Midterm 8 Flashcards
Posture and balance Cerebellum and motor control
1
Q
The point where the mass of the body is equally distributed
A
Center of mass
2
Q
The area of the body in contact with the support surface
A
Base of support
3
Q
The center of distribution of force applied to the supporting surface
A
Center of pressure
4
Q
The center of pressure moves continuously around the center of mass, true or false?
A
True, the center of pressure moves continuously around the center of mass
5
Q
The center of _____________ is an indirect measure of postural sway
A
The center of pressure is an indirect measure of postural sway
6
Q
The center or ___________________ is like a herding dog and the center of ______________ is like the sheep.
A
The center of pressure is like a herding dog and the center of mass is like the sheep (the center of pressure keeps the center of mass in check).
7
Q
Postural control relates to controlling the body position in space for the dual purpose of ________________ and ________________.
A
Postural control relates to controlling the body position in space for the dual purpose of orientation and stability.
8
Q
Postural orientation = ______________
Postural stability = ________________
A
Postural orientation = posture
Postural stability = balance
9
Q
Ability to maintain an appropriate position of the whole body with respect to the environment and the task.
A
Postural orientation
10
Q
Ability to control center of mass relative to gravity and base of support during perturbation or motor tasks.
A
Postural stability (balance)
11
Q
Challenges to balance include:
A
- Gravitational forces
- Forces arising from muscle contraction
- Interaction between limbs during movement
- External perturbations
12
Q
What are the three main sources of sensory input to the central nervous system? What percentage do they contribute?
A
Vestibular system (20%)
Vision (10%)
Somatosensory (70%)
13
Q
People rely more on ______________ sensory input when learning a new skill.
A
People rely more on visual sensory input when learning a new skill.
14
Q
Name the parts of the vestibular apparatus:
A
Bony labyrinth:
Auditory: cochlea
Vestibular: Otolith organs (utricle and saccule), semicircular canals
Membranous labyrinth: suspended within the bony labyrinth, surrounded by fluid (perilymph), filled with fluid (endolymph), sensory receptors (hair cells)
15
Q
What are the two main aspects (parts) of the vestibular apparatus?
A
The bony labyrinth and the membranous labyrinth
16
Q
The bony labyrinth is comprised of…
A
Auditory components:
- Cochlea
Vestibular components:
- Otolith organs (utricle and saccule)
- Semicircular canals
17
Q
The bony labyrinth is comprised of three general components:
A
- Cochlea
- Otolith organs (utricle and saccule)
- Semicircular canals
18
Q
The otolith organs include the ___________ and _______________.
A
Otolith organs: utricle and saccule
19
Q
The semicircular canals are 3 perpendicular bones in each ear, each canal has an ________________.
A
The semicircular canals are 3 perpendicular bones in each ear, each canal has an ampulla.
20
Q
The semicircular canals are 3 perpendicular bones in each ear, each canal has an ampulla, within each ampulla is the ___________.
A
The semicircular canals are 3 perpendicular bones in each ear, each canal has an ampulla, within each ampulla is the cupula (gelatinous mass) with hair bundles embedded within.
21
Q
What structure is found within the ampulla?
A
The cupula (gelatinous mass) with hair bundles.
22
Q
In each of the semicircular canals is an ampulla, ____________ acceleration rotates gel, and displaces hair cells.
A
In each of the semicircular canals is an ampulla, angular acceleration rotates gel, and displaces hair cells.
23
Q
In each of the semicircular canals is an ampulla, angular acceleration rotates gel, and displaces hair cells, this _______________ all hair cells together.
A
In each of the semicircular canals is an ampulla, angular acceleration rotates gel, and displaces hair cells, this depolarizes all hair cells together.
24
Q
The semicircular canals are very sensitive to…
A
Active or passive angular acceleration.
25
What is the purpose of the semicircular canals?
Stabilize vision during head turns.
26
The semicircular canals are oriented at ______ degrees to one another.
The semicircular canals are oriented at 90 degrees to one another.
27
What are the three semicircular canals named?
Superior (anterior), posterior, and horizontal.
28
The superior and posterior canals are positioned how?
