Amiel-Tison Method of Neonatal Neurological Assessment

Objectives

1. Detect neurological abnormalities early in newborns.
2. Identify infants at risk of later motor impairment, particularly cerebral palsy.
3. Help determine whether a suspected brain insult is prenatal, perinatal, or postnatal in timing.
4. Provide a baseline for serial follow-up and early intervention.
5. Supplement, not replace, history, imaging, EEG, developmental surveillance, and formal neurologic review.

Preparation and general principles

• Perform the examination when the baby is awake, calm, and not crying, preferably between feeds.
• Ensure the infant is warm and undressed enough to observe posture and movements.
• Correct interpretation requires consideration of:
  • Gestational age
  • Postnatal age
  • Sleep-wake state
  • Effects of sedatives, anticonvulsants, illness, hypoglycaemia, sepsis, or ventilation
  • Prematurity and intrauterine growth restriction
• The examination should be systematic and repeated, because neonatal signs can change over time.

Components of the Amiel-Tison Method

1. Cranial examination

Assess

• Head circumference and its relation to gestational age
• Shape of skull and symmetry
• Fontanelles:
  • Size
  • Tension
  • Bulging or depression
• Cranial sutures:
  • Separation may occur in raised intracranial pressure.
  • Overriding sutures may be seen after vaginal delivery.
• Facial symmetry and dysmorphic features
• Signs of microcephaly or macrocephaly

Significance

• Microcephaly can indicate impaired prenatal brain growth.
• A rapidly increasing head circumference, separated sutures, and bulging fontanelle suggest raised intracranial pressure or hydrocephalus.
• Cranial deformities or dysmorphism may point toward congenital malformation or genetic disease.

2. State of alertness and behaviour

Assess

• Level of consciousness: alert, drowsy, lethargic, stuporous, or comatose
• Quality of cry: normal, weak, shrill, high-pitched, or absent
• Consolability and irritability
• Response to sound, light, and handling
• Quality of spontaneous movements

Abnormal findings

• Lethargy, poor responsiveness, weak cry, and poor interaction may occur in hypoxic-ischaemic encephalopathy, infection, metabolic disturbance, or intracranial pathology.
• Excessive irritability and a high-pitched cry may occur in withdrawal, raised intracranial pressure, or neurologic dysfunction.

3. Posture

Normal term newborn posture

• Symmetrical posture
• Predominant flexion of the arms and legs
• Flexed hips and knees
• Arms adducted and flexed
• Hands often partially closed

Abnormal postures

4. Assessment of muscle tone

A. Passive tone

Tests of passive tone

a. Scarf sign

• The infant lies supine.
• Pull one arm across the chest toward the opposite shoulder.
• In a term infant, the elbow usually does not cross the midline easily because of normal flexor tone.

• Elbow crosses the midline easily: hypotonia or immaturity.
• Marked resistance: hypertonia.

b. Popliteal angle

• With the infant supine, flex the thigh over the abdomen and extend the leg at the knee.
• Observe the angle at the knee.

• A wide angle indicates reduced flexor tone.
• A very limited angle indicates increased tone.

c. Heel-to-ear manoeuvre

• Gently draw the infant's foot toward the ipsilateral ear while keeping the pelvis on the surface.
• Note the resistance and how near the heel comes to the ear.

• Minimal resistance and easy approximation of heel to ear suggest hypotonia.
• Strong resistance and limited movement suggest hypertonia.

d. Adductor angle

• Flex the infant's hips and knees.
• Gently abduct the thighs.
• Observe the angle between the thighs and resistance to movement.

• Increased adductor tone gives limited abduction.
• Reduced resistance suggests hypotonia.

e. Dorsiflexion of foot

• Flex the foot upward toward the shin.
• Assess resistance at the ankle.

B. Active tone

Tests of active tone

a. Head control or head lag

• Pull the infant gently from supine to sitting, supporting the head initially.
• Observe control of the head.

• Excessive head lag: hypotonia.
• Marked head retraction: extensor hypertonia.
• Persistent asymmetry: focal neurologic or musculoskeletal lesion.

b. Ventral suspension

• Hold the infant prone, supported under the chest and abdomen.
• Observe the relation of head, trunk, and limbs to the horizontal plane.

c. Axillary suspension

• Hold the infant upright under the axillae.
• Observe shoulder girdle tone, trunk control, and lower-limb position.

