[Paleopsych] NYT: Inside the Injured Brain, Many Kinds of Awareness

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Inside the Injured Brain, Many Kinds of Awareness
http://www.nytimes.com/2005/04/05/health/05coma.html
5.4.5

    By BENEDICT CAREY

    The debate over Terri Schiavo's fate comes at a time when researchers
    are deepening their understanding of the unconscious brain.

    Neuroscientists now understand at least some of the physiology behind
    a wide range of unconscious states, from deep sleep to coma, from
    partially conscious conditions to a persistent vegetative state, the
    condition diagnosed in Ms. Schiavo.

    New research, by laboratories in New York and Europe, has allowed for
    much clearer distinctions to be made between the uncounted number of
    people who at some time become comatose, the 10,000 to 15,000
    Americans who subsist in vegetative states and the estimated 100,000
    or more who exist in states of partial consciousness.

    This emerging picture should make it easier for doctors to judge which
    brain-damaged patients have some hope of recovering awareness, experts
    say, and already it is providing clues to the specific brain processes
    that sustain conscious awareness.

    "Understanding what these processes are will give us a better sense of
    how to help the whole range of people living with brain injuries,"
    said Dr. Nicholas Schiff, an assistant professor of neurology and
    neuroscience at NewYork-Presbyterian/Weill Cornell hospital. "That is
    where this field is ultimately headed: toward a better understanding
    of what consciousness is."

    The most familiar unconscious state is sleep, which in its deepest
    phases is characterized by little electrical activity in the brain and
    almost complete unresponsiveness. Coma, the most widely known state of
    impaired unconsciousness, is in fact a continuum. Doctors rate the
    extent to which a comatose person shows pain responses and reactions
    to verbal sounds on a scale from 3, for no response, to 13, for
    consistent responses.

    As in sleep, people in comas may move or make sounds and typically
    have no memory of either. But they almost always emerge from this
    state in two to three weeks, doctors say, when the eyes open
    spontaneously. What follows is critical for the person's recovery.

    Those who are lucky, or who have less severe injuries, gradually
    awaken. "The first thing I remember was telling my ex-boyfriend, who
    was at the foot of the bed, to shut up," said Trisha Meili, who fell
    into a coma after being beaten and raped in 1990, and wrote about the
    experience in the book, "I Am the Central Park Jogger."

    In the days after this memory, Ms. Meili said, she slipped in and out
    of conscious awareness, "as if my body was taking care of the most
    important things first, and leaving my moment to moment awareness for
    last."

    In fact, researchers say, this is precisely what happens. The
    primitive brain stem, which controls sleep-wake cycles as well as
    reflexes, asserts itself first, as the eyes open. Ideally, areas of
    the cerebral cortex, the seat of conscious thought, soon follow, like
    lights flicking on in the upper rooms of a darkened house.

    But in some cases - Ms. Schiavo's was one of them - the cortical areas
    fail to engage, and the patient's prognosis becomes dire.

    Neurologists were all but unanimous in diagnosing the condition of Ms.
    Schiavo, whose heart stopped temporarily in 1990, depriving her brain
    of oxygen. Brain cells and neural connections wither and die without
    oxygen, like marine life in a drained lake, leaving virtually nothing
    unharmed.

    People with these kinds of injuries - Nancy Cruzan, whose case reached
    the Supreme Court in 1990 is an example - almost always remain
    unresponsive if they have not regained awareness in the first months
    after the injury.

    In medical terms, they become persistently vegetative, a diagnosis
    first described in 1972 by Dr. Fred Plum of Cornell University and Dr.
    Bryan Jennett, a neurosurgeon at Glasgow University in Scotland. In a
    sense, the description of the diagnosis began the modern study of
    disorders of consciousness. "Before 1972 people talked about permanent
    comas, or irrecoverable comas, but we defined a different state
    altogether, with the eyes open, some reflex activity, but no sign of
    meaningful psychological responsiveness," Dr. Jennett, now a professor
    emeritus, said in an interview.

    In an exhaustive review of the medical histories of more than 700
    persistently vegetative patients, a team of doctors in 1994 reported
    that about 15 percent of those who suffered brain damage from oxygen
    deprivation, like Ms. Schiavo, recovered some awareness within three
    months. After that, however, very few recovered and none did so after
    two years.

    About 52 percent of people with traumatic wounds to the head, often
    from car accidents, recovered some awareness in the first year after
    the injury, the study found; very few recovered after that. "It's the
    difference between taking a blow to the brain, which affects a local
    area - and taking this global, whole-brain hit," said Dr. Joseph Fins,
    chief of the medical ethics division of NewYork-Presbyterian/Weill
    Cornell hospital.

    Yet these statistics cannot explain the stories of remarkable recovery
    that surfaced during the debate over Ms. Schiavo's fate. There was
    Terry Wallis, a mechanic in Arkansas who regained awareness in 2003,
    more than 18 years after he fell into unconsciousness from a car
    accident; Sarah Scantlin, a Kansas woman who, also a victim of a car
    accident, emerged from a similar state after 19 years; and several
    others, whose collective human spirit seemed to defy the experts, and
    trump science.

