December 17, 2013
Vegetative Patients Recognize Pictures Of Loved Ones
redOrbit Staff & Wire Reports - Your Universe Online
Patients in a vegetative state may be able to recognize photographs of their family and friends, according to a new study published this month in the journal PLOS ONE.
Although patients in a vegetative state are awake, can breathe on their own, and appear to go in and out of sleep, they do not respond to what is happening around them, and exhibit no signs of conscious awareness. Since communicating with these patients is impossible, friends and family are often left wondering if their loved one even knows they are there.
In the current study, Dr. Haggai Sharon and Dr. Yotam Pasternak of Tel Aviv University's Functional Brain Center and Sackler Faculty of Medicine used functional magnetic resonance imaging (fMRI) to show that the brains of patients in a vegetative state emotionally react to photographs of people they personally know as though they recognize them.
"We showed that patients in a vegetative state can react differently to different stimuli in the environment depending on their emotional value," said Dr. Sharon in an interview with American Friends of Tel Aviv University.
"It's not a generic thing; it's personal and autobiographical. We engaged the person, the individual, inside the patient."
The findings deepen our understanding of the vegetative state, and may offer hope for better care and the development of novel treatments, the researchers said.
For many years, unresponsive patients were believed to have no awareness of self or environment. But in recent years doctors have made use of fMRI to examine brain activity in these patients, and found that some patients in a vegetative state can perform complex cognitive tasks on command, such as imagining a physical activity or even answering yes-or-no questions. However, these cases are rare and lack any indication as to whether or not patients are having personal emotional experiences in such a state.
To gain insight into what it feels like to be in a vegetative state, the researchers worked with four patients in a persistent (defined as "month-long") or permanent (persisting for more than three months) vegetative state. They showed the patients photographs of people they did and did not personally know, and then evaluated the patients' reactions using fMRI, which measures blood flow in the brain to detect areas of neurological activity in real time.
In response to all the photographs, a region specific to facial recognition was activated in the patients' brains, indicating that their brains had correctly identified that they were looking at faces. However, in response to the photographs of close family members and friends, brain regions involved in emotional significance and autobiographical information were also activated.
In other words, the patients reacted with activations of brain centers involved in processing emotion, suggesting patients in a vegetative state can register and categorize complex visual information and connect it to memories, findings the researchers called groundbreaking.
To determine whether or not the patients were conscious of their emotions, or just reacting spontaneously, the researchers verbally asked the patients to imagine their parents' faces. Surprisingly, one patient, a 60-year-old kindergarten teacher who was hit by a car while crossing the street, exhibited complex brain activity in the face and emotion-specific brain regions, identical to brain activity seen in healthy people.
The researchers called her response “the strongest evidence yet that vegetative-state patients can be emotionally aware."
A second patient, a 23-year-old woman, exhibited activity just in the emotion-specific brain regions. Significantly, both patients woke up within two months of the tests, and had no memory of being in a vegetative state.
"This experiment, a first of its kind, demonstrates that some vegetative patients may not only possess emotional awareness of the environment but also experience emotional awareness driven by internal processes, such as images," said Dr. Sharon.
Research focused on the emotional awareness of patients in a vegetative state is relatively new. The TAU researchers said they hope their work will ultimately contribute to improved care and treatment. They are now working with patients in a minimally conscious state to better understand how regions of the brain interact in response to familiar cues. Emotions, they say, could help unlock the secrets of consciousness.