Yes, people in a vegetative state (or unresponsive wakefulness) can smile, but these are usually reflexive, automatic facial movements, not expressions of happiness or awareness, occurring alongside other involuntary actions like crying, grunting, or blinking without response to stimuli. These expressions, while potentially distressing for families, generally stem from brainstem activity and lack conscious meaning, distinguishing them from voluntary smiles in minimally conscious states.
Patients may smile, grimace, cry, grunt, or groan while awake, and families will often take these as signs of pain and pleasure. But their doctors usually remain skeptical, suspecting these behaviors are merely reflexes.
People in a vegetative state cannot do things that require thought or conscious intention. They cannot speak, follow commands, move their limbs purposefully, or move to avoid a painful stimulus. Most people in a vegetative state have lost all capacity for awareness, thought, and conscious behavior.
Voluntary behavior or movements are absent, but facial expressions such as smiling, frowning, and crying can occur. These are not linked to any external stimulus. Sleep–wake cycles are present but do not necessarily reflect a specific circadian rhythm and are not associated with the environment.
Sleep-wake cycles may resume or patients may appear to be in a state of chronic wakefulness. They may grind their teeth, swallow, smile, shed tears, grunt, moan, or scream without any apparent external stimulus. VS/UWS patients do not respond to sound, hunger, or pain.
Conclusions: Strong evidence shows that some patients diagnosed as being in a vegetative state can hear and understand what is being said in their environment.
Hypoxic Brain Injury
In most cases, the injury is caused by a medical incident or emergency, such as a heart attack or stroke. If an individual does not receive immediate medical attention or help to restore oxygen flow, the brain suffers irreversible damage, possibly leading to death.
Patients in a vegetative state may have awoken from a coma, but still have not regained awareness. In the vegetative state patients can open their eyelids occasionally and demonstrate sleep-wake cycles, but completely lack cognitive function. The vegetative state is also called a "coma vigil".
Normal facial asymmetries are reduced in both schizophrenia and bipolar disorder. These findings implicate loss of face-brain asymmetries in psychotic illness.
On a background of minor dysmorphologies of the upper face, maxilla, midface and periorbital region, the main features in bipolar disorder are (a) retrusion and shortening of the premaxilla, nose, philtrum, lips and mouth (the frontonasal prominences), with (b) protrusion and widening of the mandible-chin.
Thus some patients can regain awareness after more than four months in a vegetative state, and, although few reach full independence, most can achieve an improved quality of life within the limitations of their disabilities. The recovery period is prolonged and may continue for several years.
I've written a news story for New Scientist about a recent study which shows that patients in the minimally conscious state may be capable of dreaming, and that studying the brain wave patterns associated with sleep could be helpful in distinguishing minimally conscious patients from those in the vegetative state.
When a patient is in a comatose state, he/she does not demonstrate any signs of communication or communication attempts. When a patient is in a vegetative state, he/she may demonstrate oral reflexive movement and reflexive voicing.
Two distinct brain regions control different types of facial movement: Motor cortex – Initiates voluntary facial movements like deliberate smiles. Limbic system – Triggers spontaneous emotional expressions.
People in a vegetative state can: Open their eyes and blink. Sleep and wake up on a regular schedule. Do basic automatic movements, such as breathing, sucking, chewing, gagging, coughing, and swallowing.
VEGETATIVE STATE
They may move parts of their body, but this movement is not voluntary. Movements can include grinding their teeth, thrashing, and facial movements such as grimacing, yawning or smiling.
The results suggested that the eye movements of schizophrenic patients were more limited than those of normal control subjects and that the abnormal eye movement inspection patterns in schizophrenic patients may reflect a lack of visual investigation of novel stimuli in the environment.
Prosopometamorphopsia (PMO), also known as demon face syndrome, is a neurological disorder characterized by altered perceptions of faces. In the perception of a person with the disorder, facial features are distorted in a variety of ways including drooping, swelling, discoloration, and shifts of position.
May moan or make other sounds, especially when tight muscles are stretched. May cry or smile or make other facial expressions without a clear cause. May briefly move eyes toward people or things but these looks are not sustained.
Brain death is different from a vegetative state
The difference between brain death and a vegetative state (a disorder of consciousness), which can happen after extensive brain damage, is that it's possible to recover from a vegetative state, but brain death is permanent.
People in a vegetative state can do some things because some parts of the brain are functioning: They can open their eyes. They have relatively regular sleeping and waking patterns (but not necessarily related to day and night). They can breathe, suck, chew, cough, gag, swallow, and make guttural sounds.
In a vegetative state, the patient will regain some of their reflexes. They react to stimuli such as loud noises or pain. The patient may also open their eyes and appear awake, but they are not yet fully conscious. Reflexes are a good sign that the brain is on the right track to healing.
Vital Signs
It may be helpful to have a baseline as some patients living with lung disease can tolerate low oxygen levels for months and months. Generally, if the oxygen level is 79% or lower, they will likely die in the next 24 hours.
Symptoms of mild cerebral hypoxia include inattentiveness, poor judgment, memory loss, and a decrease in motor coordination. Brain cells are extremely sensitive to oxygen deprivation and can begin to die within five minutes after oxygen supply has been cut off.