Physical and Motor Development of Newborns

Physical Growth of the Newborn and Motor Skills Acquisition

Overview of Physical and Motor Development

  • Study the physical growth of the newborn and how it acquires motor skills.

Newborn Physical Assessment

  • Purpose:

    • Behavior is closely related to neurological mechanisms.

    • Identifying infants who are at risk is essential.

At-Risk Infants

  • Infants may be classified as at risk due to various factors:

    • Exposure to Teratogens: Substances that can cause developmental malformations.

    • Poverty: Socioeconomic factors that influence health access and development.

    • Teenage Mothers: Increased risk of complications due to immaturity and social factors.

    • Unmarried Mothers: Associated stigma and lack of support.

    • Mothers without High School Degree: Lower educational levels correlate with health risk factors.

    • Low Birth Weight: Critical indicator of health outcomes.

    • Caesarean Section: Possible implications of surgery on recovery and development (questioned).

Low Birth Weight (LBW)

  • Categories of Low Birth Weight:

    • Pre-term Infants: Born before 37 weeks of gestation.

    • Small for Gestational Age (SGA): Below the 10th percentile for weight at a given gestational age.

  • Complications related to LBW:

    • Trouble Breathing and Anoxia: Insufficient oxygen leading to developmental issues.

    • Poor Muscle Tone: Impedes movement and physical development.

    • Later Behavioral and Academic Problems: Correlation with developmental delays and educational challenges.

Newborn Assessment Methods

  • APGAR Exam:

    • Measures: Heart rate, respiration, muscle tone, skin color, and response to stimulus.

    • Timing: Assessed at birth, then at 5 and sometimes 20 minutes post-delivery.

    • Score Range: 0 - 10 scale; below 4 indicates 'at risk' status.

  • Hammersmith Infant Neurological Examination (HINE):

    • First used around 3 months of age; consists of 26 measures evaluating:

    • Posture

    • Movement

    • Muscle tone

    • Reflexes

    • Cranial nerve function using behavioral responses.

APGAR Scoring System

Sign

0 Point

1 Point

2 Points

Activity (Muscle Tone)

Absent

Arms and Legs Flexed

Active Movement

Pulse

Absent

< 100 bpm

> 100 bpm

Grimace (Reflex Irritability)

No Response

Grimace

Sneeze, Cough, Pulls Away

Appearance (Skin Color)

Blue-Gray, Pale All Over

Normal Except for Extremities

Normal Over Entire Body

Respiration

Absent

Slow, Irregular

Good, Crying

APGAR: Links & Predictions

  • Conditions affecting scores:

    • Prenatal drug exposure: Associated with lower scores.

    • Caesarean section: May yield lower scores.

  • Developmental Predictions:

    • Lower APGAR scores do not predict physical growth and development at 6 months.

    • Predictive for growth and development abilities assessed at around 4.5 years.

Hammersmith Infant Neurological Examination (HINE)

Assessment of Posture

  • Metrics include symmetry and positioning.

  • Scoring grades: 3 (optimal) to 0 (poor). Examples include:

    • Score 3: Straight; in midline; hands open.

    • Score 0: Marked asymmetries or unable to maintain posture.

Assessment of Movement

  • Measures quantity and quality of movement:

  • Conditions observed:

    • Quantity: Normal, excessive, sluggish, minimal.

    • Quality: Free and smooth, jerky, cramped, tremors.

Assessment of Cranial Nerve Function

  • Observes:

    • Facial expression at rest/stimulation, eye movements, visual responses, auditory responses, and suck/swallow reflex.

    • Scoring from 0 (none) to 3 (normal).

Brazelton Neonatal Behavioural Assessment Scale (NBAS)

  • Categories Assessed:

    • Attention, Physical Movement, Alertness (habituation, irritability, excitability), Physiological Response to Stress.

Links to Other Factors

  • Preterm Infants: Lower threshold for attentional stimulation.

  • Cocaine Exposure: Results in lower NBAS scores and habituation.

Key Relationships

  • Attention/Orientation: Related to birth weight and mother's age.

  • Personality: Correlates with 5-minute APGAR score.

Concerns with Brazelton NBAS

  • Problems noted include:

    • Low test-retest reliability.

    • Inconsistent correlation with later developmental status.

    • Poor predictive measures after a few months.

Sleep/Wake Development

  • Changes with Age:

    • Overall sleep time decreases as age advances.

    • Percentage of REM sleep decreases from approximately 50% in the first month to about 20% in adulthood.

Sleep Patterns by Age

  • Chart indicates expected sleep hours across different ages:

    • Total hours of sleep decreases significantly as children mature, specific months listed with corresponding hours.

Sudden Infant Death Syndrome (SIDS)

  • Vulnerability:

    • Highest risk observed between 2 and 4 months of age.

  • Unknown Causes: Contributing factors include:

    • Sleep position, soft bedding, overheating, and maternal smoking habits.

States of Alertness

  • Quiet Sleep: No eye movements, inactive.

  • Active Sleep: Characterized by REM, irregular breathing.

  • Drowsiness: Smooth physical movements, delayed responses.

  • Alert Inactivity: Open eyes, focused attention, little activity.

  • Alert Activity: Eyes open, increased activity with stimulation, crying indicates high levels of activity.

Reflexes in Newborns

  • Types of reflexes:

    • Rooting Reflex: Present until about 3 months.

    • Palmar Reflex: Present until around 4 months.

    • Stepping Reflex: Disappears around 2.5 months.

Early Behaviors

  • Types include looking, sucking, and crying.

  • Noted impact of crying: A study suggested crying production causes cognitive shifts in attention and memory.

Motor Development

  • Focus on:

    • Locomotion and Prehension.

Motor Development Progression

  • Motor development follows two principles:

    • Proximodistal: Control from the center of the body outwards.

    • Cephalocaudal: Development occurs from head to foot.

Standing and Walking Milestones

  • Infants follow a sequence:

    • Sequence and timing influenced by proximodistal and cephalocaudal principles.

    • Regular sequences noted across most infants.

Typical Motor Milestones Chart

  • Example development milestones with average onset ages include:

    • Walks alone: ~12 months

    • Stands alone: ~11 months

    • Crawls: ~8-10 months

Development of Locomotion

  • Prevalence percentages:

    • Rolling over (87%), crawling (various measures with percentages), and standing/walking (<1%).

Nature/Nurture of Motor Development

  • Cultural differences noted:

    • African infants often walk earlier, while some Asian infants may walk later.

    • Regardless of culture, timing influenced by experience (e.g., tummy time).

Thelen’s Dynamic Systems Approach

  • Infants use inherent behaviors to adapt to environmental challenges.

Thelen’s Experiment

  • Focused on simultaneous leg kicking in infants to move a mobile, demonstrating behavioral adaptation and efficiency.

Visual Cliff Experiment by Gibson & Walk (1960)

  • Research indicates young infants tend to crawl toward the shallow side and avoid deep sides, highlighting environmental interaction with age of crawling onset.

Function of Motor Development

  • Locomotion: Promotes perceptual development, enhancing spatial and three-dimensional perceptions, among others.

  • Prehension: Facilitates object exploration and direct manipulation of the environment, vital for cognitive and physical interaction.