Introduction: Neurologic Examination of the Child and Infant
John H. Menkes
Franklin G. Moser
The ever-increasing sophistication and accuracy of neurodiagnostic procedures might cause younger physicians to view the neurologic examination of the pediatric patient as obsolete and, like cardiac auscultation, a nostalgic ceremony engaged in by physicians trained before magnetic resonance imaging (MRI) and DNA hybridization (1). This is not how we view it. Excessive reliance on diagnostic procedures at the expense of an organized plan of approach, the “let’s order an MRI and an electroencephalogram and then take a look at the kid” attitude, not only has been responsible for the depersonalization of neurologic care and the escalation of its costs, but also has made the analysis of neurologic problems unduly complex for the pediatrician or general practitioner. For these reasons, a presentation of some of the techniques of neurologic examination is still in order.
The pediatric neurologist who, through experience, has individualized the examination will find little new in this section, which was written with the pediatrician and general neurologist in mind. The pediatrician will find the section on the neurologic examination helpful; the general neurologist, who at times is called on to consult on an infant not much larger than the palm of the hand, may benefit from the section on the neurologic examination of the infant.
At its best, the neurologic evaluation is a challenge in logical deduction. It requires a clear plan at each step with the goal of answering the following questions:
Does the child have a neurologic disorder?
If so, where is the site of the lesion, or, as so often is the case in pediatric neurology, does it involve all parts of the brain to an equal degree?
What pathologic lesions are most likely to produce lesions at these sites?
The course of the illness, whether acute, subacute, static, or remitting, may provide a clue to the nature of the disease process.
It is at this point, and only at this point, that the physician draws up a differential diagnosis and calls on neurodiagnostic procedures to help decide which of the suspected conditions is the most likely.
If this systematic approach is followed, useless diagnostic procedures are avoided. For instance, an assay for arylsulfatase to exclude metachromatic leukodystrophy is inappropriate in a neurologic disorder that is clearly static. Similarly, neither computed tomography (CT) scans nor MRI of the brain assist materially in the differential diagnosis of a lower motor neuron disease.
NEUROLOGIC HISTORY
An accurate history, obtained from one or more members of the family, is often the most vital part of the neurologic evaluation. Additionally, if properly questioned, a child older than 3 to 5 years might provide information that not only is valuable, but also may be more reliable than that related by his or her parents. In taking a history from a youngster, the physician must learn not to ask leading questions and not to phrase them to obtain yes or no answers. The physician also must be responsive to the youngster’s mood and cease taking a history as soon as fatigue or restlessness becomes evident. In a younger child or one with a limited attention span, the salient points of the history are best secured at the onset of the evaluation. The history is followed by the neurologic examination and, finally, by a second, more extensive review of the history.
In the assessment of a neurologic problem, an accurate review of the presenting illness is important. This is particularly the case in the youngster with headaches, seizures, or other types of recurrent disease and for the youngster with a learning disability or an attention-deficit disorder. In such patients, the history, particularly its social and environmental aspects, can be extensive enough to require more than one appointment.
A review of the developmental history necessitates a survey of antenatal, perinatal, and postnatal development.
This includes questioning the mother about the length of the pregnancy, any complications, including intercurrent infections, and drug intake. The mother who is concerned about her youngster may already have reviewed her pregnancy many times and may well provide much irrelevant information. For instance, an accident occurring during the second trimester is hardly the explanation for a meningomyelocele. The physician might well interrupt the questioning to reassure the mother that this event was not responsible for the child’s neurologic defect.
This includes questioning the mother about the length of the pregnancy, any complications, including intercurrent infections, and drug intake. The mother who is concerned about her youngster may already have reviewed her pregnancy many times and may well provide much irrelevant information. For instance, an accident occurring during the second trimester is hardly the explanation for a meningomyelocele. The physician might well interrupt the questioning to reassure the mother that this event was not responsible for the child’s neurologic defect.
A review of the perinatal events is always in order. As a rule, the youngster who has had an uncomplicated neonatal period and was discharged with the mother will not have sustained perinatal asphyxia, even though the infant might have had low Apgar scores or passage of meconium. The physician should not forget to obtain some information about the feeding history. Many children who later present with delayed development have had feeding problems, notably regurgitation, excessive colic, or frequent formula changes. A history of abnormal sleeping habits is also not unusual in the brain-damaged youngster.
The developmental milestones must always be recorded. Most mothers recall these and can compare one youngster with the siblings. Failure to remember any of the milestones is unusual, even in those of lower socioeconomic status; it suggests a postpartum depression.
A system review focuses on the major childhood illnesses, immunizations, and injuries. Recurrent injuries suggest hyperactivity, impaired coordination, or poor impulse control.
The family history is relevant in some of the neurologic disorders. The physician should remember that most neurodegenerative disorders are transmitted as a recessive gene and that questions about the health of siblings and the presence of consanguinity are in order. On the other hand, some of the epilepsies or migraine headaches tend to be transmitted as dominant traits; in fact, in children experiencing migraine headaches, a history of migraine in a first-degree relative can almost always be elicited.
GENERAL PHYSICAL EXAMINATION
The child’s height, weight, blood pressure, and head circumference must always be measured and recorded. The youngster should be undressed by the parents, with the physician absent.
