The Canadian Neurological Scale is a validated tool to evaluate stroke severity 1,2 designed to be performed on patients who are alert or drowsy. Patients who are stuporous or comatose are evaluated with the Glasgow Coma Scale (GCS) instead.
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Classification
Section A is completed first. In the second part of the scale calculation, either section A1 or A2 is completed depending on whether a comprehension deficit is present or not.
Section A – patient alert or drowsy
Mentation
level of consciousness: alert (3), drowsy (1.5)
orientation: oriented (1), disoriented or non-applicable (0)
speech: normal (1), expressive deficit (0.5), receptive deficit (0)
Section A1 – no comprehension deficit
Motor weakness
face: none (0.5), present (0)
arm proximal: none (1.5), mild (1), significant (0.5), total (0)
arm distal: none (1.5), mild (1), significant (0.5), total (0)
leg proximal: none (1.5), mild (1), significant (0.5), total (0)
leg distal: none (1.5), mild (1), significant (0.5), total (0)
Section A2 - comprehension deficit
Motor response
face: symmetrical (0.5), asymmetrical (0)
arms: equal (1.5), unequal (0)
legs: equal (1.5), unequal (0)
Section B – patient stuporous or comatose
use GCS
Interpretation
Scores range from 1.5 to 11.5, with a lower score indicating greater stroke severity.
Practical points
The Canadian Stroke Scale can be converted 3 to the National Institutes of Health Stroke Scale (NIHSS) using NIHSS = 23 - 2 x CNS