Infancy Lecture

PTA 2210 FUNCTIONAL MOVEMENT DEVELOPMENT

The INFANT

What Will We Discuss

• Developmental tasks of infants

• Milestones

• Reflexes and reactions in each infancy stage

• Developmental delay and its significance

Infancy

• Duration: Birth to 12 months

• Rapid physical and developmental maturation

• Significant CNS maturation and behavioral changes

• Underlying growth processes:

  • Intrinsic

  • Extrinsic factors:

    • Caregiving practices

    • Deprivation

    • Abuse

    • Overstimulation

• Growth metrics:

  • Increase in length by 50%

  • Birth weight triples by end of first year

  • Heart rate slows to approx. 80-100 bpm

  • Blood pressure ~100/55 by end of first year

Stages of Infancy

First Year Subdivided Into 4 Periods:

1. Early infancy: Birth to 3 months

2. Middle infancy: 4 to 6 months

3. Late infancy: 7 to 9 months

4. Infancy Transition: 10 to 12 months

• Domains of development:

  • Gross motor

  • Fine motor/adaptive

  • Oral motor

  • Cognitive-language

  • Personal-social behavior

Definitions

• Righting: Aligning body parts

• Postural equilibrium: Establishing center of mass over base of support

• Postural control: Maintaining position with center of gravity over base of support

• Balance: Maintaining equilibrium at rest or during movement

• Postural set: Alignment of body parts at a given time

• Prehension: Using hands for grasping and manipulating objects

Early Infancy (Birth to 3 months)

Gross Motor

• Present reflexes: ATNR, Tonic Labyrinthine, Standing reactions

• Behaviors:

  • Lifts head in prone position

  • Increasing extension at rest

  • Decreasing total head lag in pull-to-sit

Fine Motor

• Present reflexes: Palmar grasp, upper extremity traction

• Behaviors:

  • Hands closed most of the time, gradually opening

  • Engages with mouth

Oral Motor

• Present reflexes: Suck-swallow, rooting, gag

• Behaviors:

  • Suckling, breastfeeding, coordination of suck and swallow

Cognitive-Language

• Behaviors:

  • Cries, coos, vocalizations

Personal-Social

• Behaviors:

  • Cries to communicate, recognizes human face and voice, smiles

Middle Infancy (4 to 6 months)

Gross Motor

• Reflexes integrated: All primitive reflexes

• Behaviors:

  • Rolling, shifting positions and lifting head

  • Sitting propped, supported standing

  • Independently sitting by 5-6 months

• Antigravity control:

  • Landau reaction

  • Pivot prone pattern

  • Prone extension pattern

Fine Motor

• Reflexes integrated:

  • Palmar graps

• Behaviors:

  • Hands to midline, reaches, rakes objects

  • Transfer of object by 6 months

  • Object release after 6 months

  • Reaching becomes more functional

Oral Motor

• Reflexes integrated:

  • rooting reactions, phasic bite reflex

• Behaviors:

  • Spoon feeding initiation, increased tongue movement

  • upper lip activate later in stage

Cognitive-Language

• Behaviors:

  • Babbling, increased vocal sounds

Personal-Social

• Behaviors:

  • Engages in early play, shows delight

Late Infancy (7 to 9 months)

Gross Motor

• Reflexes integrated: STNR, protective extension to sides (7-8), backwards (9-10), sitting equilibrium (7-8)

• Behaviors:

  • Sits independently, begins crawling, assumes sitting

Fine Motor

• Behaviors:

  • Lateral and radial grasping, through active play using containers

Oral Motor

• Behaviors:

  • Eats effectively with a spoon, begins to chew solids

Cognitive-Language

• Behaviors:

  • Repeats sounds, aware of environment, babbles clear vowel-consonant sounds

Personal-Social

• Behaviors:

  • Social play, laughter and interaction with others

Infancy Transition (10 to 12 months)

Gross Motor

• Behaviors:

  • Assumes quadruped, creeps hand and knees, starts cruising

  • Walks with two hands held, then one hand

  • Walks independently

    • Immature gait

    • upper extremities help up and abducted

    • lumbar lordosis and protruding belly

    • lower limbs abducted, wide stance

    • rapid cadence

Fine Motor

• Behaviors:

  • Inferior and superior pincer grasp development

  • Flinging of objects

  • Reaching (demonstrates adaptive skills; dressing )

Oral Motor

• Behaviors:

  • Independent drinking from a sippy cup

  • Eats solids with tongue lateralization

Cognitive-Language

• Behaviors:

  • First true words emerge, solidifying object permanence

Personal-Social

• Behaviors:

  • Shows attachment styles, develops fear of strangers

Importance of the Developmental Sequence

• Exact timing may vary; sequence is critical

• Influenced by environment and caregiving

• Assessment based on norms; delays in achieving milestones indicate need for evaluation

Developmental Delay and Abnormal Development

• Developmental

  • Global: Delays across all areas

  • Focal: Specific delays (motor/language)

  • quantitative

• Abnormal

  • Related to qualitative aspects of development

  • Importance of early intervention due to brain neuroplasticity

Congenital Torticollis

• Congenital damage to sternocleidomastoid muscle

• Effects:

  • Limited ROM in head movements

  • Clinical practice guidelines exist for evidence-based interventions

References

• National Human Genome Research Institute

• Centers for Disease Control and Prevention

• Cronin, A. & Mandich, M. (2016). Human Development and Performance Throughout the Lifespan. Cengage.