Chapter 3. Neurological Examination: Normal and Abnormal Features

122

TABLE 3-1



Unit II



NEUROLOGICAL EVALUATION



Neonatal Neurological Examination:

Basic Elements



Level of Alertness

Cranial Nerves

Olfaction (I)

Vision (II)

Optic fundi (II)

Pupils (III)

Extraocular movements (III, IV, VI)

Facial sensation and masticatory power (V)

Facial motility (VII)

Audition (VIII)

Sucking and swallowing (V, VII, IX, X, XII)

Sternocleidomastoid function (XI)

Tongue function (XII)

Taste (VII, IX)



V1



V2



V3



Motor Examination

Tone and posture

Motility and power

Tendon reflexes and plantar response

Primary Neonatal Reflexes

Moro reflex

Palmar grasp

Tonic neck response



Figure 3-1 Dermatomal distribution of the face. Note the delineation

of the three branches of the trigeminal nerve: ophthalmic (V1), maxillary

(V2), and mandibular (V3). (From Enjolras O, Riche MC, Merland JJ:

Facial port-wine stains and Sturge-Weber syndrome, Pediatrics 76:4851, 1985.)



Sensory Examination



Skin. The skin of the head should be examined carefully for the presence of dimples or tracts, subcutaneous masses (e.g., encephalocele, tumor), or cutaneous

lesions, all generally discussed elsewhere in this book.

In this setting, I discuss only the significance of portwine stains, congenital vascular abnormalities that are

present at birth and persist into adulthood. At birth,

these lesions are most often pale pink, macular lesions

that subsequently become dark red to purple and often

nodular.13 Port-wine stains are categorized according

to their dermatomal distribution (Fig. 3-1). Their

importance, apart from the significant cosmetic issue,

relates principally to their association with abnormalities of choroidal vessels in the eye, which may result



TABLE 3-2



in glaucoma, and of meningeal and superficial cerebral

vessels, which may result in cortical lesions with

seizures and other neurological deficits (i.e., SturgeWeber syndrome). The relationships between the

location of the port-wine stain and the incidence

of glaucoma or intracranial vascular lesion are shown

in Table 3-3. In one large series, the intracranial vascular lesion of Sturge-Weber syndrome occurred in

40% to 50% of children with total involvement of

V1.14,15 Notably, with partial involvement of V1, the

risk was markedly lower (1 of 17 children affected),

and none of the 64 children with involvement of V2

or V3, or both, developed either the intracranial

lesion or glaucoma.14,15 The particular prognostic

importance of involvement of V1 was confirmed in



External Characteristics Useful for Estimation of Gestational Age

GESTATIONAL AGE



External

Characteristic



28 Weeks



32 Weeks



36 Weeks



40 Weeks



Ear cartilage



Pinna soft, remains

folded



Pinna harder, springs

back



Pinna firm, stands

erect from head



Breast tissue

External genitalia:

male



None

Testes undescended,

smooth scrotum



1–2-mm nodule

Testes high in scrotum,

more scrotal rugae



External genitalia:

female



Prominent clitoris,

small, widely separated labia

Smooth



Pinna slightly harder

but remains

folded

None

Testes in inguinal

canal, few scrotal

rugae

Prominent clitoris,

larger separated

labia

One or two anterior

creases



6–7-mm nodule

Testes descended,

pendulous scrotum

covered with rugae

Clitoris covered by

labia majora



Plantar surface



Adapted from references 3, 5, and 7 to 10.



Clitoris less prominent,

labia majora cover

labia minora

Two or three anterior

creases



Creases cover sole



Chapter 3

TABLE 3-3



Neurological Examination: Normal and Abnormal Features



123



Relation between Location of Port-Wine Stain and Subsequent Incidence of Glaucoma or SturgeWeber Syndrome



Location of Port-Wine Stain

(Dermatomal Distribution)



Total Number



V1 (total) alone

V1 (total) with other

dermatomes

V1 (partial) with or without

other dermatomes

V2 alone

V3 alone

V2 and V3 (unilateral or

bilateral)



Intracranial Vascular

Lesion with or without

Glaucoma



Glaucoma Alone



Port-Wine Stain Only



4

21



2

9



1

3



1

9



17



1



0



16



29

13

22



0

0

0



0

0

0



29

13

22



Data from Enjolras O, Riche MC, Merland JJ: Facial port-wine stains and Sturge-Weber syndrome, Pediatrics 76:48-51, 1985.



more selected series.16,17 The optimal timing of therapy

has been the subject of debate; a large prospective study

did not report treatment early in infancy and childhood

to be superior to later treatment.18-21

Head Size and Shape. Head circumference is a useful

measure of intracranial volume and therefore also of

volume of brain and cerebrospinal fluid. Less commonly, head circumference is significantly affected

by the size of extracerebral spaces, subdural and subarachnoid, or by the intracranial blood volume. Scalp

edema, subcutaneous infiltration of fluid from

intravenous infusion, and cephalhematoma also have

obvious effects. Nevertheless, measurement of head

circumference remains one of the most readily available

and useful means for evaluating the status of the central

nervous system in the newborn period. Longitudinal measurements in particular provide valuable

information.

Head circumference is influenced by head shape: the

more circular the head shape, the smaller the circumference needs to be to contain the same area and the

same intracranial volume. Infants with relatively large

occipital-frontal diameters have larger measured head



circumferences than infants with relatively large biparietal diameters. This finding has important implications for evaluating the head circumference of an

infant with a skull deformity such as craniosynostosis

(see next paragraph). In premature infants, over the first

2 to 3 months of life, an impressive change in head

shape is characterized by an increase in occipital-frontal diameter relative to biparietal diameter (Fig. 3-2).

