CENTRAL NERVOUS SYSTEM

CENTRAL NERVOUS SYSTEM

History

Identify the precise timing and onset of the neurological disease, whether acute, subacute or insidious. Ask in detail the development status of the child before the onset of the disease. History of perinatal distress factors and abnormalities, head injury and immunisations before the onset should be recorded. Ask for any history of medications and accidental or suicidal poisoning in a comatosed child. Assess whether the disease is stationary, progressive or improving. Ask for symptoms suggestive of raised intracranial tension such as headache especially on rising up in the morning, vomiting without preceding nausea, enlargement of head size, and diplopia. Excessive and unexplained high-pitched crying may be the sole symptom of raised ICT in infants. Enquire details about seizures i.e. onset, type, preceding aura, seizure morophology, post seizure phenomenon, frequency of fits, response to previous treatment etc. Ask about any disturbances referable to special senses and sphincters. Family history of similar disease, tuberculosis and epilepsy Should be enquired. History of consanguinity should be asked.

CENTRAL NERVOUS SYSTEMGeneral Physical Examination

The ‘containers’ of CNS i.e: skull and spine should be examined in detail. Look for size, shape, symmetry, swellings, sutures and fontanels of skull. In craniosynostosis, skull becomes odd shaped because of cessation of growth of the skull bones at right angle to the prematurely fused sutures. Macewen’s sign (cracked pot sound on percussion of skull) should be looked for. It is physiological during early infancy because sutures are open. Auscultation and transillumination of skull is useful in selected cases. Face should be examined for any dysmorphism and characteristic facies suggestive of developmental, chromosomal and metabolic disorders. Obesity, sleep disturbances and features of diabetes inspidus are suggestive of hypothalamic disorder. The skin should be screened for any evidences of neuroectodermal dysplasia e.g. adenoma sebaceum, straw-berry mark on the face, telangiectasia of bulbar conjunctiva or vascular malformation of the retina, cafe-au-lait spots, shagreen spots etc. Skin rash and petechiae should be searched for. Teeth should be examined for brownish discoloration, blue-line over the gums and Hutchison’s teeth. Eyes should be examined for proptosis, corneal opacities, buphthalmos, Kayser-Fleischer ring (golden-green discoloration in the form of crescent in the inner layer of peripheral cornea just inside the limbus), and cataracts. Vital signs should be recorded keeping in mind that bradycardia, rise in blood pressure and Cheyne-Stokes breathing may be indicative of raised intracranial tension. Trousseau’s sign and nerve irritability (Chvostek’s sign) should be looked for in a child with history of tetanic spasms. Look for anemia, cyanosis, jaundice, lymphadenopathy, hepatosplenomegaly and abdominal mass. Spine should be examined for any evidences of developmental defects (platybasia, Klippel-Feil deformity, meningocele, pilonidal sinus, tuft of hair etc.), trauma, Pott’s disease, epidural abscess, primary neoplasm or metastatic deposits. Sinus tract over the region of dorsal spine and fracture of base of skull may be associated with recurrent pyogenic meningitis. Enquire whether child is right or left handed. The handedness is established around 3 years of age. Left handers have a diffuse representation of language function in the brain and their recovery from aphasia is better compared to right handers.

Examination of Central Nervous System

Most pediatricians lack the confidence and are often frustrated while conducting neurological examination of young children. With tact, experience and patience, the neurological examination of an infant should not be an ordeal, rather it should be fun both for the examiner and the patient. Adopt an attitude of play activity in conformity with the age and developmental status of the child. Harness your ingenuity, imagination and tact effectively by literally coming down to the level of the child. Smiling at the infant and speaking in soft and reassuring tones during the examination are highly effective to elicit cooperation. Attempts should be made to identify all neurological abnormalities, localize the probable site of lesion in CNS and identify etiology and diagnosis of the disease process.

Essential Tools

The pediatric neurologist should have colored toys/cubes, reflex hammer, bell, flash light with rubber adaptor, fibre glass tape measure, objects for testing stereognosis, tuning fork (128 Hz for vibration sense and 256 Hz for Rinne test), two-point discriminator, development kit, and ophthalmoscope.

Higher Mental Functions

1. Level of consciousness. The level of consciousness can be clinically classified into six stages: (a) Alert or fully conscious, (b) Drowsy but gives response to verbal commands, (c) Semiconscious and gives withdrawal response to pain, (d) Unconscious with flexion of upper and lower limbs to pain (decorticate posture with lesion high in the brain stem or basal nuclei),(e) unconscious with hyperextension of upper and lower limbs, pronation of upper limbs and plantar flexion of feet (decerebrate rigidity due to lesion in the midbrain between the superior colliculus and pons) (f) Unconscious with no response. Coma can be quantified by objective coma scales. In hysterical coma, the eyes are tightly closed and if opened by force, the child would promptly reclose them. The demonstration of nystagmus on cold caloric test is diagnostic of hysterical or feigned coma. In children with extensive brain damage (due to anoxia, meningitis, encephalitis and near-drowning) coma may be followed by persistent vegetative state. The child is awake but gives a blank staring look with roving eye movements and without any response to social interaction (coma vigile). The child remains inattentive, does not speak or show any signs of awareness, pain or pleasure.

2. Emotional status. Assess behaviour, perception and emotional lability. Look for signs of hyperactivity, short span of attention, distractibility and impulsiveness.

3. Memory and orientation. Assess orientation in time, place, person and memory of immediate, recent and past events in children above the age of 5 years. Ask name of school and its location, names of teachers, father, friends and siblings, day of the week and time and ability to obey simple commands. Tell a brief story and ask the child to repeat. Ask the child to repeat a set of numbers forwards and backwards. A normal 6-year old can repeat five digits forwards and count three digits backwards while a 10-year old can count six digits forwards and four digits backwards.

4. Delusions and hallucinations. Delusion is a false belief which the patient maintains for which there is no evidence. Hallucination is a false signal or impression from the organ of special senses.

5. Speech. The cortical center for speech production is located in the Broca’s area in the left cerebral hemisphere in a right handed person and vice versa.

(i) Disorders of cerebral hemisphere may produce sensory or motor aphasia. Development dyslexia is characterized by slowness in learning to read, mirror-image writing and reading from right to left.

Coma scales
Parameter Glasgow coma scale Adelaid coma scale
Eye opening
Spontaneous
Responds to speech
Responds to pain*
Nil

4
3
2
1


As in Glasgow
Scale
Best motor respons
Obeys commands
Localises pain
Withdrawal of limb
Flexion to pain
Extension to pain
Nil

6
5
4
3
2
1



As in Glasgow
Scale

Best verbal response
Oriented**

5

Oriented         5
 Confused 4 Words             4
Inappropriate words 3 Vocal sounds 3
Incomprehensible sounds 2 Cries                2
Nil 1 Nil                    1

* Pain is imparted by a strong pinch, applying pressure on the finger nail with a pencil, squeezing big toe or applying pressure over the supratrochlear notch located on the medial end of upper margin of orbit.

** Orientation cannot be evaluated below 5 years of age. During first 6 months best verbal response is cry. After one year recognisable sounds may be produced.

*** In all comatosed children, brain stem reflexes such as pupillary response to light, corneal reflex, oculo-cephalic and oculo-vestibular reflexes must be assessed.

