Canadian Neurological Scale

Purpose

The CNS provides a standardized neurological assessment of cognitive and motor function in stroke patients (alert or drowsy).

Link to Instrument

Instrument Details

Acronym CNS

Area of Assessment

Aphasia
Cognition
Functional Mobility

Assessment Type

Observer

Administration Mode

Paper & Pencil

Cost

Free

Diagnosis/Conditions

Stroke Recovery

Stroke

The CNS assesses alertness in stroke patients.
Includes the following assessments:
1) Level of consciousness
2) Orientation
3) Aphasia
4) Motor strength
Assessments of motor function are separated into two sections:
1) A1 - administered if patient is able to understand and follow instructions
2) A2 - administered in the presence of comprehension deficits
Each motor item is rated for severity and each rating is weighted “according to the relative importance of a particular neurologic deficit” (Cote et al., 1989).
Scores submitted form each domain section are summed to provide a total score out of a possible 11.5.
Lower scores are representative of increasing severity.
CNS scores can be converted into NIHSS Scores using: NIHSS = 23 – (2 X CNS Score).

10 minutes

Required Training

No Training

Adult

18 - 64

years

ICF Domain

Body Function
Activity

Measurement Domain

Cognition
Motor

Considerations

Assessment using the CNS is focused on limb weakness over other possible neurological impairments (Cuspineda et al, 2003; Muir et al, 1996).

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Normative Data

Acute Stroke: (Nilanont et al. 2010; n = 350; mean age = 63.4 (range 19 to 93) years; Thai sample)

Scale	Score Median (range)
CNS score	9 (1.5–11.5)
NIHSS score	4 (0–26)

CNS scores can be reliably converted into NIHSS Scores using the following conversion:

NIHSS = 23 – (2 X CNS Score)

Interrater/Intrarater Reliability

Acute Stroke: (Bushnell at al. 2001; n = 59 retrospective study; Cote et al. 1989; n = 157; mean age = 68.8 years)

Excellent interrater reliability (ICC = 0.97; raters = 2 neurologists)
Excellent intra-rater reliability (r = 0.924; correlation of nurse and physician ratings)

Review of common stroke measures: (D'Olhaberriague et al, 1996)

Excellent Interrater Agreement; Kappa = 0.76

Internal Consistency

Acute Stroke: (Cote et al, 1986; n = 34; mean age = 61.2 years & Cote et al, 1989)

Excellent internal consistency (Cronbach's alpha = 0.89)
Excellent internal consistency (Cronbach's alpha = 0.79)

Criterion Validity (Predictive/Concurrent)

Acute Stroke: (Cote et al, 1989)

Excellent concurrent validity with Neurologic Examination (r = 0.775; mean of 3.71 hours between assessments)

Item	Number	Spearman r	95% CI
Level of consciousness	155	0.574*	0.384 - 0.764
Orientation	149	O.71S*	0.583 - 0.849
Speech	153	0.S91*	0.581 - 0.801
Weakneas	134	0.767*	0.695 - 0.839
Global score versus total score	155	0.776*	0.720 - 0.830
*p < .001

Excellent to moderate predictive validity with:

Death within 6 months (crude odds ratio = 0.73)
Cardio/CVA event within 6 months (crude odds ratio = 0.70)
Independence with ADLs within 6 months (crude odds ratio = 1.60)
Overall, low initial scores correlated with higher mortality, greater incidence of recurrent vascular events, and lower independence at 6 months post-stroke

Acute Stroke: (Muir et al, 1996; n = 344, median age = 69 years; CNS and other common measures used in stroke)

	MCANS	NIHSS	Guy's
CNS	.977**	-.948**	.397*
** Excellent; * Adequate
MCANS = Middle Cerebral Artery Neurological Score
NIHSS = National Institutes of Health Stroke Scale
Guy's = Guy's prognostic score (from clinical data)

Construct Validity

Acute Stroke: (Cote et al, 1989)

Excellent correlation between the CNS and a standard neurologic examination (r = 0.769)

Content Validity

The scales content scale was validated by a panel of experts who agreed on the items to be included and their respective weights No statistical analysis provided (Cote et al, 1989).

Responsiveness

Acute Stroke: (Hagen et al, 2003; n = 136; mean age 70 (11) years; sensitivity compared across 3 measures)

Outcome measure (months)	Mean difference	SD	Min	Max	P-value~	SRM
Barthel Index (1–3)	1.1982	2.3696	-3	9	<0.001***	0.5057
CNS (1–3)	0.2072	0.7245	-1.5	2	0.004**	0.286
MMSE (1–3)	1.036	2.6317	-8	8	<0.001***	0.3937
Barthel Index (3–6)	0.1532	1.8887	-8	5	0.263	0.0811
CNS (3–6)	0.7115	0.7115	-2	3.5	0.003**	0.2849
MMSE (3–6)	0.5586	2.2225	-5	8	0.011*	0.2513
CNS = Canadian Neurological Scale
MMSE = Mini-Mental State Examination
~Wilcoxon signed rank test; P < 0.05; P < 0.01; **P < 0.001

Bibliography

Bushnell, C., Johnston, D., et al. (2001). "Retrospective assessment of initial stroke severity: comparison of the NIH Stroke Scale and the Canadian Neurological Scale." Stroke 32(3): 656. Find it on PubMed

Cote, R., Battista, R., et al. (1989). "The Canadian Neurological Scale: validation and reliability assessment." Neurology 39(5): 638. Find it on PubMed

Cote, R., Hachinski, V., et al. (1986). "The Canadian Neurological Scale: a preliminary study in acute stroke." Stroke 17(4): 731. Find it on PubMed

Cuspineda, E., Machado, C., et al. (2003). "Predicting outcome in acute stroke: a comparison between QEEG and the Canadian Neurological Scale." Clinical EEG electroencephalography 34(1): 1-4. Find it on PubMed

D'Olhaberriague, L., Litvan, I., et al. (1996). "A reappraisal of reliability and validity studies in stroke." Stroke 27(12): 2331. Find it on PubMed

Hagen, S., Bugge, C., et al. (2003). "Psychometric properties of the SF-36 in the early post-stroke phase." J Adv Nurs 44: 461-468. Find it on PubMed

Muir, K., Weir, C., et al. (1996). "Comparison of neurological scales and scoring systems for acute stroke prognosis." Stroke 27(10): 1817. Find it on PubMed

Nilanont, Y., Komoltri, C., et al. (2010). "The Canadian Neurological Scale and the NIHSS: development and validation of a simple conversion model." Cerebrovasc Dis 30(2): 120-126. Find it on PubMed