How should I report the cranial nerve examination in an adult stroke patient?

How to Report Cranial Nerve Examination in a Stroke Patient

Document cranial nerve findings systematically using the National Institutes of Health Stroke Scale (NIHSS) components, which provides standardized, validated assessment of cranial nerve function relevant to stroke outcomes and should be completed within 24 hours of presentation. 1

Use the NIHSS as Your Primary Framework

The NIHSS is the gold standard for stroke assessment and directly incorporates cranial nerve examination into a prognostic scoring system. 1 Report the NIHSS score by its individual components rather than just the total, as this provides more granular clinical information for patient management. 2

Cranial Nerve Components Within NIHSS

Level of Consciousness (CN assessment foundation):

• 1a. Alertness: 0=alert, 1=arousable to minor stimulation, 2=arousable only to pain, 3=reflex responses or unarousable 1
• 1b. Orientation: Ask age and month (must be exact); 0=both correct, 1=one correct, 2=neither correct 1
• 1c. Commands: Open/close eyes and grip/release hand; 0=both correct, 1=one correct, 2=neither correct 1

CN II (Optic Nerve) - Visual Fields:

• Test using confrontation or visual threat 1
• 0=no visual loss, 1=partial hemianopia/quadrantanopia/extinction, 2=complete hemianopia, 3=bilateral hemianopia or blindness 1

CN II, III, IV, VI (Oculomotor Function) - Best Gaze:

• Test only horizontal eye movements by voluntary or reflexive movement (Doll's eyes, not calorics) 1
• 0=normal, 1=partial gaze palsy, 2=forced deviation or total paresis not overcome by Doll's eyes 1

CN VII (Facial Nerve) - Facial Palsy:

• If stuporous, check symmetry of grimace to pain 1
• 0=normal, 1=minor paralysis (flat nasolabial fold or asymmetric smile), 2=partial paralysis (lower face), 3=complete paralysis (upper and lower face) 1

CN IX, X (Glossopharyngeal/Vagus) - Dysarthria:

• Have patient read list of words 1
• 0=normal, 1=mild-to-moderate slurred but intelligible, 2=severe unintelligible or mute, X=intubated or mechanical barrier 1

CN XII (Hypoglossal) - Best Language:

• Describe cookie jar picture, name objects, read sentences 1
• 0=normal, 1=mild-to-moderate aphasia (partly comprehensible), 2=severe aphasia (almost no information exchanged), 3=mute, global aphasia, coma 1

Additional Cranial Nerve Documentation Beyond NIHSS

While the NIHSS captures most clinically relevant cranial nerve deficits in stroke, perform and document a complete ophthalmic evaluation including best-corrected acuity, check for afferent pupillary defect, and fundus examination to look for papilledema or optic atrophy as indicators of elevated intracranial pressure. 1

Critical Additional Elements:

Pupillary Assessment (CN II, III):

• Document pupil size and reactivity at each assessment, as these are independent prognostic indicators separate from the GCS/NIHSS 2
• Look for afferent defects suggesting orbital or cavernous sinus pathology 1

Sensory Examination (CN V):

• Use safety pin to check grimace or withdrawal if stuporous 1
• 0=normal, 1=mild-to-moderate unilateral loss but patient aware of touch, 2=total loss or bilateral loss 1

Extinction/Inattention (Cortical Function):

• Simultaneously touch both hands, show fingers in both visual fields, ask if patient recognizes own left hand 1
• 0=none detected, 1=neglects or extinguishes to double simultaneous stimulation in any modality, 2=profound neglect in more than one modality 1

Documentation Format and Timing

Report the complete NIHSS score at presentation/hospital admission or within the first 24 hours. 1 For example: "NIHSS 13 (1a=0, 1b=1, 1c=0, CN II=1, Gaze=0, Face=2, Motor Arm R=4, Motor Arm L=0, Motor Leg R=3, Motor Leg L=0, Ataxia=0, Sensory=1, Language=1, Dysarthria=0, Extinction=0)."

If the patient has aphasia, explicitly document this: "NIHSS 13 (E4 V4 M5), motor aphasia present" to clarify why verbal components may be affected. 2

Serial Monitoring Requirements

Perform serial physical examinations to identify worsening brain swelling in patients with massive strokes. 1 The frequency should be:

• Every 15 minutes for the first 2 hours 2
• Hourly for the subsequent 12 hours 2
• A decline of ≥2 points in total NIHSS score mandates immediate repeat head CT. 2

Common Pitfalls to Avoid

Do not confuse absence of voluntary movement (motor grade 0) with flaccidity - grade 0 specifically refers to no active motion regardless of tone. 3 Ensure the patient understands the command and is attempting movement before scoring. 3

Never rely solely on clinical examination to exclude posterior circulation stroke - beam hardening artifact on CT significantly limits detection of brainstem infarcts, and clinical signs may be subtle. 4 Consider immediate MRI with diffusion-weighted imaging if clinical suspicion remains high despite normal CT. 4

Document the motor component most carefully - it is the strongest predictor of neurological outcome, especially in intubated patients where verbal assessment cannot be performed. 2