Because this alteration occurs over a matter of weeks,

it usually does not cause major difficulties in the interpretation of head circumference, but it does need to be

considered, especially in infants with unusually marked

dolichocephalic change.

Craniosynostosis, defined as premature cranial suture

closure, may affect one or more cranial sutures (Table

3-4).22 Simple sagittal synostosis is most common.22,23

The diagnosis can be suspected by the shape of the

head; with synostosis of a suture, growth of the skull

can occur parallel to the affected suture but not at right

angles (Fig. 3-3). The ‘‘keel-shaped’’ head of sagittal

synostosis is termed dolichocephaly or scaphocephaly, the

wide head of coronal synostosis is brachycephaly, and the

tower-shaped head of combined coronal, sagittal, and

lambdoid synostosis is acrocephaly. A few cases of



AP/BP ratio

1.3



AP/BP ratio

1.48



AP/BP ratio

1.54



Figure 3-2 Change in head shape in premature infants. Measurements of AP/BP

ratio (anterior-posterior [AP] and biparietal

[BP] diameters) and drawings of head

shape (vertex view) of an infant, born at

28 weeks of gestation, made at, A, 1

week, B, 5 weeks, and, C, 111=2 weeks.

(From Baum JD, Searls D: Head shape

and size of pre-term low-birthweight infants,

Med Child Neurol 13:576-581, 1971.)



A



B



C



124

TABLE 3-4



Unit II



NEUROLOGICAL EVALUATION



Coronal



Distribution of Suture Involvement in

Craniosynostosis



Sutures

Sagittal only

Coronal only

One

Both

Metopic only

Lambdoid only (one or both)

Various combinations



Percentage of

Cases*



Lambdoid



56

25

13

12

4

2

13



*Total of 519 patients.

Data from Matson D: Neurosurgery of Infancy and Childhood,

Springfield, IL: 1969, Charles C Thomas.



cranial synostosis represent complex syndromes,

the major features, genetics, and neurological outcome

of which are summarized in Table 3-5.24-30 The importance of early correction of synostosis for optimal

cosmetic appearance and the other aspects of management are discussed in standard textbooks of

neurosurgery.

Positional or deformational plagiocephaly has become a

frequent clinical issue. The term plagiocephaly (‘‘oblique

head,’’ from the Greek) refers to a head appearance in

which the occipital region is flattened and the ipsilateral frontal area is prominent (i.e., anteriorly displaced)

(Fig. 3-4). In positional or deformational plagiocephaly,

caused by external molding forces, the ipsilateral ear is

also displaced anteriorly, and the contralateral side of

the face may appear flattened.31,32 Torticollis may be

associated and may cause a head tilt. Deformation plagiocephaly may be present at birth, secondary to intrauterine restriction to head movement as occurs with

multiple gestation, abnormal uterine lie, or neck

abnormality (e.g., torticollis), or it may evolve over the

first weeks to months of life, usually secondary to supine

sleeping position as part of the ‘‘Back to Sleep’’

program.31,33 Differentiation of deformational plagiocephaly from the rare unilateral lambdoid synostosis,

which can also cause occipital flattening, is usually

readily made clinically. In unilateral lambdoid

synostosis, the anterior displacement of the frontal area

is usually less pronounced, the ear is posterior, not

anterior, and is displaced inferiorly, and facial

deformity is rare. Management of deformational

plagiocephaly consists of parental counseling regarding head positioning with the infant supine,

supervised time in the prone position, various

exercises, and skull-molding helmets if necessary

(see Fig. 3-4).31,34-36

Rate of Head Growth

Interpretation of the rate of head growth in premature

infants is often difficult, in part because ‘‘normal’’ postnatal rates have been difficult to define conclusively (in

contrast to normal rates of intrauterine growth, as

plotted on most standard charts) and in part because

commonly occurring systemic diseases and caloric

deprivation in the neonatal period may interfere with

brain and head growth.



Metopic

Coronal

Sagittal

Lambdoid



A



Metopic



B



C

Figure 3-3 Changes related to premature closure of cranial sutures.

Schematic diagram of, A, cranial sutures and changes in cranial shape

with premature closure of, B, sagittal or, C, coronal sutures.



The rate of head growth in premature infants has

been the subject of numerous reports.37-50 In the

healthy premature infant, change in the head circumference in the first days of life is minimal; indeed, a small