(ii) Disorders of articulation (dysarthria) may lead to following speech defects:

Stammering, tailing or baby speech, scanning or staccato speech (speaks slowly and deliberately in monosyllables as if scanning a line of poetry), dysphonia or aphonia (laryngeal disorders). Slurring speech when syllables are slurred or scanned as if in a state of intoxication interspersed with explosive monotonous speech is seen in cerebellar disorders. Spastic dysarthria is seen in children with cerebral palsy and is associated with brisk jaw jerk (pseudobulbar palsy). Bulbar dysarthria due to bulbar palsy (involvement of nuclei of 9th, 10th, 12th cranial nerves in the medulla oblongata which appears like a bulb) is characterized by slurring dysarthria, dysphagia with nasal regurgitation of feeds and accumulation of secretions in the throat. Nasal speech occurs due to palatal paralysis or cleft palate. To test for articulation ask the child to say “ka, pa, ta” first slowly and then as fast as he can. These three words can test the main components of articulation effectively because ‘ka’ is produced deep in the throat, the word ‘pa’ is produced by the lips and ‘ta’ is produced by the tongue and palate.

6. Automatic neonatal reflexes. The persistence of Moro reflex and palmar grasp beyond 5 to 6 months of age is pathological and indicative of neuromotor retardation.

7. Doll’s eye phenomenon (oculo-cephalic reflex). The infant is placed supine and head is suddenly turned towards either side. The baby’s eyes lag behind like a doll i.e. there is conjugate deviation of the eyes towards the opposite side. Absence of doll’s eye phenomenon in a comatosed child is indicative of damage to brain stem due to increased intracranial pressure and transtentorial herniation. It may be associated with unilateral dilated fixed pupil.

Signs of Meningeal Irritation

Look for photophobia, neck rigidity, Kernig’s sign, Brudzinski’s sign, and tripod sign. The signs of meningeal irritation may be absent in infants below 3 months and seriously sick or malnourished children. In a struggling infant, suspend the head beyond the edge of table and then test for neck rigidity. The older child may be asked to touch his chest with the chin without opening the mouth. Kernig’s sign will be absent if neck rigidity is due to local causes rather than meningeal irritation. The spinal meningeal irritation causes rigidity of back and child sits with a “poker spine” with extended legs and by supporting the trunk on palms of both hands which are placed behind the back (tripod sign). Infants with acute poliomyelitis may have positive tripod sign and head drop due to weakness of neck flexors. Refer to chapter 7 for detailed list of conditions producing neck rigidity. Opisthotonos is characterized by marked neck rigidity with ventral arching of whole trunk.

Developmental Screening

Developmental status should be assessed on history and physical examination. Intelligence and school attainments should be checked in older children. The child may be asked to draw or imitate a circle (3 years), triangle (4 years), square or pyramid (5 years) or draw a man (3 years for circle and one year each for drawing different parts of the face). Look for evidences of minimal brain dysfunction in the form of hyperkinetic behaviour, short attention span, easy distractibility, motor clumsiness and soft neurological signs.

Cranial Nerves

The precise evaluation may be difficult due to lack of cooperation in young children.

First nerve (oflactory nerve). Ask for any defect in the smell and let the child identify some common odorous materials i.e. rose water, peppermint, orange, chocolates, ilaichi etc. Avoid use of irritating substances like ammonia and acetic acid which may be appreciated through fifth nerve. It is difficult to assess the individual nostril separately. Anosmia in children may be seen following fracture of cribriform plate, meningitis, thrombosis of anterior cerebral artery, lead poisoning, hydrocephalus, Kallmann syndrome, Rud syndrome and hysteria.

Second nerve (optic nerve). The following functions of optic nerve should be tested:

(a) Acuity of vision. In children above 3 years vision can be screened by use of E chart or Snellen’s picture charts. The E’s in the chart have their limbs directed to different directions: up, down, right and left. Visual acuity (V) is recorded according to the formula V=d/D where d is the distance at which patient is able to read the letters and D is the distance at which the letters are readable by a person with normal vision. The patient is positioned at a distance of 6 meters from the test types (d=6) and each eye is tested separately.

In infants, vision is tested by checking blinking response to bright light, turning of head towards diffuse light or following red moving ball or ring. Pupils may be dilated and fixed in optic atrophy while in cortical blindness pupillary responses are normal. The visual acuity in a term newborn baby is around 6/45 and it gruadally matures to an adult level of 6/6 by the age of 6 to 7 years.

Congenital blindness should be differentiated from global mental retardation. Roving nystagmoid eye movements, persistent squint beyond 6 months of age, absence of opticokinetic nystagmus (tested with rotating striped drum), lack of blink response to bright light or to sudden movement of examiner’s finger towards infant’s eye are suggestive of congenital blindness. A blind infant is extrasensitive to noise and gets easily frightened by sudden noise.

(b) Field of vision (confrontation test). It can be tested in children above the age of 3 years. The child sits opposite the examiner on the same eye level and is asked to fix gaze on the nasion of examiner. The examiner places his hands at the lateral limit of his own visual field midway between himself and the patient. He quickly flexes or moves one of the fingers of either hand and child is asked to identify. Alternatively an object suspended from a thread is gradually brought from the periphery towards the eye and child is asked to indicate when the object is visualized. Visual field of each eye is tested separately. The conventional perimetry is feasible in children only after 8 to 9 years of age. Bitemporal hemianopsia is characteristically seen due to craniopharyngioma producing lesion in the region of optic chiasma while homonymous hemianopsia (temporal field of one eye and nasal field of opposite eye) occurs due to lesions in optic radiations or visual cortex.

(C) Color vision. It is difficult to evaluate color vision in children below 3 years.

(D) Fundus examination. Effective pupillary dilatation in children can be achieved by instillation of 10% phenylephrine eye drops every 5 minutes for a period of 15 to 20 minutes. Better pupillary dilatation can be achieved by additional instillation of 0.5% tropicamide drops. By holding the ophthalmoscope a few centimetres from the patient’s eye, examine the iris and lens for evidences of iridocyclitis and cataract by using + 10 or + 12 diopters lens. The ophthalmoscope should then be brought as close as possible to the patient’s eye to examine the fundus by using appropriate lens depending upon the refractive error of the patient.

Fundus is the window to the central nervous system. Look for papilledema, papillitis, optic atrophy, chorioretinitis, hypertensive retinopathy, retinal hemorrhages, cherry red spot, retinitis pigmentosa, phakomata and choroidal tubercles. Optic disc is relatively pale in infants. Papilledema and papillitis are characterized by elevated disc with obliteration of physiological cup and blurred edges. The veins are engorged with marked hyperemia and hemorrhages. Visual loss in papillitis differentiates it from papilledema. Hypertensive retinopathy is characterized by generalized constriction and irregular narrowing of arterioles, thickening of vessels giving silver-wire appearance, flame-shaped hemorrhages, “cotton-wool patches”, retinal edema and papilledema. In primary optic atrophy, the disc is white with sharp distinct margins. The disc is dirty-pale with blurred margins in post-papilledematous optic atrophy. Unilateral optic atrophy with contralateral papilledema due to frontal lobe tumor is designated as Foster-Kennedy syndrome. Toxoplasmosis is characterized by yellow-white exudates which later turn into pigmented scars, which have special predilection for macula. Focal or generalized “salt and pepper” type of pigmentary mottling is seen in infants with congenital rubella syndrome. Congenital CMV infection is characterized by multifocal atrophic pigmentary lesions over the peripheral areas. Diffuse “salt and pepper” pigmentary changes along with arteriolar attenuation and periphlebitis may be seen in patients with congenital syphilis. Most infants with TORCH infections usually develop optic atrophy, strabismus and microphthalmos or bulbar phthisis.