The physician should note the general appearance of the child, in particular the facial configuration and the presence of any dysmorphic features. Cutaneous lesions such as café au lait spots, angiomas, or areas of depigmentation are clues to the presence of phakomatoses. The condition of the teeth provides information about antenatal defects or kernicterus. The location of the hair whorl and the appearance of the palmar creases should always be noted. Abnormalities of whorl patterns can indicate the presence of cerebral malformations (2). The quality of the scalp hair, eyebrows, and nails also should be taken into account. It is important to inspect the midline of the neck, back, and pilonidal area for any defects, particularly for small dimples that might indicate the presence of a dermoid sinus tract. Comparison of the size of the thumbnails and their convexity might disclose a growth disturbance, a frequent accompaniment to a hemiparesis. Examination of chest, heart, and abdomen and palpation of the femoral pulses should always be part of the general physical examination. Finally, the presence of an unusual body odor may offer a clue to a metabolic disorder.
NEUROLOGIC EXAMINATION OF THE CHILD
In addition to the standard instruments used in neurologic examination, the following have been found useful: a tennis ball; a few small toys, including a toy car that can be used to assess fine motor coordination; a bell; and some object that attracts the child’s attention (e.g., a pinwheel). A flashlight with a rubber adapter for transillumination is still used by some pediatric neurologists; it is cheaper and quicker than a CT scan or an ultrasound and often provides the same information. Most pediatric neurologists do not wear white coats.
In most intellectually healthy school-aged children, the general physical and neurologic examinations can be performed in the same manner as for adults, except that their more uncomfortable aspects, such as funduscopic examination, corneal and gag reflexes, and sensory testing, should be postponed until the end.
In younger children, the neurologic examination is a catch-as-catch-can procedure, with a considerable amount of information revealed by the youngster’s play activities, including the child’s dominant handedness and the presence of cerebellar deficits, a hemiparesis, and perhaps even a visual field defect.
The toddler is more difficult to examine. The toddler is best approached by seating the child in the mother’s or father’s lap and talking to the child. Because toddlers are fearful of strangers, the physician must first observe the youngster and defer touching him or her until some degree of rapport has been established. Offering a small, interesting toy may bridge the gap. In any case, the physician must be patient and wait for the youngster to make the first approach. Once frightened, most toddlers are difficult to reassure and are lost for the remainder of the examination.
Skull
The general appearance of the skull can suggest the presence of macrocephaly, microcephaly, or craniosynostosis. Prominence of the venous pattern might accompany
increased intracranial pressure. Flattening of the occiput is seen in many developmentally delayed youngsters. Conversely, occipital prominence can indicate the Dandy-Walker malformation complex. Biparietal enlargement suggests the presence of subdural hematomas and should raise the suspicion of child abuse. Palpation of the skull can disclose ridging of the sutures, as occurs in craniosynostosis. Biparietal foramina are usually benign and are often transmitted as a dominant trait (3). Some are due to mutations in the MSX2 gene, whereas in other families it is part of the 11p11.2 deletion syndrome (4). Prominence of the metopic suture is seen in some youngsters with developmental malformations. Percussion of the skull can reveal areas of tenderness resulting from localized osteomyelitis, an indication of an underlying brain abscess. Macewen (cracked pot) sign accompanies the separation of sutures and reflects increased intracranial pressure.
increased intracranial pressure. Flattening of the occiput is seen in many developmentally delayed youngsters. Conversely, occipital prominence can indicate the Dandy-Walker malformation complex. Biparietal enlargement suggests the presence of subdural hematomas and should raise the suspicion of child abuse. Palpation of the skull can disclose ridging of the sutures, as occurs in craniosynostosis. Biparietal foramina are usually benign and are often transmitted as a dominant trait (3). Some are due to mutations in the MSX2 gene, whereas in other families it is part of the 11p11.2 deletion syndrome (4). Prominence of the metopic suture is seen in some youngsters with developmental malformations. Percussion of the skull can reveal areas of tenderness resulting from localized osteomyelitis, an indication of an underlying brain abscess. Macewen (cracked pot) sign accompanies the separation of sutures and reflects increased intracranial pressure.
If accurately measured, serial head circumferences continue to be one of the most valuable parameters for assessing the presence of hydrocephalus or microcephaly. After multiple measurements are made with a good cloth or steel tape to ensure that the maximum circumference has been obtained, the value should be recorded on a head growth chart (Fig. I.1). Delayed head growth, particularly with evidence of arrest or slowing of head growth, reflects impaired brain growth from a variety of causes. Scalloping of the temporal fossae frequently accompanies microcephaly and suggests underdeveloped frontal and temporal lobes. Occasionally, one encounters a youngster, usually a girl, with a head circumference at or below the third percentile whose somatic measurements are commensurate and whose intellectual development is normal.
