Fulton County prosecutors sought to counter the testimony of an Emory University sleep expert who testified at the ongoing murder trial of Atlanta attorney Claud “Tex” McIver with an expert of their own.

On Monday, prosecutors called Dr. Mark Pressman, a psychologist and forensic sleep specialist who is also an adjunct law professor at Villanova University's Charles Widger School of Law. Pressman is also a clinical professor of medicine at Jefferson Medical College in Philadelphia.

Pressman was called to offer his opinion as to whether McIver's diagnosed sleep disorder could have led to the fatal shooting of his wife, Diane, as the couple was traveling at night in their SUV through the streets of downtown Atlanta. McIver was sitting in the rear passenger seat and a family friend was driving when he shot his wife who was sitting in front.

Pressman's testimony concluded the state's rebuttal case. Jurors were then allowed to view and, if desired, sit inside the McIvers' SUV where Diane McIver was fatally shot. The SUV has been in the prosecutors' custody since October 2016. Closing arguments are scheduled to begin Tuesday morning.

McIver's defense has argued that the lawyer, who retired as a partner at Fisher & Phillips in Atlanta after his wife's death, suffers from two sleep disorders. One, Rapid Eye Movement Sleep Behaviorial Disorder (known as RBD) can cause people to act out their dreams, sometimes violently. McIver was diagnosed with that disorder by the Mayo Clinic in Jacksonville, Florida, in 2004.

McIver was diagnosed with the second disorder — confusional arousal, also known as sleep drunkenness — last January after he had been charged with murder stemming from his wife's shooting.

Dr. David Rye, an Emory neurologist, had suggested during this testimony last week that confusional arousal might be “one possible explanation” for how McIver came to pull the trigger on the gun he was holding in his hand at the time but had largely discounted RBD as a cause of the shooting.

McIver and his attorneys have said that he had fallen asleep, but woke up as the SUV exited the interstate and, wary of that section of downtown Atlanta, had asked his wife for, and taken charge of, a Smith & Wesson .38-caliber revolver he kept in the SUV's front console.

McIver then claimed, in a narrative whose details appear to have shifted over time, that he had fallen back asleep only to wake a few minutes later when the gun discharged. Dani Jo Carter, who was driving the SUV, had told police that she believed McIver was asleep when the gun went off.

Pressman said that McIver's story that he had been alarmed enough about pedestrians on the downtown street they were traveling on to get his gun and his later story to police that he was nervous enough that the hair was standing up on the back of his neck were “absolutely incompatible” with sleep.

“People who are very fearful will have a very hard time falling asleep,” he said. “I would say that it is not possible that he fell back asleep.”

Pressman also said the circumstances that led to Diane McIver's shooting were inconsistent with an episode of RBD. He said that those episodes are experienced only after an individual slides into a deep REM sleep. If, as McIver has said, he dozed off almost immediately after his wife handed him his gun, only three to 10 minutes had passed before the gun fired. “That [is] not much time to get to REM, much less a deep sleep,” he said.

He also said alcohol consumption delays and may even suppress REM sleep. Numerous witnesses have testified that McIver as well as his wife appeared to have been drinking wine in the hours before the shooting, an allegation that McIver has denied.

Rye thought differently, testifying there was nothing that would have prevented McIver from falling back asleep, even after he had perceived a danger and asked for his gun.

Pressman also said that the timing of the shooting and McIver's actions in the immediate aftermath were also not consistent with confusional arousal. When someone is in the throes of a confusional arousal, they don't immediately recognize their circumstances or surroundings and generally take some time to reorient themselves.

“Confusional arousals don't occur in light sleep,” he said. It can't happen, he added, “If you are only a little bit past being awake.”

He said it was “impossible” to experience an episode of RBD and confusional arousal at the same time because they occurred at different stages in the sleep process.

Asked by Assistant District Attorney Adam Abbate if McIver could have been experiencing a confusional arousal if he were immediately aware that he was handling a gun and that it had fired, and then give instructions to the driver to take his wife to Emory University Hospital, a 20-minute drive away, Pressman replied, “No.” That kind of awareness, he added, “should not occur for several minutes after arousal.”

Defense attorney Amanda Clark Palmer noted during her cross-examination of Pressman that during the sleep study McIver underwent at Emory in January during a series of four naps, he fell asleep within five minutes during one of those naps.

But Pressman countered that McIver didn't fall asleep during three of those designated nap times, a circumstance he described as “very, very, very atypical.”

“People who stay awake are people who are naturally alert, naturally anxious,” he said. “They are getting enough sleep.”

And when Palmer suggested that an episode of confusional arousal could be facilitated by alcohol, Pressman replied, “No, that's junk science.”