Observation

A proper examination begins with observation. The infant’s clothing should be removed slowly and gently, and the diaper should be opened only for the period in which the covered area is evaluated. The examiner should make no quick moves. It is a common error to begin handling the infant before an adequate and systematic observation period.

The examiner should delineate the presence of congenital abnormalities, including midline defects of the cranium, face, palate, and spine. Midline defects are often associated with abnormalities of the neural tube. Abnormalities of the trunk, limbs, and skin are readily observed. Skin pigmentation changes are important because of the shared ectodermal beginnings of the integument and the nervous system. In particular, the presence of abnormalities associated with neurocutaneous syndromes should be ascertained, even though manifestations may not be present in the newborn. Freckling in the axillary areas is highly suggestive of neurofibromatosis.

Assessment of most cranial nerves can be accomplished in part through observation. The cranial nerves enabling eye movements and facial movements can be readily monitored.

Gross motor abilities of the newborn infant can be partially evaluated by observation. The head is preferentially turned to the right for longer periods than to the left. Term infants have predominant flexor tone, with resultant flexion of the arms at the elbows and of the legs at the knees. Bilateral fisting of the hands, including adduction and infolding of the thumbs (i.e., cortical thumbs), is expected. Limb position and posturing should be roughly symmetric. While supine, the infant manifests spontaneous limb movements that are often asymmetric and have a rapidly jerking quality. Jitteriness or tremulousness of the hands or jaw is sometimes spontaneous. These movements may indicate hyperexcitability of the central nervous system (CNS). Causes of hyperexcitability are discussed later in this chapter.

The examiner should mentally quantitate frequency and amplitude of limb movements. Diminished frequency or amplitude of arm movements may indicate brachial plexus injury; involvement of an arm and ipsilateral leg may indicate hemiparesis. While prone, the infant normally maintains a flexed posture of the arms and legs, with resultant elevation of the pelvis and flexion of the hips and knees.

The infant’s respiratory rhythm and chest movement should be observed to indicate adequate contraction of intercostal muscles. Although diaphragmatic breathing is normally accentuated in the newborn, the absence of intercostal muscle participation and a “sucking in” of the sternum may indicate anterior horn cell disease, neuromuscular junction disease, or spinal cord injury. The presence of a pectus excavatum deformity in the newborn should not be regarded as an isolated congenital deformity until neuromuscular conditions in which the diaphragm overpowers the intercostal muscles have been excluded.

The level of alertness increases with CNS maturation. At 37 weeks’ gestation, crying is common during wakefulness. At term, the infant remains alert for reasonable periods and responds to visual, auditory, and tactile stimulation. Crying is often forceful. Sleep and wake periods are clearly delineated.

Cranial Vault Evaluation

Among the most important facets of the examination is the measurement of the occipitofrontal (head) circumference. For the most part, this measurement is a reflection of brain growth. However, undue enlargement may be associated with cephalohematoma, subdural fluid collection, hydrocephalus, hydranencephaly, macrocephaly, or megalencephaly (Chapters 21–28). Serial measurements provide an index of brain growth in sick neonates. Microcephaly may be associated with many conditions, including intrauterine infection, hereditary abnormalities, maternal substance abuse, and poor nutrition.

The measurement of the occipitofrontal circumference should be performed carefully. An assistant may be necessary to stabilize the head during measurement. The measuring tape should be moved up and down the head until the largest circumference is obtained. The shape of the head influences the measure of the circumference. The nearer the head shape approximates a perfect circle, the smaller is the head circumference compared with the circumference of a noncircular head, despite the fact that the area of a plane through the maximal circumference and the brain volumes are the same. A similar relationship exists between a perfect sphere and the volume contained within it. The occipitofrontal circumference should be plotted on a graph standardized for gender, race, and gestational age to determine if the measurement falls within the normal range (i.e., two standard deviations above or below the mean) (Figure 4-1) [Braun et al., 2004]. On average, occipitofrontal circumference increases 2 cm during the first month of life, 6 cm during the first 4 months, 7 cm during the first 6 months, and 12 cm during the first 12 months of life [Fujimura and Seryu, 1977].

Fig. 4-1 Head circumference charts.

(From Nellhaus G. Composite international and interracial graphs. Pediatrics 1968;41:106.)

