The National Institutes of Health Stroke Scale, or NIH Stroke Scale (NIHSS), is a tool used by healthcare providers to objectively quantify the impairment caused by a stroke and aid planning post-acute care disposition, though was intended to assess differences in interventions in clinical trials. The NIHSS was designed for the National Institute of Neurological Disorders and Stroke (NINDS) Recombinant Tissue Plasminogen Activator (rt-PA) for Acute Stroke Trial and was first published by neurologist Dr. Patrick Lyden and colleagues in 2001. Prior to the NIHSS, during the late 1980s, several stroke-deficit rating scales were in use (e.g., University of Cincinnati scale, Canadian neurological scale, the Edinburgh-2 coma scale, and the Oxbury initial severity scale).
The NIHSS is composed of 11 items, each of which scores a specific ability between a 0 and 4. For each item, a score of 0 typically indicates normal function in that specific ability, while a higher score is indicative of some level of impairment.[1]
The individual scores from each item are summed in order to calculate a patient's total NIHSS score. The maximum possible score is 42, with the minimum score being a 0.[2][3]
| Score [3] | Stroke severity |
|---|---|
| 0 | No stroke symptoms |
| 1–4 | Minor stroke |
| 5–15 | Moderate stroke |
| 16–20 | Moderate to severe stroke |
| 21–42 | Severe stroke |