COMA STIMULATION IN TBI: DEFINITIONS AND ASSESMENT OF COMA

  • Coma is the prolonged period of unconsciousness immediately following traumatic brain injury. In this sleep-like state, there is no speech, the eyelids are usually closed, and there is no response to commands. The person in coma may have a simple reflex in response to touch or pain, but essentially there is no meaningful response to external stimuli. There is an absence of awareness of self and the environment, even under conditions of vigorous external stimulation.

  • Arousal is the general state of readiness to respond to the environment. Arousal is necessary for selective attention and purposeful responses. Arousal is a function of the reticular activating system (RAS), a network of neurons and nerve pathways that extends from the lower brainstem into the pons, midbrain, thalamus, and cerebral cortex. Any disruption of the RAS can reduce the level of consciousness and lead to coma.

Assessment of Coma - On the following scales, coma stimulation techniques are appropriate at all levels of coma.

  • Rancho Los Amigos Scale (RLAS) is used as the patient improves or stabilizes. There are 8 levels in this scale:
    • Level I - No response to any stimuli - indicates coma
    • Level II - Generalized response, i.e. patient reacts inconsistently and nonpurposefully to stimuli in a non-specific manner, such as eye blinking, changes in breathing rate, gross body movement, and vocalization - indicates coma
    • Level III - Localized response, i.e. patient reacts specifically but inconsistently to stimuli, such as turning head toward a sound or focusing on an object presented and following simple commands in an inconsistent, delayed manner - not considered coma, but stimulation techniques appropriate through Levels III.
    • Level IV - Confused-Agitated, i.e. patient is in a heightened state of activity with severely decreased ability to process information. The patient is detached from the present and responds primarily to his/her own internal confusion. Behavior is often bizarre.
    • Level V - Confused, Inappropriate, Non-Agitated, i.e. patient appears alert and is able to respond to simple commands fairly consistently, but responds to more complex commands in a non-purposeful, random manner and is agitated by external stimuli
    • Level VI - Confused-Appropriate, i.e. the patient shows goal-directed behavior, but is dependent on external input for direction. He/she follows simple directions and shows carryover for tasks that have been relearned, such as self-care activities. Responses may be incorrect due to memory problems, but they are appropriate to the situation.
    • Level VII - Automatic-Appropriate, i.e. the patient appears appropriate and oriented, but goes through daily routines automatically, and has shallow recall of what he/she has been doing. The patient shows increased, but superficial awareness of self and other people, demonstrates decreased judgement and problem-solving abilities, lacks realistic planning for the future, and requires at least minimal supervision for learning and safety purposes. Judgment and other higher level cognitive abilities remain compromised.
    • Level VIII - Purposeful and Appropriate, i.e. the patient is alert and oriented able to recall and integrate past and recent events, is aware of and responsive to the environment, and needs no supervision once learning has occurred. He/she may continue to show decreased reasoning, tolerance for stress, judgment in emergencies or unusual circumstances, and decreased social, emotional, and intellectual capacities.

     The following chart of behaviors is adapted from the above levels of cognitive functioning of the Rancho Los Amigos Scale.