45 degrees from midline
29
Explain the counterbalanced design of semicircular canals:
Each canal works with a partner on the opposite side and responds to a different direction.
The semicircular canal on the side the person is moving toward activates and the semicircular canal on the side the person is moving away from deactivates.
30
When the head rotates to the right, firing rate increases in the _________ horizontal semicircular canal. Meanwhile, the firing rate decreases in the ______ horizontal semicircular canal.
When the head rotates to the right, firing rate increases in the RIGHT horizontal semicircular canal. Meanwhile, the firing rate decreases in the LEFT horizontal semicircular canal.
31
In the semicircular canals, the direction of movement will correspond with an increase in...
the activity of that canal.
32
When the head is rotated on the transverse plane (head turns), there is maximal activity in which semicircular canal?
Horizontal canal
33
When the head is moved in the sagittal plane (nodding head forward), there is maximal activity in which semicircular canal?
Superior/anterior canal
34
When the head is moved in the coronal plane (side bending), there is maximal activity in which semicircular canal?
Superior/anterior canal and posterior canal
35
When the head is moved in the sagittal plane (tilting head backwards), there is maximal activity in which semicircular canal?
Posterior canal
36
Which semicircular canal would you expect to be activated during this movement:
Turning head to the right
Right horizontal canal
37
Which semicircular canal would you expect to be activated during this movement:
Nodding head forward
Superior/anterior canals (both sides)
38
Which semicircular canal would you expect to be activated during this movement:
Tilting head to the right
Right superior/anterior canal
and
Right posterior canal
39
In semicircular canals, the frequency of action potentials increases with...
higher angular acceleration
40
There is _______ utricle and _______ saccule on each side of the head.
There is one utricle and one saccule on each side of the head.
41
Otolith organs each contain...
Each saccule and utricle contain a sensory epithelium (macula), consisting of hair cells enclosed by a gelatinous mass topped by crystals (otoconia).
42
The sensory epithelium found in otolith organs is called:
Macula
43
The crystals found in otolith organs are called:
Otoconia
44
The otolith organs are sensitive to...
The otolith organs are sensitive to linear movements of the head and static head tilts (gravitational forces).
45
The orientation of the otolith organs is different making each type more sensitive to different movements, explain:
Utricles are more horizontal and therefore are more responsive to side bending and side stepping.
Saccules are more vertical and therefore are more responsive to up-down and tilting forward and backward.
46
Utricle = ______________ movements
Saccule = _____________ movements
Utricle = horizontal movements
Saccule = vertical movements
47
The saccular and utricular maculae are mirror images with the opposite side, true or false?
True
48
On opposite sides of each macula (of the utricle and saccule), hair cells are sensitive to...
On opposite sides of each macula (of the utricle and saccule), hair cells are sensitive to opposite movements.
49
During side-bending, the discharge rate of the vestibular nerve axon coming from the utricle ________________.
Increases
50
During side-bending, the discharge rate of the vestibular nerve axon coming from the utricle increases. There is an _______________ response from that neuron when moving in the opposite direction.
During side-bending, the discharge rate of the vestibular nerve axon coming from the utricle increases. There is an opposite response from that neuron when moving in the opposite direction.
Decreased firing rate.
51
Vestibular pathways are ____________sensory (receive visual and vestibular input).
Vestibular pathways are multisensory (receive visual and vestibular input).
52
Vestibular pathways are multisensory (receive visual and vestibular input). This is essential for...
Postural control and control of eye movements
53
Vestibular nuclei provide very fast compensatory ________________and _____________ movements.
Vestibular nuclei provide very fast compensatory EYE and HEAD movements.
54
The __________________ fasciculus tells the eyes which way they should move via connections with cranial nerves.
The medial longitudinal fasciculus tells the eyes which way they should move via connections with cranial nerves.
55
Which fasciculus is involved in the vestibulo-ocular reflex?
The medial longitudinal fasciculus is involved in the vestibulo-ocular reflex.
56
Explain the purpose of the vestibulo-occular reflex
Keep eyes on target while head is moving
57
Explain the vestibulo-ocular reflex through describing what happens as the head turns to the right...
