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Instructions for rating each of the 11 items are included on the rating scale form. It is recommended to have at least two independent raters as well as an individual to do the actual testing. Complete ratings when patients are "awake" (based on observations such as eye opening, postural and motor movements, yawning, and some degree of arousability upon stimulation).
Individual Parameters
AUDITORY
Stimulus 1.
Stimulus: Bell ringing 5 seconds at 10 second intervals.
Number of trials: 3
Response measure: Eye opening or orientation toward sound.
Scoring:
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0
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Responds 3X
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| 2 |
Responds 1 or 2X
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| 4 |
No response
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Note: If possible use brain stem auditory evoked response (BAER) test at 80 db nHL to establish ability to hear in at least one ear.
COMMAND RESPONSIVITY (with priming*)
Stimulus 2.
Stimulus: Request patient to open or close eyes, mouth, or move finger, hand or leg.
Number of trials: 3
Response measure: Response to command.
Scoring:
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0
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Responds to command 2 or 3X
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| 2 |
Tentative or inconsistent 1X
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| 4 |
No response
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*Note: Whether or not patient appears receptive to speech, speak encouragingly and supportively for about 30 seconds to help establish awareness that another person is present and advise patient that you will be asking him/her to make a simple response. Then request the patient to try to make the same response with brief priming before 2nd, 3rd, and subsequent trials.
VISUAL (with priming*)
Stimulus 3.
Stimulus: Light flashes (1/sec x5) in front, slightly left, right, and up and down each trial
Number of trials: 5
Response measure: Fixation or avoidance.
Scoring:
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0
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Sustained fixation or avoidance 3X
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| 2 |
Partial fixation 1 or 2X
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| 4 |
None
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*Note: Whether or not patient appears receptive to speech, speak encouragingly and supportively for about 30 seconds to help establish awareness that another person is present and advise patient that you will be asking him/her to make a simple response. Then request the patient to try to make the same response with brief priming before 2nd, 3rd, and subsequent trials.
Make sure patient is not sleeping. Check with nursing staff on eye opening and arousability.
Stimulus 4.
Stimulus: Tell patient "Look at me"; move face 20" away, from side to side.
Number of trials: 5
Response measure: Fixation and tracking.
Scoring:
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0
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Sustained tracking (at least 3X)
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| 2 |
Partial tracking 1 or 2X
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| 4 |
No tracking
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*Note: Whether or not patient appears receptive to speech, speak encouragingly and supportively for about 30 seconds to help establish awareness that another person is present and advise patient that you will be asking him/her to make a simple response. Then request the patient to try to make the same response with brief priming before 2nd, 3rd, and subsequent trials.
Make sure patient is not sleeping. Check with nursing staff on eye opening and arousability.
FOR VISUAL ITEMS: Must be able to open eyes. If not, score 4 for each stimulus situation (items 3, 4, 5).
THREAT
Stimulus 5.
Stimulus: Quickly move hand forward to within 1"-3" of eyes.
Number of trials: 3
Response measure: Eye blink.
Scoring:
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0
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3 blinks
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| 2 |
1 or 2 blinks
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| 4 |
No blinks
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OLFACTORY (block tracheostomy 3-5 seconds if present)
Stimulus 6.
Stimulus: Ammonia capsule/bottle 1" under nose for about two seconds.
Number of trials: 3
Response measure: Withdrawal or other response linked to stimulus.
Scoring:
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0
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Responds 2 or 3X quickly (less than or equal to 3 secs)
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| 2 |
Slowed/partial withdrawal; grimacing 1X
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| 4 |
No withdrawal or grimacing
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TACTILE
Stimulus 7.
Stimulus: Shoulder tap- Tap shoulder briskly 3X without speaking to patient; each side.
Number of trials: 3 (each side up to 3X if needed)
Response measure: Head or eye orientation or shoulder movement to tap.
Scoring:
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0
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Orients towards tap 2 or 3X
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| 2 |
Partially orients 1X
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| 4 |
No orienting or response
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Stimulus 8.
Stimulus: Nasal swab (each nostril; entrance only- do not penetrate deeply).
Number of trials: 3 (each side up to 3X if needed)
Response measure: Withdrawal or eye blink or mouth twitch.
Scoring:
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0
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Clear, quick (within 2 seconds) 2 to 3X
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| 2 |
Delayed or partial response 1X
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| 4 |
No response
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PAIN
Stimulus 9.
Stimulus: Firm pinch on finger tip; pressure of wood pencil across nail; each side.
Number of trials: 3 (each side up to 3X if needed)
Response measure: Head or eye orientation or shoulder movement to tap.
Scoring:
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0
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Withdrawal 2 or 3X
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| 2 |
General agitation/ nonspecific movement 1X
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| 4 |
No response
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Stimulus 10.
Stimulus: Robust ear pinch/pull 3X; each side.
Number of trials: 3 (each side up to 3X if needed)
Response measure: Withdrawal or other response linked to stimulus.
Scoring:
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0
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Responds 2 to 3X
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| 2 |
General agitation/ nonspecific movement 1X
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| 4 |
No response
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FOR PAIN: Allow up to 10 seconds for a response. If spinal cord injured skip stimulus 9.
VOCALIZATION
Stimulus 11.
Stimulus: None. Score best response.
Number of trials: -
Response measure: See score criteria.
Scoring:
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0
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Spontaneous words
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| 2 |
Nonverbal vocalizations (moan, groan)
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| 4 |
No sounds
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Scoring
The Total Score is calculated by adding the ratings (zero, two, or four) from each of the eleven items. The sum score is then divided by the number of items scored to give the Average CNC score.
Average scores are divided into five categories:
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Level
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Range
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Level of Awareness/Responsivity
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0
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0.00-0.89
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NO COMA: consistently and readily responsive to at least 3 sensory stimulation tests* plus consistent responsivity to simple commands
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1
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0.90-2.00
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NEAR COMA: consistently responsive to stimulus presented to 2 sensory modalities and/or inconsistently or partially responsive to simple commands
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2
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2.01-2.89
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MODERATE COMA: inconsistently responsive to stimulation presented to 2 or 3 sensory modalities but not responsive to simple commands. May vocalize (in absence of tracheostomy) with moans, groans & grunts but no recognizable words.
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3
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2.90-3.49
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MARKED COMA: inconsistently responsive to stimulation presented to one sensory modality and not responsive to simple commands. No vocalization.
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4
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3.50-4.00
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EXTREME COMA: no responsivity to any sensory stimulation tests; no response to simple commands. No vocalization.
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* Sensory stimulation tests are items 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
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A project funded by the National Institute on Disability and Rehabilitation Research.