Palpation of the anterior fontanelle provides a simple way of estimating intracranial pressure. Normally, the fontanelle is slightly depressed and the pulsations are hardly felt. Auscultation of the skull using a bell stethoscope with the child in the erect position is performed over six standard listening points: globes, the temporal fossae, and the retroauricular or mastoid regions. In all cases, conduction of a cardiac murmur should be excluded. Spontaneous intracranial bruits are common in children. These are augmented by contralateral carotid compression. Wadia and Monckton (5) heard unilateral or bilateral bruits in 60% of 4- to 5-year-old children, 10% of 10-year-old children, and 45% of 15- to 16-year-old adolescents. Intracranial bruits are heard in more than 80% of patients with angiomas. Unlike benign bruits, they are accompanied by a thrill and are much louder and harsher. Intracranial bruits are heard in a variety of other conditions characterized by increased cerebral blood flow. These include anemia, thyrotoxicosis, and meningitis. Bruits also accompany hydrocephalus and some (not necessarily vascular) intracranial tumors. The technique and the history of auscultation for intracranial bruits are reviewed by Mackenzie (6).
Cranial Nerves
Olfactory Nerve
The olfactory nerve is only rarely assessed. Loss of olfactory nerve function can follow a head injury with fracture of the cribriform plate. Nerve function also can be lost when a tumor involves the olfactory bulbs. Olfactory sensation as transmitted by the olfactory nerve is not functional in the newborn, but is present by 5 to 7 months of age. By contrast, newborns do respond to inhalation of irritants, such as ammonia or vinegar, because the reflex is transmitted by the trigeminal nerve; hence, this reflex is preserved in the infant with arhinencephaly (7).
Optic Nerve
Much can be learned from a funduscopic examination, and more time is often spent with this than with any other part of the neurologic examination. With assistance from the parent or nurse, it is possible to examine even the most uncooperative youngster. If necessary, a mydriatic such as 2.5% or 10.0% phenylephrine (Neo-Synephrine) or 1% cyclopentolate (Cyclogyl) is used. Particular attention is paid to the optic discs, maculae, and appearance of the retina. In infants, the optic disc is normally pale and gray, an appearance similar to optic atrophy in later life. Optic nerve hypoplasia can be diagnosed if the discs are less than one-half normal size. The macular light reflex is absent until approximately 4 months of age. Premature and newborn infants have incompletely developed uveal pigment, resulting in a pale appearance of the fundus and a clear view of the choroidal blood vessels. Hyperemia of the disk, obliteration of the disc margins and absent pulsations of the central veins are the earliest and most important indications for papilledema. The differential diagnosis of papilledema is reviewed in Chapter 11.
Retinal hemorrhages are seen in one-third of vaginally delivered newborns. They are usually small and multiple, and their presence does not necessarily indicate intracranial bleeding. Persistence of the hyaloid artery is common in premature infants and is seen in approximately 3% of full-term infants. Chorioretinitis suggests an intrauterine infection. Less extensive and grouped pigmentation resembling the footprints of an animal (bear tracks) represents a harmless and common anomaly. This condition must be distinguished from the more extensive pigmentation seen in retinitis pigmentosa.
Visual acuity can be tested in the older child by standard means. In the toddler, an approximation can be obtained by observing him or her at play or by offering objects of varying sizes. Optokinetic nystagmus can be elicited by rotating a striped drum or by drawing a strip of cloth with black and white squares in front of the child’s eyes. The presence of optokinetic nystagmus confirms cortical vision; its absence, however, is inconclusive. Unilateral
optokinetic nystagmus suggests the presence of hemianopia. The visual fields can be assessed in toddlers and in infants younger than 12 months of age. The baby is placed in the mother’s lap and the physician is seated in front of them, using a small toy to attract the baby’s attention. An assistant standing in back of the infant brings another object into the field of vision, and the point at which the infant’s eyes or head turns toward the object is noted.
optokinetic nystagmus suggests the presence of hemianopia. The visual fields can be assessed in toddlers and in infants younger than 12 months of age. The baby is placed in the mother’s lap and the physician is seated in front of them, using a small toy to attract the baby’s attention. An assistant standing in back of the infant brings another object into the field of vision, and the point at which the infant’s eyes or head turns toward the object is noted.
 FIGURE I.1. Composite international and interracial head circumference graph. A: Boys. B: Girls. SD, standard deviation. (Courtesy of the late Dr. G. Nellhaus, Napa VA Hospital, Napa, CA.) |
The blink reflex, closure of the eyelids when an object is suddenly moved toward the eyes, is often used to determine the presence of functional vision in small infants. The reflex is absent in the newborn and does not appear until 3 or 4 months of age. It is present in approximately one-half of healthy 5-month-old infants and should be present in all infants by 1 year of age (8).
Oculomotor, Trochlear, and Abducens Nerves: Extraocular Movements
The physician notes the position of the eyes at rest. Noting the points of reflection of a flashlight assists in detecting a nonparallel alignment of the eyes. Paralysis of the oculomotor nerve results in lateral and slightly downward deviation of the affected eye. Paralysis of the abducens nerve produces a medial deviation of the affected eye, whereas paralysis of the trochlear nerve produces little change at rest. The setting sun sign, a forced downward deviation of the eyes at rest with paresis of upward gaze, is an indication of increased intracranial pressure, in particular pressure on the quadrigeminal plate causing impairment of the vertical gaze centers. This phenomenon also can be elicited in healthy infants younger than 4 weeks of age by suddenly changing the position of the head and in infants up to 20, or even 40, weeks of age by removing a bright light that had been placed in front of their eyes (9). Downward deviation of the eyes, skew deviation, and intermittent opsoclonus (irregular, chaotic oscillations of the eyes in horizontal, vertical, or oblique directions) may be noted transiently in healthy newborns (10).