As head turns to the right, the right horizontal semicircular canal is activated (the left horizontal semicircular canal is inhibited).
The eye musculature responsible for moving the eyes to the left are activated. Eye musculature responsible for moving the eyes to the right are inhibited.
58
Explain the vestibulo-ocular reflex through describing what happens as the head turns to the left...
As the head turns to the left, the left horizontal semicircular canal is activated, the right semicircular canal is inhibited.
The eye musculature responsible for moving the eyes to the right is activated. The eye musculature responsible for moving the eyes to the left is inhibited.
59
The vestibulospinal tract is involved in the control of postural orientation and stability. Information from the vestibular nerve travels to the vestibular nuclei and cerebellum. Vestibular nuclei give rise to the...
lateral and medial vestibulospinal tracts
60
The medial vestibulospinal tract arises from the...
Medial vestibular nucleus
61
The medial vestibulospinal tract arises from the medial vestibular nucleus, then descends ____________ in the spinal cord.
The medial vestibulospinal tract arises from the medial vestibular nucleus, then descends BILATERALLY in the spinal cord.
62
The medial vestibulospinal tract arises from the medial vestibular nucleus, descends bilaterally in the spinal cord, then terminates...
The medial vestibulospinal tract arises from the medial vestibular nucleus, descends bilaterally in the spinal cord, then terminates in the medial anterior horn of the cervical cord.
63
Where does the medial vestibulospinal tract terminate?
The medial anterior horn of the cervical spinal cord.
64
The medial vestibulospinal tract regulates...
The medial vestibulospinal tract regulates head and neck position.
65
The _________________ reflex moves head in opposite direction of motion.
The vestibular cervical reflex moves head in opposite direction of motion.
66
The lateral vestibulospinal tract arises from ______________________.
The lateral vestibulospinal tract arises from lateral vestibula nuclei.
67
The lateral vestibulospinal tract project the full length of the spinal cord, true or false?
True
68
The lateral corticospinal tract arises from the lateral vestibular nuclei then projects...
ipsilaterally (same-side it originates from) down the full length of the spinal cord.
69
The medial vestibulospinal tract projects ipsilaterally down the full length spinal cord, whereas the lateral vestibulospinal tract projects bilaterally down the spinal cord and terminates in the cervical region, true or false?
False (opposite), the LATERAL vestibulospinal tract projects ipsilaterally down the full length spinal cord, whereas the MEDIAL vestibulospinal tract projects bilaterally down the spinal cord and terminates in the cervical region, true or false?
70
The _____________ vestibulospinal tract controls proximal extensor muscle tone for maintenance of posture.
The lateral vestibulospinal tract controls proximal extensor muscle tone for maintenance of posture.
71
Which tract(s) are involved in the vestibular-spinal reflex?
The medial vestibulospinal tract
The lateral vestibulospinal tract
The reticulospinal tract
72
Which reflex causes the body to flex in the opposite direction of motion?
Vestibular-spinal reflex
73
The lateral corticospinal tract controls...
Proximal extensor muscle tone for maintenance of posture (particularly for lower limbs).
74
The cerebellum provides input to the medial and lateral vestibular nuclei, and plays a role in posture and balance, how?
The cerebellum distinguishes between motions detected by the otoliths and motions detected by the semicircular canals.
It also distinguishes between active and passive movements.
75
Vestibular information ascends ____________ from the vestibular nuclei to the ventral posterior nucleus of the thalamus.
Vestibular information ascends BILATERALLY from the vestibular nuclei to the ventral posterior nucleus of the thalamus.
76
Vestibular information ascends bilaterally from the vestibular nuclei to the ventral posterior nucleus of the thalamus, then goes to...
Multiple cortical areas (parietal cortex and insula) and generates a head-in-space picture.
77
Vestibular information ascends and ultimately ends in which cortical area(s)?
The parietal cortex and insula
78
The vestibular and visual systems are unmatched, true or false?
False, the vestibular and visual systems are matched to one another.
79
Physiological vertigo occurs because...
There is a conflict between the sensory systems (vestibular and visual)
80
Pathological vertigo is caused by...
