The neurologic examination is a systematized sampling of various kinds of neurologic function that allows the physician to assess the intactness of various anatomic parts of the nervous system. The concern for localization of brain lesions evolved from the study of adults with localized and lateralized lesions, such as infarctions, emboli, and neopiasms. Lesions in children are less often focal, but the same approach to describing the patient's neurologic function is of great value. The goals of the examination are the same in children as in adults. On completion of the examination, the physician should be able to review his notes and satisfy himself that each of six categories of function has been adequately described. These are:
1. Mental status and speech
2. Cranial nerves
3. Muscle coordination and control
4. Reflex functions:
5. Sensory functions
6. Autonomie functions
Once a child reaches school age, the neurologic examination is essentially the same as that for an adult. Only the mental status is different, but it is constantly being monitored by parents and school personnel. It is useful for the physician to have reading paragraphs, arithmetic problems, and a few general-information questions for each grade level of school. Acquaintance with a few simple psychologic tests - such as the Draw -a -Pe r son, Peabody Picture Vocabulary Test, and the Denver Developmental Screening Test - is of great value.
Coordination and muscle functions are only mildly changed in children when compared with adults. Cranial nerve, reflex, sensory, and autonomie functions are virtually identical to those seen in the adult. Younger children, however, present a challenging problem in the demonstration of these functions. The remainder of this discussion will be a brief consideration of the examination of the young, potentially uncooperative child.
The quality of information extracted from an examination is a function of the ability and willingness of the child to cooperate, along with the physician's recognition that a spectrum of neurologic functions are constantly on display in any awake patient. The following sequence is useful in approaching the young child. Each portion of the examination should be introduced as it can be fitted into the hierarchy:
First: Observe covertly.
Second: Observe overtly - e.g., establish eye contact.
Third: Attempt to establish a nonthreatening (playful) relationship without touching the child.
Fourth: Introduce painless touching - e.g., with finger or reflex hammer.
Fifth: Introduce manipulation that is painless - e.g., moving an extremity.
Sixth: Carry out those procedures that require restraint or that may be frightening or painful.
Last: If possible, praise or reward the child.
Many children cry and become uncooperative when the formal examination begins, and it is desirable to observe the child closely before touching him. The child should be allowed to roam the room or sit in his mother's lap as the history is taken. This is reassuring to the child, who probably remembers that unpleasant and painful things frequently happen in the doctor's office. It also minimizes the possibility of having a crying, terrified child, the most difficult to examine adequately. Finally, it offers a valuable opportunity to observe the child's level of function and the parents' interaction with him.
If the room is equipped with a range of sturdy toys and differentlevel books, one can sometimes quickly guess the child's level of function by his choices. Young school-age children may perform an informal Draw-a-Person test with a pencil or crayon and paper. The hyperactive child is frequently all too obvious.
Although any organ or part of the body may have implications for a neurologic diagnosis, certain portions of the general examination require special attention because they so frequently give important clues to neurologic diagnosis.
Skin. If the physician remembers that the nervous system is an ectodermal structure, he will not forget to completely undress the patient. More than two cafe-au-lait spots rarely occur in a normal subject.1 Spots less than 1 cm. long may not be significant. Blacks and other darkskinned persons are no different, except that spots are found in slightly higher frequency in normals, and the hue may be darker than "caféau-lait." The presence of more than six café-au-lait spots should raise a strong suspicion of neurofibromatosis. Depigmented nevi resemble a negative image of caféau-lait spots. They may be the first indication of tuberous sclerosis, a common cause of the complex of infantile spasms and hypsarrhythmia.2 The typical facial lesions of tuberous sclerosis, so-called adenoma sebaceum (fibroadenomas), do not develop until the later part of the first decade. The typical fiat facial hemangioma of Sturge-Weber syndrome can be seen in the newborn nursery, but the diagnosis of the important piai angioma cannot be assumed until there is clinical, electrical, or radiologie evidence of its presence. Not all facial angiomas indicate Sturge-Weber syndrome. These represent only those of the commonest neurocutaneous syndromes.
It is especially important to examine the skin of the back, as angiomas, hairy patches, and other ectodermal defects in the midline usually suggest an abnormality in formation of the neural tube (spinal cord). vertebral bodies, or the overlying skin. A number of highly treatable congenital malformations - such as dermal sinus, predisposing to recurrent meningitis, and diastematomyelia - are associated with visible midline skin defects on the back.
