National Institutes of Health Stroke Scale (NIHSS)

The NIH Stroke Scale is the standard way of putting a number on how much a stroke has affected someone in the first hours. It is used to guide treatment decisions, to hand information between clinicians, and to track whether a person is improving or worsening.

Eleven items are examined and scored: level of consciousness, gaze, visual fields, facial palsy, motor function in each arm and leg, limb ataxia, sensation, language, dysarthria, and extinction or inattention. Because consciousness and the motor items break down further, fifteen elements are actually scored, totalling 0 to 42. Zero means a normal examination. Items that genuinely cannot be tested — an amputated limb, a fused joint — are marked untestable rather than scored.

• Official Training Certification

Licensing Notes: The scale, instructions, and training materials are free at ninds.nih.gov and nihstrokescale.org. Certification is required for clinical trial administration and is standard practice in stroke centres; free training and certification are available through the NIH and the American Heart Association.

Learn More: Three scoring rules matter and are easy to get wrong. Score the first attempt only — do not coach, and do not go back and change a score once the next item has begun. Score what the patient does, not what you think they can do. And the deficit must be attributable to the stroke; pre-existing loss is not scored. Severity is conventionally banded: 1–4 minor, 5–15 moderate, 16–20 moderate to severe, 21+ severe. Always record the exact time of examination.