amount of head shrinkage with suture overriding has

been documented.39,51 Head shrinkage reaches a peak

at approximately 3 days of life, usually averages 2% to

3% of the head circumference at birth, and correlates

closely with postnatal weight and urinary sodium

losses. In view of these findings and the overriding of



Chapter 3

TABLE 3-5



125



Craniosynostosis Syndromes



Syndrome

Name

Crouzon



Carpenter



Apert



SaethreChotzen

Pfeiffer



Antley-Bixler



Greig

Baller-Gerold



Opitz



Neurological Examination: Normal and Abnormal Features



Cranium



Other Major Features



Acrocephaly (tower-shaped) Ocular proptosis (shallow

orbits) and maxillary

with synostosis of

hypoplasia

coronal, sagittal, and

lambdoid sutures

Acrobrachycephaly with

Lateral displacement of

synostosis of coronal,

inner canthi, polydactyly

sagittal, and lambdoid

and syndactyly of feet

sutures

Brachycephaly with irregu- Midfacial hypoplasia,

syndactyly of fingers and

lar synostosis, espetoes, broad distal

cially of coronal suture

phalanx of thumb

and big toe

Brachycephaly with synos- Prominent ear crus, maxiltosis of coronal suture

lary hypoplasia, partial

syndactyly of fingers and

toes

Brachycephaly with synos- Hypertelorism, broad

tosis of coronal and/or

thumbs and toes, partial

sagittal sutures

syndactyly of fingers and

toes

Brachycephaly with multiple Maxillary hypoplasia, radiosynostosis, especially of

humeral synostosis,

coronal suture

choanal atresia,

arthrogryposis

High forehead with variable Hypertelorism, polydactyly

synostosis

and syndactyly of fingers

and toes

Radial dysplasia with

Synostosis of variable

absent thumbs

sutures, including

metopic with

trigonocephaly

Trigonocephaly with

Upward slant of palpebral

synostosis of metopic

fissures, epicanthal

suture

folds, narrow palate,

anomalies of external

ear, loose skin, variable

polydactyly or syndactyly

of fingers



sutures, investigators have suggested that the head

shrinkage relates to water loss from the intracranial

compartment.39

A longitudinal study of 41 premature infants

(<1500 g birth weight) with favorable neurological outcome at age 2 years, as assessed by neurological examination and Bayley Mental Developmental Scale,

defined the rates of head growth shown in Table 3-6.

Thus, after a period of decreasing head circumference

in the first week, head growth increased by a mean of

approximately 0.50 cm in the second week, 0.75 cm in

the third week, and 1.0 cm per week thereafter in the

neonatal period. Slower rates of head growth were

observed in infants with serious systemic disorders

and subsequent neurological impairment.41 Faster

rates of head growth in the first 6 weeks suggest hydrocephalus (e.g., after intraventricular hemorrhage), as

detailed in Chapter 11.38,41 ‘‘Sick’’ preterm infants

with systemic disease often exhibit a ‘‘normal’’ acceleration of head growth (i.e., ‘‘catch-up’’ head growth)

after recovery from their illness.52 However, the



Genetics



Neurological Outcome



Autosomal dominant

(variable

expression)



Mental retardation

occasional



Autosomal recessive



Mental retardation

common



Autosomal dominant

(usually new

mutation)



Mental retardation or

borderline intelligence

common



Autosomal dominant

(variable

expression)



Mental retardation

uncommon



Autosomal dominant



Normal intelligence

usual



Autosomal recessive



Intelligence probably

normal



Autosomal dominant



Mild mental retardation

occasional



Autosomal recessive



Mental retardation

common



Autosomal recessive



Mental retardation

common



smallest infants, those who weigh less than 1000 g at

birth, generally do not exhibit as rapid growth as premature infants whose birth weight is greater than

2000 g and do not catch up even by 2 years of age.45

Additionally, preterm infants born small for their gestational age often do not exhibit as rapid head growth

or as effective catch-up growth as infants born average

for their gestational age.48

The importance of duration of neonatal caloric deprivation (<85 kcal/kg/day) on head growth in the neonatal period was shown in a study of 73 preterm infants

(mean gestational age, 30 ± 2 weeks) (Fig. 3-5).53 Three

phases of head growth were defined: an initial period of

growth arrest or suboptimal head growth, followed by a

period of catch-up growth, and terminated by a period

of growth along standard curves. The duration of the

period of growth arrest or suboptimal growth was

directly related to the initial period of caloric deprivation and to the duration of mechanical ventilation, and

the period of catch-up growth was directly related to

the duration of the preceding caloric deprivation only.



126



Unit II



NEUROLOGICAL EVALUATION



Frontal prominence



+2 S



Head circumference (cm)



46



D



42



D



–2 S



38



3



34

30



2



26



1



22

30



Flattening



Ipsilateral ear

displaced

anteriorly



Contralateral

occipital

prominence

Figure 3-4 Positional or deformational plagiocephaly. Note the flattening of the right occiput, because the infant is placed primarily in a

supine position and the infant’s preferred head position is to the right.

The other changes are described in the text.



The rate of head growth along standard curves was

between the mean and 1 standard deviation (SD)

below the mean for all infants except those calorically

deprived the longest (4 to 6 weeks), in whom values

were more than 1 SD below the mean. Indeed, such

infants calorically deprived for more than 4 weeks had

developmental scores lower than normal ranges at

1 year of corrected age. The deleterious effect of postnatal caloric deprivation is worse for preterm infants

born small for their gestational age.48

Level of Alertness

The formal neonatal neurological examination should

begin with assessment of the level of alertness. The level

of alertness is perhaps the most sensitive of all neurological functions because it depends on the integrity of

several levels of the central nervous system (see later).

Terms used to describe this aspect of neurological

function include state54,55 and vigilance56 (Table 3-7).



TABLE 3-6



Rates of Head Growth in Premature Infants

with Favorable Neurological Outcome



Postnatal Week

First

Second

Third

After third



Rate of Head Growth

(cm/week)

–0.60

0.50

0.75

1.0



Data from a study of 41 premature infants (<1500 g birth weight) in

Gross SJ, Oehler JM, Eckerman CO: Head growth and developmental outcome in very low-birth-weight infants, Pediatrics 71:70-75,

1983.



34



Gestational

age (wk)



40



3



6



9



Postterm

age (mo)



Figure 3-5 Phases of head growth. Phases of head growth derived

from data of Georgieff and co-workers and based on study of 73

premature infants of 30±2 weeks of gestation (mean ± 2 SDs). The

three phases shown are discussed in the text. (From Georgieff MD,

Hoffman JS, Pereira GR, Bernbaum J, et al: Effect of neonatal caloric

deprivation on head growth and 1-year development status in preterm

infants, J Pediatr 107:581-587, 1985.)