Third, Fourth and Sixth Nerves. They are tested together because they are concerned with ocular movements. Diplopia is the most reliable symptom of involvement of any of these nerves. Look for squint, movements of eye balls diplopia and nystagmus. Doll’s eye movement phenomenon is used to test the ocular movements in infants. Supranuclear lesions of ocular nerves lead to paralysis of conjugate movements of the eyes.

Paralytic squint should be differentiated from concomitant squint which is characterized by early onset (below 3 years), normal eye movements in all directions, absence of diplopia, identical primary and secondary deviation and defective vision in the deviating eye.

Oculomotor (third nerve). Its nucleus lies in the midbrain and it supplies all the extraocular muscles of the eye except external rectus and superior oblique. It also supplies ciliary muscles and levator pelpebrae superioris.

Look for the following abnormalities:
(i) Diplopia

(ii) Ptosis (ptosis and pupillary changes may not occur in children who have a nuclear lesion of the oculomotor nerve). Bilateral ptosis which becomes worse in the evening is characteristically seen in patients with myasthenia gravis.

(iii) Pupils should be examined for size, shape, equality of size on two sides, response to light, response to light on opposite side (consensual light reflex),

Salient differences between paralytic and concomitant squints
Feature Paralytic squint Concomitant squint
• Onset Sudden Gradual and insidious
• Amblyopia (visual loss) Uncommon Common
• Diplopia Common Absent
• Ocular movements Ocular movements are limited Ocular movements are normal
• Deviation of visual axis Varies as gaze is turned to different directions Constant
• False projection Common Absent
• Vertigo May occur Absent

response to accommodation and response to pain (cilio-spinal reflex). The pupil is best seen when torch light is shone obliquely over the eye.

(iv) Dilated and fixed pupil. There is no response to light and consensual reflex. The consensual reflex is tested by shining light into one eye and noting the contraction of pupil in the other eye. In retrobulbar neuritis pupillary response to direct light is lost but consensual reflex is maintained. Unilateral dilatation of pupil with deteriorating consciousness should be considered as a sign of unilateral tentorial herniation unless proved otherwise. Pupils are normally larger in size in children than in adults and its diameter is normally upto 5 mm.

(v) Pin point pupils are seen in children with pontine lesions and following intoxication with certain drugs especially opioids, barbiturates, phenothiazines, ehtanol, phencyclidine, organophosphate insectiside poisoning

(vi) Loss of accomodation. The child is asked to look at a far object in the room. The examiner suddenly brings his finger in front of patient’s nose, and child is told to look at it. The eyes converge and the pupils should contract on both sides as the child accomodates for the finger.

(vii) Argyll-Robertson pupil (neurosyphilis, diabetes mellitus, Perinaud’s syndrome). The pupillary light reflex is lost but the accomodation reflex is preserved.

(viii) The eye is displaced outwards and downwards. There is loss of all movements of the eye and it can only be moved slightly outwards and little downwards.

Deviation of eye ball due to paralysis of individual extraocular muscles. Diplopia occurs when child is asked to look to the direction towards which the paralysed muscle normally moves the eye ball.

Trochlear (fourth nerve). The nucleus lies in the midbrain and it supplies superior oblique muscle. There is slight upward and outward deviation of the eye. The downward movements of the eye ball is impaired and child complains of diplopia on looking below the horizontal plane.

Deviation of eye ball due to paralysis of individual eye muscles
Muscle Nerve Deviation of eye ball Diplopia occurs when child looks
Internal rectus III Outward Towards nose
Superior rectus III Downward and inward Upward and outward
Inferior rectus III Upward and inward Downward and outward
Inferior oblique III Downward and outward Upward and inward
Superior oblique IV Upward and ouward Downward and inward
External rectus VI Inward Toward temple

Abducent (sixth nerve). Its nucleus lies in the pons and it has a long intracranial course and may get compressed due to raised intracranial tension. It supplies external rectus muscle. The paralysis would cause internal squint and inability to move the eye ball outwards and diplopia occurs on looking outwards. The paralysis of 6th nerve may occur due to generalized increase in intracranial pressure as a false localizing sign.

During examination of ocular movements, look for nystagmus. The child is asked to look at the examiner’s finger which is moved slowly horizontally in either direction and vertically up and down. Note the position of the eye when nystagmus occurs, its character, and direction of fast component. The nystagmus may be pendular (amblyopia), jerky (vestibular), rotary (labyrinthine), horizontal (cerebellar) and vertical (brain stem).

Syndromes involving 3rd, 4th and 6th Cranial Nerves

A number of syndromes arc associated with congenital and acquired affection of ocular cranial nerves.

Horner syndrome (C8, TI) is characterized by miosis, ptosis, enophthalmos and lack of sweating over the face on the affected side. The ciliospinal reflex is lost i.e. pinching of skin of neck is not followed by dilatation of pupil.

Perinaud’s syndrome. There is paralysis of conjugate upward gaze due to involvement of superior colliculi which may occur due to pineal tumor, hydrocephalus, encephalitis, vascular lesions and disseminated sclerosis. There may be nystagmas, enophthalmos and pupils contract on accommodation but do not respond to light (Argyll-Robertson pupil).

Gradenigo’s syndrome. There is paralysis of unilateral rectus muscle with tenderness or swelling behind the ipsilateral ear due to inflammatory disease in the petrous bone.

Moebius syndrome. There is bilateral paralysis of external recti associated with paresis of facial muscles due to aplasia of the 6th nerve nuclei in the brain stem.

Benedikt’s syndrome is characterized by ipsilateral oculomotor palsy with contralateral tremors, ataxia or hyperkinesis of upper extremity due to involvement of 3rd nerve as it passes through the red nucleus.

Weber’s syndrome. Paralysis of third nerve with contralateral hemiparesis occurs due to involvement of 3rd nerve as it passes through the cerebral peduncles due to lesion in the mid brain.

Pontine crossed paralysis. A lesion in the pons involving nucleus of the 7th nerve causes ipsilateral facial paralysis and contralateral spastic paralysis of arm and leg.

Millard-Gubler syndrome is characterized by ipsilateral 6th and 7th nerve paralysis with contralateral pyramidal hemiparesis due to lesion in the brain stem.

Foville’s syndrome. There is ipsilateral 7th nerve paralysis with contralateral pyramidal hemiparesis and paresis of lateral gaze due to involvement of paraabducens nucleus.

Fifth nerve (Trigeminal). It has three branches supplying ophthalmic, maxillary and mandibular regions of the face. The motor component supplies masseters, temporalis and pterygoid muscles. Sensory fibres supply face, conjunctiva, cornea and anterior two-third of the tongue.

(i) Corneal or conjunctival reflex is lost (efferent fibres for this reflex are carried by the seventh nerve).

(ii) Sensory loss over scalp, cheek or mandible depending upon which branch is affected. The patient gets a feeling of broken glass or cup on the affected side while drinking.

(iii) Loss of pain sensations over anterior two-third of tongue.

