INTRODUCTION
Neurological assessment by history and examination in a child is itself an art and it can be mastered only by constant practice. As in any pediatric case, steps can be followed as per the usual teaching. However, improvization may be needed at every step. During the conversation with the guardian, observation of the child must also be done. History from the child should also not be forgotten. The aim in the neurologic assessment is to obtain an accurate localization thereby helping in the etiological diagnosis and management. By taking a neurological examination, one should try to:
- Assimilate the pertinent findings and make a list of differential diagnoses regarding localization and etiologies. Remember—common things are common. So, exclude the less likely ones and narrow down to the possible differential diagnoses.
- Plan the investigations and order tests systematically to confirm or support the most probable diagnosis or to exclude others.
- Discuss the management options with the parents and establish a follow-up plan.
HISTORY
History is the most fundamental part of the neurologic evaluation. Most neurological disorders can be diagnosed to a considerable extend by a good history. Do not forget to ask the child about the disease. A child older than 3 years will be able to provide very useful information that is more accurate than the parent.
- Review of the presenting illness in a chronological manner and evolution of specific symptoms like headaches, seizures, weakness, etc. must be listed and evaluated systematically.
- For the youngster with a learning disability or an attention deficit disorder, social and environmental aspects are also to be covered.
- Review of the developmental history necessitates a survey of antenatal, perinatal, and postnatal development.
- Information about the feeding history other than dietary intake and calculation of calorie must be obtained. This includes failure to establish breastfeeding, regurgitation, excessive colic, or frequent formula changes. These symptoms along with abnormal sleeping habits will be an important clue for a perinatal brain injury or a developing progressive disorder.
- The developmental milestones must always be recorded. Most mothers recall these and can compare one youngster with the siblings.
- Recurrent injuries suggest hyperactivity, impaired coordination, or poor impulse control.
- The family history is relevant in most neurodegenerative disorders, which are transmitted as a recessive or dominant trait and that questions about the health of siblings and the presence of consanguinity are in order.
NEUROLOGICAL EXAMINATION
Neurological examination of child is not only different, complex, and takes longer than any other organ, but is also unfamiliar to the majority. Childhood neurological examination starts as soon as you see the child whether he is crying or smiling. Do assess the sensorium, cranial nerve (CN) and axial musculature at that observation. Similarly, observe while he walks or resists being carried. Each activity must be considered as an examination opportunity. It is important to get a good rapport with the child and to explain to the parent what you are going to do. Play and communication with the child during the examination is crucial. To gain trust and cooperation from your young patient and the parents, pay more attention to the problem; you may want to examine this area first, and if you decided to check it later, inform the parent. The comfort of the patient should be considered during the examination. For example, if the patient is lying on the bed, start with the areas that can be tested in that position, such as leg movement, leg reflexes, abdominal reflexes, sensory testing, Babinski sign, and so on. Then, examine the child in the sitting position.
GENERAL EXAMINATION
This includes the head-to-toe examination including vital signs and the anthropometry.
In addition to the knee hammer and the usual neurological gadgets for a pediatric neurological examination, handy instruments include a ball; a few small toys like a 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 and a flashlight with a rubber adapter for transillumination).
In the child above 5 years of age, general physical and neurological examinations can be performed in the same manner as for adults, except that the more uncomfortable aspects, such as fundus examination, corneal and gag reflexes, and sensory testing should be postponed until the end.
Child of 1–3 years of age is best approached by seating the child in the mother's or father's lap and talking to the child and infant either in the cradle or in the mother's lap as he wishes.
- Height, weight, blood pressure, and head circumference must always be measured
- As far as possible, examine the child undressed—but remember the modesty.
- Look specifically:
- Dysmorphic features
- Cutaneous lesions
- Scalp hair, eyebrows, and nails
- Comparison of the size of the limbs and thumbnails (for hemiatrophy with hemiparesis)
- Presence of an unusual body/urine odor
- Child's dominant handedness and the presence of cerebellar deficits, hemiparesis, and perhaps even a visual field defect
- General appearance of the skull as it gives a lot of idea about the brain inside.
