Autopsy Won’t Be Gauge of Awareness

The autopsy of Terri Schiavo may not provide a definitive answer to the most pressing question about her medical condition: Did some glimmer of meaningful human consciousness remain?

In the coming weeks, doctors will weigh Schiavo’s brain to gauge how much it had atrophied in the 15 years since a heart attack cut off the blood supply for about 5 crucial minutes. They will examine thin slices of tissue under a microscope and look for the glial cells that are the hallmark of brain damage.

They will also pay close attention to the thalamus, the mass of neurons in the center of the brain that processes information from the outside world. If the connections between the thalamus and the outer brain have wasted away, it would have been impossible for Schiavo to comprehend her situation, neurologists said Thursday.

Terri Schiavo’s husband, Michael, arranged to have an autopsy performed to try to dispel persistent rumors that he was hiding information about his wife’s medical condition, said his attorney, George J. Felos. The medical examiner for Pinellas County, where Terri Schiavo spent her last days in hospice care, will perform the autopsy.

Based on a single image from a 2002 CT scan of Schiavo’s brain released by Felos, doctors said it was probable that pathologists would find severe damage.

But for some, even proof of widespread brain damage may not settle the question of whether she was able to feel pain, recognize her mother’s voice or have any awareness.

For all the advances of medical science, measuring consciousness can still be an uncertain proposition. Evaluating a patient from bedside cannot provide a definitive view of the brain’s inner workings. Even looking at the brain itself -- through advanced medical scanning devices and direct observation after death -- can provide only clues to the state of a mind.

The physical state of a brain is no clear evidence of consciousness. Patients can have relatively normal-looking brains, yet suffer from profound brain damage, said Dr. Martin A. Samuels, chairman of the department of neurology at Brigham and Women’s Hospital in Boston.

“The brain can be functionally abnormal and structurally normal,” Samuels said.

The autopsy will not overrule the long-standing diagnosis that the 41-year-old Florida woman was in a persistent vegetative state.

That is a determination based on a physician’s observation and interaction with the patient, not on the condition of brain tissue, said Dr. Robert Lisak, chairman of the department of neurology at Wayne State University School of Medicine in Detroit.

The primitive parts of Schiavo’s brain are likely to be relatively intact, doctors said. She could breathe on her own, maintain a steady blood pressure and pulse, and wake up and fall asleep on her own -- all indications that her brain stem was functioning normally.

The greatest amount of damage, doctors said, will be in the cerebral cortex, the two large hemispheres responsible for language, thought and interaction with the outside world.

When deprived of oxygen and nutrients from blood, the neurons in the cortex die off and are replaced by glial cells, the brain’s version of scar tissue. As the gray matter atrophies, the empty space fills with spinal fluid.

With the cortex unable to function, the parts of the thalamus designed to interact with it will waste away as well, and pathologists will look for glial cells there to support the diagnosis of persistent vegetative state, doctors said.

“If everything were really gone, you could probably conclude it was hard to imagine that a person could have been aware,” Samuels said.

Though Schiavo lingered for 15 years, doctors said, the damage to her brain probably occurred very soon after she fell to the floor of her apartment Feb. 25, 1990.

“Whether one is allowed to die six months after the original injury or 15 years later, I wouldn’t expect so much difference,” said Dr. Nicholas Gonatas, a pathologist at the University of Pennsylvania’s Mahoney Institute of Neurological Sciences. “The damage and scarring happens within hours of deprivation of the brain of oxygen and blood and glucose. After a few weeks, the whole process is more or less finished.”