Motor Control Exam 2 Flashcards
When does the heel rocker take place in the gait cycle?
from initial contact to loading response
When does the ankle rocker take place?
from time of flat foot to heel rise
When does forefoot rocker take place?
lasts from heel rise until terminal stance (end of stance)
What is probe reaction time?
the time it takes for the individual to start their response to the signal
What does it mean if reaction time is slow?
the task is more difficult or complex for them
What do the cell phone studies test?
structural interference vs. capacity interference
What is structural interference?
physically interfering with what you are doing
How is gait variability affected when executive function declines?
gait variability increases
What happens to the timing of steps as cognitive functions decline?
timing of steps increases
When does the stepping reflex disappear and reappear according to Thelen?
disappears at about 2-3 months and reappears at about 10-12 months
Why are kids not able to walk until 10 to 18 months?
postural control
What does gait look like for toddlers?
a lot movement from left to right for balance, large BOS, and small step length
What are the 3 types of equilibriums for postural control?
Stable, unstable, and neutral
What is meant by a stable equilibrium?
a small displacement leads to an unbalanced force that tends to restore the object to the equilibrium location
What is meant by an unstable equilibrium?
a small displacement leads to an unbalanced force that further increases the displacement from the equilibrium?
What is meant by a neutral equilibrium?
an equilibrium at any location
What are the 4 components of balance?
center of mass, center of gravity, base of support, and center of pressure
What is center of pressure?
where the resultant forces are under you foot or wherever you are pushing off (ground reaction force)
When are COP and COM in the same location?
standing
Where should COP be during gait?
want COP on the foot that is going to swing before it swings
Why do you sway less when using your phone while standing?
less focused on swaying and more focused on using your phone
True or false: People usually do better when told to focus on their body rather than the task.
False
What are the 3 sensory systems in postural control?
visual, vestibular, somatosensory
Which of the 3 sensory systems for postural control is the least important?
vestibular
What is the vestibular system not good at detecting?
gravity
What is the clinical test for sensory integration imbalance (CTSIB)?
taking sensory systems away to look at balance
In the CTSIB, when did balance decrease?
when vision was taken away
In the CTSIB, why did older people sway more when vision was taken away?
they are more reliant on vision
Why do you sway more on a block of foam, even with eyes open?
the surface is less stable and the motor system is compromised
When standing on a foam block, do you sway more with eyes open or closed?
eyes closed
Does the block of foam change the somatosensory system?
no
What are the components of the ankle strategy? (8 of them)
= used when perturbation is slow or has low amplitude
- contact surface is firm, wide, and longer than foot
- muscles recruited distal-to-proximal
- head movements in-phase with hips
- needs firm support surface
- could be argued to be a reflexive movement
- surface has to be longer than their foot
What are the components of the hip strategy? (4 of them)
- used when perturbation is fast or has large amplitude
- surface is unstable or shorter than feet
- muscles recruited proximal-to-distal
- head movement out-of-phase with hips
What are the components of the stepping strategy? (3 of them)
- used to prevent a fall
- used when perturbations are fast or large amplitudes
- used when other strategies fail
- body moves to “catch up with” base of support
What are the 3 controls theories?
motor programs, muscles synergies, and feedback control
What are the clinical implications for using the 3 control theories?
training the whole system (don’t use only one theory within your rehab, rather combine the 3 theories)
In the vestibular system, how many degrees of freedom are there for acceleration?
6
How can you stimulate somatosensory perturbation?
move the floor underneath you
Can you respond faster to somatosensory information or visual information?
somatosensory
Do we end up using somatosensory or visual information more often?
visual
Why are older adults more reliant on vision?
vestibular and somatosensory systems are not good enough (not developed or declined)
Why does placing one finger on a stable surface improve your balance when standing tandem with your eyes closed?
provides proprioceptive input
True or false: putting your body weight through the finger that is on the stable surface will improve your balance.
false
Why is muscle emg more active when you are not touching the stable surface?
you are not able to make corrections earlier
True or false: canes provide proprioceptive input.
true
When is reaction time the fastest, during sitting or standing?
sitting, because it takes less effort to sit rather than to stand
When is reaction time the fastest, when standing one 2 feet or 1 foot?
2 feet
What is open-loop phase of an aim or reach?
movement you make without any feedback involved
What is closed-loop phase during aim or reach?
movement you make with feedback involved
What pathway controls the closed-loop phase?
corticospinal pathways
What pathways control the open-loop phase?
extra pyramidal pathways
True or false: the closed-loop is present during a movement with the eyes closed.
false
Is closed-loop or open-loop more difficult to get back?
closed loop
Is the wine glass effect a cerebrum issue?
no, it is a cerebellar and spinal cord issue
If there is a stroke in the right hemisphere, what hand will power grip be lost on?
left hand
What does Hick’s law deal with?
reaction time
If there is a stroke in the right hemisphere, the pincer grip is lost in what hand?
both the left and right hand
What does Fitt’s law deal with?
movement time
What is reaction time a measure of?
brain processing speed
