NIHSS Calculator (National Institutes of Health Stroke Scale)
Standard tool to quantify the severity of acute ischemic stroke.
Important Medical Disclaimer
This calculator is an educational and clinical decision support tool. Results DO NOT replace professional medical evaluation, laboratory tests, or clinical judgment. Always consult a qualified healthcare professional for diagnosis, treatment, and clinical decisions. Calculations are based on scientifically validated formulas but may not be applicable to all patients.
Calculate NIHSS
What is the NIHSS Scale?
The NIH Stroke Scale (NIHSS) is a systematic tool used to quantitatively quantify stroke-related neurologic impairment. The scale evaluates 15 neurological exam items and provides a total score ranging from 0 to 42. Higher scores indicate greater stroke severity.
Interpretation
| Score | Stroke Severity |
|---|---|
| 0 | No Stroke / Full Recovery |
| 1-4 | Minor Stroke |
| 5-15 | Moderate Stroke |
| 16-20 | Moderate to Severe Stroke |
| 21-42 | Severe Stroke |
When to Use
The scale should be applied on admission of patients with suspected acute ischemic stroke, during evolution to monitor changes in neurological status, and at discharge to determine prognosis and rehabilitation planning.
Limitations
The scale focuses more on motor and language deficits (left hemisphere), potentially underestimating right hemisphere or posterior circulation (brainstem/cerebellum) strokes. Assessment requires proper training to ensure reliability.
Frequent Questions
What does an NIHSS score of 0 mean?
A score of 0 indicates a normal neurological exam, suggesting absence of detectable neurological deficit by the scale, though it does not fully rule out small strokes.
What is the maximum possible score?
The maximum score is 42, indicating a devastating stroke and severe neurological impairment.
References
- Brott T, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20:864-870.
- Adams HP Jr, et al. Baseline NIH Stroke Scale score strongly predicts outcome after stroke. Neurology. 1999;53:126-131.