(iv) Ask the patient to clench his teeth. The masseter and temporalis muscles do not contract on the paralysed side.

(v) Ask the patient to open his mouth. The jaw is deviated towards the paralysed side by the unopposed action of healthy pterygoid muscle. The patient cannot move the jaw from side to side.

Seventh nerve (Facial). It is purely a motor nerve and its nucleus lies in the pons. It supplies all the facial muscles, scalp muscles and platysma except levator pelpebrae superioris.

(i) Pelpebral fissure is wider on the affected side. Affected eye cannot be closed firmly. When attempt is made to forcibly close the eye, the eyeball rolls upwards exposing the sclera (Bell’s phenomenon).

(ii) Forehead cannot be wrinkled on the affected side when child is asked lo look upwards.

(iii) When the child cries, there is asymmetry of the face and angle of the mouth is pulled up on the healthy side while naso-labial fold is flat on the affected side. The sign can be elicited by asking the patient to show the teeth.

(iv) Ask the patient to whistle or blow. The air leaks from the paralysed side. Ask him to blow out his cheeks with air under pressure and test the tension on both sides by tapping each cheek with the finger. The air leaks from the mouth more easily from the paralysed side.

(v) Taste fibres from anterior two-third of tongue are carried by chorda tympani branch of 7th nerve (taste over posterior one-third of tongue is supplied by the 9th nerve). The taste is examined with sugar, salt, lemon and quinine in that order. Taste, salivation and tears may be affected if lesion lies between the brain stem and origin of chorda tympani in the middle ear.

(vi) Hyperacusis may occur due to involvement of nerve to the stapedius in the facial canal which is supplied by 7th nerve.

In lower motor neuron paralysis (nuclear and infranuclear) the facial palsy is total but in upper motor neuron paralysis, eyes and forehead are partially spared and emotional expressions of face are preserved due to bilateral representation of the Upper face in the cortex.

The common causes of unilateral infranuclear facial paralysis include Bell’s palsy, Ramsay Hunt syndrome, otitis media, hypertension, meningitis, Kawasaki disease, Lyme disease, sarcoidosis, Henoch-Schonlein purpura and rhabdomyosarcoma of middle ear.

Bilateral facial palsy is difficult to diagnose and gives a mask like flat non expressive appearance to the face. It is a recognised feature of Guillain-Barre syndrome, Moebius syndrome, infantile botulism, and various myopathies.

Eighth nerve (Auditory). The nerve has two components, auditory and vestibular. Enquire about any hearing defect, tinnitis, hyperacusis, objective vertigo (vestibular), subjective vertigo (8th nerve, middle ear or brain stem) and dizziness. Ask for response of the child to noise of jet plane, banging of door, music and calling of his name etc. In infants, assess for startle response, blinking of eyes, sudden change or cessation of activity, change in heart rate, turning of head towards the sound stimulus of a bell or 60 db vocal sound. The sound stimulus should not be visible to the infant and should not produce a whiff of air. In infants, lack of response to sound may occur due to generalized developmental retardation rather than deafness. If hearing defect is present, ascertain whether it is due to middle ear disease or nerve deafness. Normally air conduction is better than bone conduction. In middle ear disease, bone conduction is unaffected but air conduction is diminished while in nerve deafness both are affected. This can be evaluated clinically with the help of a tuning fork (256 Hz).

In Rinne’s test vibrating tuning fork is placed infront of the ear (air conduction) and then over the mastoid bone (bone conduction), in nerve deafness both air and bone conduction are proportionately reduced while in conduction deafness bone conduction is retained and becomes better than air conduction. In Weber’s test, the vibrating tuning fork is placed over the middle of patient’s forehead. In conduction deafness. Weber’s test is lateralized to the abnormal side while in nerve deafness it is lateralized towards the normal side.

Audiometric evaluation reveals loss of high tones in children with nerve deafness while middle ear deafness is characterized by loss of hearing capability for low tone sounds. When there is gross hearing loss, there is global loss of all sound frequencies.

Ninth and Tenth nerves (Glossopharyngeal and vagus nerves). They supply sensory and motor fibres to soft palate and pharynx respectively. The glossopharyngeal nerve supplies taste fibres to posterior one-third of tongue.

Vagus supplies sensory and motor fibres (through accessory nerve) to respiratory tract, heart and abdominal viscera. The child may complain of dysphagia and nasal regurgitation of fluids and nasal twang of voice due to paralysis of soft palate and pharynx. There is loss of swallowing reflex with drooling and choking. The gag reflex or pharyngeal reflex is lost. The soft palate is pulled or deviated towards the normal side when child with mouth open is asked to say ‘ah’. The bilateral affection of vagus may produce hoarseness of voice or aphonia while unilateral paralysis can be diagnosed on examination of larynx. The left recurrent laryngeal branch of the vagus may be damaged by mediastinal tumor causing stridor due to abductor paralysis.

Eleventh nerve (Accessory nerve). The nerve comprises of two parts, spinal and accessory. The accessory nerve supplies motor fibres to vagus for larynx and pharynx while spinal nerve supplies trapezius and sternomastoid muscles. The paralysis results in inability to shrug the shoulders against resistance and weakness in rotation of chin towards the opposite side.

Twelfth nerve (Hypoglossal). The paralysis is characterized by deviation of protruded tongue towards the paralysed side. The apparent deviation in a patient with facial palsy should be kept in mind. Ask the child to move his tongue from side to side and lick inner side of each cheek with it. The tongue is wasted and shows fasciculations in nuclear and infranuclear lesions. Bilateral weakness, atrophy and faciculations of tongue is pathognomonic of Werdnig-Hoffmanns’s disease.

Bulbar paralysis occurs due to involvement of bulbar nerves or their nuclei (9th, 10th 11th and 12th cranial nerves) in medulla oblongata. It is characterized by pooling of secretions in the posterior pharynx, drooling of saliva, dysphagia, nasal regurgitation of feeds, dysarthria with nasal twang in the voice. There may also be involvement of the medullary respiratory and vasomotor centers producing respiratory irregularity and cardiac dysrhythmia. The common conditions causing bulbar paralysis include acute poliomyelitis, nasopharyngeal carcinoma or sarcoma, Moebius syndrome, Guillain-Barre syndrome, infantile botulism, diphtheritic neuritis, tuberculous meningitis, encephalitis, demyelinating diseases and phenothiazine toxcity.

Pseudobulbar or suprabulbar paralysis is characterized by difficulty in articulation and swallowing with facial rigidity due to bilateral involvement of corticospinal fibres to the bulbar nuclei. The jaw jerk is exaggerated. Pseudobulbar paralysis may occur due to encephalitis, bilateral cerebral thrombosis, infantile form of Gaucher disease, glycogen storage disease type II (Pompe disease) and children with acquired immunodeficiency disorder.

Motor System

Examine upper limbs, trunk and lower limbs in that order.

1. Posture. The limbs may be placed in an abnormal position due to alterations in muscle tone and power. The paralysed lower limb is kept in a state of extension and external rotation at the hip. Pithed frog position of legs is seen in Werdnig-Hoffmann disease, scurvy and poliomyelitis. Decerebrate rigidity results from brain stem lesion any where between inter-collicular level and vestibular nucleus. It is characterized by persistent or episodes of extensor hypertonia and internal rotation of all the four limbs with opisthotonos. The site of lesion in decorticate rigidity is more cephalad, at the interphase of cerebral hemispheres and diencephalon. It is characterized by flexor hypertonia of upper limbs and extensor hypertonia of lower limbs. Decerebrate rigidiy is of graver prognostic significance as compared to decorticate rigidity.