The first two states correspond to quiet and active

sleep, respectively (see Chapter 4), and the next three

states describe different levels of wakefulness. The level

of alertness in the normal infant varies, depending particularly on time of last feeding, environmental stimuli,

recent experiences (e.g., painful venipuncture), and

gestational age.57-61 Before 28 weeks of gestation, it is

difficult to identify periods of wakefulness. Persistent

stimulation leads to eye opening and apparent alerting

for time periods measured principally in seconds. At

approximately 28 weeks, however, a distinct change

occurs in the level of alertness.56 At that time,

a gentle shake rouses the infant from apparent

sleep and results in alerting for several minutes.

Spontaneous alerting also occasionally occurs at this

age. Sleep-waking cycles are difficult to observe clinically but can be shown electrophysiologically.62 By

32 weeks, stimulation is no longer necessary; frequently, the eyes remain open, and spontaneous

roving eye movements appear. Sleep-waking alternation, as defined by clinical observation, is apparent.56

By 36 weeks, increased alertness can be observed readily, and vigorous crying appears during wakefulness. By

term, the infant exhibits distinct periods of attention to

visual and auditory stimuli, and it is possible to study

sleep-waking patterns in detail.58,61,63-67



Cranial Nerves

Olfaction (I)

Olfaction, a function subserved by the first cranial nerve,

is evaluated only rarely in the newborn period. In a

study of 100 term and preterm infants, Sarnat observed

that all normal infants of more than 32 weeks of gestation responded with sucking, arousal-withdrawal, or

both, to a cotton pledget soaked with peppermint



Chapter 3

TABLE 3-7



State

1

2

3

4

5



Neurological Examination: Normal and Abnormal Features



127



Major Features of Neonatal Behavioral States in Term Infants

Eyes Open



Respiration Regular



Gross Movements



Vocalization



–

–

+

+

±



+

–

+

–

–



–

±

–

+

+



–

–

–

–

+



–, absent; +, present; ±, present or absent.

Data from Prechtl HFR, O’Brien, MJ: Behavioural states of the full-term newborn: The emergence of a concept. In Stratton P, editor: Psychobiology of

the Human Newborn, New York: 1982, John Wiley & Sons.



extract.68 Eight of 11 infants of 29 to 32 weeks of gestation, but only one of six infants of 26 to 28 weeks of

gestation also responded. Activation of orbitofrontal,

olfactory cortex was detected by near-infrared spectroscopy in full-term newborns exposed to vanilla or

maternal colostrum in the first weeks of life.69

Olfactory Discriminations. More sophisticated techniques have demonstrated olfactory discriminations in

newborns.70,71 Using habituation-dishabituation techniques and recordings of respiration, heart rate, and

motor activity, Lipsitt and colleagues demonstrated

detection and discrimination among a variety of odorants.72-74 Mediation of discriminations at a higher level

than the periphery was shown by the observation that

infants, initially habituated to mixtures of odorants,

exhibited dishabituation when presented with the

pure components of the mixtures. A particularly interesting demonstration of olfactory discrimination in the

infant involved discrimination of the odor of breast

pads of the infant’s mother from unused pads or

those of other nursing mothers.70,75 Infants consistently adjusted their faces and gazes toward the

pads of their own mothers. Later work involving

coupling of stroking with different odorants demonstrated complex associative olfactory learning in the

first 48 hours of life.70,76 That olfactory discrimination

develops in utero is suggested by the demonstration

of neonatal preference for the odors of amniotic

fluid.77 Finally, nutrient (breast milk or formula) odor

exposure through a pacifier was shown to stimulate

nonnutritive sucking during gavage feeding of premature newborns.78

Vision (II)

Visual responses, the afferent segment of which is subserved by the second cranial nerve, exhibit distinct

changes with maturation in the neonatal period. By

26 weeks, the infant consistently blinks to light.56,79

By 32 weeks, light provokes eye closure that persists

for as long as the light is present (dazzle reflex of

Peiper).80 More sophisticated studies indicate that a

series of behaviors associated with visual fixation can

be identified by 32 weeks of gestation and can be

shown to increase considerably over the next

4 weeks.81 By 34 weeks, more than 90% of infants

will track a fluffy ball of red wool.82 At 37 weeks, the

infant will turn the eyes toward a soft light.56 By term,

visual fixation and following are well developed.83-85

For testing of visual fixation and following, I have



found a most useful target to be a fluffy ball of red

yarn. Opticokinetic nystagmus, elicited by a rotating

drum, is present in the majority of infants at 36

weeks and is present consistently at term.80,84,86,87

The anatomical substrate for visual fixation and for

following a moving object in the newborn may not be

primarily the occipital cortex, as usually thought. Thus,

two studies of newborn infants with apparent absence

of occipital cortex secondary to maldevelopment (holoprosencephaly) or destructive lesion (congenital hydrocephalus, ischemic injury) suggested that these abilities

are mediated at subcortical sites.88-90 Experimental studies in subhuman primates defined such a subcortical

system involving retina, optic nerves and tract, pulvinar, and superior colliculus—the so-called collicular

visual system.91,92 Visual abilities beyond the ability to

track a moving object (i.e., visual discriminatory skills;

see the following paragraphs), however, do require the

geniculocalcarine cortical system.

Visual Acuity, Color, and Other Discriminations.

