NEUROPEDIATRIC EXAMINATION PRIMITIVE REFLEXES

Why is the study of infant reflexes important? Dominant form of movement for last 4 months prenatally and first 4 months postnatally. Primitive reflexes critical for human survival. Postural reflexes believed to be foundation for later voluntary movements. Appearance and disappearance helpful in diagnosing neurological disorders.

INTRODUCTION The Central Nervous System (CNS) is the control center for all thinking, learning, and moving. The development of an efficient CNS is complex yet a certain amount is understood. There are many factors which contribute to a person being able to move well, speak fluently, play and develop the skills necessary for every day living and learning. The development of the CNS commences from conception, develops in a regular sequence and is the same for all humans regardless of cultural influences.

PRIMITIVE REFLEXES - Survival reflexes occurring sequentially in the first few weeks of fetal development - Automatic, stereotyped movements, directed by a very primitive part of the brain (brainstem). - executed without involvement of higher levels of the brain (the cortex). - Ideally short lived and as each fulfils its function is replaced by more sophisticated structures (Postural Reflexes) which are controlled by the cortex - Considered aberrant and evidence of an immaturity within the CNS if present beyond their time.

Importance of Infant Reflexes Reflexive movements occur during the last 4 months of prenatal life and the first 4 months after birth Reflexes occur subcortically (below the level of the higher brain centers) E.g., palmer grasp

Infant vs. Lifespan Reflexes Many of the reflexes do not completely disappear First, they are inhibited by the maturing nervous system Second, they are integrated into new movement behaviors

Role of the Reflexes in Survival Infant reflexes are called primitive reflexes Asymmetric tonic neck reflex Symmetric tonic neck reflex Moro reflexes Startle reflex Primitive reflexes are repressed by 6 months of age Primitive reflexes are important for Protection Nutrition Sucking reflex Rooting reflex Survival Labyrinthine reflex

Role of Reflexes in Developing Future Movement Postural reflexes Prevalent belief: automatic movement is “practice” for future voluntary movement Other experts believe these reflexes may not be related to future motor development Emanate from higher brain centers These reflexes disappear when voluntary behavior surfaces

Role of Reflexes in Developing Future Movement When the stepping reflex is stimulated, walking may begin at an earlier age Link between stimulation of the reflex preceding the disappearance phase and early movement Small amounts of practice can lead to significant results

Role of Reflexes in Developing Future Movement Infant Reflex Future Voluntary Movement Crawling Labyrinthine Upright posture Palmar grasp Grasping Stepping Walking

Reflexes as Diagnostic Tools Can help determine the level of neurological maturation Reflexes are age-specific in normal, healthy infants Moro reflex May signify a cerebral birth injury if lacking or asymmetrical Asymmetric tonic neck reflex May indicate cerebral palsy or other neurological problem

Reflexes as Diagnostic Tools Concern when lacking, weak, asymmetrical or persisting Moro Cerebral birth injury Asymmetric tonic reflex Cerebral palsy; other neural damage

Reflexes as Diagnostic Tools Development Examination Measures several infant reflexes from birth to 24 months Purpose: develop profile of child’s movement in relation to what is expected at a specific age Useful in determining motor delay

PRIMITIVE REFLEXES Galant Palmar Grasp Sucking Search Moro Startle Asymmetric Tonic Neck Symmetric Tonic Neck Plantar Grasp Babinski Palmar Madibular Palmar Mental POSTURAL REFLEXES Stepping Crawling Swimming Head and Body Righting Parachuting Labyrinthine Pull Up

GALANT REACTION If the child is stroke para-vertebrally with one finger, the body will curves The concavity of pelvis proceed toward the direction of the stimulus given. The leg and arm ipsilateral will be strach, and the contralateral will be curve Syn: Spinal reaction Disappear in 2-3 months Patologic: dissapear  Spinal medulla lesion, CNS depression

MORO REFLEX Palm of hand lifts back of head Hand is removed suddenly so that head begins to fall Head is supported Moro reflex precedes the startle reflex and causes the arms and legs to extend immediately rather than flex Duration: prenatal 4-6 months postpartum Patologic: disappear  CNS depression, persists  RM, CNS dysfunction, delay sitting/head control, asymmetrical  injury to one side of brain, parese plexus brachialis, fracture clavicula/humerus

