Stroke scales

Scandinavian Neurological Stroke Scale (SNSS)

Main reference: Scandinavian Stroke Study Group: Multicenter trial of hemodilution in ischemic stroke: background and study protocol. Stroke 16:885–890, 1985.

Type: Clinician-rated scale.

Main indications: Used to assess neurological impairment following stroke, with an initial prognostic component and a long-term functional component.

Rating performed by: Trained health professionals.

Time period covered by scale: The present.

Time required to complete rating: 15 minutes.

Remarks: The SNSS assesses both an initial prognostic score and a long-term functional score. The initial prognostic score is based on an assessment of four areas (consciousness, eye movements, and motor power in the affected arm and the affected leg), with a possible maximum score of 22.

The long-term functional score is performed on day 1 and day 6 and at 3 months. It is based on an assessment of seven areas (motor power in the affected arm, hand, and leg, orientation, speech, facial palsy, and gait), with a possible maximum score of 48. Two of these areas overlap with the areas used to assess the initial prognostic score.

The SSNS deliberately focuses on items that are both easy to assess and of functional significance to patients, and it therefore deliberately omits dysarthria, visual fields, sensibility, and motor reflexes from the assessment.

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National Institutes of Health Stroke Scale (NIHSS)

Main reference: Goldstein LB, Bertels C, Davis JN: Interrater reliability of the NIH stroke scale. Arch Neurol 46:660–662, 1989.

Type: Structured clinician-rated scale incorporating physical examination, pre-set questions, and language assessment.

Main indications: Used to assess and quantify neurological deficit following stroke.

Rating performed by: Trained health professionals.

Time period covered by scale: The present. Suggested use at presentation (baseline), at 2 hours, at 24 hours, at 7–10 days, and at 3 months.

Time required to complete rating: 30–45 minutes. Structured examination and questionnaires.

Remarks: Contains 12 items that assess level of

• consciousness (by examination, by questioning, and by testing ability to follow commands)
• extraocular movements
• visual fields
• facial palsy
• motor strength in the upper and lower limbs
• limb ataxia
• sensory loss
• neglect
• dysarthria
• language ability

An extra item, that assesses distal motor function, is often included. The scale has been shown to have an acceptable level of interobserver reliability. It is important that the examiner rates each item on the basis of what the patient does, not on what the examiner thinks the patient could do.