Reach & Grasp

Question 1

T or F: Key Elements of reach, grasp, and manipulation skills include Visual Regard, Reaching, Grasping, and In-Hand Manipulation

Answer 1

True!

Question 2

Visual Regard

Answer 2

locating target; coordinating eye-head movements

Question 3

Reaching

Answer 3

transport UE in space; postural control

Question 4

Grasping

Answer 4

grip formation, grasp & release

Question 5

Musculoskeletal Components of Reach & Grasp

Answer 5

Joint ROM
Spinal Flexibilty
Muscle Properties
Biomechanical relationships among linked segments

Question 6

Neural Components of Reach and Grasp

Answer 6

Motor coordination of eye, head, trunk, UE
Sensory system processes
Internal representations for mapping sensation to action
Higher level anticipatory and adaptive function processes

Question 7

Feedback Control

Answer 7

input from sensory systems compared to refrence sigla
represent desired state

Uses error signals to update output of system

Question 8

Error Signal

Answer 8

Difference between sensory signal and reference signal

Question 9

Feedforward (anticipatory) Control

Answer 9

uses previous experience to predict consequences of sensory information that is received

occurs before feedback sensors are stimulated & reduces reliance on feedback control

Question 10

T or F : Control of arm movements changes depending on the task goal

Answer 10

True! We may utilize pointing or reach to grasp strategies

Question 11

Pointing Strategy

Answer 11

all segments of arm controlled as a unit

Question 12

Reach to Grasp

Answer 12

Hand controlled independently of other arm segments
Arm transports/reaches
Hand grasps

Question 13

Dorsal Visual Pathway Stream

Answer 13

provides action relevant information
Where Pathway visual to parietal cortex

Question 14

Ventral Stream Visual Pathway

Answer 14

provides concious perception

What Pathway visual cortex to temporal lobe

Question 15

Ebbinghaus Illusion

Answer 15

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

Question 16

T or F : Dorsal Stream mediates the transformation for visually guided actions

Answer 16

True!

Question 17

T or F : The Ventral Stream mediates perceptual identification

Answer 17

True!

Question 18

Fitt’s Law

Answer 18

Movement time becomes longer when distance or precision requirements increase

ex: narrow widths and longer distances = longer movement time

Question 19

Distance Programming Theory

Answer 19

when making arm movement toward a target

1. perceive distance to be covered
2. activate agonist muscles to propel arm proper distance
3. inhibit agonist and activate antagonist to stop the movement

Question 20

Location Programming Theory

Answer 20

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

Question 21

Bimanual Coordination

Answer 21

Interlimb coupling used to organize movements

Question 22

T or F : According to a Location Programming Theory known as Multiple Correction Theory, movment accuracy decreases when vision is removed during the reach

Answer 22

False! Multiple Correction Theory is a Distance Programming Theory

Question 23

Schmidt’s Impulse Variability Theory

Answer 23

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

Question 24

Optimized Initial Impulse Model

Answer 24

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

Question 25

T or F: According to Location Programming Theories, in a closed position both agonist and antagonist muscles at mid-length

Answer 25

True!

Question 26

T or F : According to Location Programming Theory, in an open position, the agonist muscle is contracting and the antagonist is relaxing

Answer 26

True!

Question 26

Clinical Implications of Cafe Door/Location Programming Theories

Answer 26

Ability to modulate stiffness between agonist and antagonist muscles is important for retraining accurate movements