Ocular bobbing refers to abnormal spontaneous vertical eye movements. In its most typical appearance, it consists of intermittent, often conjugate, fast downward movement of the eyes followed by, after a brief tonic interval, a slower return to the primary position (11). It is generally seen with pontine pathology, but also can be encountered
in encephalitis and in some metabolic encephalopathies. It probably reflects residual eye movements of patients who have severe limitations of horizontal and vertical eye movements.
in encephalitis and in some metabolic encephalopathies. It probably reflects residual eye movements of patients who have severe limitations of horizontal and vertical eye movements.
The doll’s-eye phenomenon refers to the apparent turning of the eyes to the opposite direction in response to rotation of the head. It is seen in healthy newborns, in coma, and whenever optic fixation is impaired.
The size of the pupils, their reactivity to light, and accommodation and convergence are noted. In infants younger than 30 weeks’ gestation, pupils are large and no response to light occurs. After 32 weeks’ gestation, an absent light response is abnormal (12).
The association of meiosis, enophthalmos, ptosis, and lack of sweating on the ipsilateral side of the face was first described in 1869 and is known as Horner syndrome (13). The condition can result from damage to the cervical sympathetic nerves when it accompanies brachial plexus injuries or can be congenital, being transmitted as an autosomal dominant condition (14). A slight degree of anisocoria is not unusual, particularly in infants and small children. Fatigue-induced anisocoria also has been noted to be transmitted as an autosomal dominant trait (15).
Eye movements are examined by having the child follow an object while the mother holds the child’s head. If the child permits it, the movement of each eye is examined separately while the other one is kept covered. The actions of the extraocular muscles are depicted in Fig. I.2. At birth, doll’s-eye movements are normally elicitable, but little or no conjugation occurs. Shortly after birth, the eyes become conjugated, and by 2 weeks of age, the infant moves the eyes toward light and fixates. Following movements are complete in all directions by approximately 4 months of age, and acoustically elicited eye movements appear at 5 months of age (16). Depth perception using solely binocular cues appears by 24 months of age along with stable binocular alignment and optokinetic nystagmus.
Strabismus owing to muscular imbalance can be differentiated from a paralytic strabismus. In the former, the ocular movements are concomitant and full. In the latter, the disassociation of the eyes increases when the eyes enter the field of action of the paralyzed muscle. In abducens nerve palsies, failure of abduction is readily demonstrable. The combination of defective adduction and elevation with outward and downward displacement of the eye suggests a third-nerve palsy. Internuclear ophthalmoplegia
(syndrome of the median longitudinal fasciculus) in its classical appearance consists of paralysis of adduction of the contralateral eye on lateral gaze, with nystagmus of the abducting eye and preservation of convergence. Ptosis and a large pupil with impaired constriction to light also can be present. Unilateral or bilateral congenital ptosis is relatively common, being transmitted as a dominant trait in some instance, and as X-linked in others (17). In some subjects with ptosis, reflex elevation or closure of the ptotic lid occurs in response to swallowing or movements of the jaw. Elevation has been termed the Marcus Gunn sign and closure the reverse Marcus Gunn sign. In instances of trochlear nerve palsy, the eye fails to move down when adducted. This defect is often accompanied by a head tilt.
(syndrome of the median longitudinal fasciculus) in its classical appearance consists of paralysis of adduction of the contralateral eye on lateral gaze, with nystagmus of the abducting eye and preservation of convergence. Ptosis and a large pupil with impaired constriction to light also can be present. Unilateral or bilateral congenital ptosis is relatively common, being transmitted as a dominant trait in some instance, and as X-linked in others (17). In some subjects with ptosis, reflex elevation or closure of the ptotic lid occurs in response to swallowing or movements of the jaw. Elevation has been termed the Marcus Gunn sign and closure the reverse Marcus Gunn sign. In instances of trochlear nerve palsy, the eye fails to move down when adducted. This defect is often accompanied by a head tilt.
 FIGURE I.2. Extraocular muscles involved in the various eye movements. Ext., exterior; inf., inferior; Lt., left; Rt., right; sup., superior. (Adapted from Farmer TW. Pediatric neurology, 3rd ed. New York: Harper & Row, 1983. With permission.) |
In describing the presence of nystagmus, the physician should note the position of the eyes that produces the greatest amplitude of the nystagmus, the direction of the fast movement, and the quality or speed of the nystagmus. When the nystagmus is of small amplitude, it might be noted only on funduscopic examination.
Trigeminal Nerve
The action of the temporalis and masseter muscles is noted. Unilateral lesions of the trigeminal nerve result in a deviation of the jaw to the paralytic side and atrophy of the temporalis muscle. The jaw jerk can be elicited by placing one’s finger below the lower lip of the slightly open mouth and tapping downward. An absent jaw jerk is rarely significant; upper motor neuron lesions above the level of the pons exaggerate the reflex.
