ADDONS / SCALES
NIH Stroke Scale (NIHSS)
Created 27/09/2022, last revision 31/01/2023
- NIHSS is a standardized neurological scale developed to help physicians objectively assess the severity of ischemic stroke
- scoring rules must be strictly followed to ensure reproducibility
- variants of NIHSS have been introduced:
- modified NIHSS
- some items are easier to score; data show higher reproducibility compared to the original NIH score
- still never became popular
- some items are easier to score; data show higher reproducibility compared to the original NIH score
- NIHSS-8
- modified NIHSS
- 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 types of verbal and nonverbal cues and ensure reproducibility
- never assist/coach the patient during the examination (unless the instructions explicitly allow this)
- some items are only scored if they are present
- for example, ataxia is scored as absent in a plegic patient
- older deficits are also scored, except for sensory impairment
- NIHSS is NOT a guide to select tPA-suitable patients – 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 higher risk of hemorrhage
- NIHSS of >20 was associated with a 17% rate of intracranial hemorrhage with tPA compared with a 3% hemorrhage rate in patients with a score of <10 (The NINDS t-PA Stroke Study Group 1997).
- NIHSS can predict large vessel occlusion (LVO)
- higher NIHSS means a higher probability of LVO; low NIHSS, however, doesn’t exclude LVO!
- some cut-off values for predicting LVO have been reported
- NIHSS scores ≥ 9 within 3 hours after symptom onset and NIHSS scores ≥ 7 within >3 to 6 hours (Heldner, 2013)
- baseline NIHSS may predict clinical outcomes
- a retrospective review of 1281 patients with ischemic stroke found that each 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 3 times more likely to be placed in a nursing home after discharge and 8 times more 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)
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1a. Level of Consciousness
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0 – alert; keenly responsive
1 – not alert; arousable by mild stimulation to obey 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 |
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1b. LOC – Answers
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0 – answers both questions correctly
1 – answers 1 question correctly or severe dysarthria/mechanical or language barrier 2 = answers neither question correctly, aphasia, coma |
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1c. LOC – Tasks
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0 – performs both tasks correctly
1 – performs one task correctly 2 = performs neither task correctly, coma |
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2. Best gaze
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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; cannot be overcome |
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3. Visual fields
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0 – normal
1 – partial hemianopia, extinction 2 – complete hemianopia 3 – bilateral hemianopia or blindness (including cortical blindness) |
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4. Facial palsy
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0 – normal
1 – mild paralysis (flattened nasolabial fold, asymmetry when 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
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0 – no drift; limb holds 90 (or 45) degrees for full 10 seconds
1 – drift before full 10 seconds; arm does not hit the bed or other support 2 – some effort against gravity; limb fails to reach 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 |
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6. Motor leg
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0 – no drift; leg holds 30-degree position for the whole 5 seconds
1 – drift by the end of 5 seconds, but the leg does not 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 |
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7. Limb ataxia
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0 – absent / paralyzed / does not understand / coma
1 – present in one limb 2 – present in two limbs UN = Amputation or joint fusion, explain |
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8. Sensory
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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 unaware of being touched, coma/unresponsive |
9. Best Langauge
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0 – no aphasia
1 – mild-to-moderate aphasia; loss of fluency or ability to understand, 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
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10. Dysarthria
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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 / other physical barrier – explain
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11. Extinction and Inattention (formerly neglect)
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0 – no abnormality
1 – neglects 1 modality – visual, tactile, auditory, spatial, or personal inattention, or extinction to simultaneous bilateral stimulation in any of the sensory modalities 2 – neglects >1 modality, profound hemi-inattention (fails to recognize own hand or orients to only one side of space), coma |
Scoring patients in coma (item 1a = 3)
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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)
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3 2 2 test oculocephalic maneuver test blink reflex 3 16 0 2 3 2 2 |