Normal Control of Reach, Grasp and Manipulation Flashcards

1
Q

What are 6 concepts related to reach and grasp?

A
  • Movement control principles
  • Locating a target
  • Characteristics of reach and grasp
  • Systems contributing to reach and grasp
  • Grasping patterns
  • Neural control of reach and grasp
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2
Q

What type of control mechanisms (1) contribute to the control of upper extremity movement? (for example catching a ball)

A

Both feedforward (anticipatory) and feedback

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3
Q

What does feedback control involve?

A

Input from sensory receptors (visual or somatosensory) being compared to a reference signal, representing a desired state of the system (e.g., a position of the arm)

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4
Q

What does feedforward or anticipatory control take advantage of?

A

prior experience to predict consequences of sensory information

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5
Q

Because of feedforward control there is ___ reliance on feedback control

A

less

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6
Q

When dropping a ball the initial input is ______ (using vision), while final input is _____ (using somatosensory inputs).

A

feedforward

feedback

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7
Q

In order to reach for an object successfully, what must wee do first?

A

locate the object in space (2)

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8
Q

Describe the sequence of events that occur when locating a target

A

1) Eye movements
2) Head movements
3) Trunk movements

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9
Q

When working with a patient having problems with functional grasp what may clinicians consider for treatment? Why?

A

Training the different control systems separately, as the patient’s problem may be related to the eye movements with little head movement, or eye-head movements for visual regards

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10
Q

What do kinematic studies show once an object appears in the peripheral visual field?

A

Eye movement begins first due to low inertia; then head movements and followed by hand movement

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11
Q

EMG studies indicate that muscle responses are activated _____ rather than sequentially.

A

synchronously

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12
Q

What are 2 ways in which eye and hand movements interact and influence each other?

A
  • hand movement becomes more accurate when accompanied by eye movement
  • there is an increase in gain during smooth pursuit if the hand is also following the target
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13
Q

When patients are asked to reach and grasp an object the movement duration is of the reach was much ______ than if the subject was asked to grasp the object

A

longer

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14
Q

When preparing to grasp an object, the acceleration phase of the reaching movement is much ______ than the deceleration phase.

A

shorter

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15
Q

When asked to point at an object, the acceleration phase of the reaching movement is much ______ than the deceleration phase.

A

longer

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16
Q

True or False

Reach and Grasp are controlled by different neural mechanisms.

A

True

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17
Q

In helping patients with problems related to reach and grasp, movements need to be practiced in a variety of task conditions. What are a few examples?

A
  • reach and point
  • reach and grasp
  • reach, grasp and manipulate
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18
Q

What are 3 areas of the cerebral cortex are critical to the control of reach and grasp(4)?

A
  • primary motor cortex
  • premotor cortex
  • areas of the posterior parietal lobe
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19
Q

What are the 2 pathways in which sensory inputs from the visual system go through during goal-directed reaching?

A
  • dorsal stream pathway

- ventral stream pathway

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20
Q

What is the dorsal stream pathway related to?

A

Where the object is in extrapersonal space (localization) and the action systems involved in object manipulation

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21
Q

Therefore, the dorsal stream pathway is aka what?

A

localization and action pathway

22
Q

The localization and action (dorsal stream) pathway transmits information from the visual cortex to the _____ cortex

A

parietal

23
Q

What is the ventral stream pathway related to?

A

What is being reached for (perception and object recognition)

24
Q

Therefore, the ventral stream pathway is aka what?

A

The perceptual pathway

25
Q

The perceptual (ventral stream) pathway transmits information from the visual cortex to the _____ cortex

A

temporal

26
Q

What are 3 somatosensory receptors that contribute to position sense?

A
  • muscle spindles
  • cutaneous afferents
  • joint receptors (at the extremes of joint motion)
27
Q

What is the major somatosensory input contribution to grasping?

A

control of grip forces

28
Q

______ _____ receptors contribute to the control of grip force

A

cutaneous afferents

29
Q

What are the 2 contributions that visual and somatosensory inputs (in combination) provide for reaching and grasping?

A
  • Used to plan movement proactively

- Used reactively for error corrects during the execution of movement

30
Q

What are the 2 separate descending pathways for reach and grasp?

A
  • midbrain (red nucleus) and brainstem (reticular nuclei) pathways
  • pyramidal pathways
31
Q

What do the midbrain (red nucleus) and brainstem (reticular nuclei) pathways control?

A

the proximal muscles involved in reaching

32
Q

What do the pyramidal pathways control?

A

fine motor control of grasping movements

33
Q

Reaching also involves a complex interaction of what musculoskeletal and neural system components?

A
  • Joint ROM
  • Spinal flexibility
  • Muscle strength, tone and coordination
  • Biomechanical relationship among limb segments
  • Postural support of reaching (task-dependent control)
34
Q

What are the 2 classifications of grasping patterns (5)?

A
  • Power or Precision grip

- Grasp and Lift task

35
Q

What types of factors determine power or precision grip?

A
  • intrinsic factors such as object size, shape, and texture

- extrinsic factors such as orientation, distance and location

36
Q

What are 4 types of power grips?

A
  • Cylindrical
  • Spherical
  • Hook
  • Lateral prehension
37
Q

A precision grip the forces are between what?

A

the thumb and fingers

38
Q

What does a precision grip allow?

A

in-hand control

39
Q

What are the parameters for grip force based on?

A
  • previous experience

- perception of the characteristics of the object to be grasped (using information from visual & somatosensory)

40
Q

Define reaction time

A

the duration between the stimulus and the onset of voluntary movement

41
Q

Reaction time is ____ than reflex latency

A

longer

42
Q

Reflex latency = approximately __ ms in response to somatosensory cues, whereas reaction time = __-__ ms

A

40

80-120

43
Q

Reaction time varies according to what? What is this called?

A

the amount of information to be processed

choice RT

44
Q

Choice reaction time is increasingly ____ by adding choices

A

slowed

45
Q

What describes relationship between movement time, distance and accuracy?

A

Fitt’s Law

46
Q

According to Fitt’s law, movement time _____ with the increase of movement distance

A

increases

47
Q

According to Fitt’s law, movement time _____ with the increase of arm-movement precision

A

increases

48
Q

What is the clinical implication of Fitt’s law?

A

It is an effective way to increase the level of difficulty of a task while objectively monitoring the patients’ progress

49
Q

True or False

Reach and Grasp are two distinct components that appear to be controlled by different mechanisms.

A

True

50
Q

Based on research concerning the control mechanisms of reach and grasp, what is the suggested intervention paradigm for a client with upper extremity paresis complicated by spasticity?

a. Train only reach and grasp together.
b. Begin by practicing the reach component without actually grasping/lifting an object.
c. Begin by practicing grasp of objects of varying sizes.
d. Train only the reach and lift components together.

A

B