Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

musculoskeletal rehabilitation > balance > Flashcards

balance Flashcards

1
Q

what is the vestibular system? when is it activated?

A
  • balance organ
  • only activated when it reaches sensory threshold
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

do you need the vestibular system to stand up?

A
  • no
  • can stand without the system if well adapted
  • proprioception more important
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is proprioception?

A
  • sense of the relative position of neighbouring parts of the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

can you give an example of proprioception

A
  • relationship of upper arm to trunk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does proprioception normally involve?

A
  • joint angle
  • joint position
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is sometimes included in proprioception?

A
  • vestibular sensation sometimes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is proprioception highly sensitive for? what is it the most important for?

A
  • highly sensitive for balance
  • most important sensory modality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how do I know my elbow is at 90 degrees? what information isn’t useful?

A
  • different sources of information contribute
  • joint information found to not be a useful tool
  • evidence via animal cases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what was historically thought to be the main source of joint position sense?

A
  • joint capsule receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is contained within the joint capsule?

A
  • ruffini, paciniform, golgi- type and free nerve endings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what do joint capsule receptors provide? what do they detect?

A
  • provide limited information
  • detect pressure as they contain different peripheral sense neurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are recent developments of joint capsule role based on?

A
  • animal recordings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what do animal recordings involve?

A
  • animal under anaesthesia
  • records primary afferents (from joints) & physically rotates to determine how the neuron firing rate encodes the joint position
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

do the primary afferents recorded give useful information?

A
  • no
  • poor information as it is difficult to reconstruct the position of the joints from firing rate
  • but do code the limit of the joint accurately
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the recent understanding of joint capsule afferents?

A
  • provide ambiguous information
  • mainly act as limit detectors (injury prevention)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens to joint position sense if you remove all sensory input?

A
  • joint position sense doesn’t change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the three main sources of evidence showing the joint capsule role?

A
  • normal sense of joint rotation after hip replacement
  • knee anaesthesia barely affects sense of joint rotation
  • disengaging muscles from joint motion leads to poor motion detection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe disengaging muscle from joint motion leading to poor motion detection

A
  • decoupled joint movements from its associated tendon & muscle
  • take the middle finger and rotate the end of the peripheral joint
  • ask people to judge whether its moving or not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

in the middle finger experiment, when are we useless at detecting joint motion ?

A
  • useless until you get up to high velocities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does golgi tendon organ signal? what stimuli?

A
  • signals force and heaviness
  • kinetic stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

where is the golgi tendon organ situated?

A
  • interface between muscle and tendon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does golgi tendon organ contribute to? and how?

A
  • indirectly contributes to joint rotation sense
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

when is golgi tendon organ important?

A
  • important when muscle movement is ambiguous
  • concentric vs eccentric
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what happens if there is an increase in force through golgi tendon and associated muscle?

A
  • greater firing rate of 1b afferents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are muscle spindles?

A
  • intrafusal muscle
  • embedded throughout muscles are 100s of sensors made by muscle tissue itself but doesn’t produce any useful force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what does muscle spindle provide? what does it contain?

A
  • main signal of joint angle
  • contains primary and secondary endings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what do primary endings signal?

A
  • position and velocity
  • kinematics stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are primary endings transmitted by?

A
  • transmitted via 1a afferents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are primary endings sensitive to?

A
  • vibration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what do secondary endings involve?

A
  • position only
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are secondary endings transmitted by?

A
  • group II afferents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are gamma fibres?

A
  • contractile elements of a spindle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what do gamma fibres do?

A
  • tighten up the sensors to help maintain their roles
34
Q

what does alpha- gamma coactivation maintain?

A
  • sensitivity in the face of changing muscle length
35
Q

what is the alpha motor system?

A
  • contraction of the main body of the muscle to produce force
36
Q

what is the gamma motor system?

A
  • contraction of the intrafusal fibres
  • maintains taut
37
Q

what evidence is there supporting the role of spindles?

A
  • ways of artificially activating muscle spindles via muscle vibration or associated tendon vibration
  • seen by direct recordings
38
Q

what hertz activates 1a afferents?

A
  • 80 to 100 hertz vibration selectively activates 1a afferents
39
Q

what does 80 to 100 Hz vibration produce?

A
  • illusions of muscle stretch
  • both position and velocity
40
Q

what is an example of the illusion of muscle stretch?

A
  • pinocchio illusion
  • grab your nose and place a muscle vibrator on biceps to evoke the sensation that your biceps is stretching, and nose is growing longer
41
Q

what does the central nervous system think with the illusion?

A
  • thinks the muscle is elongating
42
Q

what does calf muscle vibration evoke?

A
  • strong sway response
  • in the backwards direction as interpret that you’re going forward so illusion is opposite
43
Q

what are muscle spindle signals dependent on?

