NIH Stroke Scale (NIHSS) Calculator

Interactive NIHSS tool with all 15 items, scoring guidance, automatic total, and stroke severity bands. Designed for trained clinicians to document and trend stroke severity.

Clinical use only – for trained healthcare professionals. This tool does not provide medical advice and must not replace clinical judgment, local protocols, or official NIHSS training materials.

NIHSS Scoring Tool

Total NIHSS Score

0

Automatically updated as you score each item.

Stroke Severity (Approximate)

No stroke symptoms

0 = no symptoms · 1–4 = minor · 5–15 = moderate · 16–20 = moderate–severe · 21–42 = severe

1a. Level of Consciousness (LOC) (0–3)

Assess arousal: is the patient alert, drowsy, or only responsive to repeated or painful stimulation?

1a LOC
1b. LOC Questions (0–2)

Ask the month and the patient’s age. Do not coach or give multiple choices.

1b LOC Questions
1c. LOC Commands (0–2)

Ask the patient to open/close eyes and then grip/release the non-paretic hand. Substitute commands if needed.

1c LOC Commands
2. Best Gaze (0–2)

Horizontal eye movements only. Use oculocephalic maneuver if needed (unless contraindicated).

2 Best Gaze
3. Visual Fields (0–3)

Test visual fields by confrontation. Use blink-to-threat in patients with decreased LOC.

3 Visual Fields
4. Facial Palsy (0–3)

Ask the patient to show teeth, raise eyebrows, and close eyes tightly.

4 Facial Palsy
5a. Motor – Left Arm (0–4)

Arm outstretched 90° (sitting) or 45° (supine) for 10 seconds. Score drift or fall.

5a Motor Left Arm
5b. Motor – Right Arm (0–4)

Same method as left arm, scored separately.

5b Motor Right Arm
6a. Motor – Left Leg (0–4)

Leg raised 30° in supine position for 5 seconds.

6a Motor Left Leg
6b. Motor – Right Leg (0–4)

Same method as left leg, scored separately.

6b Motor Right Leg
7. Limb Ataxia (0–2)

Finger–nose–finger and heel–shin tests. Score only if ataxia is present and not due to weakness.

7 Limb Ataxia
8. Sensory (0–2)

Pinprick to face, arms, trunk, and legs. Compare sides.

8 Sensory
9. Best Language (0–3)

Assess comprehension and expression using picture description, naming, and reading tasks.

9 Best Language
10. Dysarthria (0–2)

Listen to speech during NIHSS tasks or have patient read/say words. Do not score if intubated or other mechanical barrier.

10 Dysarthria
11. Extinction and Inattention (Neglect) (0–2)

Use double simultaneous stimulation for visual, tactile, auditory, or spatial neglect.

11 Extinction and Inattention

Note: This implementation follows the standard 15-item NIHSS structure. Some clinical situations (e.g., amputations, intubation) require special scoring rules that should be applied according to official NIHSS training materials.

What is the NIH Stroke Scale (NIHSS)?

The National Institutes of Health Stroke Scale (NIHSS) is a standardized 15‑item neurological examination used to quantify the severity of a stroke. It evaluates level of consciousness, visual fields, motor strength, language, neglect, and other key domains.

The total NIHSS score ranges from 0 to 42, with higher scores indicating more severe neurological impairment. The scale is widely used in emergency departments, stroke units, and clinical trials to:

  • Screen and document initial stroke severity
  • Support eligibility assessment for reperfusion therapies
  • Monitor neurological changes over time
  • Standardize communication between clinicians and centers

NIHSS score interpretation

The NIHSS was not originally designed to define strict severity categories, but the following bands are commonly used in practice and research:

Total NIHSS score Approximate severity Clinical notes
0 No stroke symptoms Normal exam on NIHSS items.
1–4 Minor stroke Often associated with good functional outcome, but disabling deficits may still be present.
5–15 Moderate stroke Common range for many thrombolysis candidates; outcome depends on multiple factors.
16–20 Moderate to severe stroke Higher risk of complications and disability.
21–42 Severe stroke Often associated with large infarcts, high mortality, and significant disability.

These ranges are approximate and should not be used in isolation for prognostication or treatment decisions.

How to perform the NIHSS correctly

Consistency is critical. The NIHSS is only reliable when performed according to the official instructions and training videos. Key principles include:

  • Score what the patient does, not what you think they can do.
  • Do not coach, repeat excessively, or give multiple-choice prompts.
  • Use the first effort for scoring when possible.
  • When in doubt between two scores, choose the more severe (higher) score.
  • Document reasons for any non-standard scoring (e.g., amputation, intubation).

NIHSS items overview

  1. 1a–c: Level of consciousness – arousal, orientation, and ability to follow simple commands.
  2. 2–4: Cranial nerves – gaze, visual fields, and facial movement.
  3. 5–6: Motor function – strength in arms and legs against gravity.
  4. 7: Limb ataxia – cerebellar coordination.
  5. 8: Sensory – response to pinprick.
  6. 9–10: Language and speech – aphasia and dysarthria.
  7. 11: Neglect – extinction and inattention.

Limitations and clinical caveats

  • The NIHSS is more sensitive to anterior circulation strokes and may underestimate severity in posterior circulation events (e.g., isolated ataxia, vertigo).
  • Pre-existing deficits (e.g., old stroke, dementia, blindness, deafness) must be considered and documented.
  • A low NIHSS score does not guarantee a good outcome if the deficit is disabling (e.g., isolated aphasia or hemianopia).
  • Treatment decisions (thrombolysis, thrombectomy, blood pressure management) must follow guidelines and specialist input, not the NIHSS alone.

Frequently asked questions (FAQ)

Is there a “good” NIHSS score?

A score of 0 is considered normal. Scores of 1–4 are often labeled “minor stroke”, but even a low score can represent a disabling deficit (for example, isolated aphasia in a professional speaker). Always interpret the score in the context of the patient’s baseline and functional needs.

Can non‑neurologists use the NIHSS?

Yes. The NIHSS was designed to be used by a wide range of clinicians, including emergency physicians and nurses, after appropriate training and certification. Many hospitals require documented NIHSS training for staff involved in acute stroke care.

How does NIHSS relate to imaging?

Higher NIHSS scores generally correlate with larger infarct volumes and more proximal vessel occlusions, but the relationship is imperfect. Imaging (CT/CTA/MRI) remains essential for diagnosis, exclusion of hemorrhage, and selection for reperfusion therapies.

Disclaimer

This NIHSS calculator is provided for educational and documentation support only. It does not replace:

  • Formal NIHSS training and certification
  • Local stroke protocols and national/international guidelines
  • Clinical judgment by qualified healthcare professionals

Always consult your institution’s policies and official NIH resources when performing and interpreting the NIH Stroke Scale.