    Researchers say these cases can be accounted for by recent studies
    that indicate the existence of yet another state of subdued
    responsiveness, one that represents a clear break from the vegetative.

    For years, doctors who specialize in rehabilitation have known that
    some of their severely brain-damaged patients were responsive, at
    least once in a while. In their good moments, these patients could
    track objects with their eyes. They could follow commands, like
    reaching for a glass, or grabbing someone's hand. They were -
    intermittently, unpredictably, but unequivocally - responsive.

    In 2002, a panel of experts established a new diagnosis on the basis
    of exactly these reactions: the minimally conscious state. "It took
    years to get some agreement on the definition, and it's only now
    getting some acceptance," said Dr. Nancy Childs, at Texas NeuroRehab
    Center in Austin, "but we've known for years that there was this other
    group."

    In a landmark study published in February, a team of neuroscientists
    in New York, New Jersey and Washington, led by Dr. Schiff, used
    imaging technology to compare the brain activity in two young men who
    were deemed to be minimally conscious with the brain activity of seven
    healthy men and women. The researchers recorded an audiotape for each
    of the nine subjects in which a relative or loved one reminisced,
    telling familiar stories or recalling shared experiences.

    In each of the brain-damaged patients, the sound of the voice prompted
    a pattern of brain activity similar to that of the healthy
    participants. The team has since replicated the results in other
    minimally conscious patients.

    Like an interlocking set of old Christmas lights, blinking on and then
    off, the neural connections in minimally conscious patients seem to be
    in place, the research suggests. In persistently vegetative brains, by
    contrast, the crucial connections are apparently shot: maybe one light
    blinks here, another over there, but the full network is dark.

    One case, of a 26-year-old English woman named Kate who emerged from a
    subdued unconscious state after six months, suggests such patients may
    be at times acutely aware of what is happening around them. During
    rehabilitation, though unable to communicate, this woman had a visit
    from a college friend.

    "I have just met an old friend from Uni and it really upset me," the
    woman recalled thinking, doctors reported. "I can now see how much I
    am missing. She has been married for five years and she has a house
    and a life. I just scream as I can't cry, which I would do if I
    could."

    Recovery from severe brain damage is viewed in this new understanding
    as a step-wise progression: people who regain conscious awareness pass
    from a coma to a vegetative state to minimal consciousness - and
    almost always do so quickly, usually within a month or so of shaking
    the coma. Those who regain awareness within hours of emerging from a
    coma probably also pass through the same progression, but so swiftly
    the changes go unnoticed, some experts say.

    "If you look at these cases of recovery closely, you will find that
    many of these patients were showing signs of consciousness much
    earlier" than is sometimes portrayed in news media accounts, Dr. Fins
    of NewYork-Presbyterian said.

    Researchers know little about how to draw a person out of a minimally
    conscious state, which itself can last a lifetime. In one study of 124
    brain-damaged patients, doctors in Philadelphia and New Jersey
    reported in March that amantadine, a drug for Parkinson's disease,
    appeared to speed recovery in some people. But the evidence was not
    definitive and will require confirmation, the authors wrote.

    Rehabilitation, such as it is, typically includes life support, if
    needed, and regular visits from medical staff, typically to change the
    patient's position in bed and to stimulate the senses with bright
    lights, noises, sharp smells and tastes, including lemon and
    chocolate. "I always tell families that it's time and nature and God
    taking care of things, that what we do mostly is monitor the
    patients," said Dr. Childs.

    Dr. Joseph Giacino, a neuropsychologist at the JFK Johnson
    Rehabilitation Institute in Edison, N.J., has been following a group
    of brain-damaged patients with both oxygen-deprivation and traumatic
    injuries, and finds that the group with traumatic injuries - if they
    become minimally conscious - are far more likely to show signs of
    recovery than the others. "There is a real separation between these
    patients and the others in terms of improvement in the first year,"
    Dr. Giacino said.

    Ms. Schiavo showed no evidence of having ever entered a minimally
    conscious state, either in the early 90's or later, neurologists say.
    An EEG of her cerebral cortex showed almost no electrical activity,
    said a neurologist who examined her, and a dozen experts interviewed
    about her case agreed that an M.R.I. scan would have added no
    information.

    In Dr. Schiff's study comparing M.R.I. activity of minimally conscious
    with normal subjects, the researchers also found a striking
    difference. The overall rate of energy consumption was significantly
    higher in the normal brains than in the minimally conscious ones. This
    difference in idling speed may be crucial to maintaining conscious
    awareness, Dr. Schiff and others suggested.

    Because signaling between brain cells requires one cell to overwhelm
    the other, Dr. Schiff said, a lower idling speed may make the
    signaling threshold harder to overcome - effectively damping activity
    throughout the brain. "The idea is that maybe if you were to activate
    that substrate, you may cross the threshold and generate enough
    activity" to produce more awareness, he said.