Elegant studies provided important information about

neonatal visual acuity, color perception, contrast sensitivity,

and visual discrimination.85,93-102 Through use of the opticokinetic nystagmus response to striped patterns of

varying width, investigators demonstrated that the

newborn exhibits at least 20/150 vision.103 Using a

visual fixation technique, Fantz showed that the newborn attended to stripes of 1/8-inch width.104 Visual

acuity in premature infants with birth weights of 1500

to 2500 g who were studied at approximately 38 weeks

of gestational age was similar to that of term infants.99

Although studies of color perception in the newborn

period often have not rigorously distinguished brightness and color, newborn infants clearly follow a colored

object.105 Color vision is demonstrable by at least as

early as 2 months of age.106,107 Contrast sensitivity

increases dramatically between 4 and 9 postnatal

weeks.96

Discrimination of a rather complex degree has been

demonstrated for newborn infants.85,94,97,98,108-114

Infants as young as 35 weeks of gestation exhibit a distinct visual preference for patterns, particularly those

with a greater number of and larger details. Curved

contours are favored over straight lines. Preference for

novel patterns becomes apparent at 3 to 5 months.98

Preference for patterns with facial resemblance

develops between approximately 10 and 15 weeks of

age,115 and promptly thereafter discrimination occurs

according to facial features.116 The degree of contrast



128



Unit II



NEUROLOGICAL EVALUATION



has a direct effect on preferences.117 Binocular vision

and appreciation of depth also appear by approximately

3 to 4 postnatal months.94 Binocular visual acuity

increases most rapidly during the same interval.95

These higher-level visual abilities may reflect a

change in the major anatomical substrate from subcortical to cortical structures.85,92,118 Nevertheless, two

studies of infants from the first days of life by functional

magnetic resonance imaging (MRI) did show some

evidence for activation of the visual cortex with visual

stimulation; subcortical structures could not be

addressed because of small anatomical size.119,120

Infants in the first days of life also have been shown

to imitate facial gestures (Fig. 3-6).121,122 Additionally,

imitation of finger movements, especially involving

the left hand, has been demonstrated in healthy

term infants.123 Thus, striking changes in cortically

mediated visual function occur in the first weeks

and months of postnatal life. This is a period for

rapid dendritic growth and synaptogenesis in visual

cortex and myelination of the optic radiation (see

Chapter 2).

Optic Fundi (II)

The funduscopic examination in the newborn period is

facilitated considerably by the aid of a nurse and

patience on the part of the examiner. The optic disc of

the newborn lacks much of the pinkish color observed

in the older infant and has a paler, gray-white appearance. This color and the less prominent vascularity of

the neonatal optic disc may make distinction from optic



atrophy difficult. Retinal hemorrhages have been observed

in 20% to 40% of all newborn infants, with no association with obvious perinatal difficulties, concomitant

central nervous system injury, or neurological sequelae.80,124-126 A relationship with vaginal delivery is

apparent; in one study, 38% of infants delivered vaginally exhibited retinal hemorrhages, in contrast to 3% of

infants delivered by cesarean section (Table 3-8).125

The hemorrhages generally resolve completely within

7 to 14 days. Consistent with these findings, an evaluation of eight consecutive newborns with retinal

hemorrhages by MRI scan revealed no intracranial

abnormalities.127

Pupils (III)

The pupils are sometimes difficult to evaluate in the

newborn, especially the premature baby, because the

eyes are often closed and resist forced opening, and

the poorly pigmented iris provides poor contrast for

visualizing the pupil. The size of the pupils in the premature infant is approximately 3 to 4 mm and is slightly

greater in the full-term infant. Reaction to light begins

to appear at approximately 30 weeks of gestation, but it

is not present consistently until approximately 32 to

35 weeks.79,128 The amplitude of the pupillary response

increases markedly between 30 weeks and term

(Fig. 3-7).129 The afferent arc of this reflex leaves the

optic tract before the lateral geniculate nucleus and

synapses in the pretectal region of midbrain before

innervating the Edinger-Westphal nucleus of the oculomotor nerve, the efferent arc of the reflex.



Figure 3-6 Imitation of facial gestures. Sample photographs from videotape recordings of 2- to 3-week-old infants imitating tongue protrusion,

mouth opening, and lip protrusion demonstrated by an adult experimenter. (From Meltzoff AN, Moore MK: Imitation of facial and manual gestures by

human neonates, Science 198:74-78, 1977.)



Chapter 3

TABLE 3-8



Neonatal Retinal Hemorrhage:

Influence of Perinatal Factors

RETINAL HEMORRHAGES

No. Affected/

Total No.



Perinatal Factor

Normal vaginal delivery

Abnormal vaginal delivery

Vaginal delivery

Spontaneous

Forceps

Cesarean section



Affected (%)



48/127

22/69



38

32



61/160

9/36

1/38



38

25

3



Data from Besio R, Caballero C, Meerhoff E, Schwarcz R: Neonatal

retinal hemorrhages and influence of perinatal factors, Am J

Ophthalmol 87:74-76, 1979.



Extraocular Movements (III, IV, VI)

Particular attention should be paid to eye position,

spontaneous eye movements, and movements elicited

by the doll’s eyes maneuver, vertical spin, or caloric

stimulation, as well as to a variety of abnormal eye

movements (see later). These oculomotor functions

are subserved by cranial nerves III, IV, and VI and

their interconnections within the brain stem. In most

premature and some full-term infants, the eyes are

slightly disconjugate at rest, with one or the other 1

to 2 mm out. (This feature is demonstrated readily by

observing the light reflected off each pupil with the



4.5

Pupil diameter

in relative darkness



3.5

3.0

2.5

2.0

1.5

1.0

Net pupil

response to light



0.5

0

26



28



30

32

34

36

38

Postconceptional age (wk)



129



light source in the midline at approximately 2 feet

from the face.)

As early as 25 weeks of gestation, full ocular movement with the doll’s eyes maneuver can be elicited.

Because interfering ocular fixation is not well developed at this stage, elicitation of lateral eye movements

with the doll’s eyes maneuver is much easier in the

small premature infant than in the full-term infant.

