Rudimentary Movements n First forms of voluntary movement n Sequential, predictable, universal.
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Transcript of © 2007 McGraw-Hill Higher Education. All rights reserved. Voluntary Movements of Infancy Chapter...
© 2007 McGraw-Hill Higher Education. All rights reserved.
Voluntary Movements of Infancy
Chapter 10
© 2007 McGraw-Hill Higher Education. All rights reserved.
Objectives
• List and categorize the voluntary movements of infancy
• Describe the development of head control during infancy
• Describe the development of general body control during infancy
© 2007 McGraw-Hill Higher Education. All rights reserved.
Objectives
• Describe the development of prone locomotion during infancy
• Describe the development of upright locomotion during infancy
• Describe the development of reaching, grasping, and releasing during infancy
© 2007 McGraw-Hill Higher Education. All rights reserved.
“Voluntary movement is the ultimate expression in the striated muscle of the integrated effects of a host of cortical and subcortical facilitory and inhibitory influences”
© 2007 McGraw-Hill Higher Education. All rights reserved.
The rate of acquisition for all voluntary
movements during infancy may vary
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Categorizing the Movements
Voluntary movement groupsStability
Head control, upright postureLocomotion
Creeping, crawling, walkingManipulation
Reaching, grasping, releasing
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Categorizing the Movements
Cephalocaudal pattern of developmentHead controlUpper body controlLower body control
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Stability ~ Head Control
Voluntary movements begin at the head Milestone: infant raises head while prone
Accomplished by 3 months of age
Infant will then push the chest up with arms Raise head in supine position
Accomplished by 5 months of age
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Stability ~ Head Control
Minimal voluntary control of the head
Elevates head when prone with effort
Positions head from left to right or right to left when prone
Elevates head when supine
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Stability ~ Body Control
Chest elevation Segmented rolling back to front
(visa versa) Crawling Ability to maintain upright posture
frees the hands and arms for reaching and grasping
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Voluntary Controlof the Body
3 months: tries to roll from supine to prone position; maintains sitting position when assisted
5 months: sits when holding external supporting object
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Voluntary Controlof the Body
6 months: rolls from supine to prone position; maintains standing positionwhen assisted
7 months: achieves sitting position from prone to supine position
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Voluntary Controlof the Body
8 months: sits alone; rolls from prone to supine position
9-10 months: pulls self to standing position, briefly maintains stand whileholding external supporting object
12 months: stand unassisted
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Study on Infant’s Ability to Self-sit Phillipe Rochat (1992)(Emery University) Studied the impact of an infant’s ability to self-sit on
the development of early eye-hand coordination Half were able to sit on own Half were not able to sit on own Infants presented with display in seated, reclined,
prone and supine positions
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Rochat’s Key Findings
Half of the infants were unable to sit on their own Sitters were more accurate in their reach than non-sitters All infants were more successful in the accuracy of their
reach when supine versus sitting Non-sitters used two hands to reach more often than sitters Sitters reached more with one hand in all positions Non-sitters used one hand only when seated Overall, infants’ ability to sit appears to influence the use of
hands in reaching activities
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Locomotion ~ Prone
Rate of acquisition for attaining prone locomotor movements varies more than any other voluntary movement
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Locomotion ~ Prone
Locomotion evolves from children gaining the ability to position their bodies for movement from one location in space to another
7 months: elevates trunk slightly; forward arm extension and flexion creates occasional forward Movement;leg flexion occasionally creates backward crawling
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Locomotion ~ Prone
Crawling (7-8 months) Precedes creeping Inefficient, highly variable
arm and leg movements intended to propel the body forward
Body is dragged Creeping (9-12 months)
Contralateral or homolateral pattern
More efficient form of prone locomotion
Body is elevated
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Locomotion ~ Upright
Walking ~ the culmination of the acquisition of voluntary movement
There is little evidence demonstrating that early walking will accelerate or refine future skill performance
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Locomotion ~ Upright
7 months: walks with considerable support or assistance
10 months: walks laterally around furniture using handhold for support
7 months
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Locomotion ~ Upright
11 months: walks when led with slight handhold to maintain balance
12 months: walks unassisted
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Locomotion ~ Upright
Experience is an important indicator in mature walking patterns
Children with smaller bones or linear frames walk somewhat earlier than larger-boned or larger-framed children
A child's muscle mass at 6 months of age may predict onset of independent walking
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Locomotion ~ Upright
Training children on a treadmill Increases number of steps taken Aids children with non-stable walking patterns
Ground reaction forces may be used to help children with gait abnormalities and neurological disease
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Manipulation ~ Reaching, Grasping, Releasing
Use of the hands enables children to gather information about their environment in a new way
Recall that early manipulation is reflexive Palmar grasp reflex
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Manipulation ~ Reaching, Grasping, Releasing
Phase I Phase II
Simultaneous reaching and grasping
Differentiated reaching and grasping
One-handed reaching Two-handed reaching
Visual initiation of the reach Visual initiation and guidance of the reach
Visual control of the grasp Tactile control of the grasp
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Manipulation ~ Reaching, Grasping, Releasing
Birth Phase I reaching
1 month Phase I reaching disappears
4 months Phase I reaching reappears
4-5 months Unable to receive multiple toys
5-6 months Thumb used to oppose fingers in grasping
6 months Receives two toys while storing one toy in opposite hand
6-8 months Receives two toys while storing one toy in opposite hand
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Manipulation ~ Reaching, Grasping, Releasing
9 months Adjusts arm and hand tension to object’s weight after grasping
9-10 months Thumb can oppose one finger in grasping
9-11 months Receives three toys; stores first two toys on lap or chair
12 months Adjusts arm and hand tension upon repeatedly receiving the same object
12-14 months Receives three or more toys and crosses midline to hand toys to other person
18 months Releases objects with relative ease; anticipates arm and hand tension for repeated presentation of same object; expects unknown long objects to weigh more than short objects
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Manipulation ~ Reaching, Grasping, Releasing
Development of prehension continues to evolve until the end of the first decade of life
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Anticipation and Object Control in Reaching and Grasping
By 18 months, infants exhibit anticipation Given the same object, repeatedly, infants
display awareness that an object weighs the same
Anticipation is not always accurate Expects unknown long object to weigh more that
short object Anticipation and strength of grip develop over
several years (2yr to 9yr)
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Anticipation and Object Control in Reaching and Grasping
9 months Adjust weight of object after grasping itLimited anticipatory abilities
1 year Develops skill in adjusting arm and hand tension when handed an objectNo carry-over to new objects
18 months Child exhibits anticipationAware that the same object weighs the sameDevelops a rule that similar objects weigh more or less than the familiar object (uses length)Not always accurate
2 years Greater speed with grasping an object coupled with less force
3 years Greater speed with grasping an object couplded with greater force
4 years Children control rate of speed in grasping
Burst of speed to grasp
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Bimanual Control
Complementary use of two hands to achieve a goal (receiving toys) is evident at 6-8 months
4-5 months Varying abilities
Child cannot handle more than one toy
6-8 months Highly developed reaching and grasping
Easily grasps first toy and sometimes a second one
Cannot handle three toys
9-11 months Can hold on to three toys
May place one of the objects on the lap or table
12-17 months Hands toys to parent or other adult for safekeeping while more toys are grasped
Older children use a storage method to handle more toys
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Bimanual Control
Walking is correlated with child’s ability to grasp with one hand
Using a one or two hand grasp may be related to walking experience Less walking experience: one hand Greater walking experience: two hands
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