Motor development

Reflexes

hard wired units/synergies of movement

All movement is supported by

reflexes because fastest response time with little variability

Postural control responses

righting reactions, equilibrium responses

Anticipatory postural adjustments

Intermediate response time with some variability based on prior experience

Volitional movements

can be broken down into reach and grasp, mobility

Motor development

how motor control develops in a typically developing child, Involves motor control and motor learning

Motor control

how the CNS controls movement

Motor learning

how movement is learned

Neuromaturationist

a form of the “hierarchical” theory

Normal motor development is due to

corticalisation of the CNS

CNS maturation gives rise to

high level of control over lower levels of reflexes

Developmental sequence theory

there is a “normal sequence” of development

What does the developmental sequence theory exclude

those who don’t develop in the “normal” fashion but have no deficits

Systems theory

most contemporary, movements control neither centrally nor peripherally, but rather by interactions of all of the movement systems

Distributed control

better explanation for automatic and reflexive movement

Reflexes can

be spinal (mm spindle, GTO, tendon jerks), primitive, or righting and equilibrium (that continue through life)

Primitive

don’t persist through life (self generated or spontaneous)

Righting

head against gravity

Equilibrium

response to a loss of position

Spontaneous movements in infants

Kick reciprocally, then unilaterally, then return to BL kicking, The frequency of these movements declines with introduction to walking

Full term infants have

flexor dominance

Pre term infants have

extensor dominance, kick less

Prechtl’s framework for identifying motor development delays differs from other systems due to

assesses spontaneous motion through observation only, no external perturbation, used to identify absent or abnormal development, Highly predictive of motor development impairments like CP

Thelen’s system theory suggests that development is non linear and dependent on 9 control variables

SPG, joint synchrony, postural control, body constraints, extensor strengths , antagonist control, visual sensitivity to movement, motivation, context

SPGs

precursor to mature function

Joint synchrony

coactivation at different levels of learning

Extensor strengths

for managing gravity

Antagonist control

flexor and extensor control together

Thelen’s systems theory context

biologic arousal level, external environment, goals

Postural control

essential for the development of skilled actions

Motor development of postural control results from systems model interactions between muscular and neural systems

Changes in MSK lead to increased strength against gravity, Development of motor coordination strategies, Development of sensory systems like mapping, Development of sensory strategies to organize multiple inputs (babies need to fall a lot to realize when they are at risk to fall and how to catch themselves), Development of cognitive resources and strategies for controlling posture during multi

Central commands can be

automatic or voluntary and adjusted by sensory input

Explain why the adult spinal cord ends at the L1 to L2 vertebral level

bone tissue and neural tissue develop at different rates during development

Roles of neuronal death and axonal retration during normal development

In adults, most muscle fibers are connected to a single motor axon, Earlier in development, several motor neurons innervate each muscle fiber, After the first few weeks post

Describe the way in which muscle and neural development are interrelated

neuronal connections sculpt the musculature, muscle fiber type is dependent on innervation

The state of neural connections in infants

Infants are born with 100

Neural connections first few years of life and throughout the lifespan

· Rapid connections are developed in the first 2 years and throughout life

When does myelination begin

at the 4th fetal month and complete by the end of the 3rd year

What can be said about the rate of myelination

The rate at which each type of neural fiber grows depends on when each area reaches adult level function

Things that can impact myelination

malnutrition and growing into deficit

Malnutrition

leads to a reduction in glial cells formed, which impacts vascular support for the nervous system

Growing into deficit

nervous system damage occurring early is not evident until the damaged system becomes functional

Why neural damage that occurs in utero may not be evident until a year or more after the damage occurred

Development begins in utero and continues throughout early childhood in stages, as the stages advance, if a lack of development occurs within the period it was supposed to, neuroplasticity may initially mask the damage

Experience Expectant

overproduction of nerve cells and synapses prenatally that await fine

Experience Dependent

development and functioning of a system are shaped by experience in an environment, Experiences are unique to individuals and dependent on context

Apoptosis is a

normal part of the development process, many neurons in the brain send axons to multiple targets, as the growth of the neural system develops, inputs that dominate are kept, and axons that are not used as frequently undergo selective cell death to further enhance the neural systems that work

Critical periods

when neural projections compete for synaptic sites; this optimizes connections (Think neural development)

Sensitive period

a time in which there is a greater susceptibility to forms of experience and learning that may be essential to later behavior (Think motor learning)

Why is sensory evolution important

An infant’s exposure to the world is guided by sensory experiences paired with movement to initiate the development of motor control, communication, and cognition, with increased efficiency of input, motor output becomes more refined

Various senses develop at different rates

Vision, hearing, touch, vestibular system, proprioception, taste, smell, and pain

Anencephaly

rudimentary brainstem without cerebral or cerebellar hemispheres, most die before birth or within first week of life

Arnold Chiari Malformation

developmental deformity of hindbrain

Type 1 Chiari malformation

herniation of cerebellar tonsils through foramen magnum

Type 2 chiarir malformation

malformation of brainstem and cerebellum causing extension through foramen magnum

Spina Bifida (Aperta)

neural tube defect that results when inferior neuropore doesn’t close

Meningocele

sac of fluid comes through an opening in infants back, but tissue does not protrude out

Myelomeningocele

part of SC and nerves are in the sac and damaged

Spinal Muscular Atrophy

degeneration of LMN with cell bodies in SC that innervate skeletal muscle

Genetic

autosomal recessive disorder

Fetal Alcohol Syndrome

cognitive, movement, and behavioral problems

Intellectual Disability

abnormalities of dendritic spines (not pruned or shaped appropriately)

Cerebral Palsy

movement and postural disorder that is permanent and non

What is the most common cause of severe physical disability in childhood

cerebral palsy

Hypotonic CP

very low tone, little to no ability to move

Spastic CP

increased spasticity and increased muscle stiffness

Dyskinetic CP

tone fluctuates, and dystonia is involved

Ataxic CP

incoordination and shaking during voluntary movement

Developmental Coordination Disorder

normal intellect, no TBI or CP or other neurologic symptoms, but lack coordination to perform tasks that kids their age should perform

Attention Deficit Hyperactivity Disorder (ADHD)

neurotype that affects the way the brain processes info due to ineffective NT use

ADHD, combined

most common, impulsive and hyperactive, trouble paying attention and are easily distracted

ADHD, impulsive/hyperactive

least common, same as above except no attention or distraction issues

ADHD, inattentive and distractable

mostly inattentive and easily distracted

Autism Spectrum Disorders

spectrum disorders with wide range of signs, symptoms, and behaviors

When can signs start to be seen for autism and what do they consist of

1 years old and lack of eye contact, decreased communication, and social interaction, reduced communication among cerebral hemispheres, abnormal caudate