2. Abnormal movements. Look for abnormal movements and note whether they persist during sleep or disappear.

(a) Tremors. Rhythmical oscillations of parts of a limb due to alternate contractions of opposing muscles produce tremors. They may be fine or coarse, static or action or intention tremors. Fine tremors of outstretched hands are seen in anxiety and thyrotoxicosis while more proximal coarse tremors of the outstretched arms and wrists (wing-beating tremors) are seen in Wilson disease.

(b) Chorea. It is characterized by jerky arrhythmic, irregular semipurposive movements of limb or part of a limb almost simulating a bizarre dance. The movements occur at the proximal joints. They are increased by agitation, decreased by voluntary activity and disappear during sleep. If the movements involve one side of the body, it is called as hemichorea. They are accompanied by respiratory irregularity and rapid protrusion and retraction of the tongue with “flapping” of its tip. There is hypotonia, hyperextensibility of joints and inability to hold the hands above the head with palms extended.

(c) Athetosis. It is characterized by continuous, slow sinuous, writhing movements mostly located over the peripheral or distal parts of the extremities. The patient is unable to maintain the fingers and toes in any one position.

(d) Dystonia musculorum deformans or torsion spasms. It is characterized by contorsions and torsion spasms of wide amplitude involving muscles of neck, trunk and proximal parts of limbs. The head, trunk and limbs may be maintained in a bizarre position. Chorea, athetosis and dystonia are produced due to disorders of basal ganglia. It is usually associated with grimacing, grunting and protrusion of tongue. The abnormal movements disappear during sleep and may become less severe during relaxation and volitional activity like dressing and feeding. The common predisposing conditions include birth asphyxia, birth trauma and encephalitis.

(e) Hemiballismus. It is characterized by frequent, violent, rapid, flinging movements of proximal joints of one arm which may injure the patient or others. The condition is usually of sudden onset and is extremely disabling and exhausting. It occurs due to a vascular or neoplastic lesions near the vicinity of sub-thalamic nucleus.

(f) Myoclonus. It is unpredictable, sudden, rapid jerk or twitch of one or more muscle groups. It is distinguished from chorea by virtue of its abruptness and brevity. It usually occurs due to lesions in brain stem and reticular formation.

3. Fibrillations and twitchings. Twitching of muscle fibres of tongue and limbs may occur due to slow degeneration of anterior horn cells or motor nuclei of cranial nerves.

4. Tics. Tics or habit spasms are bizarre facial and shoulder movements without any organic disease. They are stereotyped, repetitive movements which are easily produced voluntarily such as blinking of eyes, pursing of lips, frowning of forehead, shrugging of shoulders etc. They increase during anxiety, tension and nervousness when child is being watched and often disappear while concentrating on a job. Gilles de la Tourette syndrome is a rare disorder which is characterized by multiple persistent tics often accompanied by inarticulate cries or barks and compulsive utterances of obscenities.

5. Wasting. The wasting of muscles is marked in cases of lower motor neuron paralysis. Assess whether it is predominently affecting proximal or distal groups of muscles and whether involvement is symmetrical or asymmetrical on the two sides. The circumference of the limbs should be measured at identical points identified in relation to reliable bony landmarks like anterior superior iliac spine and olecranon. In congenital hemiatrophy or hemihypertrophy all the tissues of the limb including the bones are affected.

6. Trophic changes. Look for painless effusion of joints, vasomotor distubances, bed sores or trophic ulcers, erythema or pigmentary changes.

7. Muscle tone. The muscle tone is evaluated by (i) looking for abnormal posture of the limb, (ii) palpation of muscles for soft or flabby and stiff feel, (iii) resistance to and range of passive movements at major joints (iv) and by shaking the unsupported limb for range and flaility of movements. Refer to Chapters 6 and 13 for assessment of tone in infants. The tone should be compared on the two sides by maintaining the head in midline. It may be normal, decreased or increased. In pyramidal lesions, the patient develops claspknife type of spasticity when resistance is most marked at the beginning of passive movements. In cerebral diplegia due to pyramidal lesion, the neck and trunk remain relatively hypotonic. Plastic or lead-type of rigidity is seen due to increased tone of both protognists and antagonists muscles in patients with extra-pyramidal lesion. The presence of tremors in such a patient leads to cogwheel type of rigidity.

8. Power. Assess the motor disability by asking as to which acts of daily life routine the child cannot perform. Whether the child can self feed, undress and dress himself, look after toilet needs, comb his hair etc. or not. Apraxia is defined as inability to carry out a well-organized voluntary acitivity on command without having any significant impairment of motor, sensory and coordination function. Watch the manner and dexterity with which an infant holds and manipulates the toy and his responses to what is going around him. During first 2 years most children are ambidexterous and donot have any preference to use a particular hand. When there is unequivocal preference to use a particular hand during infancy, it should be considered as an earliest manifestation of infantile hermiplegia due to neonatal stroke. Ask the child to hop on one foot, walk forwards and backwards, toe walk, heel walk, rise from squatting or lying down position etc. The active movements at all the joints should be tested without and against varying grades of resistance. The infant should be watched for spontaneous movements. Assess whether weakness is affecting predominantly proximal (myopathy, Gullain-Barre syndrome) or distal (peripheral neuropathy) group of muscles and whether it is symmetrical or asymmetrical. In hemiplegia, arm is usually more severely affected than the leg while in tetraparesis or diplegia, lower extremities are usually more affected than the upper. For assessment of trunk muscles, ask the patient to sit up from supine position without taking support of his anus. When he tries to sit up, watch the umbilicus whether it deviates upwards, downwards or sidewards (Beevor’s sign) and whether any portion of abdomen baloons out. By using various tricks and innovations, test the strength of group of muscles used to execute movements of flexion, extension, adduction, abduction and rotation at various joints beginning from the proximal and going towards the distal joints. Some of the important individual muscles can be tested as follows:

1. Ask the child to elevate or shrug the shoulders (trapezius).

2. Ask the patient to abduct the arms to horizontal position (deltoid C5,C6).

3. Ask the patient to flex the elbow with forearm supinated and palm facing upwards (biceps C5,C6).

4. Ask the child to extend the arm against resistance (triceps C7, C8).

5. With the patient sitting at the edge of table, ask him to raise the leg to extend the knee (quadriceps L2,L3,L4).

6. Patient lies in lateral decubitus and is asked to flex the knee and abduct the hip of superior leg (gluteus medius L4,L5,S1).

7. Patient lies prone with both the knees flexed and is asked to lift the hips off the bed (gluteus maximus L5,S 1 ,S2).

8. Patient lies supine and is asked to push down examiner’s palm with sole of the foot (gastrocnemius and soleus L5,S1,S2).