Another convenient means of eliciting oculovestibular

responses is to spin the baby held upright; the eyes

deviate in a direction opposite to the spin. Rapid maturation of this response with development of nystagmus as well as eye deviation occurs in the first

2 postnatal months.130 Additionally, at 30 weeks of

gestation, caloric stimulation with cold water leads to

deviation of the eyes toward the side of the stimulated

ear.131 Spontaneous roving eye movements are common

at approximately 32 weeks.132 The tracking movements

of the full-term and older infants at first are rather jerky

and do not become smooth and gliding until approximately the third month of life.80

Facial Sensation and Masticatory Power (V)

Subserved by cranial nerve V (i.e., the trigeminal nerve),

facial sensation is examined best with pinprick. The

resulting facial grimace begins on the stimulated side

of the face. If the infant has facial palsy, this response

will be impaired and may be attributed mistakenly to

involvement of the trigeminal nerve or nucleus. The

strength of masseters and pterygoids also depends on

the function of the trigeminal nerve. This strength is

assessed by evaluation of sucking and by allowing the

infant to bite down on the examiner’s finger.

Facial Motility (VII)

The parameters of interest are the position of the face at

rest, the onset of movement, and the amplitude and

symmetry of spontaneous and elicited movement.

Facial motility is subserved by cranial nerve VII. While

the infant’s face is at rest, attention should be paid to the

vertical width of the palpebral fissure, the nasolabial

fold, and the position of the corner of the mouth.

Examination of the face should not be restricted to

observation of elicited movements (e.g., crying) because

the quality of spontaneous facial movement is of greatest

importance in the assessment of cerebral lesions. Subtle

lesions at all central levels are best detected by close

observation of the onset of movement.



5.0



4.0



Neurological Examination: Normal and Abnormal Features



40



42



Figure 3-7 Pupil diameter in relation to light. Diameter of pupil in

millimeters (mean ± SD) in term and preterm neonates in relative

darkness (<10 foot-candles) and after light stimulation (600 foot-candles). (From Isenberg SJ: Clinical application of the pupil examination in

neonates, J Pediatr 118:650-652, 1991.)



Audition (VIII)

The eighth cranial nerve, through its connections in

the brain stem and cerebral cortex, subserves auditory

function. By 28 weeks, the infant startles or blinks to a

sudden, loud noise.56 As the infant matures, more

subtle responses become evident, such as cessation of

motor activity, change in respiratory pattern, opening

of mouth, and wide opening of eyes.80 The relation of

such responses to the development of hearing has been

the subject of considerable study and controversy, but

these responses likely represent the presence of at least

some auditory function. Inability to elicit these

responses is related usually to the failure to test in a



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NEUROLOGICAL EVALUATION



quiet surrounding, while the baby is alert and not agitated or very hungry, and to ensure that the ear canals

are free of the often copious vernix. In most cases, an

infant who does not respond on the initial examination

will respond when retested under more favorable conditions. More detailed evaluation of auditory function,

including electrophysiological measurements (e.g.,

brain stem auditory evoked responses; see Chapter 4),

certainly is indicated if behavioral responses are consistently absent.



respond to normal speech with activation of the

temporal regions preferentially in the left hemisphere.151,152 These interesting observations demonstrate that the newborn brain exhibits the cortical

organization to process speech and the regional

specification for the left hemisphere for language.

Similarly, a magnetoencephalographic study using a

paradigm based on sound discrimination and important in auditory cognitive function demonstrated positive responses in newborns shortly after birth.153



Auditory Acuity, Localization, and Discriminations. More sophisticated studies have provided insight

into neonatal auditory acuity, localization, and discriminations. Using the occurrence in the newborn of cardiac acceleration in relation to sound intensity,

Steinschneider demonstrated a threshold for cardiac

acceleration of approximately 40 decibels.133 Auditory

localization has been shown by demonstrating loss and

recovery of habituation to an auditory stimulus

by changing the locus of the stimulus.134,135 Auditoryvisual coordination in localization was shown by exposing

an infant to the mother speaking before the infant

through a soundproof glass screen, with her voice transmitted by a stereo system.136,137 When the stereo system

was in balance (i.e., the voice came from straight ahead),

the infant was content, but when the voice appeared to

come from a location different from that of the face, the

infant became very upset. Maturation of connections

between brain stem auditory nuclei (superior olivary

nucleus, nucleus of lateral lemniscus, inferior colliculus), sensory nuclei, and facial nerve nucleus has been

studied by measurement of the amplitude of the blink

response to glabellar tap when the tap is preceded by an

auditory tone.138,139

Through the use of heart rate patterns and a

habituation-dishabituation model, it has been possible

to demonstrate auditory discriminations in 3- to 5-day-old

newborn infants on the basis of intensity, pitch, and

rhythm. These findings are of particular interest in

view of information suggesting that intensity and pitch

discriminations may be mediated at subcortical levels,

whereas cortical levels are required for discrimination of

temporal patterns.140 Discrimination of synthetic

speech sounds according to phonemic category and

of tonal sounds of different frequencies was demonstrated in newborns in the first days of life.141-144

Discrimination of real and computer-simulated cries

by newborn infants was shown by observing much restlessness and crying in infants stimulated by the real cry

and considerably less such behavior in those stimulated

by the computer-simulated cry.145,146 Moreover, results

of other studies indicate a preference of the newborn for

human voice rather than nonhuman sounds147 and particular preference for the mother’s voice rather than

another human voice.148,149 Finally, 2- to 4-week-old

infants can learn to recognize a word that their mothers

repeat to them over a period of time (2 weeks) and

‘‘remember’’ the word for up to 2 days without

intervening presentations.150

Studies based on optical topography or functional

MRI show that newborns in the first days of life



Sucking and Swallowing (V, VII, IX, X, XII)

Sucking requires the function of cranial nerves V, VII,

and XII,80,154 swallowing requires cranial nerves IX and

X, and tongue function uses cranial nerve XII. The

importance of tongue function, particularly the

‘‘stripping’’ action of the medial tongue, was demonstrated in ultrasonographic and fiberoptic studies of neonatal feeding.155-158 The act of feeding requires the

concerted action of breathing, sucking, and swallowing.157,159-163 Not surprisingly, the brain stem control

centers for these actions, termed pattern generators, are

closely situated.163,164 Sucking and swallowing are coordinated sufficiently for oral feeding as early as

28 weeks.132 This finding perhaps is not surprising

because swallowing is observed in utero as early as

11 weeks of gestation.165 The development of rooting

at approximately 28 weeks is a relevant complementing

feature. At this early age, however, the synchrony of

breathing with sucking and swallowing is not well developed,157 and thus oral feeding is difficult and, in fact,

dangerous. By 34 weeks of gestation, however, the

normal infant is able to maintain a concerted synchronous action for productive oral feeding.161,163,166

However, maturation continues rapidly, and linkage of

breathing, sucking, and swallowing is not achieved fully

until 37 weeks of gestation or more.157,163 Moreover,

even in the healthy term infant, coordination of swallowing and breathing rhythms is not optimal in the first

48 hours of life.160

The gag reflex, subserved by cranial nerves IX and X,

is an important part of the neurological evaluation in this

context. A small tongue blade or a cotton-tipped swab

can be used to elicit the reflex. Active contraction of the

soft palate, with upward movement of the uvula and of

the posterior pharyngeal muscles, should be observed.

Sternocleidomastoid Function (XI)

Function of the sternocleidomastoid muscle is mediated

by cranial nerve XI. Because the function of the muscle

is to flex and rotate the head to the opposite side, it is

difficult to test in the newborn, especially in the premature infant. One useful maneuver with the full-term

infant is to extend the head gently over the side of the

bed with the child in the supine position. Passive

rotation of the head reveals the configuration and bulk

of the muscle, and function sometimes can be estimated

if the infant attempts to flex the head.

Tongue Function (XII)

Function of tongue is mediated by cranial nerve XII.

The parameters of interest are the size and symmetry of



Chapter 3



the muscle, the activity at rest, and the movement.

Tongue movement is assessed best during the infant’s

sucking on the examiner’s fingertip. The important

role of the tongue in oral feeding was discussed in

relation to sucking and swallowing.

Taste (VII, IX)

Taste is evaluated only rarely in the neonatal neurological examination. This function is subserved by cranial

nerves VII (anterior two thirds of tongue) and IX (posterior one third of tongue). The newborn infant is very

responsive to variations in taste and is capable of sharp

discriminations. Lipsitt and co-workers used various

parameters of sucking behavior, not only to define gustatory discriminations but also to study learning processes in the newborn.167,168 An apparatus that allows

control of the fluid to be obtained by sucking, as well as

measurement of duration and frequency of sucking,

has been used to demonstrate that, when presented

with a sweet fluid (e.g., 15% sucrose), the infant

sucks in longer bursts and with fewer rest periods

than when presented with water or a salty fluid.167-169

When sucking the sweet fluid, the heart rate increased.

It was presumed from these data that the newborn

infant ‘‘hedonically monitors oral stimuli and signals

the pleasantness of such stimuli with the heart rate as

an indicator response.’’74

Motor Examination

The major features of the motor examination to be

evaluated in the neonatal period are muscle tone and

the posture of limbs, motility and muscle power, and

the tendon reflexes and plantar response. The postnatal

age and level of alertness of the infant have an important bearing on essentially all these features. Most of

the observations described next are applicable to an

infant of more than 24 hours of age and in an optimal

level of alertness, unless otherwise indicated.

Tone and Posture

Muscle tone is assessed best by passive manipulation of

limbs with the head placed in the midline. Moreover,

because tone of various muscles in part determines the

posture of the limbs at rest, careful observation of posture is valuable for the proper evaluation of tone. Some

investigators have devised various maneuvers of passive

manipulation of limbs (e.g., approximation of heel to

ear, hand to opposite ear [scarf sign], or measurement

of angles of certain joints, such as the popliteal angle)

to attempt to quantitate tone.4,11,12,170 These maneuvers have not been particularly useful for me and are

not discussed in detail.

Developmental Aspects. Saint-Anne Dargassies and

co-workers described an approximate caudal-rostral

progression in the development of tone, particularly

flexor tone, with maturation.56 At 28 weeks, resistance

to passive manipulation is minimal in all limbs, but by

32 weeks, distinct flexor tone becomes apparent in

the lower extremities. By 36 weeks, flexor tone is prominent in the lower extremities and is palpable in the



Neurological Examination: Normal and Abnormal Features



131



upper extremities. By term, passive manipulation affords

appreciation of strong flexor tone in all extremities.

The posture of the infant in repose reflects these

changes in tone to some extent. In my experience,

these postures are apparent principally when the

infant is in a slightly drowsy state. The alert infant at

these various gestational ages is more active and motile,

and fixed postures or so-called preference postures are

difficult to define. This finding was well documented

by Prechtl and co-workers and by others.171-175

Nevertheless, the very quiet infant at 28 weeks often

lies with minimally flexed limbs, whereas by 32 weeks

one notes distinct flexion of the lower extremities at the

knees and hips. By 36 weeks, flexor tone in the lower

extremities results in a popliteal angle of 90%, and consistent and frequent flexion occurs at the elbows. By

term, the infant assumes a flexed posture of all

limbs.56 Fisting, usually bilateral, is the predominant

hand posture.56,176 The evolution of hip (and knee)

flexor tone with maturation is reflected in the developmental increase in pelvic elevation when the infant is in

the prone position.177

Preference of Head Position. A consistent and interesting aspect of posture in newborn infants is a preference for position of the head toward the right

side.171,178-180 Prechtl and co-workers demonstrated

head position toward the right side 79% of the time

versus 19% toward the left and 2% toward the midline

(Fig. 3-8).171 In one study, this preference increased

with gestational age,179 whereas in another it decreased.180 The head orientation preference may be

less prominent in the first 24 hours of life.181 This preference has not been attributable to differences in lighting, nursing practices, or other factors, but it appears to

reflect a normal asymmetry of cerebral function at this

age. Notably the left hemisphere, particularly the frontal region, mediates movement of the head to the right.

As noted earlier, the left hemisphere appears dominant

for speech perception in the newborn.

Motility and Power

The quantity, quality, and symmetry of motility and

muscle power are the parameters of interest. Prechtl

and co-workers182-184 combined videotape and electrophysiological methods to describe the postnatal development of motor activity in the term infant. In the

first 8 weeks, movements with a writhing quality

predominate; in the period from 8 to 20 weeks,

‘‘fidgety’’ movements are prominent, and after the

latter period, rapid large-amplitude antigravity and

intentional movements (‘‘swipes’’ and ‘‘swats’’) are

prominent. In general, preterm infants exhibited similar patterns of motor development when they attained

comparable postmenstrual ages, albeit with minor

delays in tone and quality of movements.175,184-186

Prechtl and others184,187-199a emphasized that the quality of spontaneous movements in preterm and term

infants are of major importance with regard to the

status of the central nervous system.

Saint-Anne Dargassies, using less sophisticated

techniques, described the developmental changes in



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Unit II



NEUROLOGICAL EVALUATION



Means and SD of head positions face to

right

120



100



80



60



left

40



20



0



20



40



60 %



7

9

10

5

17

50

3

4

2

8

1

11

15

6



Figure 3-8 Preference of head position. Mean ± SD percentage of

minutes from all observations in which each infant (series of 14) had

face to right or left side. (From Prechtl HF, Fargel JW, Weinmann HM,

Bakker HH: Postures, motility and respiration of low-risk pre-term

infants, Dev Med Child Neurol 21:3-27, 1979.)



motility in the preterm infant.56 At 28 weeks, movements tend to involve the entire limb or trunk and

have either a slow rotational component or a

fast, large-amplitude characteristic. By 32 weeks of

gestation, movements are seen to be predominately

flexor, especially at the hips and knees, often occurring

in unison.56 Although head turning is present,

neck flexor and extensor power are negligible, as

judged by complete head lag on pull to sit or when

the infant is held in the sitting position. By 36 weeks,

the active flexor movements of the lower extremities are

stronger and often occur in an alternating rather than

symmetrical fashion. Flexor movements of the upper

extremities are prominent. For the first time, definite

neck extensor power can be observed. When

the infant is supported in the sitting position,

the head is lifted off the chest and remains upright

for several seconds. By term, the awake infant is particularly active if stimulated with a gentle shake. Limbs

move in an alternating manner, and neck extensor

power is still better. Neck flexor power becomes

apparent; when the infant is pulled to a sitting position



with firm grasp of the proximal upper limbs, the head is

held in the same plane as the rest of the body for several

seconds.56

The importance of a fixed developmental program in

motor development is suggested by the similarities

in such development when comparing (at the same

postmenstrual age) the fetus, the premature infant,

and the term infant, albeit with minor exceptions.56,63,171,175,182,184,186,191,200,201 The similarities

outweigh the rather small differences.

Tendon Reflexes and Plantar Response

Tendon Reflexes. Tendon reflexes readily elicited in

the term newborn are the pectoralis, biceps, brachioradialis, knee, and ankle jerks. I have considerable

difficulty obtaining triceps jerks in term infants.

Most of these reflexes are elicitable but less active in

preterm infants. The knee jerk is often accompanied

by crossed adductor responses, which should be

considered normal findings in the first months of

life (<10% of normal infants demonstrate crossed adductor responses after 8 months of age).202 Useful

techniques for eliciting tendon reflexes in the newborn

and the frequency and intensity of the reflexes in

preterm and term infants are illustrated in Figures 3-9

and 3-10.203

Ankle clonus of 5 to 10 beats also should

be accepted as a normal finding in the newborn

infant, if no other abnormal neurological signs are

present and the clonus is not distinctly asymmetrical.

Ankle clonus usually disappears rapidly, and the existence of more than a few beats beyond 3 months of age

is abnormal.

Plantar Response. The plantar response is usually

stated to be extensor in the newborn infant.201,204

This result clearly relates to the manner in which

the response is elicited. Using drag of thumbnail

along the lateral aspect of the sole, Hogan

and Milligan205 observed bilateral flexion in 93 of

100 newborn infants examined. My colleagues and

I206 observed a similar result in 116 (94%) of

124 infants. In contrast, Ross and associates,207 using

drag of pin or pinstick, observed a predominance of

extensor responses, with flexion in only about 5% of

patients.

When evaluating the neonatal plantar response, it is

necessary to consider at least four competing reflexes

leading to movements of the toes. Two reflexes that

result in extension are nociceptive withdrawal (often

accompanied by triple flexion at hip, knee, and ankle)

and contact avoidance (elicited best by stroking the

dorsum of the foot, which often occurs inadvertently

when holding the foot to elicit the plantar response).

Two responses that lead to flexion are plantar grasp and

positive supporting reaction (both elicited by pressure on

the plantar aspect of the foot). Because of these competing reflexes and the relative inconsistency of

responses, I consider the plantar response to be of limited value in the evaluation of the newborn infant when

attempting to determine the presence of an upper

motor neuron lesion.