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Reflexes-lec3.pptx

  1. Dr. Samawiya Farooq
  2. Introduction A reflex is an involuntary or automatic action that your body does in response to something without even having to think aboutit Neonatal reflexes – inborn reflexes present at birth & occur in a predictablefashion Normally developing newborn should respond to certain stimuli with thesereflexes
  3. Reflex arc Anatomical pathway for a reflex is called as reflex arc It has 5 components :  Receptor  Afferent nerve  Center  Efferent nerve  Effectororgan
  4. Classification of reflexes Depending upon whether inborn or acquired  Unconditioned reflexes, inborn reflex  Conditioned reflexes/acquired reflexes
  5. Depending upon the situation of the center  Cerebellar reflexes  Cortical reflex  Midbrain reflex  Bulbar or medullary reflexes  Spinal reflexes
  6. Depending upon the purpose  Protective/flexor reflexes  Antigravity/extensor reflexes  Depending upon clinical basis  Superficial reflexes  Mucus membrane  Cutaneous reflex  Deep reflexes  Visceral reflexes  Pathological reflexes
  7. Significance of reflexes Helps to identify whether the child is developing normally or not Tells about what abnormalities the child may be having if all reflexes are not proper Knowledge of development of motor skills – helps to identify whether development is going on at a proper rate or not
  8. Types of reflexes
  9. General bodyreflexes :  Moro reflex/Startle reflex  Palmar/grasp reflex  Plantar graspreflex  Walking/stepping reflex  Limb placement reflex  Asymmetric tonic neck reflex  Symmetric tonic neck reflex  Babinski’s reflex  Babkin reflex  Parachute reflex  Landau reflex
  10.  Withdrawal reflex  Trunk incurvation reflex  Tendon reflexes  Gallant’s reflex Tonic labyrinthine reflex Facial reflexes :  Nasal reflex  Blink reflex  Doll’s eye reflex  Auditory orienting reflex
  11. Oral reflexes :  Rooting reflex  Sucking reflex  Swallowing reflex  Gag reflex  Cry reflex
  12. General body reflexes Moro reflex/ startle reflex  Begins at 28weeks of gestation  Initiated by any sudden movementof the neck  Elicited by -- pulling the baby halfway to sitting position from supine & suddenly let the head fall back  Consists of rapid abduction & extension of arms with the opening of hands, tensing of the back muscles, flexion of the legs and crying
  13. • It is similar to moro reflex, but it is initiated by sudden noise or any other stimulus • In this, the elbows are flexed and the hands remain closed, there is less of embrace, outward and inward movement of arms. STARTLE REFLEX
  14. Within moments, the arms come together again Clinical significance Its nature gives an indication of muscle tone Failure of the arms to move freely or the hands toopen fully indicates hypotonia. It fades rapidly and is not normally elicited after 6 months of age.
  15. Palmar/grasp reflex  Begins at 32weeks ofgestation  Light touch of the palmproduces reflex flexion of the fingers  Most effective way -- slide the stimulating object, such as afinger or pencil, across the palm fromthe lateral border  Disappears at 3-4months  Replaced by voluntary grasp at45 months
  16. Clinical significance  Exceptionally strong grasp reflex -- spastic form of cerebral palsy & Kernicterus  May be asymmetrical in hemiplagia & in cases of cerebral damage  Persistence beyond 3-4months indicate spastic form of palsy
  17. Plantar/grasp reflex  Placing object or finger beneath the toes causes curling of toes around the object  Present at 32weeks ofgestation  Disappears at 9-12 months • Clinical significance :  This reflex is referred to as the "readiness tester".  Integrates at the same time that independent gait first becomes possible.
  18. Walking/stepping reflex  When sole of foot is pressed against the couch, baby tries to walk  Legs prance up & down as if baby is walking or dancing  Present at birth, disappearsat approx 2-4 months  With daily practice of reflex, infants may walk alone at 10 months
  19. Clinical significance Premature infants will tend to walk in a toe-heel fashion while more mature infants will walk in a heel-toe pattern.
