRI images indicated that he was previously diagnosed with epilepsy, said neuroradiologist Dr. Joseph Mettenburg, but the history did not include any information about the diagnosis beyond that. Mettenburg’s 2022 analysis showed white matter hyperintensities that have been linked to cognitive decline. He testified that he didn’t see any abnormalities that typically indicate epilepsy but said that doesn’t mean Bowers doesn’t have the condition.

“Plenty of MRIs of people with epilepsy are normal, from a structural standpoint,” Mettenburg said.

Radiologist James Mountz examined Bowers’ PET scans, which reflect how the brain processes glucose. He said he wasn’t able to locate a site in Bowers’ brain where a potential seizure may have originated and recommended doing further testing to corroborate Bowers’ existing diagnosis.

Mountz said determining if a patient has epilepsy using only a PET scan can be difficult, in part because there are many causes for epilepsy. In past cases he’s examined, the patient’s PET scan didn’t show decreased metabolism in the brain — a sign of epilepsy — but other types of scans supported the diagnosis. In some cases, a patients’ MRI and PET scans could show no signs of epilepsy, but the patient could still have it.

“You don’t scan patients to find epilepsy,” Mountz said. Instead, doctors typically scan patients they know are epileptic to find out where a seizure originated in the brain, which can help target their treatment down the road.

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Dr. Andrew Newberg, one of the defense’s expert witnesses in nuclear medicine, also reviewed Bowers’ PET scan in 2021. He said he was told Bowers had been diagnosed with schizophrenia and epilepsy and was asked to corroborate that diagnosis.

Newberg’s report said Bowers’ brain was generally asymmetrical and showed that “a substantial number of brain areas seem to be markedly underactive or markedly overactive.” Those abnormalities can affect the brain’s processing ability and can cause overall dysfunction. Newberg testified that, based on where the abnormalities were located, Bowers may have difficulties with appropriate stress responses. He could also have excessive reactions and misperceive threats.

Newberg also noted that PET scans alone cannot be used to diagnose a patient; doctors typically use the scans in combination with clinical evaluations.

Prosecutor Eric Olshan asked Newberg, “Is it your testimony that a person whose brain generated the PET scan you examined is incapable of killing another person?” Newberg responded that it’s not possible to know the answer to that question based on a PET scan.

Neuroradiologist Dr. Murray Solomon reviewed Bowers’ MRI looking for structural abnormalities. He testified that the scan revealed “many more white matter lesions … than are usually seen” in a man his age. Solomon told jurors that Bowers’ hippocampi are asymmetrical, which could indicate an underlying seizure disorder or past brain damage.

On cross examination, Solomon told Olshan that he wasn’t aware of Bowers’ diagnoses when he reviewed the images but was informed of them in the weeks leading up to his appearance in court. Solomon said that while schizophrenia could have caused the white matter hyperintensities in Bowers’ brain, he was not aware that was a possibility until recently.

Solomon also said defense lawyers had done some “minor rewording” to his report, but said the final report included “basically my ideas.”

Some drug use, cigarettes, and untreated hypertension can also contribute to white matter lesions in the brain, Solomon said. He did not receive any information about Bowers’ lifestyle before conducting his analysis, though Olshan shared evidence that Bowers smoked regularly.

Solomon testified that regardless of the cause of the white matter lesions, they negatively affect brain activity.

Julia Zenkevich reports on Allegheny County government for 90.5 WESA. She first joined the station as a production assistant on The Confluence, and more recently served as a fill-in producer for The Confluence and Morning Edition. She’s a life-long Pittsburgher, and attended the University of Pittsburgh. She can be reached at