NIH Stroke Scale (NIHSS)

Thomas Brott, Harold P. Adams Jr, National Institute of Neurological Disorders and Stroke · 1989

The fifteen scored items of the NIH Stroke Scale — the instrument whose certification consists of rating patients on video.

The NIHSS is the most-video-rated instrument in medicine. Certification to use it consists of scoring recorded patient examinations, and the reliability literature that established it was built on video training tapes. If you are running rater training, drift monitoring or an inter-rater reliability study on stroke assessment, this is the scale and video is the medium.

Eleven numbered items, fifteen scores. Level of consciousness is rated three ways (responsiveness, questions, commands), and the motor items are scored per limb — 5a and 5b for the left and right arm, 6a and 6b for the left and right leg. Here each score is its own code, so a rating is attached to the moment of the examination that produced it.

Two rules the official instructions insist on. Administer the items in order and do not go back and change scores — the scale is deliberately a record of first performance, not a considered final impression. And score what the patient does, not what you believe they could do. Both rules are easy to break when you can scrub a video backwards, so make them explicit in your protocol; a rater who rewinds and revises is not producing NIHSS data.

Untestable is UN, never a number. Amputation, joint fusion, intubation and similar situations make an item untestable. Record that in the rationale as UN and leave the score unrated. Never code untestable as 9: nine is a legal sum on this scale and the confusion is dangerous.

The total is a sum, and the bands are not part of the scale. Adding the fifteen scores gives 0 to 42. The severity bands widely quoted for those totals appear on no official NINDS document, so if your study uses them, cite whoever defined them rather than implying they are part of the instrument.

What a recording has to contain. This is an examination scale, not an interview scale. Gaze, visual fields, facial palsy, drift, ataxia and inattention all require the manoeuvres to be performed on camera and the relevant body part to be in frame. Language and dysarthria are partly audible, which makes them the items where a time-stamped transcript can genuinely assist — the rest are for your eyes.

Domains (15)

1a Level of ConsciousnessN1A

Responsiveness, from fully alert to reflex-only or unresponsive.

Curated skill
1b LOC QuestionsN1B

Asked the current month and their age — accuracy of the two answers only.

Curated skill
1c LOC CommandsN1C

Asked to open and close the eyes, then to grip and release the non-paretic hand.

Curated skill
2 Best GazeNGZ

Horizontal eye movements only — partial gaze palsy through forced deviation.

Curated skill
3 VisualNVI

Visual fields tested by confrontation in the upper and lower quadrants.

Curated skill
4 Facial PalsyNFP

Symmetry of facial movement on showing teeth, raising brows and closing the eyes.

Curated skill
5a Left ArmN5A

Left arm held against gravity — drift over ten seconds. Code untestable as UN in the rationale.

Curated skill
5b Right ArmN5B

Right arm held against gravity — drift over ten seconds. Code untestable as UN in the rationale.

Curated skill
6a Left LegN6A

Left leg held at thirty degrees — drift over five seconds. Code untestable as UN in the rationale.

Curated skill
6b Right LegN6B

Right leg held at thirty degrees — drift over five seconds. Code untestable as UN in the rationale.

Curated skill
7 Limb AtaxiaNAT

Finger-to-nose and heel-to-shin, tested bilaterally but scored once. Code untestable as UN in the rationale.

Curated skill
8 SensoryNSE

Sensation to pinprick or noxious stimulus, testing enough of the body to establish hemisensory loss.

Curated skill
9 Best LanguageNLA

Comprehension and expression across the whole examination — naming, description, reading.

Curated skill
10 DysarthriaNDY

Clarity of articulation, judged from the patient reading or repeating words. Code untestable as UN in the rationale.

Curated skill
11 Extinction and InattentionNEX

Neglect — visual, tactile, auditory, spatial or personal. Never untestable.

Curated skill
Brott T, Adams HP Jr, Olinger CP, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20(7):864-870. doi:10.1161/01.STR.20.7.864

Public domain: NINDS states that all NINDS-prepared information is in the public domain and may be freely copied, and publishes the official scale. Item labels follow the current NINDS form; per-level descriptions are condensed for a one-line rating control — rate against the official form and its instructions. The picture and naming cards used in the language items are separately copyrighted by their publisher and are not included. Cite Brott et al. (1989) and NINDS.