Behavior

Level 1
No Response

Level 2
General
Response

Level 3
Localized
Response

Level 4
Confused
Agitated

Level 5
Confused
Inappropriate

Level 6
Confused
Appropriate

Level 7
Automatic
Appropriate

Level 8
Purposeful
Appropriate

Attention to the
environment and tasks
None None None Gross attention present.  Selective attention often non-existent. Gross attention present.  Selective attention highly distractible.  Patient lacks the ability to focus attention on a specific task without frequent redirection. Gross attention present.  Selective attention to tasks may be impaired especially with difficult tasks and in unstructured settings. Present, though requires minimal supervision for learning & safety. Present
Responses to stimuli and environment None Responses are nonspecific (ie,same reaction regardless of stimulus) inconsistent &limited Responses are specific(ie, will turn head to sound), but inconsistent.  May respond to some people and not others Responds to stimuli.  However, most responses are to patient's own internal confusion. Responds best to self, body comfort and often family members.  Patient lacks initiation of functional tasks and often shows inappropriate use of objects without external direction. Responses consistent to stimuli and environment.  However, responses to environment may be incorrect due to memory problems but are appropriate to the situation. With structure, patient is able to initiate tasks for social & recreational activities which he now shows an interest in. Fully responds to stimuli & environment.  However, tolerance for stress & judgement in emergencies might decrease in comparison to patient's tolerance before the acident.
Ability to process information None None None Has minimal ability. Has minimal ability.  Processes simple self-oriented information. Processes simple information re: self and immediate environment Processing remains reduced relative to length, complexity and rate of presentation of information. Present.  Rate of processing may remain reduced.
Ability to follow commands (simple and complex) None None None Does not respond consistently to simple commands.  May respond inconsistently when agitation is lessened. Responds to simple commands consistently.  Responses to complex commands are nonpurposeful & fragmented. Follows simple and somewhat complex directions consistently. Present.  Encounters difficulty when directions are lengthy and/or complex. Present
Awareness of present None None None Unaware of present events.  Responds primarily to own state of extremely severe confusion. Memory is severely impaired with confusion of past and present events. Past memories show more depth and detail than present memory. Patient has a shallow recall of the present and minimal absent confusion. Is able to recall & integrate past and recent events & is aware of and responsive to present.
Ability to learn new information None None None None None Yes, but with little or no carry over.  Learning may occur with multiple repetition: carry over is minimal. Yes, but at a decreased rate.  Decreased judgement, problem-solving skills. Shows carry-over for new learning aceptable to him and his life role.  Needs no supervision once activities are learned.
Awareness of self/body/treatment None Some awareness of the body.  Will respond to deep pain, however, unable to cooperate with treatment. Vague Unable to understand or cooperate with traditional prescribed activities. Becomes more aware. Shows increased awareness of self but has no insight  into condition and is not able to cooperate with tx.  Able to cooperate with tx when it is structured or simplified. Shows more awareness of self.  Has superficial awareness but lacks insight into condition. Present
Behavioral status (physical activities) Appears to be in deep sleep Little Slight.  Might react to discomfort by pulling at the nasogastric tube or catheter or by resisting restraints. Behavior is frequently bizarre and non-purposeful relative to the immediate environment.  May show aggressive behavior and attempt to remove restraints. Activity is inappropriate to situation and/or topic at hand.  If the patient can walk, he might wander away with the intention of going home. Will show goal-directed behavior but is dependent on external input for direction. Patient appears oriented, with minimal to absent confusion.  Will go through daily routine automatically but robot-like. Patient is alert & oriented.  Can carry out or direct activities in a purposeful & appropriate manner.
Ability to perform self-care activities None None None May be able to participate in parts of routines for very brief periods with maximum assistence. Able to perform with maximum assistence and structure. Needs assistence & structure to perform activities. May need supervision for thoroughness and activity completion. Can perform
Ability to converse None None May inconsistently speak on an automatic levelwith one- or two-word responses to questions. Present, though frequently incoherent or inappropriate to the environment.  Conversation reflects considerable confusion & memory deficits. With structure may be able to converse on a social automatic level for a short period of time.  However, verbalization is often inappropriate & triggered by memories of his/her past. Present Present.  Conversation reflects concrete thinking and occasional confusion. Present

  • Glasgow Coma Scale is the standard measurement of coma in the acute phase. This scale measures the depth of coma, based on (1) motor response, (2) eye opening, and (3) vocal response. Ratings range from 3 -15.
    • Total rating of 3 -5 indicates very severe brain injury
    • Total rating of 6 - 8 indicates severe brain injury (still in coma)
    • Total rating of 9 - 15 indicates brain injury out of coma
      • Total rating of 9 - 12 indicates moderate TBI
      • Total rating of 13 - 15 indicates mild TBI

  • Disability Rating Scale gauges the level of disability from "none" to "Extremely Vegetative State" based on eye opening, communication ability, and motor response (arousability, awareness and responsivity); feeding, toileting, and grooming (cognitive ability for self care activities); level of functioning (dependence on others); and employability (psychosocial adaptability). Ratings are:

0 None 7-11 Moderately Severe
1 Mild 12-16 Severe
2-3 Partial 17-21 Extremely Severe
4-6 Moderate 22-24 Vegetative State
25-29 Extreme Vegetative State

     

Based on Brain Injury Patient Care and Education Manual, by Pinecrest Rehabilitation Hospital; Neuro section of the Trauma Manual, Jackson Memorial Hospital; and Recovering from Head Injury; a Guide for Patients, by Nova University Neuropsychology Service, and edited for PoinTIS by the Louis Calder Memorial Library of the University of Miami School of Medicine and the PoinTIS Advisory Committee, and on Rehabilitation of Persons with Traumatic Brain Injury, NIH Consensus Statement 1998 Oct. 26-28.