lateral aspect of the foot, and finally arching across the ball of the foot to the great toe. The Babinski sign is present if the great toe extends with fanning of the other toes. A Babinski sign is stereotypical and similar each time you perform the maneuver.
Withdrawal from “tickling” tends to be erratic, does not look the same way each time, and is often trig-gered by touching the sole of the foot anywhere.
Frontal lobe release signs imply bilateral frontal lobe damage. The grasp reflex is elicited by nonvol-untarily persistent grasping of the examiner’s fin-gers when placed or lightly stroked across the patient’s palm. Other frontal lobe release signs are discussed in the Chapter 11 “Disorders of Higher Cortical Function.”
testing the same systems, albeit in different ways.
As a child gets older, the clinician can incorporate more and more of the adult exam into the pedi-atric exam. Therefore, the infant exam will be pre-sented, as it is the most disparate of the pediatric stages as compared with the adult.
General
Observe the baby. How does he or she act? Is the patient irritable, easily consoled, sleeping and easy to arouse, or somnolent? Encephalopathy in the infant often presents as hyperirritability. Do the face or other features appear dysmorphic? Note the set of the eyes and ears.
Skin
Always get the clothes off the infant. Look for hyper- or hypopigmentation. Check the base of the spine for dimpling or hair tufts. Examine the diaper area; note the morphology of the genitalia.
Head
Always measure head circumference. This should be compared with all previously obtained meas-ures if possible. The parents can be measured as well. Large-headed parents can produce large-headed children.
The anterior fontanel should be soft, not tense or sunken. Some pulsation is normal. The poste-rior fontanel should not be palpable after birth.
Eyes
Check eye movements by giving the child some-thing to observe. In infants, faces work well at a dis-tance of about 6 inches. In older babies, round, red objects can catch their attention. Check for smooth movements and the extent of tracking. Tracking past midline begins around age 2 months. Vertical tracking begins around 3 to 4 months.
Fundoscopic exam is important to identify the red reflex. To do this, while looking through the ophthalmoscope, aim at the child’s eye. If the red of the retina can be seen, there is a red reflex. This screens for congenital cataracts and retinoblas-toma. If the infant is cooperative, the clinician may actually be able to examine the back of the eye.
Also using the ophthalmoscope or a penlight, check for the pupillary light response.
Mouth
Using a gloved little finger, check for the suck reflex. Infants should latch on and the examiner’s finger should not slip from the mouth during suck. While this finger is in the infant’s mouth, also check for palate height. At some point during the exam, the baby will probably cry. Use this oppor-tunity to assess palate elevation.
Tone
Always assess tone when the head is midline.
When the head is turned, this triggers the asym-metric tonic neck reflex (fencer posture), produc-ing increased tone on the side opposite the head turn. Passively move the arms and legs. The child should move somewhat in response and not be totally limp. The examiner should pick up the baby, with hands around the infant’s chest. Does the baby slip through the fingers or stay between the hands without holding onto the chest? The former demonstrates hypotonia. Hypertonia is evident when the child’s legs scissor when verti-cally suspended. For further tone assessment, turn the baby on his or her belly with a hand and sup-port the stomach and chest. Does the patient flop over your hand, arch the back and neck slightly or stay rigidly extended? These are signs of hypoto-nia, normal tone, and hypertohypoto-nia, respectively.
Now place the infant on its back. A normal pos-ture in the infant is flexion of all four extremities.
As a baby gets older, the limbs assume a more extended posture. Take the baby’s hands and pull to a seated position. Resist the urge to support the head. Even at birth, the full-term infant will flex the extremities and pull the head up.
Reflexes
Always assess reflexes when the head is midline for the same reasons as above. Check the deep tendon reflexes as in the adult; however, these can usually be tapped with the fingers in infants. Ankle clonus is usually present in infants. Three to four beats bilaterally are normal. Sustained clonus or asym-metries should be noted.
20 FUNDAMENTALS OF NEUROLOGIC DISEASE 009-022_Davis02 3/2/05 4:11 PM Page 20
Primitive Reflexes
After checking for the suck reflex, one should also check Moro, grasp, and step reflexes.
MORO
With the infant on his or her back, grab the hands, lift the baby slightly off the bed, and then allow to drop back onto the bed. The response should be a symmetric brisk extension of arms and legs and then drawing of the arms back to midline.
GRASP
Place a finger into the baby’s palm. The infant should firmly grasp it, equally on both sides.
STEP
Lift the infant to standing position on the examin-ing surface (with the examiner supportexamin-ing the weight). The baby should take automatic steps on the table or bed.
ROOT
Brush the side of the child’s cheek. The head will turn toward the check touched.
Table 2-5 shows the timing of appearance and disappearance of these primitive reflexes. Always remember to re-dress and swaddle the baby after finishing.
RECOMMENDED READING
British Medical Research Council. Aids to the Exam-ination of the Peripheral Nervous System. 4th ed.
Philadelphia: W. B. Saunders; 2000. (Superb booklet that outlines how to test each muscle, describes areas of sensation for all peripheral nerves, and easily can be kept in doctor’s bag.)
CHAPTER 2—Neurologic Examination 21
Table 2-5 Primitive Reflexes with Expected Time of Appearance and Disappearance
Appears by
(Gestation Gone by
Reflex Period) (Approximate)
Suck 34 wk 4 mo
Root 34 wk 4 mo
Palmar Grasp 34 wk 6 mo
Plantar Grasp 34 wk 10 mo
Tonic Neck 34 wk 4–6 mo
Moro 34 wk 3–6 mo
Automatic Step 35 wk 2 mo
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Overview
Neurologic tests serve to (1) establish a diagnosis when several possible diagnoses exist, (2) help clini-cians make therapeutic decisions, and (3) aid in fol-lowing the results of treatment. In broad terms, neurologic tests can be divided into those that eval-uate function, structure, and molecular/genetic con-cerns. For example, the neurologic examination is the most exquisite test of neurologic function yet devised. While it will provide clues as to the general location of the disease process, it is less reliable than other tests. Cranial magnetic resonance imaging (MRI) and computed tomography (CT) precisely locate abnormal brain tissue but cannot decipher the physiologic consequences of the tissue abnormality.
In this chapter, the major neurologic tests are briefly discussed in terms of their basic principles, indications, cost, and side effects.