RS2781_RS5304 Lect 1_therories of lifespan developement_std.pdf

Maturation of the CNS, particularly the motor cortex.

• Movement that occurs in the absence of sensory input

• Voluntary movement

• Fast movement

• Ability to over-ride the reflex response

A 'phase shift' occurs and a new movement emerges.

1. Cortex

2. Subcortical

3. Brainstem

4. Spinal cord

• internal:

  • musculoskeletal, cardiovascular, pulmonary, nervous systems

• external:

  • environment or task

To accommodate in the womb (~full-term baby length: 50 cm).

weight of limb → cessation of stepping reflex → voluntary walking starts

• Inherent in developing subsystems

• Applicable to both typically and atypically developed populations

• Division: higher, middle, and lower centres

• Top-down system

  • Highest-level reflexive responses exert dominance over lower-level reflexive responses

log rolling → segmental rolling

Selective joint movements.

• Some abnormal movement patterns are due to secondary problems (contractures) or behavioral issues (compensation)

• Cannot explain the dominance of reflex behaviour in certain situations in normal adults.

It suggests that factors other than neural maturation (eg: biomechanical & environmental factors) play a role in motor development.

• Development of rotational component

• Development of intralimb dissociation

• Development of interlimb dissociation

They guide how therapists treat patients with neurological disorders.

1. Disappearance of stepping reflex by the end of 3 months normally.

2. Disappearance of stepping if the limb is weighted.

3. Stepping response re-appears when the body is submerged into water at an older age.

1. Initial Stage: sitting

2. Intermediate Stage: Weight-shift in the frontal/sagittal plane

3. Final Stage: Rotation of the trunk

Neuromaturational theory (aspect 1):

• sequence of (voluntary) motor development = sequence of CNS maturation process

  • cephalocaudal progression

  • same among infants

• CNS maturation is the PRIMARY agent for change in development

It allows a child to develop his/her potential.

• Reflex theory

• (Reflex/) Hierarchical theory

• Dynamic systems theory

Because movements occur too rapidly to allow for sensory feedback from the preceding movement to trigger the next.

• Balance control

• Moving the body

Improve/ Stimulate:

• Help the brain better (re)organize

• Facilitate normal movement patterns

Reduce/ Inhibit:

• Reduce/inhibit abnormal patterns, primitive reflexes, or spasticity

• Reflexes are the building blocks of complex behaviors.

• Reflexes work together/ in sequence [reflex chaining] to achieve a common purpose.

Goal Setting

• set a functional goal

• work on identifiable functional tasks, NOT movement patterns alone

Adaptation and Practice

• adaptation to changes in environment: practice in a variety of contexts (e.g., walking)

• practice→experience→environment

• At birth, higher levels are not functioning and reflexive movements are mediated by lower centers of the CNS.

• Primitive reflexes from the lower levels are inhibited by the higher levels before voluntary movements are developed.

Each level of the brain is correlated to a specific anatomic region.

1. Movement is the result of interactions among many subsystems of an individual for a task under an environmental context.

2. Movements emerged as a result of the ability of different subsystems to interact and self-organise.

   • No need for CNS

3. Motor skills develop in an asynchronous & nonlinear manner.

4. Changes in motor behaviour are discontinuous and being attributed to “control parameters”.

Spinal cord injury: The brain may be well-developed, but movement of limbs is hindered, showing the primary role of CNS maturation.

• Patients tend to play a more passive role

• Limited carryover effect into functional activities

rate & no. of motor skills acquired: 1st year > 2nd year

Developmental Principles:

• Cephalo-caudal

• Proximal-distal

• General-specific

• Maturation and learning

Movement Patterns:

• Extension-flexion

• Stability-mobility

Individual Differences:

• Individual variations

• First 12 months: Gross motor

• Second 12 months: Fine motor

• Third 12 months: Language

1. Cortex:

   • Voluntary movement

   • Equilibrium reactions

   • Protective reactions

2. Mid-brain:

   • Righting reactions

3. Pons/medulla:

   • Primitive reflexes

4. Spinal cord:

   • Primitive reflexes

• biomechanics

• MSK

• No one subsystem has privileged status over the other subsystems

• Each internal subsystem has its own sequence and development rate.

[senior’s notes p.15]