ASYMMETRIC TONIC NECK REFLEX Synonim: bow and arrow or fencer’s position Causes flexion on one side and extension on the other Not always seen in newborn Facilitates the development of bilateral body awareness Duration: after birth-3 months Patologic: persist  Cerebral palsy

PALMAR GRASP The palmar grasp reflex is one of the most noticeable reflexes to emerge Appears in utero Endures through the 4th month postpartum Negative palmer grasp: neurological problems (spasticity) Leads to voluntary reaching and grasping

PLANTAR GRASP The toes appear to be grasping Stimulus is touching the ball of the foot This reflex must disappear before the baby can stand or walk Duration: birth-1 years Patologic: negative  medula spinalis lesion, perifer nervous system lesion (must disappear before the baby can stand or walk)

POSTURAL REFLEXES: Parachuting Reflexes Propping reflexes Related to upright posture This reflex is a conscious attempt to break a potential fall Duration: 4 months-1 years Patologic: (-) CP, asymetris  neuromusculer/orthopaedi dysfunction

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Primitive Reflexes ~ Sucking Stimulus / Response S: touch of lips R: sucking action Duration In utero - 3 months postpartum Concerns No reflex problematic for nutrition Other Often in conjunction with searching reflex

Primitive Reflexes ~ Search Stimulus / Response S: touch cheek R: head moves toward stimuli Duration Weeks prenatal - 3 months postpartum Concerns No reflex problematic for nutrition No reflex or lack of persistence may be sign of CNS or sensorimotor dysfunction. Other Often in conjunction with sucking reflex. Contributes to head/body-righting reflexes.

Primitive Reflexes ~ Startle Stimulus / Response S: Same as Moro R: Arms and legs flex Duration 2-3 months after Moro disappears – 1 year Other Less severe startle reflexes elicited through lifespan

Primitive Reflexes ~ Symmetric Tonic Neck Stimulus / Response S: Baby sitting up and tip forward R: Neck and arms flex, legs extend S: Baby sitting up and tip backward R: Neck and arms extend, legs flex Duration After birth – 3 months Concerns Persistence may impede many motor skills and cause spinal flexion deformities

Primitive Reflexes ~ Babinski Stimulus / Response S: Stroke bottom or lateral portion of foot R: Great toe turns downward Duration Birth – 4 months Concern Test of the pyramidal tract (i.e. ability to perform conscious / voluntary movement)

Primitive Reflexes ~ Palmar Mandibular Stimulus / Response S: Pressure to both palms or hair to hand R: Eyes close, mouth opens, and/or neck flexes (which tilts the head forward) Duration Birth – 3 months Other Also called the Babkin reflex

Primitive Reflexes ~ Palmar Mental Stimulus / Response S: Scratch base of palm R: Lower jaw opens and closes Duration Birth – 3 months

Postural Reflexes ~ Stepping Stimulus / Response S: Infant upright with feet touching surface R: Legs lift and descend Duration After birth – 5-6 months Concerns Essential forerunner to walking Other Sometimes called walking reflex Developmental changes in reflex over time

Postural Reflexes ~ Crawling Stimulus / Response S: Prone position on surface, stroke alternate feet R: Legs and arms move in crawling action Duration Birth – 3-4 months Concerns Precursor to later voluntary creeping

Postural Reflexes ~ Swimming Stimulus / Response S: Infant held horizontally R: Arms and legs move in coordinated swimming type action Duration 2 weeks after birth – 5 months Other Recognition of reflex led to popularity of infant swim programs

Postural Reflexes ~ Head and Body Righting Stimulus / Response S: Supine, turn body in either direction R: Head “rights” itself with the body S: Supine, turn head in either direction R: Body “rights” itself with the head Duration Head:1-6 months; Body: 5 months-1 year Concerns Related to voluntary rolling movements.

Postural Reflexes ~ Labyrinthine Stimulus / Response S: Baby held upright, tilted in one direction R: Baby tilts head in opposite direction Duration 2-3 months – 1 year Concerns Related to upright posture Other Also considered primitive reflex

Postural Reflexes ~ Pull Up Stimulus / Response S: Sitting/standing, hold hands, tip in one direction R: Arms flex or extend in to maintain upright position Duration 3 months – 1 year Concerns Related to upright posture