The corneal reflex tests the intactness of the ophthalmic branch of the trigeminal nerve. A defect should be suspected when spontaneous blinking on one side is slower and less complete. The frequency of blinking increases with maturation and decreases in toxic illnesses.
Facial Nerve
Impaired motor function is indicated by facial asymmetry. Involvement of the facial nucleus or the nerve produces a lower motor neuron weakness in which upper and lower parts of the face are paralyzed. Normal wrinkling of the forehead is impaired, and the eye either cannot be closed or can be opened readily by the examiner. Weakness of the face can be obvious at rest and is accentuated when the child laughs or cries. When facial weakness is caused by corticobulbar involvement (upper motor neuron facial weakness), the musculature of the upper part of the face is spared. Although this sparing was believed to reflect bilateral enervation of the upper facial motor neurons, it now appears that upper facial motor neurons receive little direct cortical input, whereas lower facial neurons do (18).
Weakness is accentuated with volitional movements but disappears when the child laughs or cries. The converse, upper motor facial weakness associated with emotion and not evident on volitional movements, can be seen in thalamic lesions (19). The McCarthy reflex, ipsilateral blinking produced by tapping the supraorbital region, is diminished or absent in lower motor neuron facial weakness. Like the
palpebral reflex, bilateral blinking induced by tapping the root of the nose, it can be exaggerated by upper motor neuron lesions. In hemiparesis or peripheral facial nerve weakness, the contraction of the platysma muscle is less vigorous on the affected side. This sign also carries Babinski’s name.
palpebral reflex, bilateral blinking induced by tapping the root of the nose, it can be exaggerated by upper motor neuron lesions. In hemiparesis or peripheral facial nerve weakness, the contraction of the platysma muscle is less vigorous on the affected side. This sign also carries Babinski’s name.
An isolated weakness of the depressor of the corner of the mouth (depressor anguli oris) is relatively common in children. It results in a failure to pull the affected side of the mouth backward and downward when crying.
The sense of taste from the anterior two-thirds of the tongue is conveyed by the chorda tympani. Taste can be tested in children by applying solutions of sugar or salt to the previously dried and protruded tongue by cotton-tipped applicator sticks, making certain that the child does not withdraw the tongue into the mouth.
Cochlear and Vestibular Nerves
Hearing can be tested in the younger child by observing the child’s response to a bell. Small infants become alert to sound; the ability to turn the eyes to the direction of the sound becomes evident by 7 to 8 weeks of age, and turning with eyes and head appears by approximately 3 to 4 months of age. Hearing is tested in older children by asking them to repeat a whispered word or number. For more accurate evaluation of hearing, audiometry or brainstem auditory-evoked potentials are necessary.
Vestibular function can be assessed easily in infants or small children by holding the youngster vertically so he or she is facing the examiner, then turning the child several times in a full circle. Clockwise and counterclockwise rotations are performed. The direction and amplitude of the quick and slow movements of the eye are noted. The healthy infant demonstrates full deviation of the eyes in the direction that he or she is being rotated with the quick phase of the nystagmus backward. When rotation ceases, these directions are reversed. This test has been found to be valuable in a newborn suspected of perinatal asphyxia, with an abnormal response suggesting impaired brainstem function between the vestibular and the oculomotor nuclei.
Glossopharyngeal and Vagus Nerves
Asymmetry of the resting uvula and palate and failure to elevate the palate during phonation indicate impaired vagal motor function. When upper or lower motor neuron involvement of the vagus nerve exists, the uvula deviates toward the unaffected side, and with movement, the palate is drawn away from the affected side.
The gag reflex tests the afferent and efferent portions of the vagus. This reflex is absent in approximately one-third of healthy individuals (20). Testing taste over the posterior part of the tongue is extremely difficult and, according to some opinions, generally not worth the effort.
Spinal Accessory Nerve
Testing the sternocleidomastoid muscle can be done readily by having the child rotate his or her head against resistance.
Hypoglossal Nerve
The position of the tongue at rest should be noted with the mouth open. The tongue deviates toward the paretic side. Fasciculations are seen as small depressions that appear and disappear quickly at irregular intervals. They are most readily distinguished on the underside of the tongue. Their presence cannot be determined with any reliability if the youngster is crying.
Motor System
The child’s station (i.e., posture while standing) can usually be discerned before the start of the examination. Similarly, the walking and running gaits can be seen by playing with the youngster and asking him or her to retrieve a ball and run outside of the examining room. In the course of such an informal examination, sufficient information can be obtained so that the formal testing of muscle strength is only confirmatory.
Evaluation of the motor system in a school-aged child can be done in a formal manner. Examination of selected proximal and distal muscles of the upper and lower extremities is usually sufficient. A book published by the Medical Research Council is invaluable for this purpose (21): Muscle strength is graded from 0 to 5. The following grading system has been suggested:
No muscle contraction
Flicker or trace of contraction
Active movement with gravity eliminated
Active movement against gravity
Active movement against gravity and resistance
Normal power
Muscle tone is examined by manipulating the major joints and determining the degree of resistance. In toddlers or infants, inequalities of tone to pronation and supination of the wrist, flexion and extension of the elbow, and dorsi and plantar flexion of the ankle have been found to provide more information than assessment of muscle strength or reflexes.