Infants delivered vaginally may have some deformity of the head because of scalp and subcutaneous edema with resulting caput succedaneum formation; vacuum extraction delivery often results in caput formation. Infants delivered by cesarean section usually have relatively round heads. The caput deformity, usually transient, produces an increased diameter and may confound accurate occipitofrontal circumference measurements. Cephalohematomas, which are delimited by the periosteum of the individual cranial bones, produce asymmetry of the head and increase the occipitofrontal circumference. Most occur over the parietal bones. A caput succedaneum, unlike a cephalohematoma, extends over two or more cranial bones and is not restricted to the subperiosteal (subgaleal) space. Subgaleal hematomas result from bleeding under the scalp aponeurosis and are often preceded by forceps or vacuum-assisted delivery space [Kilani and Wetmore, 2006]. The scalp may be edematous and boggy because of underlying blood. Although most subgaleal hematomas are benign, hypovolemic shock may ensue if a large amount of blood is sequestered in the subgaleal space.

The anterior fontanel, readily palpable at birth, is concave or flat in relation to the surrounding cranium. The fontanel should be assessed with the child held in the sitting position if there is any question of increased pressure. The fontanel may bulge during crying or in the presence of pathologic increased intracranial pressure. Unfortunately, the presence of normal conformation of the fontanel does not guarantee normal pressure; conversely, a bulging anterior fontanel strongly suggests increased intracranial pressure. The anterior fontanel varies in size but usually ranges from 1 to 3 cm in its longest dimension [Popich and Smith, 1972]. The fontanel pulsates synchronously with the infant’s pulse. The posterior fontanel in the neonate usually is open but admits only a fingertip. The presence of an enlarged posterior fontanel suggests the possibility of intrauterine increased intracranial pressure. From time to time, particularly in the presence of wormian bones, auxiliary fontanels may be palpable. A detailed discussion of the infant skull can be found in Chapter 28.

The cranial sutures (e.g., sagittal, metopic, lambdoidal, squamosal) are readily palpable in the newborn. Infants delivered vaginally may manifest overriding of the sutures that, with normal head growth, resolves during the first week of life. The sagittal and lambdoidal sutures are most frequently involved. The sutures are readily separated from one another with palpation. The abrupt steplike contour of the overriding bone at the suture interface distinguishes this condition from that of premature closure of the sutures. When a suture closes prematurely, growth continues along the line of apposition of the bones across the suture. For example, sagittal synostosis causes an increase in the anteroposterior diameter (i.e., scaphocephaly). Increased bitemporal diameter occurs in the presence of coronal synostosis (i.e., brachycephaly). Asymmetric suture closure may lead to grossly asymmetric head shape (i.e., plagiocephaly).

Auscultation over the infant skull, particularly the anterior fontanel and neck vessels, usually reveals a venous hum in a number of locations. Rarely, systolic-diastolic bruits, particularly those that are focal and asymmetric, indicate the presence of an arteriovenous malformation [Dodge, 1956]; however, these bruits may be heard in normal infants.

Cranial ultrasound, computed tomography (CT), and MRI are informative concerning subdural hematomas, cystic lesions, hemorrhages, and enlarged ventricles.

Developmental Reflexes

Developmental reflexes are primitive reflexes with complex responses, and largely reflect the integrity of the brainstem and spinal cord; the role of higher centers, although of importance, is not fully known. Many of these reflexes are present at birth and undergo modification during the first 6 months of life. Detailed discussion of these reflexes is presented in Chapter 3. Their persistence beyond the expected date of dissipation suggests maturational lag or impaired CNS function. This group includes the Moro, rooting, grasping, tonic neck, stepping, and placing reflexes. Generalized diminution of the manifestation of these reflexes suggests diffuse depression of brain function. Asymmetry indicates central or peripheral nervous system dysfunction that must be further localized. It is likely that infants born after breech presentation may have significant suppression of active movements when examined at the second and fourth days of life [Sekulic et al., 2009]. A stereotypic “elbowing” movement in newborns has been described. A curved wooden model of an ultrasonographic probe is gently used to exert pressure on the right and left subcostal regions. The newborn reacts with a particular defensive arm movement in which there is a three-phase response [Saraga et al., 2007].

Motor Function

Gentle manipulation of the infant’s limbs allows for assessment of muscle tone and strength. Tone is defined as resistance to passive movement (see Chapter 5). Tone at each large joint should be evaluated while the infant is at rest. Spontaneous movements and resistance of the infant to limb and trunk movement provide a measure of muscle strength. The examiner should recall any clues from the observation period suggesting muscle weakness and corroborating changes in tone and strength at this time. The infant should be supine with the head in the midposition while tone is evaluated so that the tonic neck reflex does not augment tone unilaterally.

