Disorders of consciousness
Encyclopedia
Disorders of consciousness are medical conditions that inhibit consciousness
. This category generally includes minimally conscious state
and persistent vegetative state
, but sometimes also includes the less severe locked-in syndrome
and more severe chronic coma
. Differential diagnosis
of these disorders is an active area of biomedical research
. Finally, brain death
results in an irreversible disruption of consciousness. While other conditions may cause a moderate deterioration (e.g., dementia
and delirium
) or transient interruption (e.g., grand mal and petit mal seizures
) of consciousness, they are not included in this category.
the patient has awareness, sleep-wake cycles, and meaningful behavior (viz., eye-movement), but is isolated due to quadriplegia
and pseudobulbar palsy
.
, the patient has intermittent periods of awareness and wakefulness and displays some meaningful behavior.
, the patient has sleep-wake cycles, but lacks awareness and only displays reflexive and non-purposeful behavior.
the patient lacks awareness, sleep-wake cycles, and behavior.
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...
. This category generally includes minimally conscious state
Minimally conscious state
Minimally Conscious State is a disorder of consciousness distinct from Persistent vegetative state and Locked-in syndrome. Unlike persistent vegetative state, patients with MCS have partial preservation of conscious awareness. MCS is a relatively new category of disorders of consciousness. The...
and persistent vegetative state
Persistent vegetative state
A persistent vegetative state is a disorder of consciousness in which patients with severe brain damage are in a state of partial arousal rather than true awareness. It is a diagnosis of some uncertainty in that it deals with a syndrome. After four weeks in a vegetative state , the patient is...
, but sometimes also includes the less severe locked-in syndrome
Locked-In syndrome
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. Total locked-in syndrome is a version of locked-in syndrome where the eyes are paralyzed as...
and more severe chronic coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
. Differential diagnosis
Differential diagnosis
A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...
of these disorders is an active area of biomedical research
Biomedical research
Biomedical research , in general simply known as medical research, is the basic research, applied research, or translational research conducted to aid and support the body of knowledge in the field of medicine...
. Finally, brain death
Brain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...
results in an irreversible disruption of consciousness. While other conditions may cause a moderate deterioration (e.g., dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...
and delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
) or transient interruption (e.g., grand mal and petit mal seizures
Absence seizure
Absence seizures are one of several kinds of seizures. These seizures are sometimes referred to as petit mal seizures ....
) of consciousness, they are not included in this category.
Locked-in syndrome
In locked-in syndromeLocked-In syndrome
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. Total locked-in syndrome is a version of locked-in syndrome where the eyes are paralyzed as...
the patient has awareness, sleep-wake cycles, and meaningful behavior (viz., eye-movement), but is isolated due to quadriplegia
Quadriplegia
Tetraplegia, also known as quadriplegia, is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all their limbs and torso; paraplegia is similar but does not affect the arms...
and pseudobulbar palsy
Pseudobulbar palsy
Pseudobulbar palsy results from an upper motor neuron lesion to the corticobulbar pathways in the pyramidal tract. Patients have difficulty chewing, swallowing and demonstrate slurred speech...
.
Minimally conscious state
In a minimally conscious stateMinimally conscious state
Minimally Conscious State is a disorder of consciousness distinct from Persistent vegetative state and Locked-in syndrome. Unlike persistent vegetative state, patients with MCS have partial preservation of conscious awareness. MCS is a relatively new category of disorders of consciousness. The...
, the patient has intermittent periods of awareness and wakefulness and displays some meaningful behavior.
Persistent vegetative state
In a persistent vegetative statePersistent vegetative state
A persistent vegetative state is a disorder of consciousness in which patients with severe brain damage are in a state of partial arousal rather than true awareness. It is a diagnosis of some uncertainty in that it deals with a syndrome. After four weeks in a vegetative state , the patient is...
, the patient has sleep-wake cycles, but lacks awareness and only displays reflexive and non-purposeful behavior.
Chronic coma
In chronic coma the patient lacks awareness and sleep-wake cycles and only displays reflexive behavior.Brain death
After brain deathBrain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...
the patient lacks awareness, sleep-wake cycles, and behavior.
See also
- NeuropsychologyNeuropsychologyNeuropsychology studies the structure and function of the brain related to specific psychological processes and behaviors. The term neuropsychology has been applied to lesion studies in humans and animals. It has also been applied to efforts to record electrical activity from individual cells in...
- Neuropsychological assessmentNeuropsychological assessmentNeuropsychological assessment was traditionally carried out to assess the extent of impairment to a particular skill and to attempt to locate an area of the brain which may have been damaged after brain injury or neurological illness...