9. Patient lies supine and is asked to dorsiflex the foot against resistance (tibialis anterior L4,L5,S1).

10. Paralysis of respiratory muscles is characterized by rapid shallow breathing, weak voice or cry, inability to count beyond 10 with a single breath, anxious look and cyanosis. Paradoxical breathing i.e. retraction of abdomen with each inspiration is suggestive of diaphragmatic paralysis which is often associated with paralysis of deltoid muscles due to identical spinal innervation (C5, C6). In phrenic nerve injury, paradoxical inward movement of ipsilateral abdominal wall occurs with inspiration due to paralysis of diaphragm. The umbilicus moves upwards towards the involved side which has been called as “belly dancer’s sign”.

The muscle power is graded as follows:

 
Charting of Muscle Power Grade
No flicker 0
Flicker + 1
Movement possible with gravity eliminated 2
Movement possible against gravity 3
Movement possible against gravity and some resistance 4
Normal power 5

In hysterical paralysis, child makes little effort to execute a movement as evidenced by positive Hoover’s sign. The patient lies on his back and examiner puts one hand under the heel of the normal side. The child is asked to elevate the apparently paralysed leg keeping the knee extended. In genuine hemiplegia, while patient is attempting to raise the paralyzed limb, there is counter pressure from the normal limb. There is no muscle wasting in hysterical paralysis.

9. Coordination. Incoordination is pathognomonic of cerebellar dysfunction. The coordination cannot be tested unless child has fair degree of muscle power. Infant’s coordination can be tested by offering him small objects or toys by playful interaction.

(a) Finger-nose test with eyes open and closed. Each arm in turn is drawn out to full abduction and child is asked to alternately touch the tip of his nose and examiner’s finger (which is moved to different positions) with the help of tip of his index finger. Look for intention tremors and past pointing (dysmetria).

(b) Dysdiadochokinesia. Inability to perform alternating movements with speed and precision e.g. supination-pronation movements, clapping, rapid touching of thumb and little fingers on both sides etc. Normally children above 5 years of age are able to execute rapid alternate movements with ease and speed.

(c) Hand writing record is useful for follow up to assess the improvement. Ask the patient to draw a line between two converging lines, thread a needle or bead, draw a person, tie shoe laces etc.

(d) Rebound phenomenon. Try to extend the patient’s elbow against his biceps contraction and resistance. When wrist is suddenly released the hand would jerk back suddenly and may hit his face.

(e) Heel-knee test for lower limbs is equivalent of finger-nose test in the upper limbs. In addition, ask the patient to lie in a prone position and maintain his both legs flexed at right angle at the knees. Observe how long the legs can be kept without fatigue and tremors.

(f) Gait. Ask the patient to walk along a straight line. Make the child walk around a chair, observe his balance on sudden bending of trunk or while taking sudden turn on walking.

10. Deep tendon reflexes. Tendon reflexes are exaggerated in patients with pyramidal lesion while they are sluggish or absent if lower motor neurons or muscles are diseased. The patient should be relaxed and free from anxiety or tension when deep jerks are elicited. The attention of the infant should be diverted by offering him a toy or key ring. Look for movement of the limb and visible contraction of the muscle. The spinal segments involved in various deep tendon jerks are given below:

Jaw jerk:  Pons
Biceps jerk:  C5.C6
Triceps jerk:  C7,C8
Supinator jerk:  C5, C6
Knee jerk:  L3 , L4
Ankle jerk:  S1, S2

Jaw jerk is elicited by asking the child to relax and open his mouth slightly. The examiner places his index finger on the mid point of the child’s chin and taps it gently with a reflex hammer. Easily elicitable jaw jerk is indicative of pyramidal involvement above the level of pons. Exaggerated jaw jerk in a child with evidences of pyramidal involvement in all the limbs indicates that lesion must be higher than the cervical spine. It is commonly seen in patients with pseudobulbar palsy, motor neuron disease and disseminted sclerosis. The techniques for elicitation of other deep tendon jerks are illustrated. In newborn babies and infants, middle finger can be used (instead of reflex hammer) to elicit the deep tendon jerks. Deep tendon jerks are rather brisk during infancy. When knee jerk is elicited on one side, crossed adductor response may be obtained in normal infants. The reacting muscle should be palpated as well as observed for the movement produced. Toe jerks can be elicited in infants by tapping the base of the toes or dorsum of the foot. Brisk flexion of toes may be seen in infants with cerebral palsy and progressive degenerative brain disease.

When deep tendon jerks are sluggish, try to elicit them after diverting child’s attention or re-enforcement. When deep tendon jerks are exaggerated, look for sustained (at least 8-10 jerks) knee and ankle clonus which are elicited by sudden jerky stretching of tendons.

The deep tendon jerks are charted in the file as depicted. The tendon jerks are graded as follows:

Absent even with reinforcement:  0
Sluggish:  +
Normal:  ++
Brisk:  +++
Exaggerated and associated with clonus:  ++++

Sensations

Their precise evaluation is difficult in young children.

1. Superficial. Cotton touch, pain, and temperature (hot and cold).

2. Deep sensations. Sense of pressure, sense of position, sense of movements, vibration sense (128 Hz).

3. Cortical sensations

(a) Two-point discrimination. Two pin pricks upto 1 cm apart can be normally appreciated. A pair of compass having two sharp pin ends can be used to assess two-point discrimination.

(b) Sensory inattention. Two mirror spots on the two sides are simultaneously pricked. The patient may not feel the prick on the affected side. When proximal and distal (cheek and hand) parts of the body are touched simultaneously, the patient with parietal lobe lesion may not recognise the distal stimulus due to extinction.

(c) One point localization.

(d) Astereognosis. The child is unable to identify an object by touch (with eyes closed), due to inability to appreciate shape, texture and weight.

(e) Graphesthesia. There is inability to appreciate the figures and shapes drawn with a pen on the palms and soles.

Superficial Reflexes

1. Corneal or conjunctival reflex (5th and 7th cranial nerves). Touching of cornea or bulbar conjunctiva with a cotton wick is followed by prompt closure of the eye. Ask the child to look in one direction and approach the bulbar conjunctiva from the other side. When sensory reflex arc is disrupted (5th nerve damage), there will be no response from either lid when the affected side is stimulated, and a normal response from both sides when the normal side is stimulated.

2. Abdominal reflexes (D6-D12). Stroke gently with a pencil or key four quadrants from periphery towards the umbilicus. The underlying muscles in the quadrants stimulated contract and the umbilicus moves in that direction. Abdominal fat of infants may interfere with the response. Avoid too firm pressure which will elicit deep abdominal reflexes instead. The loss of abdominal reflexes (along with exaggerated deep tendon jerks in the lower limbs) is suggestive of pyramidal lesion above D-8 level.

3. Cremasteric reflex (L1, L2). Stroke the medial aspect of upper thigh and watch for ipsilateral contraction of cremaster muscle. It is usually lost in patients with pyramidal lesion above the level of LI. It is normally exaggerated in infants and may remain intact even when there is a pyramidal lesion. The cremasteric reflex may be absent if testes are underscended or already retracted.

4. Anal reflex (S3, S4). Perianal area is stroked and anal response observed. Anal tone should also be palpated.

5. Plantar reflex or Babinski response (S1, S2). The plantar surface of the foot is scratched with thumb nail, match stick, key or any semi-sharp object along the lateral border of the sole, from heel forwards crossing over the distal ends of the metatarsals towards the base of great toe. Younger is the child, lighter should be the stimulus. The response may be extensor (positive Babinski) with dorsiflexion of great toe and fanning of small toes, flexor (normal), equivocal or withdrawal. In infants upto two years of age, plantar response may be normally extensor on both sides and is associated with eversion of foot and dorsiflexion of ankle. Unilateral extensor plantar response is pathological even during infancy and is suggestive of pyramidal lesion. Extensor plantar response is diagnostic of pyramidal lesions above the level of S1. In addition to conventional technique of elicting plantar response, the following additional techniques may be used to elicit plantar reflex:

(a) Oppenheim’s sign. Apply firm pressure over tibia from above downwards to elicit plantar response.

