Lecture 18: threat influences Flashcards
What did Carpenter et. al. study in 2004 in regards to dynamic balance
also, what did they find?
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)
When Cleworth et al. in 2016 used virtual heights to test changes in dynamic balance, what did they find
larger and earlier muscle responses
decreased peak COP and time to peak (COM and COP)
Threat influences ____
dynamic control of posture
APAs are _____ with changes that are context dependant
influenced by threat
Postural reactions to external perturbations are ____
influenced by threat (damn pretty redundant)
Balance reactions to threat are ____
larger and earlier, generally contribute to a more constrained control of COM
what are potential mechanisms for threats and dynamic control
mechanisms are CURRENTLY UNKNOWN HOWEVER likely involve changes in:
* perception
* neural changes in sensorimotor control
* attentional focus
how does threat influence the perception of static postural sway?
although reducing overall sway, they thought they felt themselves swaying a lot
perceived instability is greater under threat conditions
what did Cleworth and Carpenter find in 2016 regarding perceived sway
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
What happens to perception when sway is induced by a platform in differing heights
despite amplitude of the sway being quite similar in low and high heights
the perceived tracking amplitudes are way larger in higher heights
how does anxiety affect vision
increased visual-balance reflexes
increased useful field of view
how does anxiety affect vestibular system
increased coupling and gain of vestibulo-spinal/occular reflexes during sensory-balance reflexes
How does anxiety affect skin/cutaneous receptors
increased cutaneous reflexes during gait
how does anxiety affect muscle spindles
increased stretch reflexes
- tendon tap
-rapid ankle rotations
how does anxiety affect golgi tendons
Reduced 1B inhibition
- electrical stimulation
how does attentional focus change with anxiety or fear
when threatened, young adults direct more attention toward
- movement processes
- threat related stimuli
- self-regulatory strategies
- task objectives
away from
- task-irrelevant information
_____ factors may mask or minic clinical symptoms
psychological
___ influences clinical balance measures
fear
what are some implications for balance control and fear/anxiety?
- 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
increased arousal can come from ___
both negative and positive feelings
similar posture changes are seen in arousal compared to ___
changes from low to high height
it is the arousal itself that causes balance changes (Sanji)
Is there a white-coat effect on balance?
yes
what can too much fear cause in balance control?
maladaptive balance behaviours
activity avoidance
What can no fear cause in terms of balance control?
over-estimating capacities
lack of protective strategies