Extremities. It takes little time to examine for asymmetry of the extremities by comparing the width of the thumbnail, first fingernail, and nail of the great toe. Less often, an obviously small arm or hand will be seen. A significant smallness (2 mm. or more) of the nail suggests the presence of undergrowth of that side (hemihypogenesis), which can be evidence of hemiparesis of central origin. In young and hence rapidly growing children, hemihypogenesis does not necessarily imply a lesion of long standing as it does in an older person.
Head. Direct examination of the head in the young child with open sutures and fontanel is tremendously valuable. The head circumference should be measured from the point where the occiput touches the examining table to the point on the forehead giving the largest circumference. Head size should be referred not to body size or chest circumference but to the age of the child, because most small human beings - even dwarfs with normal intelligence - have head circumferences in the normal range. In biologic terms, a great deal of complex brain growth normally occurs in the first two years, and failure to accomplish that growth at the normal rate is a sign of probable cerebral pathology. The maturational process must proceed in an orderly manner, and significant "catch-up growth" does not occur. Any child with a head circumference greater than 2 standard deviations below the mean for age should be considered likely to suffer brain dysfunction3 (Figure 1).
Figure 1. Head circumference chart for (A) boys and (B) girls. (From Nellhaus. G. Composite international and interracial graphs. Pediatrics 41 , 106.)
Heads larger than nonna! are not so often associated with neurologic dysfunction. Generally, if the head circumference has maintained a fixed relationship to the normal growth curve, or if the circumference is appropriate to body size, one would not be concerned in the absence of neurologic signs or symptoms.
Transillumination of the skull is one of the simplest and most often neglected examination procedures in the infant. It is valuable to use a constant power source of high intensity, such as the "Chun gun"* (Figure 2), rather than a flashlight; but standards will have to be learned for use of the brighter source, especially with premature infants. In transillumination/ as in the remainder of the examination, asymmetries are the most reliable abnormalities - except in the case of hydranencephaly or severe hydrocephalus, where the entire supratentorial space may transilluminate.
Figure 2. The Chun gun.
The significance of early closure of the fontanel is the implication of reduced cranial growth or early suture closure. If sutures remain open and head growth proceeds, there is little cause for worry. Delayed fontanel closure (after 18 months) suggests a disorder of bone metabolism, as occurs in hypothyroidism, hypophosphatasia, or cleidocranial dysostosis.
Premature closure of one or more cranial sutures should be detected early, providing the best opportunity for cosmetic repair. These children always have misshapen heads, usually with a palpable ridge over the fused suture. The diagnosis should be confirmed with tangential radiographs. It is doubtful that corrective surgery alters intellectual potential except when there is evidence of increased intracranial pressure.
Walking is one of the most useful skills in the neurologic evaluation. It reflects function in all the previously mentioned six categories except the cranial nerves. The age of walking is one of the most important developmental landmarks. Children who have not walked by 18 months must be suspected of mental retardation or static motor handicap (cerebral palsy). Children who have just started walking (toddlers) normally have a wide-based gait with arms out to the side, resembling cerebellar ataxia later in life. Asymmetry of gait should always suggest a neurologic lesion, just as does established dominance for hand preference before the first birthday. Highly automatic activities, such as running, are best for bringing out mild asymmetries suggesting a hemiparesis. The child with a mild hemiparesis may have only reduced arm swing; but when he is asked to run, the paretic arm will be adducted and flexed across the chest in a hemiparetic posture. Toe walking is seen with muscle imbalance, as occurs in spasticity, muscular dystrophy (Duchenne type), and disorders associated with weakness of the peroneal and anterior tibial muscles. Autistic children frequently toewalk, as do some who are normal.
A simple routine in a cooperative child is to ask him to walk, carefully observing from the rear or front for asymmetry of leg or arm motion. While he is walking down and back, watch carefully as he turns, as this may show early truncal ataxia. He should then be required to walk on his toes, away from the examiner; this will demonstrate distal muscle strength, which may be impaired in the presence of a peripheral neuropathy. Children of three can usually understand walking on their toes. Next the child returns towards the examiner, walking on his heels and keeping the forefoot off the floor. Children of three cannot always comprehend this task. Any significant asymmetry in this task suggests the possibility of a mild hemiparesis in the side on which there is greater difficulty in keeping the forefoot elevated. Finally, the child is asked to walk in tandem, using a line on the floor as a guide and placing heel against toe rather than taking long strides. Children under four commonly have difficulty understanding this task, but unusual difficulty explaining any part of the exam should always raise the question of an intellectual deficit or a disorder of communication. Difficulty with tandem walking suggests a midline cerebellar lesion or cerebellar tract deficit, but it may also be seen with nonspedfkally lagging gross motor coordination. This brief but informative series of acts can be concluded in the older child by asking him to hop, requiring gross motor coordination that is usually mastered between four and five but that is commonly deficient in children with minimal cerebral dysfunction. The traditional Romberg test is used primarily to assess posterior column dysfunction, which is uncommonly seen in children but can be employed as a nonspecific test of balance.
