Quiz 1 Flashcards
Define Motor Control
Ability to regulate or direct the mechanisms essential to movement
Movment emerges from the interaction between what 3 factors?
Individual
Task
Environment
The Individual Factor of Movement has 3 subsets:
Action
Cognition
Perception
Describe Action (individual)
Neuromuscular and biomechanical systems
Describe Perception/Sensory (individual)
Integration and interpretation of sensory signals into meaningful information
- information about the state of the body, relative features of the environment
Describe Cognition (individual)
Understanding the intentions or goals, having the cognitive processes involved for motor control/learning
What types of cognitive processes may be involved in the nature of movement?
Problem soliving
Judgement
Predicting upcoming forces/events
Short-term memory/Results of previous problem solving
Understanding the intentions of others
Attention
Planning
Motivation
Emotion
Describe the importance of knowing Task Constraints
Type of task being performed greatly impacts neural organization of the movement
What are the Classifications of Task Constraints
Discrete vs. Continuous vs. Sequential
Closed vs. Open
Stability vs. Mobility
Manipulation vs. Non-Manipulation
Discrete Task
recognizable beginning and end
ex: kicking a ball, moving from sitting to standing
Continuous Task
end point of task decided arbitrarily by performer
ex: walking
Sequential Tasks
Linkage of multiple discrete tasks
ex: preparing a meal
Closed Tasks
performed in relatively fixed or predictable environments
ex: walking inside of the clinic
Open Tasks
performer is required to adapt movement to a changing and unpredicatable environment
ex: walking on a busy sidewalk, playing soccer
Stability Task
non-moving base of support
ex: sitting or standing
Mobility Task
moving base of support
ex: walking or running
Manipulation Tasks
involve movement of the upper extremities/ reguire manipulation of an object
ex: kicking a ball, picking up a pen
Non-Manipulation Tasks
not utilizing an object that needs to be manipulated
Describe the importance of considering task attributes on a continuum
Taxonomy of Tasks can be identified and the level of difficulty or challenge can be understood in order to be adapted
ex: a closed stability task is standing on a non-moving surface and a open stability task is standing on a foam pad
What are the Environmental Constraints?
Regulatory vs. Non-Regulatory
Environmental Constraints can help or hinder performance and features of the environment must be understood to know how they will affect
Regulatory (environmental)
Movement must conform to features of the environment to acheive task goal
ex: stair height
Non-Regulatory (environment)
May affect performance, but movement does NOT have to conform to features
ex: background noise, carpet pattern, etc.
Taxonomy
a strategy of comparing movement tasks on a continuum
Definition of a Theory of Motor Control
A group of abstract ideas about the control of movement
Definition of Theory
a set of interconnected statements that describe unobservable structures/processes and relate them to each other
Blueprint Analogy
Theory Gives Meaning to Facts
but
Facts have different meanings based on their relative importance in different thories
Reflex Theory
Integrative Power of CNS due to reflexes coordinating activities of organs
Reflexes are the basic functional unit of complex behaviors
Response to one stimulus acts as stimulus for the next
Limitations to Reflex Theory
Doesn’t Account For:
-Voluntary Movement
-Movement w/out sensory input
-Fast movements too rapid for sensory feedback
-Same stimulus giving different responses
-New/novel movements
Clinical Implication of Reflex Theory
Testing reflex strategies helps us predict function
Movement behavior can be interpreted by presence/absence of reflexes
Hierarchical Theory
High=Association Areas ; Middle=Motor Cortex ; Low= Spinal
Each level controls the level below it (no bottom-up)
NS= discrete organs with single function, somatotopic representation
Higher centers inhibit lower reflex centers Unless cortical damage
Neuromaturational Theory of Development
Reflex/Hierarchical Theories
Neonatal reflexes in set progression = neural age
Increased Corticalization of CNS means higher levels of control over lower level reflexes
Primary driver of motor development
Limitations of Hierarchical Theory
Can’t explain dominant reflexes intact in adults (bottom-up LEGO step reaction)
Lower reflexes are not always primitive and higher behaviors not always mature
Clinical Implications Hierarchical Theory
Abnormal reflex organization implicates disorder in motor cortex
Motor Programming Theory/Central Pattern Generator