The newborn infant should be held in the horizontal position while attitude and posture of the limbs and trunk are observed. The infant should then be held in vertical suspension again to determine whether the expected flexor tone of the limbs is present and symmetric. When held in the vertical position, the hypotonic and weak infant tends to slide through the examiner’s hands. The infant’s arms are held loosely at the sides, and the expected configuration of the shoulder girdle is poorly maintained. In the horizontal position, the infant appears to be looped over the examiner’s arms. Infants with increased tone manifest an opisthotonic position in conjunction with obligate extension in both vertical and horizontal positions. Although it usually manifests in older infants, scissoring (i.e., crossing of the legs because of excessive, involuntary adductor magnus contraction) may be evident. The most common cause of generalized decreased tone is depression of CNS function, which may result from hypoxic-ischemic encephalopathy, neonatal sepsis, intraventricular hemorrhage, subdural hemorrhage, or metabolic abnormalities (e.g., hypoglycemia). Congenital malformations, including neuronal migration disorders, may be associated with hypotonia. Tone and strength may be decreased in a number of neuromuscular conditions, including spinal muscular atrophy, neonatal myasthenia gravis, congenital myopathies, and neonatal myotonic dystrophy. Muscle tone may be increased in a variety of conditions that cause a neonatal encephalopathy, including many metabolic disorders, hypoxic-ischemic encephalopathy, neonatal stroke, intrauterine infection, congenital malformations, and trauma.

While the infant is being handled, stimulation may engender jittery or tremulous movements of the jaw or limbs. Such movements are arrhythmic and do not have a definite phasic composition. The movements usually terminate when stimulation ends, although noises or abrupt changes in light may trigger them. Sometimes, there may be spontaneous tremulousness. Crying enhances the frequency and range of the movements. Such tremulousness may indicate metabolic abnormalities (e.g., electrolyte imbalance), bleeding, congenital CNS defects (structural or functional), infections, or drug withdrawal syndromes. Exaggerated and persistent tremulousness may indicate relative irritability of the cerebral cortex and potential risk for subsequent, significant neurologic dysfunction including seizures.

Deep tendon reflexes are elicited using a reflex hammer and are often brisk in the newborn, although they may be normally absent [Critchley, 1968]. They may be inordinately enhanced by upper motor neuron abnormalities and are further facilitated by crying. CNS depression may be associated with reduced deep tendon reflexes. The examiner should confirm that the deep tendon reflexes are symmetric, because asymmetry may indicate central or peripheral nervous system impairment. If previous examination has suggested the possibility of hemiparesis, deep tendon reflexes should be carefully evaluated for asymmetry; they are usually increased on the affected side. Deep tendon reflex asymmetry in the arms may be associated with upper motor neuron abnormality, but asymmetrically absent deep tendon reflexes suggest peripheral involvement, possibly the result of brachial plexus injury. Nerve conduction studies in newborns may provide an index of neurologic maturity [Dubowitz et al., 1968].

Controversy remains over the significance of the plantar response in the newborn period in term infants. Although some investigators have reported that the Babinski sign is flexor and symmetric in the newborn period [Hogan and Milligan, 1971], this finding is more likely caused by obtaining a plantar grasp than a Babinski response if only the sole of the foot is used to elicit the response. The plantar response is extensor for at least the first month of life and usually through the first year of life. However, at all times, the response should always be bilaterally symmetric. Persistence of extensor toe-sign responses beyond infancy suggests corticospinal tract impairment and may be associated with alterations in tone and other deep tendon reflex abnormalities. Ankle clonus is frequently elicited in the newborn; rarely are there more than eight beats in normal infants. The clonus is enhanced during crying and may be facilitated during hyperexcitable states, such as those associated with metabolic abnormalities, infection, and subarachnoid hemorrhage. Sustained ankle clonus has the same significance in term newborns as in later life and suggests dysfunction of the corticospinal tracts.

A reflex akin to the plantar response has been described for the hand in term and preterm newborns. The examiner strokes the ulnar aspect of the infant’s palm with the thumb, beginning distally and stroking proximally from the small finger to the hypothenar eminence. The normal response is gradual extension of the fingers, beginning with the small finger and continuing to the middle fingers [Modanlou, 1988]. Lack of response or gross alteration of response may be observed in the presence of corticospinal tract dysfunction.

Cranial Nerve Examination

A more detailed discussion of the cranial nerve examination is found in Chapter 2. Cranial nerve I, the olfactory nerve, is infrequently tested but may be evaluated by the use of pleasant but definitive aromatic substances, such as cinnamon and cloves [Sarnat, 1978]. The infant usually manifests an arrest of activity, arousal, and sucking activity when exposed to these aromas. Virtually all neonates born after more than 32 weeks’ gestation respond [Sarnat, 1978].