HIGHER CORTICAL FUNCTION TESTS
Pediatric higher cortical function testing is equivalent to cognitive developmental examination. So a developmental assessment, which includes fine motor/adaptive, language and social development, means complete higher mental function testing. Before pursuing formal developmental assessment, you must establish that the patient is awake, alert, can3 hear, and comprehend. Cognitive function in older children is tested while you are taking the history. So take the history from the child than from the parent.
Check consciousness, alertness, orientation, attention, language, and memory. A detailed higher cortical function testing is done if child has mental retardation, cognitive decline, etc.
Steps
In youngsters, do a full developmental assessment giving more attention to cognitive (fine motor, adaptive behavior, social development and language) aspect. Thus, a developmental quotient (DQ) can be obtained.
In older child, look for all the fund of knowledge, abstract thinking, calculation, thought (FACT) process (plus lobe function, if you are conversant with it).
This will vary in an acute disease and a child who has more chronic problems including a pervasive developmental disorder. A more social behavior and play activities evaluation will be required in such situations. Peculiar repertoire/repetitive behavior will be suggestive of autism and hyperactive inattentive behavior will be in favor of attention deficit hyperactivity disorder (ADHD).
In an older child, make certain that agnosia and apraxia are also tested. Agnosia and apraxia are generally indicative of a parietal or occipital lobe lesion, provided they have learned earlier and lost it. Otherwise such cases will be seen as a case of mental retardation or learning disorder.
- Inability to draw a clock or cross (constructional apraxia)
- Inability to comb hair or drink through a straw (ideational apraxia)
- Inability to name fingers (finger agnosia)
- Inability to recognize the objects by touch (astereognosis)
- Inability to recognize drawing number in hands (agraphesthesia)
- Inability to understand written language (alexia)
- Inability to write (agraphia).
Cranial Nerves
Detailed evaluation techniques can be obtained from any clinical methods.
Cranial nerves can be examined in all including a newborn. A proper observation of the child is the only thing you have to do.
For example:
- Response to light and facial regard for vision testing (CN II)
- Spontaneous eye turning to different direction and dolls eye maneuver and pupillary reflex (III, IV, VI CN) (Fig. 1)
- Mouth opening during cry/chewing (V CN)
- Nasolabial fold during cry/smile (VII CN) (Fig. 2)
- Responds to sound by stop crying or startle (VIII CN)
- Watching the throat and tongue while crying (IX, X, XII CN)
- Neck turning and sternomastoid wasting (XI CN).
Of course, one has to do a detailed and accurate testing for an exact localization of a specific lesion if some abnormality is found in above observation.
Fig. 1: Simple method of testing eye movement. Observe spontaneous movement. Normal extraocular movement—child looking to left and down = left lateral and right medial rectus + right superior oblique (in the adducting eye) and left inferior rectus (in the abducting eye). Opposite can be inferred from the lady's eyes.
Fig. 2: Left upper motor neuron (UMN) facial palsy observed while the child was crying. Reduced nasolabial fold left and deviation of angle of mouth to right.
All CNs originate from the brainstem, except CNs I and II.
- Midbrain—CN III and IV
- Pons—CNs V, VI, VII, and VIII
- Medulla—CNs IX, X, XI, and XII
- Cranial nerves I, II, and VIII are purely sensory
- Cranial nerves III, IV, VI, XI, and XII are purely motor in function and the remainders are mixed
- Cranial nerves III, VII, IX, and X have parasympathetic fibers.
Certain points to be remembered—cranial nerve lesions occur due to:
- Supranuclear lesion [upper motor neuron (UMN), facial, supranuclear eye movement abnormality, pseudobulbar palsy]
- Brainstem lesions [lower motor neuron (LMN) type with pyramidal signs]
- Cranial nerve lesions (isolated)
- Neuromuscular junction (in myasthenia gravis III, IV, and VII CNS are common)
- Surrounding structures, such as the cavernous sinus.
