April 21, 2009 -- A Mississippi woman gave police quite a surprise last Tuesday night after deputies stepped over the body of her estranged husband on the back porch and entered the couple's rural home.
Tammy Sexton, 57, sat up in bed and offered the officers a drink quite unaware that a bullet had struck beneath her left eye and exited out the back of her head.
"She had fixed herself some tea and she was holding a rag to her head," said Mike Byrd, sheriff of Jackson County, Miss. "She didn't realize that she had been shot."
"When the officer realized how badly she was injured he called for help," said Byrd.
Not only has Sexton survived her estranged husband's murder-suicide plot, she has since survived an airlift to a hospital in Mobile, Ala., and was last listed in fair condition.
Though the examples are few and far between, brain injury experts say cases of people walking and talking with gunshot wounds to the head are an example of the complexity of the human brain.
Patrick Ireland, a survivor of the 1999 Columbine High School shootings, is living proof of the brain's remarkable structure.
Ireland was shot twice in the head, once in the foot, and had lost feeling in half his body before climbing out a window to safety during the infamous shooting spree.
Today, Ireland is married and works as a financial planner in Denver. He had to learn how to walk again after the shootings and gave up basketball, but he can still go water skiing, according to reporting by ABC's Kate Snow.
"Certain parts of the brain are absolutely mission critical for every kind of function," explained Dr. Stephan Mayer, a professor of neurology and neurosurgery at Columbia University and New York Presbyterian Hospital in New York City.
"[Hit] one spot of the brain stem and you're in a coma, you're paralyzed for the rest of your life," said Mayer. "But there are other, huge amounts of the brain, vast areas that seem to serve no specific function if you remove it or damage it."
Observing the Range of Possible Brain Damage Firsthand
Mayer said he was shocked early in his career to see the rare survivor of a gunshot wound to the brain who appeared to act normal.
In many of these cases Mayer said the patient has survived a wound to the so-called "non-eloquent" parts of the brain: the portion that's responsible for complex thoughts and insight and, in part, is what differentiates humans from animals with smaller brains.
"I learned this message firsthand as a neurology resident in the early '90s," said Mayer. "I was called into the emergency room because the guy had been shot in the head execution style."
Mayer said his patient had been on his knees when he was shot behind his ear at close range. The injury didn't kill him, but blew off a part of his brain (the parietal lobe) and skull right above his ear.
"I sat there amazed. Just the incongruity of seeing his head and this guy," said Mayer. "I have this guy sitting here on a table, wide awake, talking to me. But I'm sitting there staring into his head."
But doctors say however normal people may appear to be after a gunshot wound to the brain, some damage can appear hours, days or even months after the injury.
"If the bullets really go through the brain, it's hard to imagine that it goes through without any consequence," said Dr. Alan Faden, a professor of neuroscience, neurology and pharmacology at Georgetown University Medical Center in Washington, D.C.
"The appearance of a normal reaction may be just that -- an appearance," he said.
In some unfortunate cases, Faden said the body's natural defense system overcompensates for a brain injury and the result is a cascade of chemical responses that causes more brain damage than the original injury.
"If they over-compensate they can be highly destructive," said Faden "There may be enormous consequences down the line."
In other cases, Faden said the injury to the brain can affect more subtle or "executive" thinking that would take days or months to notice. This means while someone can walk, eat, or do actions that make them appear healthy, very important parts of their thinking and their emotions may be affected.
How Brain Damage Can Change Personality
Dr. Steve Flanagan, of New York University School of Medicine, said the story of railroad worker Phineas Cage has become a textbook example of such a brain injury.
"By some bizarre accident a railroad spike went right though his frontal lobes and he survived," said Flanagan.
Cage could walk, talk, and seemingly acted normal. But Flanagan said the injury left Cage with a new dark, disturbed personality for life even though he did survive.
"A lot of it depends on the caliber of the bullet and the trajectory, how much energy hit the brain," said Flanagan. "Although survival really is exceptionally rare."