A sudden imbalance of vestibular signals due to a lesion in the vestibular system.
81
Benign paroxysmal positional vertigo is the least common cause of vertigo, true or false?
False, benign paroxysmal positional vertigo is the MOST common cause of vertigo.
82
Benign paroxysmal positional vertigo is caused by...
Displacement of otoconia (crystals) from the otoliths into the semicircular canal.
83
The Dix-Hallpike Maneuver is used to asses for?
Posterior canal benign paroxysmal positional vertigo (BPPV)
84
The Epley maneuver is used for...
The Epley maneuver is used to treat benign paroxysmal positional vertigo (BPPV), it displaces the otoconia back into the otoliths using gravity.
85
The position and motion of body and body segments with respect to supporting surfaces is known as ____________________.
Proprioception
86
The position and motion of the head with respect to gravity and inertial forces is gained from what type of sensory input?
Vestibular
87
The position and motion of the head with respect to surrounding objects is gained from what type of sensory input?
Visual
88
The _________________ mechanism involves anticipatory postural adjustments in anticipation of postural instability
Feedforward mechanism = anticipatory
89
The _________________ mechanism involves corrective postural control strategies in response to unanticipated postural instability.
Feedback mechanism = corrective
90
Feedback mechanisms use sensory information ___________ or _____________ movements to make corrections to ongoing or future movement.
During or after
91
Feedforward mechanism for posture is ________________, ________________ and ____________________.
Feedforward mechanism for posture is preprogramed, adaptive and centrally organized.
92
The feedforward mechanism for posture is based on...
Prior experience and intention (voluntary movement).
93
What are the three types of balance control?
1. Static/steady state balance
2. Anticipatory/proactive balance
3. Reactive balance
94
The ability to control the center of mass relative to the base of support in predictable and unchanging conditions is __________________ balance.
Static/ steady state balance
95
The ability to activate muscles for balance in advance of potentially destabilizing voluntary movements (picking up a box), using feedforward mechanisms is ______________________ balance.
Anticipatory/ proactive balance
96
The ability to recover a stable position following an unexpected perturbation, using feedback mechanisms is __________________ balance.
Reactive balance
97
Static and dynamic balance are two separate entities, true or false?
False, static and dynamic balance is a continuum, NOT two separate entities.
98
Anticipatory postural stability aims to...
Minimize forthcoming perturbations using feedforward control
99
Reactive postural stability aims to...
Correct for errors/limitations in anticipation, using feedback control
100
When completing a voluntary activity such as pulling on a handle (this would shift the center of mass forward) the anticipatory postural adjustment involves...
Activation of postural muscles before execution of voluntary goal
101
Anticipatory balance (postural stability) in the case of a person standing and pulling up on a handle, uses plantar flexion and elbow flexion. Which muscle activation occurs first in this case? Which system is activating which movement?
Plantar flexion (activation of the gastrocnemius) occurs first to oppose the elbow flexion which happens second, this is anticipatory of the center of mass being pulled forward with elbow flexion (anticipatory postural stability).
The extrapyramidal system (reticulospinal tract) drives the movement of the plantar flexion (activation of gastrocnemius), as it is an involuntary anticipatory response to predicted postural instability.
The pyramidal system (corticospinal tract) drives the elbow flexions, as this is the voluntary movement of the body.
102
The reticulospinal tract originates in the reticular formation, where is this located?
Brainstem
103
The input to the reticulospinal tract comes from...
Pre-motor cortex, supplementary motor area, and primary motor cortex (via cortico-reticular collaterals)
&
Areas of the cerebellum concerned with sensory systems
104
The reticulospinal tract has multi-segmental terminations in the spinal cord, where?
Bilateral terminations on spinal interneurons
105
The _____________________ tract is heavily involved in postural control to support skilled/coordinated movements and muscle tone.
Reticulospinal tract
106
The ____________________ pathway involves indirect connections to lower motor neurons from the primary motor cortex and premotor cortex.
extrapyramidal pathway
107
The __________________ pathway involves direct connections to local networks and lower motor neurons from the primary motor cortex and premotor cortex.
