The National Institutes of Health Stroke Scale (NIHSS)

Introduction

The National Institutes of Health Stroke Scale (NIHSS) is probably the most widely used assessment tool for determining the severity of stroke on neurological examination¹. NIHSS first was developed as a 15-item scale, but then later on it was reduced to 11 items.  The scoring scheme starts from 0 (no deficit) to 42 (severe stroke), and as seen in figure-1, research shows a strong correlation between the size of the ischemic lesion on brain imaging and the total score ². Although NIHSS lacks inter-rater reliability, it has become a standard communication tool between clinicians in order to stratify patients based on severity of their symptoms³ .

An example of a patient with a moderate to severe stroke with aphasia and right-sided weakness

NIH Stroke Scale/Score (NIHSS) from MDCalc.com on 2/25/2015 ­
** All calculations should be rechecked by clinician prior to use **

RESULT SUMMARY:
19 points out of 42
NIH Stroke Scale

INPUTS:
1A: Level of consciousness —> 1 = Arouses to minor stimulation
1B: Ask month and age —> 2 = Aphasic
1C: ‘Blink eyes’ & ‘squeeze hands’ —> 1 = Performs 1 task
2: Horizontal extraocular movements —> 1 = Partial gaze palsy: corrects with oculocephalic reflex
3: Visual fields —> 1 = Partial hemianopia
4: Facial palsy —> 2 = Partial paralysis (lower face)
5A: Left arm motor drift —> 0 = No drift for 10 seconds
5B: Right arm motor drift —> 3 = No effort against gravity
6A: Left leg motor drift —> 0 = No drift for 5 seconds
6B: Right leg motor drift —> 3 = No effort against gravity
7: Limb Ataxia —> 0 = Does not understand
8: Sensation —> 2 = Complete loss: cannot sense being touched at all
9: Language/aphasia —> 2 = Severe aphasia: fragmentary expression, inference needed, cannot identify materials
10: Dysarthria —> 0 = Intubated/unable to test
11: Extinction/inattention —> 1 = Visual/tactile/auditory/spatial/personal inattention

The NIHSS Booklet and PDF Forms

Certification

If your hospital does not  have a NIHSS learning protocol, or if you are office-based, you can take advantage of the professional learning portals of the heart and stroke association (you need a professional membership).

References:

1. Brott T, Adams HP, Olinger CP, et al. Measurements of acute cerebral infarction: a clinical     examination scale. Stroke. 1989;20(7):864-870.

2. Hinkle Janice L. Reliability and Validity of the National Institutes of Health Stroke Scale for  Neuroscience Nurses. Stroke. 2014;45(3):e32-e34. doi:10.1161/STROKEAHA.113.004243

3. Powers DW. Assessment of the stroke patient using the NIH stroke scale. Emerg Med Serv.  2001;30(6):52-56. 4. NIH Stroke Scale/Score (NIHSS). MDCalc. https://www.mdcalc.com/nih-stroke-scale-score-nihss. Accessed June 5, 2019.

Rémy Cohan