  20. Limb placement reflex  When the front of the leg below the knee or the arm below the elbow is brought into contact with the edge of a table, child lifts the limbs over the edge  Present at birth, fades awayrapidly in early months of life • Clinical significance  Reflex is readily demonstrable in the newborn and persistent failure to elicit it at this stage, is thought to indicate neurological abnormality
  21. Withdrawal reflex  Protective reflex  Stimulus :a pinprick or asharp painful stimulus to sole of foot  Response :flexion & withdrawal of stimulated leg  Present at birth, persists throughout life  Clinical significance – Absence of this is seen in neurologically impaired infants.
  22. Asymmetric tonic neck reflex  Most evident between 2-3months ofage  When the baby is at rest and not crying, he lies at intervals with his head on one side, the arm extended to the same side, and often with a flexion of the contra lateral knee. • Clinical significance  This reflex normally disappears after 2 or 3 months, but may persist in spastic children.
  23. Symmetric tonic neck reflex  Extension of the head causes extension of the fore limbs and flexion of the hind limbs Evident between 2-3months ofage  Clinical significance  Not normally easily seen or elicitedin normal infants  May be seen in an exaggerated form in many children with cerebral palsy.
  24. Babinski’s reflex  Stimulus consists of a firm painful stroke along the lateral border of the sole fromheel to toe  Response consists of movement (flexion or extension) of the big toe and sometimes movement (fanning) of the othertoes  Present at birth, disappears at approx9-10 months  Presence of reflex later may indicate disease
  25. Babkin reflex  Deep pressure appliedsimultaneously to the palms of both hands while the infant is in supine position  Stimulus is followed by flexion or forward bowing of the head, opening of the mouth and closing of the eyes  Fades rapidly and normally cannot be elicited after 4 months of age.
  26. • Clinical significance  Reflex can be demonstrated in the newborn, thus showing a hand-mouth neurological link, even at that early stage
  27. It appears at about 6-9 months and persists thereafter. The reflex is elicited by holding the child in ventral suspension and suddenly lowering him to couch. The arms extend as defensive a defensive reaction. In children with cerebral palsy, the reflex may be absent or abnormal. It would be asymmetrical in spastic hemiplegia.
  28. Landau reflex  Seen in horizontal suspension with the head, legs & spine extended  If the head is flexed, hip knees & elbows also flex  Appears at approximately 3months, disappears at 12-24 months • Clinical significance  Absence of reflex occurs in hypotonia, hypertonia or mental abnormality
  29. Trunk incurvation reflex  Stroking one side of spinal column while baby is on his abdomencauses  Crawling motion with legs  Lifting head from surface  Present in utero, seen at approximately 3rdor 4th day  Persists for 2-3 months
  30. Gallant’s reflex  Firm sharp stimulation along sides of the spine with the fingernails or a pin produces contraction of the underlying muscles and curving of the back.  Response is easily seen when theinfant is held upright and the trunk movement is unrestricted  Best seen in the neonatal period and thereafter graduallyfades.
  31. Tendon reflexes Simple monosynaptic reflexes, which are elicited bya sudden stretch of a muscletendon Occurs when the tendon istapped Present throughout life
  32. Spinal cord levels of the tendon reflexes
  33. Clinical significance  Useful diagnostically for : Detection of upper motor neuron lesions(exaggerated response) Myopathic conditions (depressed or absentresponse) Localization of the segmental lesions of thecord.