Pyramidal
108
Ankle strategy is activated during...
Ankle strategy is activated during small perturbations.
109
Ankle strategy is activated on ____________ surfaces.
Ankle strategy is activated on firm surfaces.
110
Ankle strategy relies heavily on ______________ input; whereas, hip strategy relies more on ________________________ input(s).
Ankle strategy relies heavily on somatosensory input; whereas, hip strategy relies more on vestibular and visual input(s).
111
In ankle strategy _____________ muscles are activated first.
In ankle strategy distal muscles are activated first.
112
In hip strategy _____________ muscles are activated first.
In hip strategy proximal muscles are activated first.
113
________ strategy is activated during larger or faster perturbations or when on compliant surfaces or small base of support.
Hip strategy
114
Humans can adapt by shifting from one strategy to another (ankle to hip) or can use a combination of strategies to regain postural stability, true or false?
True
115
Reactive balance relies heavily on ________________ input.
Reactive balance relies heavily on somatosensory input.
116
In reactive balance, early in reaction, there is a heavy reliance on ________________ input, later in reaction ____________________ input(s) may be more important.
In reactive balance, early in reaction, there is a heavy reliance on somatosensory input, later in reaction vestibular and visual input(s) may be more important.
117
Increased sway is often observed in which populations?
Older, Parkinson's disease, Cerebellar disease
118
Explain the cognitive contributions to postural control for people who have suffered a stroke
Reaction times increase with increasing postural control demands among people who have suffered a stroke.
Challenges present with dual-tasking.
119
Name the ways in which the cerebellum is similar to the cerebrum
Two hemispheres
Outer cortical layer of gray matter (cerebellar cortex)
Inner region of white matter and subcortical nuclei (deep cerebellar nuclei)
120
The cerebellum makes up only 10% of the brain has _____ as many neurons as the cerebrum.
4x
121
The cerebellum is responsible for initiating movement, true or false?
False, the cerebellum is NOT responsible for initiating movement.
122
In the cerebellum, efferents (motor neurons) do not project directly to local circuits or lower motor neurons, true or false?
True
123
The cerebellum operate primarily by modifying the activity of _________________.
upper motor neurons
124
The cerebellum is not responsible for initiating movement, instead its function is to...
Adjust the motor activity of the descending pathways to make movements more accurate.
125
The cerebellar cortex has 3 cortical layers:
1.
2.
3.
1. Molecular cells
2. Purkinjie cells
3. Granule cells
126
Name the three types of deep cerebellar nuclei
Fastigial nucleus (1)
Interposed nuclei (2)
Dentate nucleus (1)
127
The one lateral deep cerebellar nucleus is called the:
Dentate nucleus
128
The three medial deep cerebellar nuclei are called:
Interposed nuclei (2)
Fastigial nucleus
129
What is considered the honorary deep cerebellar nuclei?
Vestibular nuclei
130
There are functional divisions of the cerebellum (somewhat somatotpically organized), explain...
Axial muscles are represented more centrally
Distal muscles are represented more distally
131
Name the three functional divisions of the cerebellum:
1. Vestibulo-cerebellum
2. Spino-cerebellum
3. Cerebro-cerebellum
132
Where is the vestibulo-cerebellum located?
Flocculonodular lobe
133
Where is the spino-cerebellum located?
Vermis and paravermis
134
Where is the cerebro-cerebellum located?
Lateral hemispheres
135
What is the function of the vestibulo-cerebellum?
Postural control (vestibular)
136
What is the function of the spino-cerebellum?
Gross movements of the trunk and limbs (more proximal/central location)
137
What is the function of the cerebro-cerebellum?
Fine motor voluntary movements (more distal location)
138
The hands are controlled by which functional division of the cerebellum?
The cerebro-cerebellum
139
Which functional division of the cerebellum integrates vestibular information from the vestibular apparatus in the inner ear and vestibular nuclei?
Vestibulo-cerebellum
140
Name the function(s) of the vestibulo-cerebellum
Integrates vestibular information from the vestibular apparatus in the inner ear and vestibular nuclei.
Provides information on head position with respect to gravity.
Receives visual information from the visual cortex.
