Topic 5 - disruptions in concussion

Question 1

why does concussion sometimes cause balance impairments

Answer 1

disruption in communication with some reugalr communication = no smooth signals coming out of the cerebellum so its hard to coordinate all areas to balance properly

Question 2

what is the most common balance assessment

Answer 2

mBESS
- modified balance error scoring system
- on hard surface
- points for each error to a max of 10 on 3 tests

Question 3

what is computerised dynamic posturography

Answer 3

can test balance in differen planes (sway referenced vision)
- not common due to equipment and cost
- shows similar results to mBESS

Question 4

what sensory system is most often affected from concussion

Answer 4

vestibular system

Question 5

what are the possible mechanisms for vestibular dysfunction following concussion

Answer 5

1. peripheral receptors may be damaged and provide inaccurate senses of motion to the brain
2. brain centres responsible for central integration of vestibular, visual, and somatosensory info may be impaired

Question 6

what is the 3 metre tandem gait task and why is it better than the mBESS

Answer 6

walk 3 steps, turn, walk back
more dynamic balance - more appropriate to natural conditions
cheap and easy
(young groups = faster, old groups = slower)

Question 7

how can the 3 metre tandem gait be made more challenging

Answer 7

adding in a dual task
(cognitive on top of motor task)

(added to scat6 in 2022)

Question 8

what is the effect of adding in a dual task

Answer 8

by adding in another task, attention has to be split
speed-accuracy tradeoff
- slower with more tasks

we have a cap on attention - faster when we can put all our resources into one thing

Question 9

what does dual task show in concussion

Answer 9

shows an increase and plateau in speed during recovery but speed remains below the concussion single task and normal single/dual task

the more we challenge the system - the more likely to see subtle changes

Question 10

what is the difference in gait following concussion

Answer 10

walk slower and wider stance
(shorter and wider steps)

Question 11

what is the difference in coherence in communication between controls and concusssion

Answer 11

0.8 in controls
0.6 in concussion

Question 12

what is the potential mechanism for deficit in NM control and inability to divide cortical resources

Answer 12

result of lingering cortical impairments

Question 13

how does persistent cortical hypoexcitability impact sport mvmt

Answer 13

negatively impact
athletes rely on rapid identification and processing of their ever changing environment and need to react accordingly

Question 14

what type of accelerations happen in fighting

Answer 14

massive rotational head accelerations that can damage vestibular hair cells and brainstem centres

Question 15

how is EVS used

Answer 15

used to probe vestibular balance control function
activation of the vestibular nerve results in reflex responses in the legs
sway towards the positive electrode

Question 16

what is coherence vs cumulant density

Answer 16

coherence = correlation between EVS and EMG in frequency domain
cumulant density = correlation between EVS and EMG in time domain

Question 17

what is seen as the acute effect on fighters after a fight

Answer 17

• lower response to frequencies
• later and lower responses
• transient reduction in EVS evoked response after sparring (less communication and coherence immediately after)

return to baseline 24 hours later