Unit 1: Motor Control Theories Flashcards
What is Motor Control?
Nature of movement
-How movement is controlled
-How movement is unable to be
controlled due to an illness or other factors
What can contribute to abnormal movement patterns?
Aging, Illnesses, or Injury
Theories of Motor Control
Group of abstract ideas about the control of movement
Theory
Set of interconnected statements that describe unobservable structures or processes and relate them to each other and to observable events
Theory assists in
With interpreting behavior, guides clinical practice, new ideas, dynamic, and involving
We develop a working hypothesis for our evaluation and intervention through the use of theory
Reflex Theory
Represents an older view of motor control and motor learning. Complex behavior could be explained combined action of individual reflexes chained together
- Structure of a Reflex: Receptor, Conductor, Muscle/Effector
- Reflex is initiated by an outside stimulus
Reflex Theory Limitations
- Cannot account for rapid movements where there is not enough time for sensory info to activate the next move (ex. playing piano)
- Times when a single stimulus can produce different results or when reflexes can be overridden (not dropping a hot plate because it will break)
- Cannot account for the translation of skills to new situations
- Reflex activated by an outside agent
- Does not explain a movement that occurs in absence of sensory stimulus
- Does not explain fast movements
- Fails to explain how a single stimulus can result in varying responses
- Does not explain the ability to produce novel movements
How does reflex theory affect clinical practice?
- Reflex testing may allow therapists to predict function
- Clients movement behaviors may be interpreted in terms of the presence or absence of controlling reflexes
- As clinicians, we may want to enhance or reduce the effect of reflexes during motor tasks
Reflex theory related to practice
When an infant is developing, we expect to see certain reflexes in a given time frame, the absence of these reflexes in that time frame may be indicative of a central nervous system that isn’t developing typically.
-If reflexes persist past the point where integration is expected, it may also be indicative of an atypically developing central nervous system
(Ex. Asymmetrical tonic neck reflex: Usually see it begin at about 2 months and it’s integrated around 4 months. Persistence of this reflex past 4 months may be indicative of a central nervous system deficit.)
As clinicians its important we note the…
Presence, absence, or persistance of reflexes and consider whether the presentation is developmentally appropriate for the client
Hierarchial Theory
The brain is considered to have a higher, middle, and lower level of control.
In the vertical hierarchal view of control, the level above exerts control over the level below always.
1920 (Hierarchical Theory)
It was found that reflexes controlled by lower areas were only present with cortical damage
-Reflexes were thought to be part of this hierarchy and were inhibited by higher centers in this theory. (This is why we see primitive reflexes appearing with individuals in the ICU who have neurological trauma)
Developmental Mobility (Hierarchical Theory)
Later described as the appearance and integration of hierarchically organized reflexes.
-It was thought that skills had to occur as a prerequisite for the next skill and they were described as the basis for equilibrium in humans
(Ex. it was thought that infants must sit and crawl before walking, now we know that a child may not crawl regardless of if they are developing typically or atypically)
Reflex Hierarchical Thinking applied to Infant Behavior
Typical behavior was seen as an increase in cortical control over the lower level reflexes. This view minimized the importance of developmental changes due to the musculoskeletal system and other factors
Current Views of the Hierarchical Theory
-Elements of the hierarchical organization are important in motor control
-Each level can act on other levels depending on the task
(Still recognize reflexes as being important to movement and motor control, we now know that they are one of many important processes and not the single determinant of movement and control)
Limitations of the Hierarchical Theory
-Doesn’t explain reflex dominance in typic adults in certain situations
(Ex. Cant explain protective reflexes such as withdrawal when stepping on a sharp object or touching a hot stove- this is a reflex and the lowest level of the hierarchy exerting control over higher-level centers; Here we see the view that all cortical behaviors are mature, adaptive, and appropriate while lower-level behaviors are primitive, immature, and non-adaptive)
