NIH Stroke Scale (NIHSS)

Created 27/09/2022, last revision 11/10/2022

  • NIHSS is a standardized neurological scale developed to help physicians objectively rate the severity of ischemic strokes
  • scoring rules must be strictly followed to ensure reproducibility
  • variants of NIHSS were introduced:
    • modified NIHSS
      • some items are easier to score; data show higher reproducibility compared to the original NIHSS
      • still, it never got popular
    • NIHSS-8
  • administer items in the order listed, do not go back and change scores
  • follow the instructions provided for each item
  • score what the patient does, not what the clinician thinks he/she could do
  • always assess the first response, not the best response (except for item 9 – Best Language)
    • if, for example, a patient answers a question about his/her age incorrectly at first and then corrects himself/herself, the answer should be assessed as incorrect. This is essential because otherwise, it is not possible to account for all modes of verbal and nonverbal cues and ensure reproducibility
  • never assist/coach the patient during the examination (unless the instructions explicitly allow that)
  • some items are only assessed if they are present
    • for example, ataxia is scored absent in a plegic patient
  • older deficits are also scored, except for sensory impairment
  • NIHSS is NOT a guide to picking patients for tPA – tPA should be used regardless of severity  → see IVT contraindication
  • NIHSS indicates the severity of a stroke and has been shown to correlate with the size of the infarction and with the higher risk of hemorrhage
  • NIHSS can predict vessel occlusion
    • higher NIHSS means a higher probability of LVO; low NIHSS, however, doesn’t exclude LVO!
    • some cut-off values for predicting LVO were reported
      • NIHSS scores ≥ 9 within 3 hours after symptom onset and NIHSS scores ≥ 7 within >3 to 6 hours (Heldner, 2013)
  • NIHSS can predict clinical outcomes
    • a retrospective review of 1281 subjects with ischemic stroke found that every 1-point increase in the NIHSS decreased the likelihood of an excellent outcome by 24% at 7 days and 17% at 3 months  (Adams 1999).
    • patients with moderate (6-13 points) or severe (>14 points) NIHSS scores were 3x more likely to be placed in a nursing home after discharge and 8x more times likely to require rehabilitation therapy (Rundek 2000).
    • patients with a score of ≤ 4 are highly likely to have good clinical outcomes regardless of treatment
National Institute of Health Stroke Scale (NIHSS)
1a. Level of Consciousness
  • the investigator must choose a response if a complete evaluation is prevented by such obstacles as an endotracheal tube, language barrier, orotracheal trauma/bandages
  • a 3 is scored only if the patient does not move (other than reflexive posturing) in response to noxious stimulation
0 – alert; keenly responsive
1 – not alert;  arousable by minor stimulation to obey, answer, or respond
2 – not alert; requires repeated stimulation to arouse, requires intense or painful stimulation to make escape movements
3 – coma, reflex postures, or totally unresponsive
1b. LOC – Answers
  • the patient is asked about the month and his/her age
  • the answer must be correct – there is no partial credit for being close
  • aphasic and stuporous patients who do not comprehend the questions will score 2
  • patients unable to speak because of endotracheal intubation, orotracheal trauma, severe dysarthria from any cause, language barrier, or any other problem not secondary to aphasia are given a 1
  • only the initial answer is graded; verbal or non-verbal cues are not allowed
0 – answers both questions correctly
1 – answers 1 question correctly or severe dysarthria/mechanical or language barrier
2 = answers neither question correctly, aphasia, coma
1c. LOC – Tasks
  • the patient is asked to open and close the eyes and then to grip and release the non-paretic hand (or other tasks)
  • credit is given if an unequivocal attempt is made but not completed due to weakness
  • if the patient does not respond to the command, the task should be demonstrated (pantomime), and the result scored (i.e., follows none, one, or two commands)
  • patients with trauma, amputation or other physical impediments should be given suitable one-step commands
  • only the first attempt is scored
0 – performs both tasks correctly
1 – performs one task correctly
2 = performs neither task correctly, coma
2. Best gaze
  • only horizontal eye movements are tested
  • voluntary or reflexive (oculocephalic) eye movements are scored, not caloric testing
  • patients with an isolated peripheral nerve paresis (CN III, IV, or VI) score  1
  • patients with ocular trauma, coma, bandages, pre-existing blindness, or other disorder of visual acuity or fields should be tested with reflexive movements
0 – normal
1 – isolated peripheral paresis or partial gaze palsy in one or both eyes; can be overcome by the oculocephalic maneuver

2 – forced deviation or total gaze paresis; can not be overcome
3. Visual fields
  • test by side confrontation, use finger counting or visual threat (blink reflex) as appropriate
  • add double simultaneous stimulation as well; if there is extinction, the patient receives a 1, and the results are used for item 11
  • with unilateral blindness, visual fields in the remaining eye are scored
  • score 1 only if a clear-cut asymmetry, including quadrantanopia, is found
  • if the patient is blind from any cause, score 3
0 – normal
1 – partial hemianopia, extinction
2 – complete hemianopia
3 – bilateral hemianopia  or blindness (including cortical blindness)
4. Facial palsy
  • ask or use pantomime to encourage the patient to show teeth or raise eyebrows, and close eyes
  • score symmetry of grimace in response to noxious stimuli in the poorly responsive or non-comprehending patient
  • if facial trauma/bandages, orotracheal tube, tape, or other physical barriers obscure the face, these should be removed to the extent possible
0 – normal
1 – minor paralysis (flattened nasolabial fold, asymmetry on smiling)
2 – partial paralysis (total or near-total paralysis of the lower face)
3 – uni- or complete bilateral paralysis  (absence of facial movement in the upper and lower face), coma