- A spinal cord lesion does not give rise to symptoms and signs of CN abnormalities.
- Cranial nerve abnormalities plus ipsilateral limb motor or sensory deficits are consistent with a lesion above that CN (only seen along with VII CN).
- Lower motor neuron CN abnormalities plus contralateral, limb, motor, or sensory deficits means a brainstem lesion at the level of that CN.
- A unilateral ptosis in a child with altered sensorium and motor weakness can be due to lateral transtentorial herniation (downward and medial descent of uncus and parahippocampal gyrus). It is a dire emergency.
- Unilateral CNs V–VIII dysfunction plus contralateral motor or sensory deficit is indicative of a cerebellopontine angle lesion
- Unilateral CNs IX–XI dysfunction without appendicular deficit is seen in foramen jugular lesions.
- Unilateral abnormality of CNs III, IV, V, and VI is suggestive of cavernous sinus lesion.
- Unilateral abnormality of CNs IX, X, XI, and XII is indicative of bulbar palsy.
EXAMINING THE MOTOR SYSTEM
Examination of the motor system:
- Bulk
- Tone
- Power
- Reflexes (superficial, deep, primitive/neonatal)
- Coordination and abnormal movements.
Muscle Wasting and Fasciculation
Commonly seen in a LMN lesion, such as in spinal muscular atrophy (SMA), radiculopathy, chronic polyneuropathies, and rarely in polymyositis. Consider muscular dystrophy when there is specific muscle group wasting without fasciculations. Disuse atrophy/hemiatrophy is seen in UMN lesion.5
Muscle Tone
Tone is increased resistance to passive movements of the limb at the joint level. Tone examination is often neglected and this is partly because of the fact that the patient does not complain of a tone problem.
Young infants must be picked up to assess the tone—pull to sitting, lift by the axilla and then ventrally suspend. In older children, palpate the muscle and then move joints actively and passively and then grade the tone.
- Normal tone
- Decreased tone: Mild = hypotonia; severe = flaccid
- Increased tone (Figs. 3A and B).
Tone Abnormalities
- Spasticity: Increased tone throughout range of motion, and then there is a sudden release (catch). It is seen in UMN lesion. Spasticity is velocity dependent (sudden release).
- Rigidity: Increased tone throughout the range of motion. If intermittent and ratchet-like, is called cogwheel rigidity which is seen in extrapyramidal diseases, such as choreoathetotic cerebral palsy. Rigidity is not velocity dependent (continuous).
- Paratonia or gegenhalten: Increased tone appears when the patient opposes the movement of a limb. It is seen in a bifrontal lobe lesion and diffuse encephalopathy.
- Myotonia: Delay in muscle relaxation after the muscle is activated, either spontaneously (e.g. handgrip myotonia) or induced by percussion (percussion myotonia). It is seen typically in myotonia congenita.
- Dystonia: Contraction of agonist and antagonist muscle producing sustained abnormal limb posture. It is seen in extrapyramidal disorders.
Power Testing
- Weakness assessment by functional testing and by active resistance testing depending on the age
- The onset, course, and distribution of weakness
- Whether the weakness is because of a UMN or LMN lesion and/or nonorganic
- Keeping both hands outstretched will give lot of information about muscle weakness (Fig. 4)
Examples of functional assessment of muscle power are given in Figures 5A to C.
Interpretation
- Lower motor neuron weakness: Normal or decreased muscle tone, hyporeflexia, atrophy, fasciculation, with/without sensory deficit.
Fig. 4: Hand drift (when arm extended) and the pronator sign (when arms are raised over the head). Note the weakness of the right upper extremity.
- Upper motor neuron weakness: Weakness of extensors in the upper extremities and flexors in the lower extremities, hypo-or hypertonia, hyper-reflexia, clonus, and the presence of pathological reflexes.
- Nonorganic weakness: Nonanatomical, erratic (giveaway) weakness, discrepancy between voluntary use of muscles and when tested directly, normal reflexes, tone, and sensory examination.
