infantile reflexes
- origin: prenatal period (2nd or 3rd month), most present at birth
- form the basis for all phases of motor development
- initially controlled subcortically by the spinal chord, then by the brain stem/midbrain as CNS matures, and become suppressed as cerebral cortex matures and voluntary movement takes over
- approx 27 major reflexes, most suppressed by 6mo-some re-emerge due to neurological trauma. coughing, blinking, and sneezing persist
- abnormal reflexes indicate damage to system
rooting
-search reflex
stimulus-touching area around infant’s mouth
response-head turns toward touch, mouth opens and tongue extends
function-facilitates search for nipple (necessary for food when born)
babkin reflex (palmar mandibular)
stimulus-pressure to both palms
response-opening of mouth, closing of eyes, and flexion of head (1 or all)
sucking reflex
stimulus-nipple touching back of palate
response-jaw movements needed to express milk
step 2 stimulus-touching above or below lips
response-sucking
palmar grasp/plantar grasp
stimulus-tactile stimulation of palm
response-fingers/toes flex (not thumb)
preposed function-preparation for voluntary grasping
-begins prenatally and endures to 4 months. retention can result in poor handwriting, poor fine motor skills and manual dexterity, and slumped posture over a desk
-absence indicative of neurological abnormalities (spasticity)
Assymetric Tonic Neck Reflex
stimulus-head turning to side
response-limbs on face side extend, limbs on other side flex in supine/prone
preposed function-assistance in birthing, facilitating body awareness, developing hand-eye coordination
-retention after 6 mo impedes crawling
babinski reflex
stimulus-stroking bottom/lateral portion of foot
response-big toe extends upwards and toes separate
-absence indicates immature CNS or lack of myelination
-retention after age 2=sign of damage to corticospinal tracts
-adults have the opposite response-babinski response in adults indicates CNS damage
parachute reflex
stimulus-tipping an infant off balance
response:
1. when lowered rapidly, legs extend (from 4 mo)
2. when tilted forward or sideways, arms extend (7 mo and 6 mo)
3. when tilted backward, arms extend and body may rotate
function-attainment of upright posture/attempt to break fall
-persistence leads to broken wrists
swimming reflex
when held horizontally-arms and legs move in swimming action (11 days-5mo)
-bradycardiac response-infants open their eyes and hold their breath underwater
crawling reflex
stimulus-alternative stroking of soles of the feet (supine/prone)
response-arms and legs move in crawling motion
preposed function-essential for development of muscle tone needed for creeping
-birth to 4 months
-false crawling reflex: newborns placed on stomach move arms and legs (trying to turn over because they’d suffocate in the womb)
primary stepping reflex
stimulus-placing infant upright with soles of feel touching surface
response-legs lift and descend
-not voluntary, no postural reflexes, not enough strength to actually walk
spontaneous movements
- not a reflex, repetitive motions that appear in absence of stimuli
- ‘transitional behaviors’ some control over body parts but goal-directed action not possible-underlying temporal structure to movements
- highest frequency between 6 and 10 months
- increased frequency of movements found in children with down syndrome, tourettes, blindness, deafness, and schizophrenia
- 47 distinct movements (ex kicking)
