Reach & Grasp Flashcards
T or F: Key Elements of reach, grasp, and manipulation skills include Visual Regard, Reaching, Grasping, and In-Hand Manipulation
True!
Visual Regard
locating target; coordinating eye-head movements
Reaching
transport UE in space; postural control
Grasping
grip formation, grasp & release
Musculoskeletal Components of Reach & Grasp
Joint ROM
Spinal Flexibilty
Muscle Properties
Biomechanical relationships among linked segments
Neural Components of Reach and Grasp
Motor coordination of eye, head, trunk, UE
Sensory system processes
Internal representations for mapping sensation to action
Higher level anticipatory and adaptive function processes
Feedback Control
input from sensory systems compared to refrence sigla
represent desired state
Uses error signals to update output of system
Error Signal
Difference between sensory signal and reference signal
Feedforward (anticipatory) Control
uses previous experience to predict consequences of sensory information that is received
occurs before feedback sensors are stimulated & reduces reliance on feedback control
T or F : Control of arm movements changes depending on the task goal
True! We may utilize pointing or reach to grasp strategies
Pointing Strategy
all segments of arm controlled as a unit
Reach to Grasp
Hand controlled independently of other arm segments
Arm transports/reaches
Hand grasps
Dorsal Visual Pathway Stream
provides action relevant information
Where Pathway visual to parietal cortex
Ventral Stream Visual Pathway
provides concious perception
What Pathway visual cortex to temporal lobe
Ebbinghaus Illusion
Used visual illusion to separate perception of object’s size and ability to act on it accurately
Despite concious perception of same size, subjects could adjust grip to correct size
T or F : Dorsal Stream mediates the transformation for visually guided actions
True!
T or F : The Ventral Stream mediates perceptual identification
True!
Fitt’s Law
Movement time becomes longer when distance or precision requirements increase
ex: narrow widths and longer distances = longer movement time
Distance Programming Theory
when making arm movement toward a target
- perceive distance to be covered
- activate agonist muscles to propel arm proper distance
- inhibit agonist and activate antagonist to stop the movement
Location Programming Theory
nervous system programs the relative balance of tensions between agonst/antagonist pairs
every location in space corresponds to a family of stiffness relations between opposing muscles
Bimanual Coordination
Interlimb coupling used to organize movements
T or F : According to a Location Programming Theory known as Multiple Correction Theory, movment accuracy decreases when vision is removed during the reach
False! Multiple Correction Theory is a Distance Programming Theory
Schmidt’s Impulse Variability Theory
Distance Programming Theory
emphasizes initial phase of movement involving generation of force impulse which typically decreases movement accuracy without visual feedback
Clinically, would practice fast movements of varying at varying amplitudes to learn program forces appropriately
Optimized Initial Impulse Model
hybrid distance programming model emphasizing balance between quickness and accuracy
If first initial impulse movment is successful is only movement
If innacurate, correct movement with visual feedback for accuracy
T or F: According to Location Programming Theories, in a closed position both agonist and antagonist muscles at mid-length
True!
T or F : According to Location Programming Theory, in an open position, the agonist muscle is contracting and the antagonist is relaxing
True!
Clinical Implications of Cafe Door/Location Programming Theories
Ability to modulate stiffness between agonist and antagonist muscles is important for retraining accurate movements