Cranial nerve exam.
1. Olfaction is ordinarily not examined unless there is the possibility of a lesion in the suprasellar region or frontal lobes. Cooperation is necessary, and substances, such as vinegar, that irritate the nasal mucosa (fifth cranial nerve) should not be used.
2. Formal visual testing is difficult in the young child and requires training and cooperation. Visual fields can be examined in the uncooperative child, although the data are not of the quality of what one can obtain later. With the child sitting on the mother's lap, the examiner takes two identical bright objects, such as cotton balls. He fixes the child's gaze and extends an arm into opposite temporal visual fields with the cotton balls concealed. When the child gazes into the examiner's face, one hand is opened quickly, exposing the cotton ball, and the child is observed for evidence that he was distracted by the object. This should be carried out in each temporal field. This procedure is best for homonymous lesions and less satisfactory for bitemporal lesions, unless the child will tolerate an eye patch, allowing each eye to be tested independently. Examination of the fundus is of great importance but requires restraining most young children and thus sacrificing any cooperation previously achieved. Except in the very cooperative, funduscopy should be deferred until the end of the examination. If one elects not to do funduscopy, it is mandatory that one establish a dear cornea, lens, and normal red retinal reflex. In preschool children it is difficult at best to achieve the desired cooperation for leisurely examination of the fundus. The physician should ask himself what is the most probable pathology and go after that. In the very young, common findings are hemorrhage, chorioretinitis, and congenital malformations. If the child is Jewish, and going downhill in the later half of the first year, the macula must be seen. Remember that in children with open fontanels or easily separable sutures, papilledema is not likely to be seen.
3, 4, and 6. The oculomotor nerves are examined as a unit. Usually one can assess them by having the child follow an interesting toy with upward and downward lateral gaze. If the child will follow a light, one can observe the position of the reflection in the pupil and easily identify strabismus. While the child is sitting on the mother's lap, nystagmus or roving eye movements should be sought. The observation should be repeated when the extraocular muscles are tested. A cover test for strabismus should be carried out whenever possible, since early diagnosis and treatment of this disorder are of great importance. The cover test is carried out by having the child fix on the light while one eye is covered with a card held by the examiner. The card is then carefully removed, and the previously covered eye is observed. If the eye has deviated but immediately returns to position, the child has a heterophoria, which is common and generally unimportant. If, however, the deviation is maintained, the child has heterotropia and should be referred to an ophthalmologist. The procedure should be repeated, covering the other eye. Pupillary reactivity can be examined at the same time.
5. Abnormalities of the trigeminal nerve are uncommon in children except in those with brain-stem disease. Touching the cornea is unpleasant and may induce crying. When the child is examined in an oxygen tent, it may be permissible to blow lightly on the cornea to elicit a corneal reflex. It must be remembered that, because of the absence of protective blinking, complete anesthesia of the cornea rapidly leads to corneal opacity. Jaw strength can easily be tested in the cooperative child by asking him to bite on a tongue depressor on each side of the mouth; but beware of malocclusion, which may give the impression of weakness.
7. The facial nerve is a common source of unnecessary confusion. Bell's palsy is unusual, but virtually nothing else produces sudden onset of inability to wrinkle the forehead and dose the eye while obliterating the nasolabial fold. In the neonatal period, congenital palsies in a segment of the facial nerve are a source of confusion. The most common of these, which involves the mentalis musde and its nerve, prevents drawing down of the corner of the mouth but completely spares the nasolabial folds and palpebrai fissures. Unlike traumatic facial paresis, which usually heals, these are often permanent and may be associated with other congenital anomalies.4 To assess facial asymmetry, try to capture the moment when the child begins to cry.
