From the Guidelines
The National Institutes of Health Stroke Scale (NIHSS) is a standardized assessment tool used to measure the severity of neurological deficits in stroke patients, with a total score ranging from 0 to 42, where higher scores indicate greater impairment 1.
Overview of NIHSS
The NIHSS evaluates 11 different neurological domains, including:
- Level of consciousness
- Gaze
- Visual fields
- Facial palsy
- Motor function in arms and legs
- Limb ataxia
- Sensory function
- Language
- Dysarthria
- Extinction/inattention Each domain is scored on a scale ranging from 0 (normal function) to a maximum of 2,3, or 4 points depending on the specific item.
Scoring and Interpretation
The total NIHSS score is calculated by summing the scores of each domain, with a range of 0 to 42. Generally, scores of:
- 1-4 indicate minor stroke
- 5-15 indicate moderate stroke
- 16-20 indicate moderate to severe stroke
- 21-42 indicate severe stroke The NIHSS is valuable because it provides a quick, reproducible assessment that helps guide treatment decisions, predict outcomes, and monitor changes in a patient's condition over time 1.
Clinical Application
Healthcare providers should perform the NIHSS assessment promptly upon patient presentation and at regular intervals during treatment to track progress or deterioration 1. The NIHSS score strongly predicts the likelihood of a patient’s recovery after stroke, with a score of greater than 16 forecasting a high probability of death or severe disability, and a score of less than 6 forecasting a good recovery 1.
From the Research
NIHSS Scoring of Stroke
The National Institutes of Health Stroke Scale (NIHSS) is a systematic assessment tool designed to measure the neurologic deficits most often seen with acute stroke patients 2.
- The NIHSS is a nonlinear ordinal scale, with possible scores ranging from 0-42.
- The scale evaluates various aspects of a patient's condition, including vision, movement, sensation, and language.
- The exam performance has been timed to take 5-8 minutes 2.
- The NIHSS score is used to assess the severity of stroke and to monitor the patient's progress over time.
- A lower NIHSS score indicates less severe stroke symptoms, while a higher score indicates more severe symptoms.
Application of NIHSS in Clinical Studies
The NIHSS has been used in various clinical studies to assess the efficacy and safety of different treatments for acute ischemic stroke, including:
- Alteplase versus aspirin plus clopidogrel in acute minor stroke 3
- Safety of intravenous thrombolysis for acute ischemic stroke in patients taking warfarin with subtherapeutic INR 4
- Thrombolysis with alteplase for acute ischemic stroke patients with atrial fibrillation 5
- Comparison of alteplase and tenecteplase for thrombolysis in ischemic stroke 6
Interpretation of NIHSS Scores
NIHSS scores can be interpreted as follows:
- A score of 0 indicates no neurological deficits.
- A score of 1-4 indicates mild neurological deficits.
- A score of 5-15 indicates moderate neurological deficits.
- A score of 16-20 indicates severe neurological deficits.
- A score of 21-42 indicates very severe neurological deficits.