Neurological Examination

Mental status. Note whether the baby is alert and cries (weakly or vigorously); eye opening (spontaneously, or in response to sound, light or deep tactile stimulation, or noxious stimuli); and whether the infant stays awake for seconds/minutes after stimulation. It is important to be aware that the newborn exam changes significantly with gestational age. For infants with a reduced level of consciousness, an alternate coma scale based on the standard Glasgow Coma Scale (GCS) is available (Table 3).

Cranial nerves

I—Olfaction cannot be reliably assessed in the newborn.

II—Consists of the fundoscopic exam and pupillary reaction to light (consistent by 32-35 weeks GA). A newborn will blink to light at 26 weeks GA; persistent eye closure to light occurs at 32 weeks GA; fixing and following objects (especially red objects) occurs at 38 weeks GA. Opticokinetic nystagmus is present at term. Visual acuity is 20/150 at full term.

dIII, IV, VI—Extraocular eye movements can be assessed by examining the infant's intermittent visual fixation, as well as by examination of brain-stem reflexes. The doll's eyes reflex (horizontal reflex easily elicited with gentle turns of head) is present by 25 weeks GA. Dysconjugate gaze at rest is normal in the first months of life, and spontaneous roving eye movements appear by 32 weeks GA. V—The corneal reflex can be used to assess the first division (V1) of the trigeminal nerve. Tickling the nostril with a cotton swab specifically stimulates the second division of the trigeminal nerve.

VII—Vertical width of the palpebral fissure, prominance of the nasolabial folds, and facial movements during crying can all be observed.

VIII—At 28 weeks GA, an infant should startle or blink to noise. As an infant matures, the response is more subtle.

IX, X—The gag reflex can be tested, and palatal elevation is observed when the infant is crying. Sucking requires cranial nerves V, VII, IX, X and XII, and is usually present by 28 weeks GA. XII—Tongue symmetry and atrophy should be noted. Motor. Observe the baby's posture at rest. At 28 weeks GA, the arms and legs are maintained in an extended position; at 32 weeks GA, the arms are extended and the legs are flexed; at term, the arms and legs are flexed. Direct examination of motor function is usually divided into an assessment of muscle bulk, tone and strength.

Bulk. Muscle bulk should be determined by visual examination and palpation. Tone. It is important to keep the head midline while assessing tone and reflexes. The tonic neck (fencing) reflex causes increased tone and reflexes on the side towards which the head is turned. There are several signs of decreased tone:

1. Frog-leg posture indicates poor adductor tone.

2. Scarf sign. The examiner can adduct the baby's arm such that the elbow goes beyond midline.

3. Traction response or head lag. Elicited by pulling the baby up by his/ her arms. At term a baby should be able to keep the head in line with the body as you pull up.

4. Vertical suspension. Elicited by holding the baby up vertically under his/her arms; a baby should not slip through.

5. Horizontal suspension. When a baby is held horizontally with a hand under the chest/abdomen, a normal-term baby should transiently keep the head and legs in line with the body; a hypotonic baby will drape over the hand.

Strength. Spontaneous movements can be described as vigorous or weak. An infant should have antigravity strength throughout and symmetric movements of all extremities. The symmetry of primitive reflexes should also be checked (Table 4). Sensation. Response to light noxious stimuli in all extremities should be tested. Deep tendon reflexes. Knee reflexes are easiest to elicit. Crossed adductor response is normal in the first months of life. Triceps reflex should not be present; if

Table 4. Primitive reflexes

Reflex

Stimulus

Description

Appears

Disappears

Moro

Rooting

Stepping/ placing

Tonic neck

Parachute

Palmar grasp reflex

Rapid change in head position

Gentle stimulation around mouth Help upright and tilted forward

Manually turn head while infant is supine

Thrusting infant towards surface

Place finger in palm

Arm extension, followed by arm flexion and fanning of fingers Turning of head in direction of stimulus REFLEX alternate flexion/extension of legs

Extension of arm on same side head is turned, flexion of opposite arm; should never be obligatory or sustained

Extension of upper extremities

Firm grasp with all fingers

Birth

34 weeks gestation

Birth

Subtle at birth; prominent by

2-3 weeks

6-7 months

Birth

months

Persists

Persists as voluntary standing

months

Persists 3-4

months b present, it is a sign of hyperreflexia. Ankle clonus (5-10 beats) is normal during the first month of life, and it should be should be symmetric by 2 months.

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