Careful inspection is the most important aspect of the neonatal neurologic examination. The inspection should include the following:
Symmetry of extremities Spontaneous movements Facial expressions and symmetry Eye movements and symmetry
Notice the position of the newborn. Is hyperextension of the neck present? This sign is frequently found in infants with severe meningeal or brain-stem irritation. What is the position of the thumb? The cerebral thumb sign is the finding of the thumb curled under the flexed fingers. It is associated with many cerebral abnormalities, although it may be present intermittently in normal newborns.
The motor examination consists of testing the range of motion of all joints. Assess muscle tone and compare one side with the other. Compare the muscle sizes and strengths. Compare the resistance to passive stretch.
The sensory examination is performed only if a nerve palsy or spina bifida is suspected. Usually pain is the only sensation tested;the object is to elicit a grimace or cry, which indicates cortical perception of pain, and not just withdrawal of the limb, which can be a spinal reflex. Testing the cranial nerves is also difficult in newborns, but the presence of facial symmetry and of the rotational response indicate that cranial nerves III, IV, VI, and VII are grossly intact. Observing a feeding for coordination of sucking, swallowing, and breathing is a good test of nerves IX and X. A simple test for cranial nerve XII consists of pinching the nostrils of the newborn. A reflex opening of the mouth with extension and elevation of the tongue in the midline is the normal response. Deviation of the tongue to one side indicates a lesion of the nerve on that side.
Because the corticospinal tracts are not fully developed in newborns, the response to testing of the deep tendon reflexes is variable and is neither sensitive nor specific. Babinski's reflex is usually present in newborns and is tested as in adults. Babinski's reflex may be present in normal children until the first birthday.
Test for infantile automatisms. These are primitive reflex phenomena that may be present at birth, depending on gestational age, but disappear soon thereafter. There are many automatisms, and not all have to be tested. The most important ones are as follows:
• Rooting response Plantar grasp Palmar grasp Moro's reflex
• Perez's reflex Placing response Stepping response
The rotational response, optical blinking reflex, acoustic blink response, and sucking response are also automatisms and are discussed earlier in this chapter.
The following reflexes are elicited while the newborn infant is lying supine on the examination table.
The rooting response is elicited by having the infant lie in a quiet state with hands held against the chest. The examiner then touches the corner of the infant's mouth or cheek. The normal response is turning of the head to the same side and opening of the mouth to grasp the finger. If only the upper lip is touched, the head normally retroflexes;if only the lower lip is touched, the jaw normally drops. The rooting response is present by 32 weeks' gestation and usually disappears after 3 to 4 months after birth. This primitive response facilitates nursing. It is absent in infants with severe central nervous system disease.
The plantar grasp is elicited by flexing the leg at the hip and knee. Dorsiflex the infant's foot with your hand. The normal response is plantar flexion of the toes over the hand. This response disappears by 9 to 12 months.
The palmar grasp is elicited by stabilizing the infant's head in the midline. Place your index finger into the newborn's palm from the ulnar side. The normal response is flexion of all the fingers to grasp the index finger. If the reflex is sluggish, allow the child to suck, which normally facilitates the grasp response. The palmar grasp is usually established by 32 weeks' gestation and usually disappears after 3 to 5 months after birth. The absence of this response in a newborn or its persistence after 5 months is suggestive of cerebral disease. The newborn commonly holds the hand in a fist. After 2 months, however, the presence of this sign might suggest neurologic disease.
The infant is now picked up and held supine in the examiner's hands.
Moro's reflex, or the startle reflex, is elicited by supporting the infant's body in the right hand and supporting the head with the left hand. The head is suddenly allowed to drop a few centimeters, with immediate re-support by the examiner's hand. The Moro reflex consists of symmetric abduction of the upper extremities at the shoulders and extension of the fingers. Adduction of the arm at the shoulder completes the reflex. The infant usually then emits a loud cry. Moro's reflex is one of the most important motor automatisms. The normal response, which appears in an incomplete form at 28 weeks' gestation, indicates an intact central nervous system. The reflex normally disappears by 3 to 5 months of age. Persistence past 6 months may indicate neurologic disease.
The infant is now turned over and held in the prone position in one of the examiner's hands.
Galant's reflex is elicited by stroking one side of the back along a paravertebral line 2 to 3 cm from the midline going from the shoulder to the buttocks. The normal response is lateral curvature of the trunk toward the stimulated side, with the shoulder and hip moving toward the side stroked. Galant's reflex normally disappears after 2 to 3 months. This reflex is absent in newborns with transverse spinal cord lesions.
Perez's reflex is elicited by placing your thumb at the infant's sacrum and rubbing it firmly along the spine toward the infant's head. The normal response is extension of the head and spine with flexion of the knees. Frequently, the newborn also urinates. This reflex is normally present until 2 to 3 months of age. Its absence suggests severe neurologic disease of the cerebrum or cervical spinal cord or a myopathy.
The child is now laid down on the examination table and then picked up by the examiner, who holds the infant upright. The examiner's hands should be under the arms around the infant's chest, with the head supported by the fingers extended up the infant's back.
The placing response is elicited by allowing the dorsum of one of the infant's feet to touch the undersurface of a tabletop lightly. The normal placing response is for the infant to flex the knee and hip, then place the stimulated foot on top of the table. This response is then tested with the other foot. Placement of the soles of both feet on top of a table should elicit the stepping response, which is the alternating movements of both legs. Both these responses are best observed after 4 to 5 days after birth and disappear after 2 to 5 months. If paresis of the lower extremities is present, these responses are absent.
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