(b) Chaddock’s sign. Scratch around the lateral malleolus.

(c) Gordon’s sign. Firm squeeze of tendo achillis or muscles of calf is followed by plantar response.

(d) Hoffmann’s sign is equivalent of Babinski in the upper limbs. The patient is asked to stretch his hand towards the examiner with palm facing downwards. The terminal phalanx of the middle finger of the patient is grasped with the index and middle fingers of examiner’s hand. A sharp snap or flick is given to the terminal phalanx and nail of patient’s middle finger with the thumb and index finger of examiner’s right hand. Sudden adduction of patient’s thumb and flexion of other fingers is indicative of pyramidal lesion above C7.

(e) Wartenberg’s sign. The child is asked to supinate his hand and flex the fingers like a claw. The examiner locks his flexed fingers with the patient and exerts resistance. Normally, the thumb extends though its terminal phalax may flex slightly. In pyramidal tract lesion, thumb adducts and flexes strongly towards palm.

6. Glabellar tap reflex. Tapping of nasion is followed by blink response. The response normally disappears after 3 to 4 taps due to habituation. Persistent uninhibited glabellar tap response is suggestive of diffuse degenerative disorder of CNS.

7. Palmo-mental reflex. Scratch or tap the thenar eminence of hand. There is no response normally. Contraction of the mentalis or orbicularis oris muscle on the ipsilateral side is indicative of bilateral frontal lobe lesion.

8. Grasp reflex. The presence of unilateral grasp reflex in a child with CNS disorder is suggestive of lesion of frontal lobe on the opposite side.

9. Ciliospinal reflex. When skin of the neck is pinched, pupil dilates due to stimulation of reflex spinal arc through sympathetic trunk. The absence of ciliospinal reflex is suggestive of deep coma and is used as one of the criteria for brain death.

Spine and Sphincters

They must be checked in every patient. The spinal cord ends at the level of lower border of body of first lumbar vertebra (lower border of L3 in the newborn) but meninges are carried as far down as second sacral vertebra. The spinal segments do not correspond numerically with overlying vertebrae as shown below:

 
Vertebral Body Spinal Segment
Cervical Add 1
1st-6th Dorsal Add 2
7th-9th Dorsal Add 3

The 10th dorsal arch overlies L1 and L2, eleventh dorsal arch over L3 and L4 and twelfth dorsal arch over L5 and S1. All the sacral and coccygeal segments are located against the first lumbar vertebra. It should also be remembered that spine corresponds to the next vertebral body below.

The urinary bladder has three neural mechanisms; sacral parasympathetic (S2, S3) which is excitatory or motor, inhibitory sympathetic supply ending at L1, L2 and a voluntary excitatory corticospinal pathway. Cord lesions at the sacral level are associated with urinary retention. After a few weeks, reflex bladder evacuations occur in response to bladder distension. Lesions of the cauda equina usually result in persistent incontinence. Higher cord lesions may lead to precipitancy or urgency of micturition and at times even hesitancy of micturition and retention of urine due to involvement of voluntary excitatory corticospinal fibres. Bowel involvement is usually characterized by constipation and retention of feces irrespective of the level of lesion. The lesions at sacral level, however, are usually associated with relaxation of external rectal sphincter leading to fecal incontinece.

The salient clinical differences between extraraedullary and intra medullary spinal tumors are shown in table.

Differences between extramedullary and intramedullary spinal tumors
Extramedullary (intradural) Intramedullary
1. Root pains and local spinal tenderness are common. Root pains and spinal tenderness are rare
2. Paraesthesia is rare and often late Paraesthesia is common and early
3. Muscle spasms are common Muscle spasms are rare
4. Bladder and rectal disturbances occur late Sphincter disturbances are early
5. Hemisection of cord or Brown Sequard syndrome may occur i.e ipsilateral motor and proprioceptive impairment and contralateral loss of pain and temperature This is rare
6. Spasticity and other pyramidal signs are prominent Spasticity is less common
7. No sensory dissociation Dissociation of sensations is common i.e. there is loss of sensation of pain and temperature while touch is preserved
8. Muscle atrophy is uncommon Muscle atrophy is common
9. Trophic changes arc uncommon Trophic changes are common
10. CSF changes due to spinal block are common CSF changes are rare

Gait

Gait of the child should be closely observed to identify any abnormalities. The child should be asked to squat on the floor and watched as he gets up to the standing posture. Gower’s sign, wherein child “climbs up his legs” to stand due to weakness of glutei maximi muscles is classically seen in children with Duchenne’s muscular dystrophy. Difficulty in getting up from squatting posture is also seen in children with polymyositis, poliomyelitis and Guillain-Barre syndrome. Ask the child to walk on heels and toes, skip on one foot, and climb upstairs, etc. Children over 5 years of age are able to walk on their toes and hop. The ability to skip occurs by 7 years of age and tandem walking is achieved by 9 years. Gait is best evaluated when the child is unaware of being watched.

1. Spastic gait (pyramidal lesion). There is circumduction and lifting of the leg in the form of an arc at the hip. Hip is elevated on the affected side with slight dragging of the foot and scraping of toes.

2. Stamping gait (posterior column lesion). The foot is placed on the ground with a thud due to loss of sense of position.

3. High stepping gait. High steps are taken due to foot drop to avoid tripping of toes. The patient walks cautiously while watching the floor intently. It is seen in children with peripheral neuropathy, poliomyelitis and progressive muscular atrophy.

4. Ataxic gait or staggering gait or reeling gait (cerebellar lesion). Patient walks like a drunkard man. The gait is unsteady and uncoordinated and he cannot walk in a straight line or around a chair. Friedreich’s ataxia produces combined sensory and cerebellar ataxia.

5. Festinent gait (Parkinsonism). The patient walks with a short, stiff and shuffling steps. The arms donot swing during walking.

6. Waddling gait. The waddling gait like a duck is seen in patients with Duchenne’s muscular dystrophy, bilateral congenital dislocation of hips, bilateral coxa vara, achondroplasia, Morquio’s disease, exstrophy of bladder (pelvic bones are widely separated), bilateral slipped femoral epiphyses, polymyositis, Engelmann’s disease and myelodysplasia.

7. Scissor gait. It is seen in children with cerebral diplegia due to bilateral adduction and contractures.

8. Limping gait may occur due to a variety of neuromuscular and orthopedic disorders of the lower limbs.

9. Astasia abasia occurs due to hysterical inability to stand and walk. The patient is ataxic and sways from the hips rather than ankles. The ataxia decreases when patient is not watched or attention is diverted by asking him to execute finger-nose test. The hysterical patient does not injure himself.
He is not benefitted by holding wall or furniture unlike a patient with organic ataxia.

