Fine Motor Development in Infancy

prehension

the use of the hands for grasping, holding, and manipulation of objects

distal control

postural stability = ?

fine motor development

• Related to postural control

• Development typically and initially occurs proximal to distal

• Infants follow a typical sequence, but how they achieve hand skills is individual

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Factors that influence hand skills:

• Infant’s size and growth

• Biomechanical attributes

• Neurological maturation

• Perceptual abilities

• Sensation

• Cognition

characterisitics for fine motor control

• Motor control of the fingers

• Ability to perceive sensory information

• Ability to translate the sensory information into motor planning

• The organization of the motor cortex changes with use and experience

fine motor skills birth- 3 months

• Hands are fisted reflexively, and hands will open spontaneously

• Will swipe at mouth

• Some thumb sucking occurs prenatally, but most of the time it takes a few months for this to truly emerge

• Through the first three months we see babies keeping their hands open more and more

• Open most of the time by 4 months

0-3 months 

• Grasp is reflexive and nonfunctional at birth

• The grasp reflex can be elicited by applying pressure in the palm along the metatarsal heads

• No purposeful reaching at birth

• Visually-triggered reaching

• Newborns have some swiping at birth, still not functional or purposeful

• By 3 months they begin to have a true reach

visually triggered reaching

infants are able to see a target and attempt to reach for the target, but not purposeful

3 months

• Purposeful swiping and batting at toys/objects

• Hands go above the head in prep for an actual reach

• Hands are largely open and arm is extended, so unable to actually grasp onto something

• By the end of _ months, babies can hold onto an object that is placed in

their hand

4-6 months 

• Infants begin to use objects for functional purposes vs. sensory exploration

• More motivated to intentionally grasp and hold objects

• Begin to use various palmar grasp patterns to hold onto objects

            • Begins with the wrist flexed, eventually develops to wrist neutral

            • Ulnar → radial

• Raking grasp emerges

• Transition from reflexive reaching and grasping to purposeful reaching

visually guided

dependent on proprioceptive feedback working with visual input to guide the reach

7-9 months

• Disassociation of the thumb and fingers

• Grasps move radially

• The action of the thumb begins to differentiate from the actions of the fingers (no longer working as one whole unit)

• First seen in radial digital grasp

• Voluntary release

• Isolation of the fingers results in poking and pointing

• Improved ability to play and manipulate toys

10-12 months 

Development of the inferior pincer grasp

• Moves distally from pad of finger to tip of finger

• Increased interest in objects and play

• More complex release patterns

• Releasing against a surface or person

• Flinging the object (dropping food)

• More complex grasp, reach, and release leads to development of adaptive skills

12 months

• Pincer grasp develops by 10-11 months

• _ -month-old uses a variety of grasp patterns to manipulate objects and explore environment

• Often prefers radial side of the hand

• Purposeful release of objects

• Important for purposeful play development-combining objectives together such as in

stacking and dropping items into containers

12-18 months

• Refinement of grasp, release, and purposeful reaching

• Can stack 2 blocks by 15-18 months

• Control of the arm in space

• Precision grasp without support

• Controlled release

• Spatial relationships

• Depth perception

• Beginning of complementary hand play begin

primitive reflexes influence on grasp 

• Interconnected to sensation

• Can be elicited by sensory stimulation OR by a particular head/body position OR by tactile & proprioceptive input

• Emerge in a fairly typical sequence

• If certain reflexes fail to develop, purposeful prehension and grasp will be negatively affected

• Also true if reflexes emerge and do not integrate

•  Clinical Significance: If difficulty with development of grasp is observed, primitive reflexes should be evaluated

ATNR

• When the baby begins to swipe at objects, it is with the extended arm that they do this

• Movement still dominated by reflexes in early infancy.

• Facilitates separate use of each side of the body.

• Assists with neck turning, visual fixation, and reaching.

• CLINICAL RELEVANCE: the persistence of _ past an appropriate age impacts hand-eye coordination and crossing midline

traction

• When the hand is extended in a reach, the _ response is elicited and then the hand closes in a fist as it approaches the toy

CLINICAL RELEVANCE:

• _ needs to be integrated to allow for an open hand during volitional reach

• Persistence can inhibit a volitional reach and grasp

avoiding response 

• Causes babies to drop an object placed in the palm once it touches their fingertips

• Causes them to pull away from the object, overpronate the hand, and results in a grasp on the ulnar side of the hand (crude palmar grasp)

CLINICAL RELEVANCE:

• Helps enable release of an object from the hand

• Grasp reflex and avoiding reflex are balanced

palmar grasp reflex

A persistent grasp reflex interferes with the ability to release objects

• The avoiding response helps with this, however

• Precursor to opposition of finger and thumb

Clinical Relevance: When the absence or persistence of this reflex is observed, we look for potential neurodevelopmental abnormalities

integrative grasp reflex

• Orientation of the hand to the stimulated side of the hand to grasp the object

• Assist the child in adjusting hand position

• Improves efficiency and effectiveness of grasp patterns, and improves manipulation