5. Motor arm

  • extend the arms (palms down) 90 degrees (if sitting) or 45 degrees (if supine)
  • drift is scored if the arm falls before 10 seconds
  • the aphasic patient is encouraged to use urgency in the voice and pantomime, but not noxious stimulation
  • begin with the non-paretic arm
  • in the case of amputation or joint fusion at the shoulder, the examiner should record the score as untestable (UN) and write the explanation
0  – no drift; limb holds 90 (or 45) degrees for full 10 seconds
1 –  drift before the full 10 seconds; the arm does not hit the bed or other support
2 – some effort against gravity; limb cannot get to or maintain (if cued) 90 (or 45) degrees, drifts down to bed
3 – no effort against gravity;  arm falls to bed immediately
4 – no movement
UN = Amputation or joint fusion, explain

6. Motor leg

  • hold the leg at 30 degrees (always tested supine). Drift is scored if the leg falls before 5 seconds
  • the aphasic patient is encouraged to use urgency in the voice and pantomime but not noxious stimulation
  • begin with the non-paretic leg
  • in the case of amputation or joint fusion at the hip, the examiner should record the score as untestable (UN) and write the explanation
0 – no drift; leg holds 30-degree position for whole 5 seconds
1 – drift by the end of the 5 seconds, but the leg doesn’t hit the bed
2 – some effort against gravity; leg falls to bed by 5 seconds but has some effort against gravity
3 – no effort against gravity; leg falls to bed immediately, some movement on the surface of the bed

4 – no movement
UN = amputation or joint fusion, explain
7. Limb ataxia
  • test with eyes open.
  • the finger-nose-finger and heel-shin tests are performed on both sides
  • ataxia is scored only if present out of proportion to the weakness
  • ataxia is scored 0 in a patient who cannot understand, is paralyzed, or is in a coma
  • in case of blindness, test by having the patient touch nose from extended arm position
0 – absent / paralyzed / does not understand / coma
1 – present in one limb
2 – present in two limbs
UN = Amputation or joint fusion, explain
8. Sensory
  • a sensation of pinprick or withdrawal from the noxious stimulus in the obtunded or aphasic patient is tested
  • only sensory loss attributed to stroke is scored as abnormal
  • stuporous and aphasic patients will probably score 1 or 0
  • bilateral loss of sensation due to brainstem stroke is scored 2
  • if the patient does not respond, is quadriplegic or in a coma, score 2
0 – normal
1 – mild-to-moderate sensory loss; pinprick less sharp/more dull or a loss of superficial pain with a pinprick, but the patient can sense being touched
2 – severe or complete sensory loss; the patient is not aware of being touched, coma/unresponsive
9. Best Langauge
  • the patient is asked to name the items on the attached naming sheet and to read from the list of sentences
  • the patient is asked to describe the attached picture
  • the intubated patient should be asked to write
  • the patient in a coma (item 1a=3) will automatically score 3
0 – no aphasia
1 – mild-to-moderate aphasia; loss of fluency or facility of comprehension, without significant limitation
2 – severe aphasia with fragmentary expression; the great need for inference, questioning, and guessing by the listener
3 – global aphasia – no usable speech/auditory comprehension,  coma/unresponsive

10. Dysarthria

  • an adequate sample of speech must be obtained 
  • if the patient has severe aphasia, the clarity of articulation of spontaneous speech can be rated
  • if the patient is intubated or has other physical barriers to speaking, the examiner should record the score as untestable (UN) and write the explanation
0 – normal
1 – mild-to-moderate dysarthria; patient slurs at least some words, can be understood
2 – severe dysarthria (unintelligible slurring out of proportion to dysphasia), anarthria, mutism, coma
UN – intubated / another physical barrier – explain
11. Extinction and Inattention (formerly neglect)
  • sufficient information to identify neglect may be gathered during the prior testing
  • test simultaneous sensitivity and visual field, search for anosognosia
  • if the patient has a severe visual loss preventing visual double simultaneous stimulation, and the cutaneous stimuli are normal, the score is normal
  • the item is never untestable
0 – no abnormality
1 – neglects 1 modality – visual, tactile, auditory, spatial, or personal inattention, or extinction to simultaneous bilateral stimulation in one of the sensory modalities
2 – neglects >1 modality, profound hemi-inattention (does not recognize own hand or orients to only one side of space), coma
Scoring patients in coma (item 1a = 3)
 1a  Level of consciousness
 1b  LOQ questions (answers)
 1c  LOC questions (tasks)
   2  Best gaze
   3   Visual fields
   4   Facial palsy
 5-6  Arm and leg motor drift (left and right)
   7   Limb Ataxia
   8   Sensory
   9   Best language (aphasia)
 10   Dysarthria
 11   Extinction and Inattention (neglect)

test oculocephalic maneuver
test blink reflex

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