  34. Tonic labyrinthine reflex Labyrinths -- most importantorgans concerned with the development of anti-gravity postures and balance  Movement of the head in any dimension stimulates the labyrinths; and produces the appropriate responses  Arms & legs extend when head moves backwards, & will curl in when the head moves forward  Emerges in utero until approximately 4 months postnatally
  35. Facial reflexes Nasal reflex  Stimulation of the face or nasal cavity with water orlocal irritants produces apnea in neonates  Breathing stops in expiration with laryngeal closure in infants – bradycardia & lowering of cardiac output  Blood flow to skin, splanchnic areas muscles & kidney decreases  Flow to the heart & brain remains protected
  36. Blink reflex  A bright light suddenly shone into the eyes, a puff ofair upon the sensitive cornea or a sudden loud noise will produce immediate blinking of the eyes  Purpose – to protect the eyes from foreign bodies &bright light  May be associated tensing of the neck muscles, turning of the head away from the stimulus, frowning and crying  Reflexes are easily seen in the neonate and continue to be present throughout life
  37. Clinical significance Examination is a part of some neurological exams, particularly when evaluatingcoma Satisfactory demonstration of these reflexes indicate–  No cerebral depression  Contraction of appropriate muscles in response
  38. Doll’s eye reflex (Oculocephalic reflex) Passive turning of the head of the newborn leaves the eye “behind”  A distinct time lag occurs before the eyes move to a new position in keeping with the head position  Disappears at within a weekor two of birth  Failure of this reflex to appear indicates a cerebral lesion Head Eye
  39. Auditory orientingreflex  A sudden loud and unpleasant noise :  May produce the blink reflex  Infant may remain still and show increased alertness  Quieter sounds usually cause reflex eye and head turning tothe side of the sound, as if to locate it  Seen first at about 4 months of age  Thereafter, head turning towards sound stimuli occurs and the accuracy of localization increases rapidly by 9-10 months
  40. Clinical significance  Reflex responses are made use of in tests of infants for hearing loss  Pattern of the localization responses indicates the level of neurological maturity
  41. CORNEAL REFLEX • Consists of blinking when cornea is touched PUPIL REFLEX • Pupil reacts to light, but in preterm baby and some full term babies the duration of exposure to the light may have to be prolonged to elicit the reflex.
  42. Oral reflexes Rooting reflex  Baby’s cheek is stroked :  They respond by turning their head towards the stimulus  They start sucking, thus allowingfor breast feeding  When corner of mouth is touched, lower lip is lowered, tongue moves towards the point stimulated  When finger slides away, head turns to follow it  When center of lip is stimulated, lip elevates
  43. Onset is 28 weeks IU Disappears by 3-4 months Well- establised by 32-34 weeks IU
  44. Clinical significance Persistence can interfere withsucking Absence of this is seen in neurologically impaired infants.
  45. Sucking / Swallowing reflex Touching lips or placing something in baby’s mouth causes baby to draw liquid into mouth by creating vacuum with lips, cheeks & tongue  Onset – 28weeks IU  Well established – 32-34weeks IU  Disappears around 12months
  46. Clinical significance : Persistence may inhibit voluntary sucking Sigmund Freud - Any kind of deprivation of the activity will lead to fixation resulting in oral habits
  47. Gag reflex (Pharyngeal reflex)  Seen in 19weeks of IU life  Reflex contraction of the back of the throat  Evoked by touching the roof of the mouth, the back of the tongue, the area around the tonsils and the back of the throat
  48. Functional significance  It, along with reflexive pharyngeal swallowing, prevents something from entering the throat except as part of normal swallowing and helps prevent choking  Clinical significance  Absence of the gag reflex -- symptom of a number of severe medical conditions :  Damage to the glossopharyngeal nerve, the vagus nerve,  Brain death.
  49. It is a non- conditioned reflex which accounts for its lack of individual character and is of sporadic nature. Starts as early as 21-29 weeks IU life.
  50. Importance of cry  It is infant’s first verbal communication  Can be interpreted as a message of urgency ordistress  Indicates:  Hunger  Pain  Discomfort
  51. Begins around 12 and half weeks IU life. Full swallowing and sucking is established by 32-36 weeks of IU life. Their absence in full-term baby would suggest a developmental defect.
  52. INFANTILE SWALLOW •ACQUIRED CONGENITAL REFLEX •Until primary molars erupt, infant swallows with jaws separated and the tongue thrust forward using facial muscles. •This is non-conditional congenital reflex. •After eruption of posterior primary teeth, from18 months of age onwards, the child tends to swallow with teeth brought together by masticatory muscle action, without a tongue thrust.
  53. Conclusion Appropriate knowledge of reflexes enables apaedodontist to identify whether the child is developing normallyor not to identify whether development is going on at a proper rate or not  Knowledge of abnormalities if all reflexes are not proper
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