Pediatric CNS Examination

The paediatric central nervous system (CNS) examination is a key component of the emergency department assessment. It systematically evaluates mental status, cranial nerves, motor and sensory systems, reflexes and developmental milestones, helping to identify time-critical pathology (raised ICP, meningitis, encephalitis, status epilepticus, spinal cord lesions) and guide further investigation.

In the ED, always interpret CNS findings alongside vital signs, glucose, temperature and ABC. A normal exam does not exclude serious disease early on – reassessment is crucial.

Mental Status Examination

The mental status exam in children focuses on level of consciousness, behaviour and age-appropriate cognitive function rather than formal “mini-mental state” testing.

Appearance & behaviour: posture, movements, agitation vs lethargy, eye contact, interaction with caregiver.
Level of consciousness: alert, responds to voice, responds to pain, unresponsive (AVPU or paediatric GCS).
Speech & language: age-appropriate vocabulary, fluency, articulation, following simple/complex commands.
Mood & affect: appropriate to situation, irritable, withdrawn, inconsolable, labile.
Thought content & perception (older children): confusion, hallucinations, delusions if suspected.
Memory & orientation (age-adapted): name, parents, place, recent events in older children.

Any child with reduced GCS, new confusion, persistent irritability, or repeated vomiting must be assumed to have possible intracranial pathology or serious systemic illness until proven otherwise.

Altered Mental Status – Visual Aids

Click images to enlarge.

Algorithm for altered mental state — Algorithm for assessment of altered mental status.

Cranial Nerves Examination

Cranial nerve testing in children must be adapted to age and cooperation level. Use toys, lights and games.

I – Olfactory: usually omitted in the ED; can test with familiar scents in older children if needed.
II – Optic: visual behaviour in infants, fixing and following; older children – visual acuity, visual fields, fundi.
III, IV, VI – Oculomotor/Trochlear/Abducens: eyelid position, pupil size/reactivity, full range of eye movements; note nystagmus or diplopia.
V – Trigeminal: facial sensation (light touch), jaw opening/closing; corneal reflex if indicated.
VII – Facial: eye closure, smile, show teeth, puff cheeks; look for asymmetry or droop.
VIII – Vestibulocochlear: response to sound in infants; whisper tests or tuning fork in older children; balance if walking.
IX, X – Glossopharyngeal/Vagus: voice quality, swallow, palate elevation, gag (if needed); cough strength.
XI – Accessory: shoulder shrug and head rotation against resistance.
XII – Hypoglossal: tongue protrusion and movement; look for deviation, fasciculations or wasting.

Cranial nerves overview — Cranial nerves and areas of influence.

Cranial nerves anatomy — Anatomy of the cranial nerves.

Motor System Examination

Assess bulk, tone, power and coordination, comparing sides throughout.

Muscle bulk: look for wasting, asymmetry, pseudohypertrophy.
Tone: passive movement in limbs – hypotonia vs spasticity vs rigidity; note head lag in infants.
Power: age-appropriate tasks (pushing/pulling, standing from squat, climbing onto bed, lifting limbs against resistance).
Gait & balance: normal gait, toe/heel walking, tandem gait in older children; sitting/standing transitions in toddlers.
Coordination: finger-nose, heel-shin in older children; reaching for toys in younger children.

Upper vs lower motor neuron lesions — Upper vs lower motor neuron lesion patterns.

Sensory System Examination

Sensory testing in young children is often limited; focus on symmetry and gross deficits rather than detailed dermatomal mapping in the ED.

Light touch and pinprick: compare both sides of face, upper and lower limbs.
Temperature: cold metal or cool/warm object if needed.
Vibration: tuning fork over bony prominences (malleolus, wrist, sternum) in cooperative children.
Proprioception: up/down movements of fingers or toes, asking child to report direction.
Cortical sensations (older children): two-point discrimination, stereognosis, graphesthesia if clinically indicated.

Sensory system breakdown — Sensory system organisation.

Reflexes Examination

Deep tendon reflexes help distinguish upper vs lower motor neuron lesions.

