Cerebellum Flashcards
Functions
Initiation and control of voluntary movement Timing of movement/muscle actions Moment-to-moment error correction Compensating or cerebral cortex lesion Motor learning and adaptive adjustments
SCA damage:
Dysmetria of ipsilateral UE movement
Unsteadiness w/ walking
Dysarthric speech
Nystagmus
PICA damage:
Vertigo
Unsteadiness
Walking ataxia
Nystagmus
AICA damage:
Dysmetria
Vestibular signs
Facial sensory loss
gait usually okay
Biggest predictor of recovery:
Amount of cerebellar nuclei involvement
Function of cerebellar nuclei:
Relay station for information
Medial zone - comprised of:
Mid-line structures
Vermis
Fastigial nuclei
Medial zone - functions:
Postural control and muscle tone
Upright stance
Locomotion
Gaze and other eye movements
Vermis - function:
Postural control ==> central cerebellar problems
What are central cerebellar problems?
Initiation/timing
Using feedback to help with accuracy
NOT strength
Intermediate zone - comprised of:
Intermediate hemispheres
Globose
Emboliform nuclei
Intermediate zone - functions:
Controlling coordination of agonist-antagonist muscle pairs during walking and voluntary limb movements (for accuracy of movement)
Lateral zone - comprised of:
2 broad lateral hemispheres
Output structures
Dentate nuclei
Lateral zone - functions:
Control of complex, multi-joint, voluntary limb movements (esp for vision)
Planning of complex movement
Assessment of movement errors
Will damage to the lateral zone see improvement back to baseline?
No
Lateral zone - deficits:
Strength 2/2 communication with cortex but because of lack of timing and planning - strength can improve
Flocculonodular lobe - function:
Control of eye movement (VOR - vestib)
Balance
Vestibulocerebellum…
Flocculonodular lobe
Spinocerebellum…
Medial and intermediate zones
Cerebrocerebellum…
Lateral zone
Damage to vestibulocerebellum…
Balance deficits:
Increase postural sway
Oscillations of head and trunk
Unsteady gait
Nystagmus
Will vestib problems w/ damage to vestibulocerebellum respond to vestib tx’ment?
Will NOT respond to maneuvers bc are CENTRAL problem, not BPPV or UVH
Need VOR interventions
Damage to spinocerebellum…
Loss of “updating” afferent information (difficulty adapting)
Inappropriate amplitude of muscle force (poor recruitment)
Inappropriate timing of muscle onsets
Abnormalities of balance w/ absence or decreased preparatory postural adjustments
Difficulty jumping/hopping
Challenges with damage to spinocerebellum…
RAMs/coordination tasks
Complex motor activities
Damage to cerebrocerebellum…
Movement incoordination Problems w/ movement preparation Delays w/ movement initiation Difficulty w/ timing movements Terminal tremors Impaired temporal coordination of multi-joint movements and spatial coordination
What modifies function of the cerebellum and cerebellar circuitry?
Experience - increase in # of effective preferred synaptic paths
Signs of cerebellar dysfunction:
Dysmetria Dyssynergia Dysdiadochokinesia Decomposition Lack of check Cerebellar tremor (action) Postural tremor Kinetic tremor (intention) Imbalance Hypotonia Ataxia Oculomotor deficits (saccades slowed and dysmetric, impaired or absent VOR, nystagmus at ER vertical/lateral gaze) Ataxic dysarthria Impaired motor learning
Muscle tone with cerebellar damage…
Hypotonic
Why is tone the way it is?
Decreased excitatory drive to vestibulospinal and reticulospinal pathways
Decreased extensor tone to hold body upright against gravity
