Friday, October 7, 2016

Infantile Reflexes

In order to better understand children with severe cognitive impairments, I need to understand infancy development. A huge part of development are reflexive movements which are involuntary movements that an individual makes in response to specific stimuli. However, an infant does not have to think about making reflexive movements because they happen automatically and they are important!

Three categories of movements: 
1. Primitive Reflexes: An involuntary response to specific stimulation which is often mediated by lower brain centers. E.g.: a newborn infant grasps an object placed in their hand.
-Reflexes are responses to specific external stimuli
-Reflexive movements are specific and often localized
-The same stimulus will elicit a specific reflex over and over again
-Note: There are warning signs of the following primitive reflexes

  • Asymmetrical tonic neck: prenatal to 4 months 
  • Symmetrical tonic neck: 6 months to 7 months 
  • Doll-eye: Prental to 2 wk 
  • Palmar grasping: Prenatal to 4 months
  • Moro: prenatal to 3 months
  • Sucking: birth to 3 months
  • Babinski: birth to 4 months
  • Searching or rooting: birth to 1 year
  • Palmar-mandibular (Babkin): 1 to 3 months
  • Plantar grasping: birth to 12 months
  • Startle: 7 to 12 months (Haywood, 2009)

2. Postural Reactions: known as gravity reflexes "help the infant automatically maintain posture in a changing environment." They generally appear after the infant is 2 months old.

  • Derotative righting: from 4 months
  • Labyrinthine righting: from 4 months
  • Pull-Up: 3 to 12 months 
  • Parachute (Haywood, 2009)

3. Locomotor Reflexes: These appearch much earlier than the corresponding voluntary behaviors and typically disappear months before the infant attempts the voluntary locomotor skill.

  • Crawling: birth to 4 months 
  • Stepping: birth to 5 months 
  • Swimming: 11 days to 5 months (Haywood, 2009)
Importance/Purpose of Reflexes: In a structural explanation, "some theorists believe that reflexes merely reflect the structure of the nervous system." In a functional explanation, it suggests that "reflexes exist to help the infant survive- to eat, breathe, grasp" as well as to position itself for birth and to assist int he birthing process." And lastly "applied theories examine the role of reflexes in future volitional movements" while others believe that "reflexive movements lead to practice coordinated movements before the higher brain centers are ready to mediate such actions"(Haywood, 2009).

Haywood, K. M., & Getchell, N. (2009). Life Span Motor Development (5th ed., pp. 95-100). Champaign, IL: Human Kinetics. 

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