Movement patterns occur in absence of stimulus or reflex
Sensory input NOT essential, but helps modulate
Spinally mediated motor programs
Neural connections are hardwired and produce stereotyped behaviors
Variability is an Error
Generalized Motor Program Theory
Motor control happens in absence of feedback (ballistic movement control) and with generation of new movements
Many different movements performed with same motor program/ abstract representation
Creating of novel movements with new specified parameters
Limitations of Motor Programming Theories
CPGs: don’t replace importance of sensory input
Can’t be sole determinant of action (identical commands produce different actions)
System must deal with musculoskeletal and environmental variables
Clinical Implications of Motor Programming Theories
Help the patient re-learn the rules for actions and movements essential to a functional task
Systems Theory
Body viewed as a mechanical system w/ mass & ext/int forces acting on it
Same central command results in different movements depending on starting position
Mechanical system has many degrees of freedom that MUST be controlled/ need to master redundant degrees
Higher levels take advantage of functional capabilities of lower levels and reduce involvement of higher levels
Tonus=Spinal Cord ; Synergies= Mid Brain ; Action = Frontal Cortex
Synergies
Solve the degree of freedom problem
Groups of muscles that are constrained to act together as a unit
Dynamic Systems Theory
Mathematical, non-linear description of self-organization, individual parts and systems interact to produce motor control
Less emphasis on CNS commands: control is distributed at same levels (no higher/lower control)
Seeks physical/mechanical explanations of movement characteristics
Variability inherent to a non-linear system = Flexible/Adaptable
Attractor States*
Non-Linear Properties
dynamic systems
Output not proportional to input
Transforms into new configuration when control parameter of behavior is gradually altered and reaches a critical value (walking–> trotting —> galloping when velocity increases)
Attractor States
Highly Stable, Preferred Patterns of Movement with small amounts of variability
Energetically Efficient
Attractor Well
Amount of flexibility to change a preferred movement pattern
Shallow Well: unstable, easier to change, high variability
Deep Well: stable, harder to change, low variability
What theory is best at predicting actual behavior?
Systems Theory - considers gravity and inertia
Limitations to Systems Theory
Lack of consensus on terminology/definitions
Difficult to translate clinically
Clinical Implications of Systems Theory
Output of nervous system is filtered through mechanical system w/ interacting impairments
Movement is an emergent property
Variability is Normal
Ecological Theory
Motor system’s interaction with environment to acheive task goals
Detect and use enviornmental info to control movements (perception gives rise to action)
Motor development is driven by interaction between environmental affordances and human motivation and perception
Affordance
Possibility of an action in environment
What the environment can offer
Depends on fit between body capabilities and physical properties of the environment
Limitations of Ecological Theory
Less emphasis/insight on nervous system function/disease or health status/organization
Clinical Implications of Ecological Theory
Individual is an active explorer of task
Can acheive task in multiple ways given a set of limitations
Control and Manipulate Environment to elicit desired task outcome
Integrated Approach
Combines elements from all theories
Within the Individual, movement results form dynamic interplay between Perception, Cognition, and Action
Neuro-Facilitation Approaches
Facilitation Techniques: increase patient’s ability to move in “appropriate” ways
Inhibition Techniques: decrease patient’s use of “abnormal” movement patterns
Based on Reflex-Hierarchical Theory: higher centers must regain control over lower centers
Assumes repetition of normal movement patterns will automatically transfer to functional tasks
Clinical Implications of Neuro-Facillitation Approaches
Identify presence/absence of reflexes controlling movement
Modify CNS through stimulation
Help patient regain normal movement patterns for functional recovery
Task-Oriented Approach
Based on Systems Theory
Normal movement is interaction among different systems, goal constrained by environment
Abnormal movement from impairments in 1+ systems and remaining systems compensate
Clinical Implications of Task-Oriented Approach
Work on identifiable functional tasks rather than movement patterns
Patients actively attempt to solve problems
Focus on adapting to changes in environment
