Stroke assessment
NIH Stroke Scale (NIHSS)
Evaluate each domain based on the patient’s neurologic exam. The calculator sums the points (0–42) to quantify stroke severity and aid treatment decisions.
1a. Level of consciousness
1b. LOC questions
1c. LOC commands
2. Best gaze
3. Visual fields
4. Facial palsy
5a. Motor arm – Left
5b. Motor arm – Right
6a. Motor leg – Left
6b. Motor leg – Right
7. Limb ataxia
8. Sensory
9. Best language
10. Dysarthria
11. Extinction and inattention (neglect)
Domain contributions
- 1a0
- 1b0
- 1c0
- 20
- 30
- 40
- 5a0
- 5b0
- 6a0
- 6b0
- 70
- 80
- 90
- 100
- 110
Total NIHSS
0
Range 0–42
NIHSS 0 corresponds to normal exam; patients may still have subtle symptoms.
Reassess after interventions (e.g., thrombolysis) and at 24 hours to document response and detect complications.
How to Use This Calculator
Perform a structured neuro exam
Follow standardized NIHSS instructions to minimize inter-rater variability. Use best responses, not worst.
Select the matching option for each item
Document inability due to non-neurologic causes (e.g., intubation) with standard NIHSS conventions.
Use the total score to inform treatment
Compare against eligibility criteria for reperfusion therapy, monitoring intensity, and prognostication tools.
Formula
Total NIHSS is the sum of scores from 11 domains (15 individual items):
- Consciousness (1a, 1b, 1c)
- Best gaze, visual fields, facial palsy
- Motor arms (left/right) and legs (left/right)
- Limb ataxia, sensory
- Language, dysarthria
- Extinction/inattention
Each item contributes 0–4 points (depending on the item). Maximum total score is 42.
Full Description
The NIH Stroke Scale is a standardized tool for quantifying neurologic deficits in acute ischemic stroke. Higher scores indicate more severe deficits and predict infarct volume, mortality, and functional outcomes. The scale guides thrombolysis eligibility, thrombectomy triage, and clinical trial stratification.
Accurate scoring requires training and consistency. Certain deficits (e.g., isolated ataxia, posterior circulation strokes) may be underrepresented. Combine NIHSS with imaging and clinical context to formulate treatment plans.
Frequently Asked Questions
How long does the NIHSS take to perform?
Experienced clinicians can complete it in around 5–8 minutes. Practice improves speed and reliability.
What if the patient is intubated or aphasic?
Score based on best possible responses. For verbal items, use the standard NIHSS conventions (e.g., use card prompts, consider inability due to intubation but score actual neurologic function).
Is NIHSS valid for hemorrhagic stroke?
Yes, although it was designed for ischemic stroke. It still correlates with severity in ICH and SAH but should be used alongside hemorrhage-specific tools.
Can paramedics use the full NIHSS?
Some prehospital teams use abbreviated versions (e.g., FAST-ED). Full NIHSS requires detailed assessment typically done in hospital.