Grading of Weakness
The Medical Research Council Scale is commonly used to demonstrate the degree of weakness by manual muscle testing.
Medical Research Council Scale
5 Normal
4 Moderate movement against resistance
3 Movement against gravity
2 Movement when gravity is eliminated
1 Trace of movement
0 No movement.
Figs. 5A to C: Muscle testing in children can be done by observation of activities and functional assessment. Three examples are as follows. (A) Wheel barrowing will help in identifying upper limb proximal power of muscles like triceps latissimus dorsi and neck extensors; (B) Bridging: Tests gluteus maximus, calf muscles, hamstrings and toe flexors; and (C) Heel gait for ankle dorsiflexors.
REFLEXES
In practice, there are four groups of reflexes:
(1) Superficial reflexes; (2) Deep tendon (DT) reflexes; (3) Neonatal reflexes, and (4) Primitive (pathological) reflexes.
Remember
- The seated position is best for obtaining DT reflexes
- Abdominal reflexes, cremasteric, and Babinski's reflex are better done in the supine position
- Feel the tendon for localization or tenderness before tapping
- Relax the joint before tapping
- Swing your hammerhead to tap, not just touch the tendon
- The response to tapping may be jerking of the limb, twitching of corresponding muscles, or feeling the tendon twitch under your finger
- Listen for the sound of the taps, because true absence of reflexes has a dull sound
- Always check reflexes simultaneously between two sides to establish symmetry
- Hyper- or hyporeflexia is clinically significant when either are associated with other neurological signs, if they are asymmetric
- Bilateral absence of brachioradialis or ankle jerks in an asymptomatic patient often has no clinical significance
- Unilateral absence of ankle jerks is consistent with an S1 root lesion
- Do “reinforcement” before concluding that the reflex is absent
- Asymmetry of reflexes is significant when it is reproducible
- Reflex segmental level can be remembered by remembering the reflex man (Fig. 6).
Superficial Reflexes
Superficial reflexes are elicited by stroking the skin (abdominals, cremasteric, plantar) or mucous membranes (gag, corneal). The most important reflex in this group that has to be checked in all patients with a neurological presentation is the plantar response. The majority of superficial reflexes are polysynaptic and affected by a segmental (root, nerve) lesion, as well as suprasegmental (cortical, brainstem) lesions.
Plantar Reflexes
The plantar reflex is best obtained when the patient is supine. Hold the ankle with the other hand. Explain to the patient what you are going to do. Stroke the lateral border of the foot across to the pad of the foot with a blunt object such as thumbnail and observe the following responses:
- All toes flex = flexor plantar response. This is normal
- Extension of the big toe and spreading of the other toes = extensor plantar response or Babinski's sign. This is abnormal
- Extension of the big toe only = “toe sign,” in other words, upgoing toe. This is abnormal
- Dorsiflexion of the foot, flexion at the knee, and flexion at the hip = triple flexor or response. This is abnormal
- Nonstereotype flexion of the foot and knee = withdrawal response. This is normal
- No movement = no response
- Babinski's sign, extensor toe sign, and stereotyped tripleflex or response are abnormal, and indicative of a UMN lesion involving the pyramidal tract from the L2 level of the spinal cord to the cerebral cortex.
Babies of up to 2 years of age may have upgoing plantar; so interpret the response with relation to other definite UMN signs.
Alternate Methods for Extensor Plantar
If you do not succeed, use an alternate stimuli, such as stroking the side of foot
- Chaddock's (side of foot = Shaddock)
- Over the shin = Oppenheim's sign and
- Squeezing gastrocnemius = Gordon reflex.
Release Reflexes
Snout, rooting, sucking, etc. are clinically significant when they are hyperactive. In young children do a detailed neonatal reflex examination which includes:
- Moro reflex
- Tonic neck response
- Righting reflex
- Palmar and plantar grasp reflexes
- Landau reflex
- Parachute response
- Placing and stepping responses.