A sensitive test for weakness of the upper extremities is the pronator sign, in which the hand on the hypotonic side hyperpronates to palm outward as the arms are raised over the head. Additionally, the elbow may flex (Fig. I.3). In the lower extremities, weakness of the flexors of the knee can readily be demonstrated by having the child lie prone and asking the child to maintain his or her legs in flexion at right angles at the knee (Barré sign).
 FIGURE I.3. The pronator sign. Weakness of the right upper extremity in a girl with a Brown-Séquard syndrome after spinal cord trauma. |
Coordination
Coordination can be tested by applying specific tests for cerebellar function, such as having the youngster reach for and manipulate toys. One may be reluctant to use marbles for this purpose for fear that a small child might swallow them. Ataxia with tremor of the extremities can be demonstrated in the older child on finger-to-nose and heel-to-shin testing. Accentuation of the tremor as the extremity approaches the target is characteristic of cerebellar dysfunction (intention tremor). In the finger-to-nose test, the arm must be maintained abducted at the shoulder. The examiner can discover minor abnormalities by moving the finger to a different place each time. The ability to perform rapidly alternating movements can be assessed by having the child repeatedly pat the examiner’s hand, or by having the child perform rapid pronation and supination of the hands. In the lower extremities, rapid tapping of the foot serves a similar purpose. Pyramidal and extrapyramidal lesions slow rapid succession movements but leave intact the execution of each stage of the movement so that no true dissociation occurs. The heel-to-shin test is not an easy task for many youngsters to comprehend, and performance must be interpreted with regard to the child’s age and level of intelligence.
A variety of involuntary movements can be noted in the course of the examination. They may be seen when the child walks or is engaged in various purposeful acts.
Athetosis indicates an instability of posture, with slow swings of movement most marked in the distal portions of the limbs. The movements fluctuate between two extremes of posture in the hand, one of hyperextension of the fingers with pronation and flexion of the wrist and supination of the forearm and the other of intense flexion and adduction of the fingers and wrist and pronation of the forearm.
Choreiform movements refer to more rapid and jerky movements similar in their range to the athetoid movements but so fluid and continuous that the two extremes of posture are no longer evident (22). They commonly involve the muscles of the face, tongue, and proximal portions of the limbs. In children, athetosis and choreiform movements occur far more frequently as associated, rather than as isolated, phenomena.
Dystonia is characterized by fixation or relative fixation in one of the athetotic postures. When dystonia results from perinatal asphyxia, it is nearly always accompanied by other involuntary movements. The other manifestations of basal ganglia disorder (tremors and myoclonus) are usually less apparent. Tremors are rhythmic alterations in movement, whereas myoclonus is a relatively unpredictable contraction of one or more muscle groups. It can be precipitated by a variety of stimuli, particularly sudden changes in position, or by the start of voluntary movements. In addition to these movement disorders, children with dystonic cerebral palsy also exhibit sudden increases in muscle tone, often precipitated by attempts at voluntary movement (tension). These movements must be distinguished from seizures.
Small, choreiform-like movements are common in the healthy infant. They are transient; emerging at approximately 6 weeks of age, they become maximal between 9 and 12 weeks of age and taper off between 14 and 20 weeks of age. According to Prechtl and coworkers, their absence is highly predictive of neurologic abnormalities (23).
Sensory Examination
A proper sensory examination is difficult at any age, and almost impossible in an infant or toddler. Sensory modalities can be tested in the older child using a pin or preferably a tracing wheel. In infants or toddlers, abnormalities in skin temperature or in the amount of perspiration indicate the level of sensory deficit. The ulnar surface of the examiner’s hand has been found to be the most sensitive, and by moving the hand slowly up the child’s body, one can verify changes that one marks on the skin and rechecks on repeat testing.
Object discrimination can be determined in the healthy school-aged child by the use of coin, or small, familiar items such as paperclips or rubber bands.
Reflexes
The younger the child, the less informative are the deep tendon reflexes. Reflex inequalities are common and less reliable than inequalities of muscle tone in terms of
ascertaining the presence of an upper motor neuron lesion. The segmental levels of the major deep tendon reflexes are presented in Table I.1.
ascertaining the presence of an upper motor neuron lesion. The segmental levels of the major deep tendon reflexes are presented in Table I.1.
TABLE I.1 Segmental Levels of Major Deep Tendon Reflexes | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Little doubt exists that the Babinski response is the best-known sign of disturbed pyramidal tract function. To elicit it, the plantar surface of the foot is stimulated with a sharp object, such as the tip of a key, from the heel forward along the lateral border of the sole, crossing over the distal ends of the metatarsals toward the base of the great toe. Immediate dorsiflexion of the great toe and subsequent separation (fanning) of the other toes constitutes a positive response. Stimulation of the outer side of the foot is less objectionable and can be used in children who cannot tolerate the sensation of having their soles stimulated. The response is identical. An extensor plantar response must be distinguished from voluntary withdrawal, which, unlike the true Babinski response, is seen after a moment’s delay. It also must be distinguished from athetosis of the foot (striatal toe). According to Paine and Oppe, a positive response to Babinski sign is seen normally in the majority of 1-year-old children and in many up to 2 1/2 years of age (24). In the sequential examination of infants conducted by Gingold and her group, the plantar response becomes consistently flexor between 4 and 6 months of age (25).
