NIH Stroke Scale (NIHSS) calculator

What goes into the NIH Stroke Scale (NIHSS)

• 1a. Level of consciousness: Alert (0); Arousable by minor stimulation (1); Requires repeated or painful stimulation (2); Unresponsive or reflex only (3)
• 1b. LOC questions (month, age): Both correct (0); One correct (1); Neither correct (2)
• 1c. LOC commands (eyes, grip): Both correct (0); One correct (1); Neither correct (2)
• 2. Best gaze: Normal (0); Partial gaze palsy (1); Forced deviation (2)
• 3. Visual fields: No visual loss (0); Partial hemianopia (1); Complete hemianopia (2); Bilateral hemianopia or blind (3)
• 4. Facial palsy: Normal (0); Minor (1); Partial (lower face) (2); Complete (upper and lower) (3)
• 5a. Left arm motor: No drift for 10 s (0); Drift, does not hit bed (1); Some effort against gravity (2); No effort against gravity (3); No movement (4); Amputation or joint fusion (UN) (0)
• 5b. Right arm motor: No drift for 10 s (0); Drift, does not hit bed (1); Some effort against gravity (2); No effort against gravity (3); No movement (4); Amputation or joint fusion (UN) (0)
• 6a. Left leg motor: No drift for 5 s (0); Drift, does not hit bed (1); Some effort against gravity (2); No effort against gravity (3); No movement (4); Amputation or joint fusion (UN) (0)
• 6b. Right leg motor: No drift for 5 s (0); Drift, does not hit bed (1); Some effort against gravity (2); No effort against gravity (3); No movement (4); Amputation or joint fusion (UN) (0)
• 7. Limb ataxia: Absent (0); Present in one limb (1); Present in two limbs (2)
• 8. Sensory: Normal (0); Mild to moderate loss (1); Severe or total loss (2)
• 9. Best language: No aphasia (0); Mild to moderate aphasia (1); Severe aphasia (2); Mute or global aphasia (3)
• 10. Dysarthria: Normal (0); Mild to moderate (1); Severe or unintelligible (2); Intubated or other barrier (UN) (0)
• 11. Extinction and inattention: None (0); One modality (1); Profound or more than one modality (2)

How to interpret the result

• 0: no measurable deficit
• 1–4: minor stroke (thrombolysis still indicated if the deficit is disabling)
• 5–15: moderate stroke
• 16–20: moderate to severe stroke
• 21–42: severe stroke

Clinical pearls

• Score the first attempt; do not coach. Untestable items (amputation, intubation) score 0 and are noted as UN.
• Posterior-circulation strokes (vertigo, ataxia, dysphagia) can score low despite being dangerous.
• For thrombectomy, the AHA/ASA guideline uses NIHSS ≥ 6 with a large-vessel occlusion as a common threshold.
• An increase of ≥ 4 points after treatment suggests deterioration (e.g., hemorrhagic transformation).

Evidence

1. Brott T, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20:864-870.

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