Differences between Upper and Lower Motor Neuron Paralysis

Differences between upper and lower motor neuron paralysis
Upper motor neuron paralysis Lower motor neuron paralysis*
1. Power is reduced. Power is markedly reduced.
2. Distribution of paralysis is diffuse. Distribution of weakness is asymmetric and corresponds to individual muscles.
3. Tone is spastic. Hypotonia or atonia occurs.
4. Muscle wasting is absent or minimal. Muscle wasting is marked.
5. Deep tendon reflexes are brisk and clonus may be present. Deep tendon reflexes are sluggish or absent.
6. Plantars are extensor. Plantars are flexor or absent.
7. Convulsions or involuntary movements may be associated. Fasciculations and sensory loss may be seen.
8. No reaction of degeneration. Reaction of degeneration is present.

* The lesion may be anywhere in the spinal reflex are i.e. the sensory root, anterior horn cell, anterior spinal root, peripheral motor or sensory nerve, terminal motor end plate or muscle itself.

Cerebellar Signs

1. Tone is decreased. Power is normal but there is easy fatiguability.

2. Nystagmus. In cerebellar nystagmus the fast component is towards the side of lesion. The nystagmoid movements become slow and coarse when eyes are turned towards the side of lesion. In contrast, vestibular nystagmus is towards the affected side.

3. Skew deviation of eyes may occur in acute cerebellar lesions. The eye towards the side of lesion is turned downwards and inwards.

4. Incoordination. Its presence is assessed by following tests:
(a) Finger-nose test
(b) Dysdiadochokinesia
(c) Ankle-knee test
(d) Handwriting
(e) Rebound phenomenon
(f) Romberg’s sign is negative

5. Deep tendon jerks are pendular.

6. Speech is explosive and jerky with scanning of syllables.

7. Gait is ataxic or reeling in character. The patient has a tendency to fall towards the side of lesion. The minimal ataxia can be brought out by asking the patient to walk around a chair in both directions, taking sudden turn, sudden flexion of trunk, sits-stands etc. Trunkal ataxia is common among children due to involvement of vermis. Heel-to-toe walking and walking along a straight line are particularly difficult in these children. In midline posterior fossa or cerebellar vermis lesion (tonsillar herniation due to Arnold- Chiari malformation) no abnormalities of coordination may be detected when patient is lying in bed. However, there will be gross ataxia on walking which should not be misdiagnosed as hysteria.

Autonomic Functions

Autonomic dysfunction is evidenced by instability and excessive fluctuations of vital signs, excessive or reduced sweating, areas of skin with blanching or blotchyness, inadequate or absent salivation or lacrimation and sphincteric disturbances. Record the pulse rate at rest and following six maximal deep breaths. In normal subjects the pulse rate should fall by greater than 15 beats/min; with autonomic disturbance pulse rate slows by less than 10 beats/min. In patient with autonomic dysfunction, the systolic blood pressure may fall greater than 30 mm Hg on standing from recumbent position.

Diagnosis and Localization of CNS Disorder

Imaging technology (CT scan, MRI) has provided most reliable and noninvasive means for exact localization of the space occupying lesion and other disorders in the CNS. Nevertheless, attempt should be made to identify the following characterstics of the CNS disorder on clinical examination. In order to enhance the clinical acumen, the diagnosis based on clinical evaluation of CNS should be correlated with CT/MRI findings to augment the learning process and improve the clinical skills.

1. Is disease acute or dramatic in onset, subacute or insidious?

2. Is the disorder stationary, progressive or showing slow or fast recovery?

3. Are there any associated clinical features of raised intracranial tension?

4. Is the disease diffuse and generalized or localized to the specific area/s of central nervous system?

5. Is it primarily a white matter disease, grey matter disease or combined?

6. Summarise the positive CNS findings and their probable localization in the CNS. Provides useful guidelines for localization of the probable site of lesion in the CNS on the basis of abnormal neurological findings and basic knowledge of neuroanatomy.

7. What is the probable nature of the disease and diagnostic possibilities? Is it a space occupying lesion, infective, metabolic or degenerative CNS disorder, vascular phenomenon, anoxic insult, toxic, traumatic, psychotic, functional disorder or conduct, disorder?

Scheme for presentation

General physical examination:    General appearance, level of consciousness, nature of disability, skull for size, shape, symmetry, swellings, fontanel (flat, bulging, pulsatile or non pulsatile), sutures, Macewen’s sign, auscultation for bruit, transillumination of skull and examination of spine for deformities, Pott’s disease, epidural abscess, primary or metastatic neoplasm, meningomyelocele, tuft of hair, sinus tract, myelodysplasia etc.

Typical facies, facial dysmorphism, evidences of neuroectodermal dysplasia, and abnormalities of teeth. Eyes for proptosis, corneal opacities, buphthalmos, cataracts, pupillary changes, and Kayser-Fleischer ring. Temperature, pulse, respiration, blood pressure (including Trousseau’s sign).

Anemia, cyanosis, jaundice, lymphadenopathy, hepatosplenomegaly and abdominal mass.

Evidences of meningeal signs (neck rigidity, Kernig’s sign, Brudzunski’s sign, tripod sign, photophobia) and raised intracranial tension (enlargement of head size, sutural diastasis, bulging anterior fontanel, 6th nerve palsy, Macewen’s sign, papilledema, herniation of hippocampus with unilateral dilated and fixed pupil and involvement of vital centers). Record handedness of the child.

Higher function:    Level of consciousness, orientation in time and place, memory (immediate, recent and past), emotional status, delusions and hallucinations, speech, brain stem automatic reflexes and cortical release reflexes.

Developmental screening:    Developmental status in relation to the neurological symptoms, developmental age, development quotient and clinical grades of mental subnormality (normal, dull normal, educable in ordinary school, educable in a special school, trainable but not educable, not trainable), status of special senses i.e. vision and hearing.

Cranial nerves:    Describe abnormal findings pertaining to involvement of cranial nerves, unilateral or bilateral, whether upper motor or lower motor neuron type.

Motor system:    Describe findings in the upper limbs, trunk and lower limbs. Posture of limbs, abnormal movements, fasciculations and twitchings, wasting, trophic changes, muscle tone (normal, increased-spastic or rigid, decreased), power (nature of disability affecting daily routines of living, can he walk, stand or sit, getting up from supine position, strength in various groups of muscles i.e. flexors, extensors, adductors and rotators and some important individual muscles, is weakness affecting proximal or distal groups of muscles, is it symmetrical or asymmetrical, grade of muscle power etc.), coordination (finger-nose test, dysdiadochokinesia, hand writing, rebound phenomenon, heel-knee test, gait etc.), deep tendon jerks (normal, sluggish, absent, brisk, exaggerated, with or without ankle and knee clonus).

Describe gait, walking around a chair, sit-stands, walking upstairs, toe walking, heel walking, Romberg’s sign etc.

Sensations:    Superficial, deep and cortical sensations.

Superficial reflexes:    Corneal or conjunctival reflex, abdominal reflexes, anal reflex, plantar reflex (flexor, extensor or positive Babinski response, withdrawal response, equivocal). Hoffmann’s sign, glabeller tap reflex, palmo-mental reflex, grasp reflex, ciliospinal reflex.

Cerebellar sings:    Decrease in tone, nystagmus, skew deviation of eyes, incoordination, ataxic gait, and pendular jerks.

Autonomic dysfunction:    Sphincteric distubances, instability and wide fluctuations of vital signs, changes in salivation, lacrimation and sweating.