Many eponyms, 20 according to Wartenberg (26), have been attached to the reflexes elicitable from the sole of the foot. Some, such as Rossolimo reflex, which is elicited by tapping the plantar surface of the toe and producing a stretching of the plantar flexors, are muscle stretch reflexes. Others, such as Oppenheim reflex (a firm stroke with finger and thumb down the anterior border of the tibia) or Gordon reflex (a hard squeeze of the calf muscle), are variants of Babinski response.
In the upper extremity, Hoffmann reflex is elicited by flicking the terminal phalanx of the patient’s middle finger downward between the examiner’s finger and thumb. In hyperreflexia, the thumb flexes and adducts, and the tips of the other fingers flex. Wartenberg sign is elicited by having the patient supinate the hand, slightly flexing the fingers. The examiner pronates his or her own hand and links his or her own flexed finger with the patient’s. Both flex their fingers against each other’s resistance. In pyramidal tract disease, the thumb adducts and flexes strongly, a reemergence of the forced grasp reflex.
Clonus is a regular repetitive movement of a joint elicited by a sudden stretching of the muscle and maintaining the stretch. It is most easily demonstrable at the ankle by dorsiflexion of the foot. Clonus represents increased reflex excitability. Several beats of ankle clonus can be demonstrated in some healthy newborns and in some tense older children. A sustained ankle clonus is abnormal at any age and suggests a lesion of the pyramidal tract.
Chvostek sign, a contraction of the facial muscles after percussion of the pes anserinus of the facial nerve (just anterior to the external auditory meatus), is evidence of increased irritability of the motor fibers to mechanical stimulation such as occurs in hypocalcemia (27).
Children with developmental disabilities, such as minimal brain dysfunction and attention-deficit disorders, are often found to have soft signs on neurologic examination (see Chapter 18). These represent persistence of findings considered normal at a younger age. Of the various tests designed to elicit soft signs, tandem walking, hopping on one foot, and the ability of the child to suppress overflow movements when asked to repetitively touch the index finger to the thumb have been found to be the most useful. Forward tandem gait is performed successfully by 90% of 5-year-old children; 90% of 7-year-old children also can hop in one place, and synkinesis becomes progressively suppressed between 7 and 9 years of age (28).
Cognitive Function
Evaluation for the presence of cognitive limitations is an important part of the neurologic examination of developmentally delayed youngsters and of children with ostensibly normal intelligence who are referred because of school failure. Such an examination is extremely time consuming and might require a return visit. An outline of an evaluation of intelligence, speech, and disorders of cognitive function is presented in Chapter 18. Also provided are suggestions on how to interpret psychological data.
NEUROLOGIC EXAMINATION OF THE INFANT
The neurologic examination of an infant younger than 1 year of age can be divided into three parts: evaluation of posture and tone, evaluation of primitive reflexes, and examination of items that are relatively age invariable.
Posture and Muscle Tone
Evaluation of posture and muscle tone is a fundamental part of the neurologic examination of infants. It involves examination of the resting posture, passive tone, and active tone. Posture is appreciated by inspecting the undressed
infant as the infant lies undisturbed. During the first few months of life, normal hypertonia of the flexors of the elbows, hips, and knees occurs. The hypertonia decreases markedly during the third month of life, first in the upper extremities and later in the lower extremities. At the same time, tone in neck and trunk increases. Between 8 and 12 months of age, a further decrease occurs in the flexor tone of the extremities together with increased extensor tone (29).
infant as the infant lies undisturbed. During the first few months of life, normal hypertonia of the flexors of the elbows, hips, and knees occurs. The hypertonia decreases markedly during the third month of life, first in the upper extremities and later in the lower extremities. At the same time, tone in neck and trunk increases. Between 8 and 12 months of age, a further decrease occurs in the flexor tone of the extremities together with increased extensor tone (29).
 FIGURE I.4. Scarf sign in an infant with upper extremity hypotonia on a cerebral basis. |
Evaluation of passive tone is accomplished by determining the resistance to passive movements of the various joints with the infant awake and not crying. Because limb tone is influenced by tonic neck reflexes, it is important to keep the child’s head straight during this part of the examination. Passive flapping of the hands and the feet provides a simple means of ascertaining muscle tone. In the upper extremity, the scarf sign is a valuable maneuver. With the infant sustained in a semireclining position, the examiner takes the infant’s hand and pulls the arm across the infant’s chest toward the opposite shoulder (Fig. I.4). The position of the elbow in relationship to the midline is noted. Hypotonia is present if the elbow passes the midline. In the lower extremity, the fall-away response serves a similar purpose. The infant is suspended by the feet, upside down, and each lower extremity is released in turn. The rapidity with which the lower extremity drops when released is noted. Normally, the extremity maintains its position for a few moments, then drops. In hypotonia, the drop occurs immediately; in hypertonia, the released lower extremity remains up.