Identifying late disappearance of neonatal reflex, [e.g. asymmetrical tonic neck reflex (ATNR)] and late appearance of infantile reflex (e.g. Landau reflex) are helpful in early detection of cerebral palsy. In older children indicative of bifrontal lesions are the following. Grasp glabellar, palmomental, finger flexion, and Hoffman's reflex. Hoffman's reflex is elicited by holding the middle phalanx of middle finger and then terminal phalanx is flexed and then flicked into extension. Positive response is sudden flexion and adduction of other fingers and thumb.
Gait
Gait is a function of the motor (pyramidal and extrapyramidal), sensory, vestibular, visual, and cerebellar systems.
Observe as the child walks and runs while playing. Formal testing also includes walking on toes, heels, and tandem walking with rotation around a chair. Making the child climb up and down will also yield lot of information. When possible, do Romberg's test also.
- Circumduction gait: In children who are hemiplegic, gait is one leg swing out and then adduction
- Lurching: Cerebellar ataxia
- Scissoring: Cerebral palsy; bilateral UMN lesions.
- Waddling: Muscular dystrophy, proximal weakness
- Astasia-abasia: Inconsistent, worse when watched—psychogenic
- Antalgic gait—pain and limping—arthritis
- Steppage: Foot drop, peripheral neuropathy, and L5 root lesion.
COORDINATION AND ABNORMAL MOVEMENT
- Child's manipulation of toys and reaching and releasing objects on request will help us in assessing coordination.
- Specific tests: Finger-to-nose and heel-to-shin testing can be done in appropriate situation.
- Keeping the arm fully outstretched is very important in finger-to-nose test (Figs. 7A and B).
- Abnormal movements are also observed and defined.
- Physiological in coordination and abnormal movements must be distinguished. Small, choreiform movements are common in the healthy infant maximally between 9 weeks and 12 weeks of age.
Sensory Examination
Even though sensory examination is difficult at any age, significant sensory deficits can be determined by an examiner who uses ingenuity. Deficits can be detected by moving the hand slowly up the child's body.9
Figs. 7A and B: For testing coordination arm must be fully outstretched and then brought to the nose tip with a wide arc thus testing all the cerebellar functions like dyssynergia, dysmetria, and intention tremor.
Cortical sensory signs like object discrimination can be determined in the older one by the use of coin, or small, and familiar items, such as paper clips or mobile phone.
While doing the final assessment, do a peripheral nerve palpation and look for any signs of meningeal irritation. Description of the skull and spine concludes the neurological examination. Examination of other relevant system will definitely help in arriving at an etiological diagnosis.
How to Formulate the Diagnosis
The neurologic examination findings of the infant cannot be summarized as normal or abnormal by single sitting. Multiple examinations may also be required.
Steps in Diagnosis
- Functional diagnosis: What are the disabilities and which are the parts of nervous system involved?
- Anatomical diagnosis: Where is the lesion? UMN/LMN; cortical, subcortical, etc.
- Etiological diagnosis: Considering the onset, evolution, and associations.
Thus list the differential diagnosis:
- Plan the diagnostic tests in order to support the diagnosis
- Make available all the therapeutic measures possible and seek help of colleagues and paramedics.
- It is the child that matters.
SUGGESTED READING
- Aminoff MJ, Simon RR, Greenberg D. Clinical neurology. Europe: McGraw-Hill Education; 2015.
- Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology 7th edition. Lippincott Williams & Wilkins (LWW); 2016.
- Duderstad KG, Neurological system (Chapter 19) in Pediatric Physical Examination—An illustrated handbok Elsevier; 2013. pp. 288–310.
- Dulac O, Lassonde M, Sarnat HB. Pediatric Neurology: Part I: Handbook of Clinical Neurology. US: Elsevier; 2013.
- Kotagal A, Nordli DR Jr, Armsby C. Detailed neurologic assessment of infants and children. UptoDate Review article.
- Swaiman KF, Ashwal S, Ferriero DM. Swaiman's pediatric neurology: principles and practice, 6th edition. Philadelphia: Elsevier; 2018.