Modifies vestibular reflexes for eye movements and postural control.
141
What functional division of the cerebellum provides information on head position with respect to gravity?
Vestibulo-cerebellum
142
What functional division of the cerebellum receives visual information from the visual cortex?
Vestibulo-cerebellum
143
What functional division of the cerebellum receives information from the spinal cord, vestibular nuclei, and brainstem nuclei to adjust ongoing movements?
Spino-cerebellum
144
What is the function of the spino-cerebellum?
Adjusts ongoing movements.
Vermis is responsible for balance and proximal motor control.
Paravermis responsible for distal (fine) motor control.
145
What is the output of the spino-cerebellum?
Motor cortex via thalamus and extrapyramidal/pyramidal tracts for motor execution.
146
What functional division of the cerebro-cerebellum receives input from the the cerebral cortex via the pontine nuclei?
Cerebro-cerebellum
147
What functional division of the cerebellum is involved in the timing of highly skilled distal movements?
The cerebro-cerebellum
148
What is the function of the cerebro-cerebellum?
Planning and timing or highly skilled distal movements.
Forms a closed-loop with the cerebral cortex (modulating activity of upper motor neurons)
149
What is the output of the cerebro-cerebellum?
Cerebral cortex and lateral corticospinal and corticobulbar tracts.
150
The largest input to the cerebellar peduncles is from...
Pontine nuclei
151
Input from the pontine nuclei crosses over to the contralateral cerebellum via the middle peduncle and the ultimate destination is the ________________________.
Cerebro-cerebellum
152
The proprioceptive inputs to the cerebellar peduncles from the spinal cord go to the ___________________________.
Spino-cerebellum
153
The vestibular inputs to the cerebellar peduncles from the vestibular nuclei go to the _______________________.
Vestibulo-cerebellum
154
Inputs from the inferior olive via the inferior peduncle relay information from the ____________, ______________ and ________________ for _______________________.
Inputs from the inferior olive via the inferior peduncle relay information from the red nucleus, cortex, and spinal cord for error correction.
154
The ______________ and ___________ part of the spino-cerebellum influence vestibulo-spinal tracts.
The vestibulo-cerebellum and the vermal part of the spino-cerebellum influence vestibulospinal tracts.
155
Paravermal spino-cerebellar outputs include:
Extrapyramidal and pyramidal tracts
156
The cerebro-cerebello-cerebral loop involves output to the ________________ tract.
Corticospinal tract
157
The cerebrum and the cerebellum communicate via a closed-loop called the ______________________.
Cerebro-cerebello-cerebral loop
158
Output from the cerebro-cerebello-cerebral loop ________________ resulting in ipsilateral representation.
Double-crosses
159
What are the main functions of the cerebellum?
Planning and execution of movement.
Coordination of multi-jointed movement.
Postural control.
Error correction (integrates executive commands with sensory feedback for moment-moment adjustment of movement and facilitates motor learning)
160
How does the cerebellum achieve error correction?
Integrates sensory executive commands with sensory feedback for moment-to-moment adjustment of movement.
Compares intended and actual movement.
161
Cortical inputs provide initial feedforward blueprint of intended movement, what is this blueprint called?
Efference copy
162
What does the cerebellum do with the efference copy provided by the cortex?
Modifies the blueprint (pre-correction) and predicts the amount of sensory input that will result from the movement.
163
Sensory inputs provide ___________________ during and after movement.
afferent copy / feedback
164
The cerebellum compares the predicted sensory input with the actual sensory input, what does this help with?
Can reduce error via correcting upper motor control of movement.
165
Clinical signs of cerebellar lesions are typically _____________(contralateral or ipsilateral?) to the lesion.
Clinical signs of cerebellar lesions are typically ipsilateral (same-side) to the lesion
166
What are the clinical signs of cerebellar lesions?
Ataxia (incoordination of movement)
Poor postural control
Difficulty learning highly skilled sequences
Usually no sensory perception issues
Usually no muscle weakness
167
There is usually muscle weakness associated with cerebellar lesions, true or false?
False, there is usually NO muscle weakness with cerebellar lesions.
