What is the stepwise approach to performing a National Institutes of Health Stroke Scale (NIHSS) assessment?

NIHSS Assessment: Stepwise Approach

The NIHSS should be performed systematically through 11 core items assessing consciousness, vision, motor function, sensation, language, and attention, with proper training and certification required before administration to ensure accurate stroke severity assessment. 1

Preparation Before Assessment

• Examiners must be trained and certified in NIHSS administration by watching training videos and passing an examination to ensure accurate assessment of stroke severity 1
• The assessment takes approximately 5-8 minutes to complete when performed efficiently 2
• For telemedicine assessments, rearrange the NIHSS order to reduce camera manipulations, performing close-up items before zoomed-out views 3

Stepwise Assessment Protocol

Step 1: Level of Consciousness (LOC)

• Assess patient response to stimulation, test orientation, and ability to follow commands, focusing on alertness, language, and motor function 1
• This domain demonstrates the highest inter-rater reliability (weighted kappa = 0.99) and should be assessed first 4
• Score based on degree of arousal and responsiveness to verbal and physical stimuli 2

Step 2: Visual Fields and Gaze

• Evaluate visual field deficits by testing each quadrant separately 1
• Assess horizontal eye movements and gaze preference 1
• These items have excellent reliability in both bedside and telemedicine assessments 3

Step 3: Facial Palsy

• Test facial symmetry by asking patient to show teeth or raise eyebrows 1
• Note: This item has lower inter-rater reliability compared to other components and may require careful attention 1, 5

Step 4: Motor Arm Function

• Have patient extend arms palm down at 90 degrees (sitting) or 45 degrees (supine) and hold for 10 seconds 1, 6
• Score each arm separately based on drift, effort against gravity, and movement 1
• Scoring: 0=no drift, 1=drift before 10 seconds, 2=some effort against gravity, 3=no effort against gravity, 4=no movement 6

Step 5: Motor Leg Function

• Assess leg strength using similar principles to arm assessment 2
• Test each leg separately with patient supine 2

Step 6: Limb Ataxia

• Test for cerebellar dysfunction with finger-to-nose and heel-to-shin maneuvers 2
• This item demonstrates lower inter-rater reliability, particularly in telemedicine assessments 3

Step 7: Sensory Function

• Assess sensation to pinprick in all extremities 1
• Compare symmetry between sides 2

Step 8: Language Assessment

• Ask patient to describe a standardized picture, name objects, and read sentences 1
• Score based on fluency and comprehension 1
• This evaluates for aphasia and language dysfunction 2

Step 9: Dysarthria

• Test articulation by having patient repeat specific words 2
• This item has demonstrated lower inter-rater reliability (ICC <0.40) and may be challenging to score 5

Step 10: Extinction and Inattention

• Assess for neglect by testing simultaneous bilateral stimulation 1
• Evaluate visual and sensory extinction 2

Timing and Frequency of Assessment

• Perform NIHSS at time of presentation/hospital admission, or at least within first 24 hours 1
• Reassess using NIHSS at time of acute care discharge 1
• For patients at risk of progression, serial assessments during the first 48 hours are valuable, particularly for those with initial scores >7 who have a 65.9% worsening rate 7

Critical Scoring Interpretation

• Total scores range from 0 to 42, with higher scores indicating more severe strokes 6
• Scores >16 forecast high probability of death or severe disability, whereas scores <6 forecast good recovery 1
• A 4-point improvement or worsening may alter treatment eligibility 1
• An initial NIHSS ≤7 predicts 14.8% worsening rate versus 65.9% for scores >7 7

Important Caveats and Limitations

• The NIHSS may underestimate posterior circulation stroke severity because symptoms like vertigo and dysphagia are not included 1
• Distal motor function and balance/gait disorders are not adequately covered by the standard scale 1
• Items with lowest reliability (facial palsy, ataxia, dysarthria) require extra attention during assessment 3, 1
• When using medical records for retrospective scoring, the modified 11-item NIHSS performs better than the standard 15-item version, with 95% of scores within 5 points of actual measurements 5