Canadian Neurological Scale

The Canadian Neurological Scale is a validated tool to evaluate stroke severity 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.

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: 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  to the National Institutes of Health Stroke Scale (NIHSS) using NIHSS = 23 - 2 x CNS