5. Spontaneous motor activity

Assess

• Quantity of movement
• Symmetry between right and left sides
• Smoothness and variability
• Presence of tremors, jitteriness, myoclonus, abnormal posturing, or seizures

Interpretation

• Reduced spontaneous movement may result from encephalopathy, sedative exposure, sepsis, peripheral nerve injury, or severe hypotonia.
• Asymmetrical movement may indicate brachial plexus injury, fracture, hemiparesis, or focal cerebral lesion.
• Jitteriness is often stimulus-sensitive and stops with passive flexion of the limb. It should be differentiated from seizures.
• Seizures may appear as subtle repetitive eye deviation, lip smacking, bicycling movements, apnoea, or tonic posturing.

6. Primitive reflexes

a. Rooting reflex

• Stroke the cheek near the corner of the mouth.
• The infant turns toward the stimulus and opens the mouth.

b. Sucking reflex

• Place a clean finger or nipple in the mouth.
• Assess strength, rhythm, and coordination of suck.

c. Moro reflex

• With the head supported, allow a slight controlled drop of the head and trunk.
• Normal response:
  1. Sudden symmetrical abduction and extension of the arms with opening of hands.
  2. Followed by adduction and flexion, often with crying.

• Absent or weak bilateral Moro: CNS depression, severe hypotonia, or serious illness.
• Asymmetrical Moro: clavicle fracture, humeral fracture, brachial plexus injury, or hemiplegia.
• Exaggerated Moro: irritability, drug withdrawal, or hyperexcitability.

d. Palmar grasp

• Place a finger in the infant's palm.
• The infant flexes the fingers around it.

e. Plantar grasp

• Press the sole at the base of the toes.
• The toes flex.

f. Stepping or placing response

• Hold the infant upright with soles touching a firm surface.
• Alternating stepping-like movements may occur.

g. Tonic neck response

• When the head is turned to one side, the limbs on the face side may extend while those on the occipital side flex.
• A persistent or exaggerated obligatory tonic neck posture is abnormal.

7. Cranial nerve assessment

• Pupillary size and reaction to light
• Eye position and conjugate eye movements
• Facial symmetry during crying
• Rooting, sucking, and swallowing
• Hearing response to sound
• Quality of cry and palatal movement when indicated

Abnormal findings

• Facial asymmetry may suggest facial nerve palsy.
• Poor suck or swallowing difficulty may indicate brainstem, cranial nerve, or neuromuscular involvement.
• Abnormal eye movements may suggest seizures, cranial nerve palsy, or central neurologic disease.

Interpretation and documentation

Normal examination

• Symmetric flexed posture
• Appropriate passive and active tone for gestational age
• Symmetrical spontaneous movements
• Normal primitive reflexes
• Appropriate alertness, cry, feeding response, and cranial findings

Abnormal patterns

1. Hypotonic pattern
   • Decreased resistance to passive movement
   • Excessive head lag
   • Wide popliteal and adductor angles
   • Weak spontaneous activity
   • Poor suck and weak reflexes
2. Hypertonic pattern
   • Increased resistance to passive movement
   • Reduced adductor and popliteal angles
   • Persistent fisting, extensor posture, or arching
   • Exaggerated reflexes
3. Asymmetrical pattern
   • Unequal posture, movement, tone, or reflexes
   • Requires evaluation for peripheral injury, fracture, or focal CNS pathology.
4. Evolving or dynamic signs
   • Changes on serial examination are important.
   • A newborn may initially have hypotonia after an acute insult and later develop hypertonia.

Advantages

• Non-invasive and inexpensive.
• Can be performed at the bedside.
• Includes both neurologic signs and maturation-related findings.
• Useful for high-risk newborn follow-up.
• Serial use can identify an evolving abnormal neurological pattern.

Limitations

• Findings depend on examiner skill and the infant's behavioural state.
• Prematurity, drugs, systemic illness, and feeding state can influence tone and reflexes.
• It is a screening and follow-up assessment, not a standalone diagnostic test.
• An abnormal examination needs correlation with history, neuroimaging, EEG when indicated, and longitudinal neurodevelopmental follow-up.

Conclusion