How should I assess the cranial nerves of a 23‑month‑old child?

Assessing Cranial Nerves in a 23-Month-Old Child

Cranial nerve assessment in a 23-month-old requires age-appropriate, observation-based techniques that rely heavily on watching spontaneous behavior, using toys and visual stimuli, and incorporating play rather than formal testing commands that work in older children and adults.

Key Principle: Cooperation Through Observation

At this age, formal neurological examination techniques used in adults are impractical. The examination must be adapted to the child's developmental stage, using indirect assessment methods that don't require verbal cooperation 1. Non-cooperation itself can be a red flag for developmental concerns 2.

Systematic Approach by Cranial Nerve

CN I (Olfactory)

• Generally not formally tested at this age
• Can observe reactions to familiar pleasant/unpleasant smells if clinically indicated

CN II (Optic)

• Visual tracking: Use bright toys or objects to assess smooth pursuit movements
• Fixation: Observe if the child fixes on faces or objects
• Pupillary response: Check direct and consensual light reflexes
• Look for strabismus or abnormal eye alignment

CN III, IV, VI (Oculomotor, Trochlear, Abducens)

• Observe spontaneous eye movements during play
• Use interesting toys to elicit tracking in all directions (H-pattern)
• Look for abnormal head posture - children with diplopia often adopt compensatory head tilts rather than complaining of double vision 3
• Check for ptosis or pupil asymmetry
• Assess for strabismus at rest and with movement

CN V (Trigeminal)

• Motor: Observe jaw movement during eating or chewing
• Sensory: Watch facial reactions to light touch (cotton swab) on different areas
• Observe symmetry of facial sensation responses

CN VII (Facial)

• Most easily assessed through observation of spontaneous facial expressions
• Watch for symmetry when child smiles, cries, or makes faces
• Observe eye closure during blinking and sleep
• Check nasolabial folds for symmetry

CN VIII (Vestibulocochlear)

• Hearing: Observe response to sounds at different volumes and directions
• Turn to voice or noise
• Balance: Watch gait and ability to sit/stand without support (age-appropriate)

CN IX, X (Glossopharyngeal, Vagus)

• Observe swallowing during feeding
• Listen to voice quality (hoarseness, nasal quality)
• Watch for drooling or difficulty managing secretions
• Observe palate elevation if child opens mouth (say "ah" if cooperative)

CN XI (Spinal Accessory)

• Observe spontaneous head turning and shoulder movements
• Watch for head tilt or asymmetry
• Assess shoulder symmetry during reaching activities

CN XII (Hypoglossal)

• Observe tongue position when mouth is open
• Watch tongue movements during eating or vocalizing
• Look for fasciculations or atrophy
• Deviation suggests weakness on the side toward which tongue deviates

Critical Assessment Components

A structured examination at this age should include 37 items across three sections 4:

1. 26 items: Cranial nerve function, posture, movements, tone, and reflexes
2. 8 items: Motor function development milestones
3. 3 items: Behavioral state assessment

Common Pitfalls to Avoid

• Don't force cooperation - this creates anxiety and yields unreliable results
• Don't rely solely on reflex testing - quality of spontaneous motor behavior is equally important 2
• Don't miss subtle signs - children rarely report diplopia; look for compensatory head postures and strabismus 3
• Don't examine in isolation - integrate findings with developmental milestones and overall neuromotor assessment

Red Flags Requiring Further Investigation

• Persistent abnormal head posture
• Asymmetric facial movements or expressions
• Feeding difficulties or excessive drooling
• Lack of visual tracking or fixation
• Strabismus or abnormal eye movements
• Asymmetric muscle tone or movements

Practical Examination Strategy

Use a toy-based, play-integrated approach: Have colorful toys, lights, and age-appropriate objects available. Conduct much of the examination while the child is on the parent's lap or playing naturally. Observe first, then interact, minimizing restraint or forced positioning that triggers non-cooperation.