Evaluation of cranial nerves II, III, IV, and VI involves assessment of the eyes. The pupils should be symmetric, and there should be an equal bilateral response to light. A bright light causes the infant to blink or hold the lids closed. The presence of ptosis or increased height of the palpebral fissure should be evaluated. The examiner should ascertain the presence of heterochromia, although it may not be evident until later.

Examination of the optic fundi may be difficult but is necessary. Numerous changes, including chorioretinitis (i.e., salt-and-pepper pigmentary changes), may be observed. Hemorrhages are commonly detected after vaginal delivery, even in the absence of traumatic delivery. The optic nerve may be hypoplastic, as manifested by a small, pearl-colored optic disc. The color of the optic disc in the newborn infant is grayish white. Retinal hemorrhages may be found in a large percentage of otherwise normal infants who have no history of abnormal delivery and who later prove to be neurologically normal [Besio et al., 1979]. Further discussion of funduscopic characteristics is presented in Chapter 6.

The newborn infant turns toward a light of moderate intensity and fixes on a bright object or the examiner’s face. Most often, the newborn’s eyes are symmetrically open or closed. If one eye is open and the other closed, there should be a shifting from one side to the other. Width of palpebral fissures should be equal; if not, the presence of ptosis should suggest an abnormality of cranial nerve III function, sympathetic innervation dysfunction, neuromuscular junction difficulty, weakness of the levator muscle of the lid, or abnormality of the lid connective tissue. Among the conditions to be considered are congenital myasthenia gravis, myotonic dystrophy, Horner’s syndrome (Figure 4-2), Möbius’ syndrome, congenital myopathies, and Duane’s syndrome. Occasionally, central or peripheral seventh nerve paresis may result in asymmetry of the palpebral fissure.

Fig. 4-2 Horner’s syndrome (left eye).

Miosis and ptosis are plainly evident.

(Courtesy of the Division of Pediatric Neurology, University of Minnesota Medical School.)

Extraocular movements should be monitored while a child is lying quietly. Slight lapses of conjugate gaze are common in the newborn period. Newborn visual acuity is difficult to assess, but black and white-patterned objects can be used. The examiner’s face is often the best “target.” The intended object of focus is moved slowly in the infant’s field of vision, less than a foot from the infant’s eyes. The infant slowly follows with eye movement, particularly in lateral directions. Prolonged gaze may occur in the newborn period [Brazelton et al., 1976]. Opticokinetic nystagmus may be elicited by using a striped, rotating drum or striped cloth strip, which is slowly pulled across the infant’s visual field in the vertical and horizontal directions. The response is the same as in older children (see Chapter 2).

Although small-excursion, lateral-gaze nystagmus may be present in the newborn, the coarser to-and-fro pattern of congenital nystagmus, which is oscillatory in nature, is usually unmistakable. Although unusual, nystagmus associated with mild esotropia or exotropia may be evident in the newborn. Wild, jerky nystagmus of congenital opsoclonus is a startling and readily discernible finding suggesting midbrain involvement.

Doll’s-eye movement is elicited by the examiner gently rotating the infant’s head from one side to the other when the infant is asleep. The eyes move conjugately in the direction opposite to the rotation of the head. Movement of the head in the vertical position (upward and downward) causes similar movements in the vertical plane. Failure of the eyes to move in the expected manner or direction indicates abnormalities of the cranial nerves or brainstem nuclei. Failure of abduction is associated with cranial nerve VI impairment or lateral rectus muscle impairment. Failure of normal movement in the medial direction implicates medial rectus muscle or cranial nerve III impairment.

To gain further information, the infant may be held supine on the examiner’s arm as the examiner rotates and watches the infant’s eyes. This oculovestibular maneuver causes movement so that there is lateral conjugate deviation in the direction of the rotation. When the rotational movement is terminated abruptly, the eye movements reverse. It is possible to assess the integrity of cranial nerves III and VI with this maneuver.

Cranial nerve VII involvement may be the result of the position of the infant in the maternal pelvis and delivery by pressure incurred during forceps delivery, or by agenesis of the motor nucleus of cranial nerve VII. Facial movements are readily observed during crying; an asymmetry of mouth movement may indicate cranial nerve VII involvement. During crying, the angle of the mouth is depressed on the normal side. The syndrome referred to as asymmetric crying facies may manifest this way [Nelson and Eng, 1972]. This syndrome results from weakness of the lower lip caused by hypoplasia of the depressor muscle of the mouth angle. This phenomenon is a congenital abnormality and does not signal cranial nerve VII involvement. This condition also may be associated with somatic atrophy, vertebral and rib abnormalities, renal dysgenesis, and most importantly, cardiac defects (i.e., atrial or ventricular septal defect; cardiofacial syndrome) [Pape and Pickering, 1972].