Neuro Exam 2
Knee joint position during initial contact - CORRECT ANSWER-5 degrees of flexion
What does the knee joint do at initial contact? - CORRECT ANSWER-absorbs
impact
Muscle contraction during stance phase - CORRECT ANSWER--eccentric control of
quadriceps muscle group
-eccentric control of anterior tib
What does eccentric control of quads do during initial contact? - CORRECT
ANSWER-act as shock absorber to GRF
What does eccentric control of anterior tibialis do during initial contact? - CORRECT
ANSWER-acts to decelerate the foot on contact, opposing and slowing the plantar
flexion that results from heel strike
Why is pre-swing identified as a key portion of gait? - CORRECT ANSWER-because
muscle forces produced determine knee flexion velocity at toe-off, which is
correlated to swing phase peak knee flexion (much of energy for swing initiation
occurs)
Muscle activity during pre-swing - CORRECT ANSWER-hip flexors accelerate the
knee into flexion - assistance from Biceps Femoris
Muscle activation during initial swing - CORRECT ANSWER-concentric contraction
of hip flexors to advance thigh (iliopsoas, rectus femoris, gracilis, Sartorius, TFL
Muscle activation during mid-swing - CORRECT ANSWER--active hip flexion
-passive knee flexion
-active ankle dorsiflexion
to get to neutral for foot clearance
Muscle activation during terminal swing - CORRECT ANSWER--eccentric
contraction of hamstrings to decelerate high
-passive knee extension is preparing for the loading
-ankle DF for toe clearance
Kinetics of gait - CORRECT ANSWER-effects of force on gait:
-GRF, joint torque, CoP, CoM, mechanical energy, moments of force, power, support
moments, work, joint force reaction forces, intrinsic foot pressure
,Why are kinetic parameters less stereotyped than kinematic or muscle parameters? -
CORRECT ANSWER-die to variations in body weight, strength, and lever arms that
somebody else has
Balance in gait is controlled where? - CORRECT ANSWER-at the hip- hip controls
the HAT
Why are slower walking speeds more unstable? - CORRECT ANSWER-greater
displacement
What seems to be important for balance control during gait? - CORRECT
ANSWER-variability in torque due to variability in how the flexor and extensor forces
at hip, knee, and ankle are utilized
What evidence is there that CPGs contribute to pattern generation during gait? -
CORRECT ANSWER-spinal cord-injured individuals during partial weight support
treadmill walking
What are spinal pattern generators able to produce? - CORRECT
ANSWER-stereotyped locomotor patterns and perform certain adaptive functions
Do spinal pattern generators produce a good or bad walking pattern? - CORRECT
ANSWER-bad walking pattern due to lack of important modulating influences from
the brainstem and cerebellum
What do descending pathways and sensory feedback allow for what with gait? -
CORRECT ANSWER-Variation in locomotor patterns and adaptability to task and
environmental conditions
3 preparations most often studies when examining the control of locomotion are
what? - CORRECT ANSWER--Spinal
-Decerebrate
-Decorticate
Spinal control of locomotion - CORRECT ANSWER-CPG and Spinal pattern
generators
Decerebrate control of locomotion - CORRECT ANSWER-leaves the spinal cord,
brainstem, and cerebellum intact
What does the cerebellum do for gait? - CORRECT ANSWER-receive feedback from
the muscle sensory receptors via the spinocerebellar pathways and able to send
modulating signals to the brainstem that are relayed to motor neurons to fine tune
movement
,What does the Mesencephalic locomotor region do for gait? - CORRECT
ANSWER-responsible for descending control of locomotion (explains why patients
with a stroke in the brainstem will have poorer outcome)
Decorticate control mechanism of gait - CORRECT ANSWER-decorticate leaves the
basal ganglia intact with only the cerebral cortex removed (gait remains fairly normal)
What does basal ganglia-brainstem-spinal cord and substansia nigra-tegmental
pathways contribute to with gait? - CORRECT ANSWER-automatic control of
movements such as locomotion and postural tone and modulate rhythmic stepping
movements and initiate locomotion
-lack of perception (visual) and action (motor) that prevent adaptive skills such as
walking uneven terrain to be possible
What may patients with stroke in cortical areas lack? - CORRECT ANSWER-do well
with walking and recovery but may lack control adaptation and coordination
In animals when all sensory information has been cut what happens to gait? -
CORRECT ANSWER-stepping patterns tend to be slow and stereotyped. They cant
maintain balance or modify stepping patterns.
-in patients projected as an ataxic gait pattern particularly loss of proprioceptive info
of LE
Sensory info from limbs contribute to what? - CORRECT ANSWER-stepping
frequency (duration of step cycle significantly longer)
What do joint receptor and muscle spindle afferents appear to play a critical role in
with gait? - CORRECT ANSWER-normal locomotion from the ipsilateral hip joint
contributing to the onset of swing phase
Muscle spindles of the hip flexors do what? - CORRECT ANSWER-excite their own
muscle and inhibit the hip extensors in aiding stance to swing transition (principle
behind PWB support on treadmill training)
What do golgi tendon organs do to gait? - CORRECT ANSWER-influence timing of
locomotion- inhibit flexor burst activity and promoting extensor activity it regulates
transition from stance to swing
, What do visual flow cues do to gait? - CORRECT ANSWER--help us determine our
speed of locomotion resulting in increased step length
-influence alignment of the body with reference to gravity and the enviornment
Vestibular system controls what with gait? - CORRECT ANSWER--works with visual
system to stabilize head
-postural control for walking may be organized in relation to the control of gaze
(top-down)
Cognitive system effect on gait - CORRECT ANSWER-posture and locomotion
require attentional processing
Least amount of cognitive resources are required for what? - CORRECT
ANSWER-sitting or standing with feet apart
Attentional demands for gait increase with what? - CORRECT ANSWER--tandem
stance
-walking
-avoiding obstacles while walking
-external perturbation recovery
Non-neural contributions to gait - CORRECT ANSWER--muscular forces (moments
of inertia, torque)
-non-muscular forces (gravity)
2 ways that postural control is maintained during walking - CORRECT
ANSWER-reactive and proactive
Reactive strategies for feedback mechanisms - CORRECT ANSWER-most common
are stepping, elevating, and lowering
Avoidance proactive strategy - CORRECT ANSWER--changing foot placement
-change direction
increasing ground clearance and stopping
Accommodation proactive stratey - CORRECT ANSWER--reducing step length or
slippery surfaces
-shifting the propulsive power from ankle to hip and knee when climbing stairs
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