A
  • the nature of mechanical properties of the surrounding muscles
44
Q

can you bias the direction of the perceived location of the joint?

A
  • yes, you can condition the muscle before a perceptual experiment
45
Q

what experiment was done to bias the direction of the perceived location of the joint?

A
  • one arm manipulated passively into a position and with the eyes closed match position with other arm
  • before intervention people asked to flex or extend
46
Q

what does flexion or extension before experiment change and what does this lead to?

A
  • changes mechanical properties of the muscle transiently i.e., taut or flexible
  • consistent bias in your perception depending upon whether you flexed/ extended
47
Q

what word describes the factors that affect joint position sense?

A
  • muscle thixotropy
48
Q

what affects joint position sense?

A
  • prior muscle stretch/ contraction significantly affects joint position sense
49
Q

why does muscle thixotropy occur?

A
  • due to muscle becoming slack/ taut
  • thus affects spindle output
50
Q

what test was done in standing? what did it test of each system?

A
  • researcher evoked perturbations either by sensory channels including vision, proprioception, vestibular or all
  • tests the sensitivity of each system
51
Q

what was the adaptation for vision?

A
  • person is fixed in space
  • has a moving room around them
  • room is rotated
  • participant asked to judge when they first see it moving
52
Q

what was the adaptation for vestibular system?

A
  • fixed ankles using blocks
  • physically pushed around with eyes closed
53
Q

what was the adaptation for proprioception condition?

A
  • fixed in space with a balancing inverted pendulum
  • fall backwards unless push down on their feet
54
Q

what did the experiment work out from the different sensory conditions? what determines the usefulness of a sensor?

A
  • worked out the threshold for when you first detect motion to guide how sensitive they are
  • better at detecting motion when contracting so state determines how good it is as a sensor
55
Q

list the systems in order of sensitivity (1= highest, 3= lowest)

A

1= proprioception
2= vestibular
3= vision

56
Q

what is standing possible with?

A
  • possible with proprioception alone
57
Q

what is equivalent body used for?

A
  • used to isolate ankle joint signals
58
Q

what is used to test balance? what shows a better balance system?

A
  • imperceptible perturbations
  • larger response to perturbation shows a better balance system
59
Q

what information alone can keep the body upright?

A
  • ankle information alone is sufficient
  • need muscle spindle and golgi tendon information from calf
60
Q

what does GVS stand for? where is the GVS?

A
  • Galvanic Vestibular Stimulation
  • locked inside skull
61
Q

how is vestibular information interpreted?

A
  • must be interpreted in context of neck orientations
62
Q

what does illusions of neck orientation cause?

A
  • vestibular information to be reinterpreted
63
Q

how does GVS cause problems with balance?

A
  • because head not always fixed in respect to the body
  • swaying can alter input
64
Q

what is a efference copy? what does it do?

A
  • copy of motor command sent to sensory system
  • makes us aware of where our limbs are
65
Q

how do you artificially activate the vestibular system? what happens if you turn the head and why?

A
  • use electrodes to supply small currents across the back of the head
  • activates vestibular nerve
  • swaying sensation towards cathode electrode
  • if you turn the head, you sway in that way
  • vestibular info interpreted in context of proprioception
66
Q

what can proprioception also interact with?

A
  • vision sense
67
Q

when does evoked sway habituate?

A
  • upon repeated exposure to moving room
68
Q

which way do you sway in?

A
  • sway in the same way as the room as stationary object
69
Q

what does foam do?

A
  • reduces ankle input
  • leads to larger visually- evoked responses
70
Q

when does the body no longer react to trial?

A
  • when the body adapts
  • due to other sensory inputs conflicting with visual info e.g., proprioceptive
71
Q

why are calf muscles not useful signals of body position?

A
  • because calf muscle shortens as body sways forward
  • it is an ambiguous signal
72
Q

what is paradoxical motion? what does it tell us?

A
  • as the person sways forwards, the muscle gets shorter
  • tells us stretch reflexes cannot be useful for normal control of quiet standing as achilles tendon is elastic under low forces
73
Q

how does age affect balance?

A
  • ankle proprioception declines with age
74
Q

is the link of balance with falls strong?

A
  • proprioception falls link not strong
75
Q

what is associated with falls?

A
  • peripheral neuropathy
76
Q

what is the link between balance and falls explained by?

A
  • interaction of muscle sensation and strength
77
Q

does weakness or strength impact ability to sway?

A
  • doesn’t matter when eyes open; however, when closed there was a disproportional greater ^ in sway of weaker people
78
Q

what is a strong predictor of fall risk?

A
  • reduced strength
79
Q

is exercise aimed solely at strength training successful?

A
  • no, its not successful in reducing fall risk
80
Q

what must be challenged to reduce fall risk?

A
  • balance itself
81
Q

what increases fall risk if included?

A
  • walking exercises

musculoskeletal rehabilitation (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions