Lecture 18: threat influences

Question 1

What did Carpenter et. al. study in 2004 in regards to dynamic balance

also, what did they find?

Answer 1

threat effects on dynamic balance
support surface rotations while standing on high elevated platforms
found higher and earlier muscle responses at high heights
also saw a decreased peak COM(constraint in COM moving too far)

Question 2

When Cleworth et al. in 2016 used virtual heights to test changes in dynamic balance, what did they find

Answer 2

larger and earlier muscle responses
decreased peak COP and time to peak (COM and COP)

Question 3

Threat influences ____

Answer 3

dynamic control of posture

Question 4

APAs are _____ with changes that are context dependant

Answer 4

influenced by threat

Question 5

Postural reactions to external perturbations are ____

Answer 5

influenced by threat (damn pretty redundant)

Question 6

Balance reactions to threat are ____

Answer 6

larger and earlier, generally contribute to a more constrained control of COM

Question 7

what are potential mechanisms for threats and dynamic control

Answer 7

mechanisms are CURRENTLY UNKNOWN HOWEVER likely involve changes in:
* perception
* neural changes in sensorimotor control
* attentional focus

Question 8

how does threat influence the perception of static postural sway?

Answer 8

although reducing overall sway, they thought they felt themselves swaying a lot
perceived instability is greater under threat conditions

Question 9

what did Cleworth and Carpenter find in 2016 regarding perceived sway

Answer 9

instructed to record their sway using a joystick
saw decreases in actual COP and COM with higher height
perceived sway increased in high height
disconnected when we’re fearful btw perceived and actual

Question 10

What happens to perception when sway is induced by a platform in differing heights

Answer 10

despite amplitude of the sway being quite similar in low and high heights
the perceived tracking amplitudes are way larger in higher heights

Question 11

how does anxiety affect vision

Answer 11

increased visual-balance reflexes
increased useful field of view

Question 12

how does anxiety affect vestibular system

Answer 12

increased coupling and gain of vestibulo-spinal/occular reflexes during sensory-balance reflexes

Question 13

How does anxiety affect skin/cutaneous receptors

Answer 13

increased cutaneous reflexes during gait

Question 14

how does anxiety affect muscle spindles

Answer 14

increased stretch reflexes
- tendon tap
-rapid ankle rotations

Question 15

how does anxiety affect golgi tendons

Answer 15

Reduced 1B inhibition
- electrical stimulation

Question 16

how does attentional focus change with anxiety or fear

Answer 16

when threatened, young adults direct more attention toward
- movement processes
- threat related stimuli
- self-regulatory strategies
- task objectives
away from
- task-irrelevant information

Question 17

_____ factors may mask or minic clinical symptoms

Answer 17

psychological

Question 18

___ influences clinical balance measures

Answer 18

fear

Question 19

what are some implications for balance control and fear/anxiety?

Answer 19

• potential to mimic or mask clinical balance deficits
• potential for white-coat effects
• first trial effects-repeated testing
• task influences
• level of arousal
• need to alter rehab and training strategies
• workplace performance and injuries

Question 20

increased arousal can come from ___

Answer 20

both negative and positive feelings

Question 21

similar posture changes are seen in arousal compared to ___

Answer 21

changes from low to high height
it is the arousal itself that causes balance changes (Sanji)

Question 22

Is there a white-coat effect on balance?

Answer 22

yes

Question 23

what can too much fear cause in balance control?

Answer 23

maladaptive balance behaviours
activity avoidance

Question 24

What can no fear cause in terms of balance control?

Answer 24

over-estimating capacities
lack of protective strategies