The traction response is an excellent means of ascertaining active tone. The examiner, who should be sitting down and facing the child, places his or her thumbs in the infant’s palms and fingers around the wrists and gently pulls the infant from the supine position. In the healthy infant younger than 3 months of age, the palmar grasp reflex becomes operative, the elbows tend to flex, and the flexor muscles of the neck are stimulated to raise the head so that even in the full-term neonate the extensor and flexor tone are balanced and the head is maintained briefly in the axis of the trunk. The test is abnormal if the head is pulled passively and drops forward or if the head is maintained backward. In the former case, abnormal hypotonia of the neck and trunk muscles exists; in the latter case, abnormal hypertonia of the neck extensors exists. With abnormal hypertonia, one also might note the infant’s head to be rotated laterally and extended when the infant is in the resting prone position.
Primitive Reflexes
The evaluation of various primitive reflexes is an integral part of the neurologic examination of the infant. Many of the reflexes exhibited by the newborn infant also are observed in a spinal animal, one in which the spinal cord has been permanently transected. With progressive maturation, some of these reflexes disappear (Tables I.2 and I.3). This disappearance should not be construed as meaning that they are actually lost, for a reflex once acquired in the course of development is retained permanently. Rather, these reflexes, which develop during intrauterine life, are gradually suppressed as the higher cortical centers become functional.
Segmental Medullary Reflexes
A number of segmental medullary reflexes become functional during the last trimester of gestation. They include (a) respiratory activity, (b) cardiovascular reflexes, (c) coughing reflex mediated by the vagus nerve, (d) sneezing reflex evoked by afferent fibers of the trigeminal nerve, (e) swallowing reflex mediated by the trigeminal and glossopharyngeal nerves, and (f) sucking reflex evoked by the afferent fibers of the trigeminal and glossopharyngeal nerves and executed by the efferent fibers of the facial, glossopharyngeal, and hypoglossal nerves.
Flexion Reflex
Another reflex demonstrable in the isolated spinal cord is the flexion reflex. This response is elicited by the unpleasant stimulation of the skin of the lower extremity, most consistently the dorsum of the foot, and consists of dorsiflexion of the great toe and flexion of the ankle, knee, and hip. This reflex has been elicited in immature fetuses and can persist as a fragment, the extensor plantar response, for the first 2 years of life. It is seen also in infants whose higher cortical centers have been profoundly damaged. Reflex stepping, which is at least partly a function of the flexion response, is present in the healthy newborn when the infant is supported in the standing position; it disappears in the fourth or fifth month of life.
TABLE I.2 Postural Reactions | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Moro Reflex
The Moro reflex is best elicited by a sudden dropping of the baby’s head in relation to its trunk. Moro, however, elicited this reflex by hitting the infant’s pillow with both hands (30). The infant opens the hands, extends and abducts the upper extremities, and then draws them together. The reflex first appears between 28 and 32 weeks’ gestation and is present in all newborns. It fades out between 3 to 5 months of age (25) (Table I.3). Its persistence beyond 6 months of age or its absence or diminution during the first few weeks of life indicates neurologic dysfunction.
Tonic Neck Response
The tonic neck response is obtained by rotating the infant’s head to the side while maintaining the chest in a flat position. A positive response is extension of the arm and leg on the side toward which the face is rotated and flexion of the limbs on the opposite side (Fig. I.5). An asymmetric tonic neck response is abnormal, as is an obligatory and sustained pattern (i.e., one from which the infant is unable to extricate himself- or herself). Inconstant tonic neck responses can be elicited for as long as 6 to 7 months of age and can even be momentarily present during sleep in the healthy 2- to 3-year-old child (25) (Table I.3).
Righting Reflex
With the infant in the supine position, the examiner turns the head to one side. The healthy infant rotates the shoulder in the same direction, followed by the trunk, and finally the pelvis. An obligate neck-righting reflex in which the shoulders, trunk, and pelvis rotate simultaneously and in which the infant can be rolled over and over like a log is always abnormal. Normally, the reflex can be imposed briefly in newborns, but the infant is soon able to break through it.
Palmar and Plantar Grasp Reflexes
The palmar and plantar grasp reflexes are elicited by pressure on the palm or sole. Generally, the plantar grasp reflex is weaker than the palmar reflex. The palmar grasp reflex
appears at 28 weeks’ gestation, is well established by 32 weeks, and becomes weak and inconsistent between 2 and 3 months of age, when it is covered up by voluntary activity. Absence of the reflex before 2 or 3 months of age, persistence beyond that age, or a consistent asymmetry is abnormal. The reappearance of the grasp reflex in frontal lobe lesions reflects the unopposed parietal lobe activity.
appears at 28 weeks’ gestation, is well established by 32 weeks, and becomes weak and inconsistent between 2 and 3 months of age, when it is covered up by voluntary activity. Absence of the reflex before 2 or 3 months of age, persistence beyond that age, or a consistent asymmetry is abnormal. The reappearance of the grasp reflex in frontal lobe lesions reflects the unopposed parietal lobe activity.
TABLE I.3 Percentage of Healthy Babies Showing Various Infantile Reflexes with Increasing Age | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
