NIH Stroke Scale
Calculate the NIH Stroke Scale (NIHSS) score for stroke severity assessment. Free online tool with 15 neurological exam items, severity classification, and visual charts.
About This Calculator
The NIH Stroke Scale (NIHSS) Calculator is a standardized medical tool that helps healthcare professionals assess the severity of stroke-related neurological deficits. Developed by the National Institute of Neurological Disorders and Stroke (NINDS), the NIHSS is the gold standard for objective stroke evaluation in emergency departments, stroke units, and clinical trials worldwide.
The calculator evaluates 15 neurological examination items across 11 categories: level of consciousness (LOC questions and commands), horizontal eye movements (best gaze), visual fields, facial palsy, motor strength in both arms and legs, limb ataxia, sensory function, language ability, dysarthria (speech clarity), and extinction/inattention (neglect). Each item is scored on a scale of 0 to 2-4 points, with a total possible score ranging from 0 (no stroke symptoms) to 42 (severe stroke).
The NIHSS scoring system classifies stroke severity as follows: 0 (no stroke symptoms), 1-4 (minor stroke), 5-15 (moderate stroke), 16-20 (moderate to severe stroke), and 21-42 (severe stroke). The score at presentation strongly correlates with 90-day functional outcomes and guides critical treatment decisions including intravenous thrombolysis (alteplase) and mechanical thrombectomy.
Regional Notes
India: The NIHSS is widely used in Indian stroke centers and is incorporated into acute stroke protocols. Training programs are available through the Indian Stroke Association and the National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS).
United States: The NIHSS is mandated for use in all Joint Commission-certified Primary Stroke Centers and Comprehensive Stroke Centers. Certification through the American Heart Association/American Stroke Association NIHSS training program is required for healthcare providers.
United Kingdom: The NIHSS is recommended by the National Institute for Health and Care Excellence (NICE) guidelines for acute stroke assessment and is used by the National Health Service (NHS) in stroke units across England, Scotland, Wales, and Northern Ireland.
Important disclaimer: This calculator is for educational and clinical reference purposes only. It is not a substitute for formal NIHSS certification or professional medical judgment. Always consult a licensed healthcare provider for stroke diagnosis and treatment decisions. In case of suspected stroke, call emergency services immediately.
Frequently Asked Questions
What is the NIH Stroke Scale (NIHSS)?
The NIH Stroke Scale (NIHSS) is a 15-item neurological examination tool developed by the National Institute of Neurological Disorders and Stroke (NINDS) to objectively quantify stroke-related neurological deficits. It is widely used in hospitals worldwide for stroke assessment, treatment decisions, and outcomes research.
How is the NIHSS score interpreted?
NIHSS scores range from 0 to 42. A score of 0 indicates no stroke symptoms, 1-4 indicates a minor stroke, 5-15 indicates a moderate stroke, 16-20 indicates a moderate to severe stroke, and 21-42 indicates a severe stroke. Higher scores correlate with greater neurological impairment.
Who administers the NIH Stroke Scale?
The NIH Stroke Scale is administered by trained healthcare professionals including physicians, nurses, neurologists, emergency medical personnel, and paramedics. Proper certification through the American Heart Association or NINDS training programs is recommended for accurate and reliable scoring.
How long does it take to perform the NIHSS assessment?
A complete NIHSS assessment typically takes 5 to 10 minutes to administer. The examination covers 11 categories across 15 items assessing consciousness, eye movements, facial symmetry, motor strength, coordination, sensation, language, speech, and attention.
Can the NIHSS be used for all types of stroke?
Yes, the NIHSS is validated for both ischemic and hemorrhagic stroke assessment. It is used in clinical trials, emergency departments, and stroke units worldwide. However, it may underestimate posterior circulation stroke severity and does not capture all functional outcomes.
What is a good NIHSS score improvement after treatment?
A 4-point or greater reduction in NIHSS score within 24 hours is considered clinically meaningful improvement after thrombolysis or thrombectomy. Patients with lower baseline NIHSS scores generally have better functional outcomes at 90 days.
Is the NIHSS used outside the United States?
Yes, the NIH Stroke Scale is the international standard for stroke severity assessment and is used in hospitals across India, the United Kingdom, Europe, Australia, and Asia. It is language-adapted and validated in multiple languages including Hindi, Spanish, French, German, and Japanese.
What are the limitations of the NIH Stroke Scale?
Limitations include ceiling effects for mild strokes, underrepresentation of posterior circulation symptoms like vertigo and imbalance, inter-rater variability, and inability to assess cognitive or mood changes. The NIHSS should be used alongside imaging and other clinical assessments.