[citation needed] Patients in such a dramatically altered state of consciousness present unique problems for diagnosis, prognosis and treatment.
[citation needed] Consciousness is a complex and multifaceted concept, divided into two main components: Arousal and Awareness.
[7][8] Disorders in consciousness represent immense social and ethical issues because the diagnosis is methodologically complex and needs careful interpretation.
[citation needed] In locked-in syndrome the patient has awareness, sleep-wake cycles, and meaningful behavior (viz., eye-movement), but is isolated due to quadriplegia and pseudobulbar palsy, resulting from the disruption of corticospinal and corticobulbar pathways.
Locked-in syndrome is a condition in which a patient is aware and awake but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for the eyes.
[12] In a persistent vegetative state, the patient has sleep-wake cycles, but lacks awareness, is not able to communicate and only displays reflexive and non-purposeful behavior.
The term refers to an organic body that is able to grow and develop devoid of intellectual activity or social intercourse.
[11] The diagnosis of the vegetative state should be questioned when there is any degree of sustained and reproducible visual pursuit or fixation or response to threatening gestures.
This state reflects an intact brainstem and allied structures but severely damaged white and gray matter in both cerebral hemispheres.
This diagnosis can be further classified as a permanent vegetative state (PVS) after approximately 1 year of being in a vegetative state after traumatic brain injury[15] Like coma, chronic coma results mostly from cortical or white-matter damage after neuronal or axonal injury, or from focal brainstem lesions.
In medicine, a coma (from the Greek κῶμα koma, meaning deep sleep) is a state of unconsciousness, lasting more than six hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light, sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions.
After brain death the patient lacks any sense of awareness; sleep-wake cycles or behavior, and typically look as if they are dead or are in a deep sleep-state or coma.
However, the clinical assessments are the same and require the loss of all brainstem reflexes and the demonstration of continuing apnea in a persistently comatose patient (< 4 weeks).
Functionality can only be identified at the most general level: Metabolism in cortical and subcortical regions that may contribute to cognitive processes.
[citation needed] At present, there is no established relation between cerebral metabolic rates of glucose or oxygen as measured by PET and patient outcome.
[25] Also, the issue of radiation exposure must be considered in patients with already severely damaged brains and preclude longitudinal or follow-up studies.
[citation needed] Social issues arise from the enormous costs associated with people who have disorders of consciousness, especially chronic comatose and vegetative patients, when recovery is highly unlikely and treatment in the ICU is considered futile by clinicians.
[citation needed] In addition to the aforementioned problems, the question rises why medical resources were being used not for the broader public good but for patients who seemed to have only little to gain from them.