168
Would you expect to observe sensory perception issues in someone with a cerebellar lesion?
No
169
Vestibulo-cerebellum damage usually presents as:
Spontaneous nystagmus
Postural instability
Truncal ataxia
170
Spino-cerebellum damage usually presents as:
Damage to vermis:
- Truncal ataxia
Damage to paravermis:
- Dysarthria
- Limb ataxia (dysdiadochokinesia, dysmetria, intention tremor)
- Ataxic gait
171
Damage to which functional division of the cerebellum would cause the following?
- Truncal ataxia
- Dysarthria
- Limb ataxia (dysdiadochokinesia, dysmetria, intention tremor)
- Ataxic gait
Spino-cerebellum (vermis and paravermis)
172
Damage to which functional division of the cerebellum would cause the following?
- Spontaneous nystagmus
- Postural instability
- Truncal ataxia
Vestibulo-cerebellum
173
Cerebro-cerebellum damage usually presents as:
- Loss of coordination of fine finger movements
- Dysarthria
174
Cerebellar lesions do not cause difficulty with strength or sensory impairment, instead they present as difficulties with _________________.
Coordination
175
Limb ataxia may present as intention tremor, what does this look like?
Tremor increases during movement, increases as limb moves closer to target.
176
Limb ataxia may present as dysmetria, what does this look like?
Overshooting or undershooting as limb approaches a target, inability to gauge correct distance.
177
Limb ataxia may present as dysdiadokinesia, what does this look like?
Difficulty performing rapid alternating movements.
178
The heel-to-shin test assesses _______________.
Dysmetria (target)
179
Motor control is the ability to...
Regulate or direct the mechanisms essential to movement.
180
The basal ganglia and cerebellum are involved in similar aspects of motor control, broadly what is this shared role?
Modulating movements
181
What are the three fundamental types of movement skills?
1. Postural control
2. Walking
3. Reaching and grasping
182
What are the three phases of reaching and grasping?
1. Initiation
2. Shaping
3. Closure
183
The initiation stage of reaching and grasping involves primarily ___________________ (feedforward or feedback?) mechanism.
The initiation stage of reaching and grasping involves primarily feedforward mechanism.
184
The initiation stage of reaching and grasping relies on the ______________ to predict task requirements.
Cerebellum
185
The shaping stage of reaching and grasping involves primarily _________________ mechanism.
The shaping stage of reaching and grasping involves primarily feedforward mechanism.
186
____________ guidance is essential in the shaping stage of reaching and grasping.
Visual guidance
187
The shaping stage of reaching and grasping ends when...
Fingers are maximally opened
188
The shaping stage of reaching and grasping relies on the _____________________ and __________________________ tracts.
The shaping stage of reaching and grasping relies on the lateral corticospinal tract (fine motor control) and the reticulospinal tracts (proximal muscles and postural control).
189
The closure stage of reaching and grasping involves primarily _________________ mechanism.
Feedforward
190
In the closure stage of reaching and grasping somatosensory ________________ is integrated to adjust movement.
feedback
191
What are the three main types of upper extremity motor control impairments?
1. Perceptual problems
2. Reach and grasp impairments
3. Grasp and in-hand manipulation impairments
192
Perceptual problems can be caused by ________________, ________________ and _____________.
Perceptual problems can be caused by visual field deficits, neglect and agnosia.
193
Perceptual problems present as...
- Difficulty locating target
- Object identification (visual agnosia)
- Difficulty planning and executing reach and grasp
194
The following are indicators of ___________________?
- Difficulty locating target
- Object identification (visual agnosia)
- Difficulty planning and executing reach and grasp
Perceptual problems
195
Lose of individuation/development of abnormal synergies is an example of a _____________ impairment.
motor
196
Loss of individuation is the largest contributor to impaired reaching post _____________.
Stroke
197
Loss of individuation is stronger in ____________ muscles.
Anti-gravity muscles ( typically affects the flexors of the upper extremities) and extensors of the lower extremities.
198
Loss of individuation post-stroke may be due to...
Upregulation of extrapyramidal tracts due to corticospinal tract damage.
Cortical reorganization.
199
