Cerebellar Dysfunction Flashcards
To which side of the body does the cerebellum sends information? (Ipsi or contralateral)
ipsilateral
What are the functional division of the Cerebellum?
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebellum
Which lobe contains the vestibulocerebellum?
flocculonodular lobe
Vestibulocerebellum input from and output to?
Input
vestibular nuclei
CN8
output
Vestibular nuclei
lateral vestibular spinal tract
Function of the vestibulocerebellum
Integrates vestibular information and dictates motor control of neck and eye muscle
Allow to keep eye stable while head moves (gaze stabilization) & keep head over BOS
Control Gait and postural control
Injuries to the vestibulocerebellum can lead to….
ataxic gait (path deviation TOWARD the side of the lesion)
inability to stabilize gait
deficit in postural control
Which zone contains the spinocerebellum?
vermis
intermediate
input and output of the spinocerebellum
Input
spinal cord: Dorsal spinocerebellar tract & Vestibulocerebellar tract
Output
Vestibular nuclei
red nucleus
reticular formation
Function of the Dorsal spinocerebellar tract (DSCT)
sensory info from organ GTO, sensory, proprioception
Function of the ventral spinocerebellar tract (VSCT)
sensory from LE & Postural control
Function of the spinocerebellum
Integrates information from all decending motor tracts (VSCT)
real time information to be more successful with an intent action
location of the cerebrocerebellum
cerebellar hemispheres
input/output of the cerebrocerebellum
input:
deep pontine nuclei
output
thalamus
Function of the cerebrocerebellum
indirect information from all 4 cortical lobes
- Areas 6,4,3,1,2,5
- Primary visual cortext (17)
Lesions of the Cerebellum will lead to what types of deficits?
Impaired ability to perform controlled, precise, coordinated movements
must be large enough for symptoms to appear
hypotonia of MSRs (pendular reflex)
NO PARALYSIS and WEAKNESS (usually)
Function of Cerebellum in Movement
A regulator
feedback and feed-forward conrol ssytem
Cerebellum input/output
input:
information about body position and muscle action
output:
to descending motor systems at the brainstem level
Role of spinocerebellum in movement
output occurs while motion is occuring
the state of the motion, drives the next command fromt he cerebellum
Role of Cerebrocerebellum in movement
feed-forward
receives infromation from PMA, SMA< and primary motor and sensory areas
modify the action before it takes place
Theory: manages the model of control system
Hallmark signs of Cerebellar Dysfunction
- Ataxia (limb movement, trunkal, gait)
- Nystagmus
- Dysmetria
- dysdiadochokinesia
- Decomposition of movement ipsilateral to leasion
Clinical Presentation of Vestibulocerebellar injury
Mimics disease in vestibular nuclei or PVS
Ataxic gait (fall toward side of lesion, inadequate postural correction)
Nystagmus
Vertigo/dizziness
What is nystagmus
oscillating eye movement in which eyes move slow in one direction and rapidly in the other direction
Features of Gait Ataxia
High stepping
stagger to the side of lesion
irregular foot placement
irregular timing
patient use decomposition of complex movements to control incoordination which results in robotic look
Clinical Presentation of Spinocerebellar and Cerebrocerebellar injury
impairment in precision of movement
Dysdiadochokinesia
Dysmetria
decomposition of movement
pendular muscle stretch reflex
hypotonia (limb feel heavy)
Dysdiadochokinesia
disruption in timing of muscle
difficulty with Rapid alternating movement (RAM)
Dysmetria
Performance deterioration as motor act progresses
What test can be used to test for dysmetria?
finger to nose test
Dysmetria vs. Tremor
Dysmetria: form of incoordination secondary to cerebellar dysfunction. Performance deteriorates as target is approached (cerebellar injury)
Tremor:
rhythmic movement at constant frequency and amplitude. Result of continuous oscillatory beavior in central motor areas (e.g. Parkinson)
What is decomposition of movements?
poor timing of motor acts
normal synergistic movement of complex motor tasks is broken down and initiated separately
difficulty with sequencing repetitive task
ataxia
Role of Cerebellar in motor learning
modification of function in relation to experience
e.g. riding a bike
transfer of motor tactics from conscious to unconscious
Adaptive feedforward control system
Internal stored model controls learned movement
with cerebellar lesions, movement must use ______ and thus producing uncoordinated movements
slow sensory feedback loops
Theory of motor learning & cerebellum
Theory I:
CB learns small simple programs, facilitates triggering of small programs, in order, for complex motor tasks, recognizes and detects event sequences
Theory II:
CB role in adaptation, anticipatory ms activity across several joints, modification activity
Theory III:
CB influence not purely motor, role in mental imagery/practice, role in rapid shifts of attention
Examination of Cerebellum should include
- RAM
- gait
- dysmetria
- decomposition
- VOR
- change of symptoms with position changes
Consideration when tx patient with CB injury
- Postural control
- Motor Learning (need more attention)
- Attention (problem with switching task)
- Motor control (less automatic)
- Functional tasks
Get tired very easily: block practice
decrease distraction/obstacles
1 feedback at at time
concurrent tactile feedback, auditory feedback att he end
Ways to work on Dysmetria
Temporary reduction techniques
- as primer for functional tasks
- PNF
- full body movements
- T-band
- Frenkel exercises (Progressive exercises for ataxia and coordiantion
- Wt to dampen ataxia (use proximal not distal)
Intervention for ataxic gait
Encourage stiffening of joints (ankle)
practice setup part to whole
frequent feedback
use of device (walker tends to get far away, encourage small steps)
There is an increase firing of what structure during acquisition of complex motor task?
Cerebellum
Effect of Visual-vestibular dysfunction
Diplopia
impact on function (decrease attention on sx)
Use of visual exercises (smooth pursuit, saccades, VOR)
habituation exercises (full body position changes to get used and not get dizzy)
+ Prognosis of CB injury recovery
spared cerebral cortex
unilateral injury
degenerative disease vs acute injury
- prognosis of CB injury
bilateral injury
damage to deep CB nuclei
damage to others aspects of brain
concomitant abuse of alcohol