Deep tendon reflexes: biceps, triceps, supinator, patellar, Achilles; grade 0–4+ and compare sides.
Plantar response: flexor in older children; an extensor (Babinski) is normal up to ~1 year but abnormal thereafter.
Clonus: sustained ankle clonus suggests upper motor neuron pathology.

Mechanism of reflex — Mechanism of a reflex arc.

Neonatal Primitive Reflexes

Primitive reflexes are key indicators of brainstem and spinal cord integrity in newborns and young infants. They should appear and disappear at expected ages.

Moro (startle) reflex: extension then flexion of arms with startle; present at birth, usually gone by 4–6 months.
Babinski reflex: toe fanning with stroking of sole – normal in infants, should disappear as corticospinal tract matures.
Rooting reflex: head turns toward stimulation at cheek/mouth; helps with breastfeeding.
Palmar/plantar grasp: strong grasp of object placed in palm/sole.
Asymmetrical tonic neck reflex (ATNR): “fencer” posture when head turned; should fade by around 6 months.

Persistence of primitive reflexes beyond expected ages, or asymmetry, can indicate CNS pathology and should prompt further evaluation.

Developmental Milestones

Comparing CNS findings with developmental milestones is essential. Delays in one or more domains (gross motor, fine motor, language, cognitive, social) may be the first clue to neurological disease.

Age	Gross Motor	Fine Motor	Speech & Language	Cognitive	Social & Emotional
0–3 months	Lifts head briefly when prone	Grasps objects reflexively	Cooing, gurgling	Follows objects with eyes	Responsive to familiar faces
4–6 months	Rolls over both ways	Reaches for and holds objects	Babbling with consonants	Explores objects with hands/mouth	Laughs, shows excitement
7–9 months	Sits without support	Transfers objects between hands	Varied babble with inflection	Bangs objects together	Stranger anxiety, shows affection
10–12 months	Crawls, pulls to stand	Pincer grasp, feeds self	First words, gestures	Simple problem solving	Imitates actions, waves goodbye
13–18 months	Walks alone, climbs stairs with help	Builds tower, scribbles	5–10 words, follows simple commands	Matches objects, simple sorting	Shows affection, imitates play
19–24 months	Runs, kicks ball	Turns pages, uses utensils	2–3 word phrases, names objects	Understands simple routines	Parallel play, emerging defiance
2–3 years	Jumps with both feet	Strings beads, begins scissors	Short sentences, names self	Sorts by shape/colour, counts to 3	Plays near others, empathy emerging
3–4 years	Hops on one foot	Draws basic shapes, buttons	Asks many questions, retells stories	Matches, sorts, counts to 10	Cooperative play, shares toys
4–5 years	Skips, throws/catches ball	Prints letters, more complex drawings	Clear speech, detailed stories	Names colours, counts to 20	Group play, sense of humour
5–6 years	Balances on one foot, rides bike	Writes name, ties laces	Complex sentences, retells events	Understands time, counts higher	Stable friendships, rules in games

Common Pediatric Neurological Conditions

CNS examination findings and milestone review help screen for a range of paediatric neurological and neurodevelopmental conditions:

Cerebral palsy: non-progressive motor impairment, abnormal tone and posture, delayed milestones.
Global developmental delay / intellectual disability: delays across multiple domains; often first recognised via milestone surveillance.
Neuromuscular disorders: e.g. muscular dystrophies, spinal muscular atrophy – proximal weakness, Gowers sign, reduced/absent reflexes.
Epilepsy: recurrent unprovoked seizures; may have focal deficits or regression if poorly controlled.
Autism spectrum disorder (ASD): social communication difficulties, restricted/repetitive behaviours, sensory differences.
ADHD: inattention, hyperactivity, impulsivity affecting school and home functioning.
Childhood migraine and headache syndromes: recurrent headaches ± vomiting, photophobia, triggers.
Acute CNS infections/inflammation: meningitis, encephalitis, ADEM – fever, headache, photophobia, seizures, focal deficits or altered behaviour.

Conclusion

The paediatric CNS examination in the ED should be structured but pragmatic, adapted to the child’s age and condition. By systematically assessing mental status, cranial nerves, motor and sensory systems, reflexes and development, clinicians can promptly recognise serious pathology, initiate urgent treatment, and arrange appropriate imaging and specialist referral.