8. Parents are frequently reassured that their child hears when he responds to loud sounds, such as a telephone ring. Neural (perceptual) hearing loss may spare the low tones, however, and permit sounds to be appreciated; loss in the high frequencies will seriously limit the child's ability to differentiate words, such as "bed" and "bet," "Pam" and "pan." Be sure to note whether the child gazes at your face when you talk, as many hard-of-hearing children learn to lip-read without instruction. The child's behavior at the television set may give a valuable due as to the presence or absence of hearing loss. With a small child on a parent's lap, take two small bells of the sort used at Christmas time, and put one in each closed fist; then put a fist on each side of the child's head. As he turns towards one fist, softly ring the opposite bell to establish hearing and localization; repeat on the opposite side as he investigates the first bell.
9 and 10. The very fact that a child is not drooling establishes that some automatic swallowing is proceeding. Gagging is readily elicited, but this should be deferred if it causes the child to become uncooperative.
11. Isolated defects in the sternocleidomastoid and trapezius due to impairment of the spinal accessory nerve are uncommon.
12. Fasdculations of the tongue, which appear as constant wormlike movements when the tongue is at rest, are. an important sign of denervation, and may occur in diseases of the anterior horn cell (spinal muscular atrophy, Werdnig-Hoffmann disease). In the examination for fasciculations, the child's mouth should be open but the tongue should lie at rest on the floor of the mouth. When there is unilateral involvement of the hypoglossal nerve, there may be hemiatrophy of the tongue; when it is extended, it will deviate towards the weak side.
COORDINATION AND MUSCLE CONTROL
Coordination may have been partially assessed while the child was observed at play. A more formal evaluation can be carried out with the child sitting facing the examiner, preferably on his mother's lap. Offer him an interesting object, such as a raisin or small hard candy. (Avoid objects that are easily but inappropriately swallowed.) Observe the child's manipulation of the object with each hand. A good two-finger pincer grasp should have developed by 11 months. Also, offer the child an attractive object placed 45 degrees from the midline, at shoulder height, and far enough away so that his arm must be fully extended to reach it. Retrieving the object simulates the finger-to-nose test. Reaching across the midline for the object suggests paresis in the nonreaching arm, especially if the hand on the unused side is habitually closed (fisted). Watch what he does with the object when he retrieves it, as habitual smelling and tasting of nonfood objects are commonly observed in emotionally disturbed children.
Stretch-reflex testing can be done with the child in the same position on the parent's lap. Offer the child the hammer to inspect or to tap the parent's leg with, in order to demonstrate that the test is painless. (A quick, light tap on the quadriceps muscle before one has touched the child with the hands may also be reassuring). The knee jerks should be elicited first, since these frequently amuse the child and do not require touching with the hands. Plantar reflexes can be elicited in a game requiring the counting of toes. Always elicit the plantar reflexes with the least noxious stimulus possible. In spite of recent reports to the contrary/ we continue to find it difficult to interpret extensor plantar reflexes in the first two years of life.
Detection of sensory defects in young children is difficult. Occasionally, children as young as two years of age report vibrations from a tuning fork after hearing it. Localization of a point of touch when the eyes are closed determines cortical function, but position sense testing is difficult before age six years. Testing of pain sensation frequently spells the end of cooperation. We suggest breaking a tongue depressor in view of the child and offering it for a finger test. Sometimes this known source of mild pain will be tolerated. Position sense testing is difficult for children less than six years old to understand, but can be taught with eyes open to slightiy younger children when necessary.
Entire texts have been written on the neurologic examination as applied to both adults and children.6 Details and specifics should be sought there. If the goals of each exam are kept in mind and major efforts taken to gain the child's confidence, optimum neurologic diagnosis will result.
1. Whitehouse, D. Diagnostic value of the café-au-taìt spot. Arch. Dis. Child. 41 (1966), 376.
2. Gold, A.G.. and Freeman, J.M. Depigmented nevi: The earliest sign of tuberous sclerosis. Pediatrics 35(1965), 1003.
3- Pry, H.B., and Thelander. H. Abnormally small head size and intellect in children. J. Pediatr. 73 (1968), 593.
4. Cayler, G. An epidemic of congenital facial paresis and heart disease. Pediatrics 40 (1967), 666.
5. Hogan, G-R.. and Milligan. J.E. The plantar reflex of the newborn. N. Engl. J. Meo. 285 (1971). 502.
6. Paine. R.S.. and Oppe, I.E. The Neurological Examination of Children, London: William Heinemann, Ltd.. 1966.