Week 3 TBI Determining Extent of Brain Injury

Level of Consciousness (LOC)

The most critical indicator of nervous system function; changes can indicate neurologic improvement or deterioration; normal response is alert and oriented; abnormal responses range from confusion to coma.

Confusion

Loss of ability to think rapidly and clearly; impaired judgment and decision-making.

Disorientation

Beginning loss of consciousness; disorientation to time occurs first, followed by disorientation to place and impaired memory; recognition of self is lost last.

Lethargy

Limited spontaneous movement or speech; easily aroused by normal speech or touch; may be disoriented to time, place, or person.

Obtundation

Mild-to-moderate reduction in alertness; limited response to the environment; falls asleep unless verbally or physically stimulated; provides minimal answers to questions.

Stupor

Deep sleep or unresponsiveness; can only be aroused by vigorous and repeated stimulation; often responds by withdrawing or grabbing at the stimulus.

Light Coma

Severely reduced consciousness but purposeful movement may occur in response to stimulation.

Coma

No verbal response to the external environment or stimuli; noxious stimulation, such as deep pain or suctioning, may still produce motor movement.

Deep Coma

Complete unresponsiveness with no response to any stimulus.

Cheyne-Stokes Respirations

Alternating periods of hyperventilation and apnea; associated with injury or lesions in the forebrain and diencephalon.

Central Neurogenic Hyperventilation

Sustained, continuous hyperventilation; associated with lesions of the midbrain, pons, or medulla.

Apneustic Respirations

Prolonged inspiratory and expiratory phases; associated with injury to the pons or upper medulla.

Cluster Respirations

Periods or clusters of rapid respirations of approximately equal depth; associated with trauma or compression of the medulla.

Ataxic Respirations

Irregular respirations with prolonged periods of apnea; associated with damage to the medulla.

Pupillary Reaction

Assessment of pupil size and response to light; abnormal pupillary changes help indicate the level of brainstem dysfunction.

Oculocephalic Reflex (Doll's Eyes)

Brainstem reflex used in evaluating dysfunction in coma; assesses eye movement responses when the head is moved. Test only when cervical spine injury has been excluded.

Oculovestibular Reflex (Caloric Ice-Water Test)

Brainstem reflex used to evaluate levels of brain dysfunction in coma by assessing eye movements in response to cold-water stimulation of the ear.

Motor Responses

Used to evaluate the level of brain dysfunction and determine which side of the brain is most severely damaged; responses may be purposeful, inappropriate or nonpurposeful, or absent.

Purposeful Motor Response

An intentional movement in response to stimulation; suggests more preserved motor and neurologic function than an inappropriate or absent response.

Decorticate Posturing

Abnormal flexor posturing characterized by upper-extremity flexion toward the body and lower-extremity extension; indicates severe neurologic dysfunction.

Decerebrate Posturing

Abnormal extensor posturing characterized by extension of the arms and legs; indicates severe neurologic dysfunction.

Pathologic Reflexes

Abnormal reflex responses used in neurologic assessment to help evaluate dysfunction of the corticospinal system.

Vomiting Without Nausea

May indicate direct involvement of central neural mechanisms associated with the medulla; the lecture also identifies pyloric obstruction as another possible cause.

Glasgow Coma Scale (GCS)

Assessment tool used to determine the severity of brain injury; evaluates eye opening, verbal response, and motor response; total score ranges from 3 to 15.

Mild TBI - GCS

GCS score of 13–15; associated with mild concussion.

Moderate TBI - GCS

GCS score of 9–12; associated with structural injury such as hemorrhage or contusion.

Severe TBI - GCS

GCS score of 3–8; associated with severe neurologic injury and risk of cognitive disability, physical disability, or death.

Brain Death

Irreversible cessation of function of the entire brain, including the brainstem and cerebellum; unresponsive coma, no spontaneous respirations, and absence of brainstem function; no potential for recovery.

Cerebral Death

Irreversible loss of cerebral hemisphere function while the brainstem and cerebellum may continue functioning; respiratory and cardiovascular functions, temperature control, and metabolic processes may be maintained.

Vegetative State

A condition following severe cerebral injury in which wakefulness may occur but meaningful awareness of self or the environment is absent.

Minimally Conscious State

A condition in which the person demonstrates minimal but definite behavioral evidence of awareness of self or the environment.

Locked-In Syndrome

A condition in which the person is fully conscious with intact cognitive function but cannot communicate through normal speech or body movement.