Cerebellar Impairments Flashcards
List some of the roles the cerebellum has
- Coordination
- Balance
- Muscle tone
- VOR suppression
- Motor Control
- Motor learning
List the functional lobes of the cerebellum as well as their role/what they communicate with
- Cerebrocerebellum
- cerebellum ⇔ cortex
- distal extremities
- Spinocerebellum
- cerebellum ⇔ spinal cord
- Trunk, EOMs, proximal muscles
- Vestibulocerebellum
- cerebellum ⇔ vestibular apparatus and system
- VOR, equilibrium/balance
List major brainstem nuclei that communicate with the cerebellum
- Vestibular Nuclei
- Deep Pontine nuclei
- Red nuclei
- Superior and Inferior Olivary Nuclei
- Reticular Formation
what are the major afferents and efferents to the vestibulocerebellum?
- Afferents:
- Vestibular primary afferents
- Vestibular nuclei
- Visual areas
- Efferents:
- M/L vestibular nuclei
List the roles in movement that the vestibulocerebellum has
- VOR
- Gaze and eye movements
- Posture and balance
List clinical signs that can indicate damage to the vestibulocerebellum
- Nystagmus
- Impaired VOR
- Imbalance
what are the major afferents and efferents to the spinocerebellum?
- Afferents
- Vestibular and reticular nuclei
- DSCT and VSCT
- cerebrum
- Efferents
- Vestibular and reticular nuclei
- Cerebrum
- red nuclei
List the roles in movement that the spinocerebellum has
- Gaze and eye movements
- Postural tone
- Balance
- Locomotion
- Limb movements
- Coordinate agonist-antagonist muscle pairs
List clinical signs that can indicate damage to the spinocerebellum
- Oculomotor deficits
- Hypotonia
- Imbalance
- Falls
- Gait ataxia
- Tremor
- Lack of check
- Dysdiadochokinesia
- Dysmetria
List the major afferents and efferents to the cerebrocerebellum
- Afferents
- cerebrum (wide range of areas)
- Efferents
- cerebrum
- red nucleus
List the roles in movement that the cerebrocerebellum has
- Complex, multijoint voluntary limb movements
- Visually guided movements
- Motor planning
- Sensoriomotor error assessment
List clinical signs that can indicate damage to the cerebrocerebellum
- Dysdiadochokinesia
- Dysmetria
- Dyssynergia
- Decomposition
List broad clinical manifestations of cerebellar lesions
- Ataxia
- Dysmetria
- Dyssnergia
- Dysdiadochokinesia
- Hypotonia
- Cerebellar tremor
- Imbalance
- Oculomotor deficits
- Speech deficits
- Impaired MC
Define ataxia
- Generally uncoordinated or disordered movement
- worsens with movement of multiple joints together or by moving quickly
what are the 3 types of ataxia?
- Truncal
- Appendicular (limb)
- Gait
Describe truncal ataxia
- Oscillations in sitting and standing
- tends to be more pronounced in sitting
- Falling/LOB often occurs towards side of lesion
Describe appendicular (limb) ataxia
- Tends to be more noticeable in arms and hands
- Associated with tremors
Describe gait ataxia
- “Drunken ataxia”
- lack consistency in timing, length and direction of steps typical of healthy adults
- widened BOS
- arms up in low, medium or high guard position
- increased variability in both timing of and movement excursion
- influenced by multitude of cerebellar impairments
- leads to sig balance difficulties
- falls common
- backwards and/or to side of lesion
Define dysmetria
describe its mechanism
inability to properly scale movement distance
mechanism → inability to account for interaction torques → impaired ability to predict and account for dynamics of limbs as they interact
examination for dysmetria
- Finger-to-nose, finger-to-finger
- Heel-to-shin, ankle circles/alphabet
What is dyssnergia?
- Impairment of multi-joint movements leading to decompensation of movement
- Loss of proper sequencing, movement becomes fragmented
- Commonly compensated w/massed patterns of movements
- Closely associated w/dysmetria
what is asynergia?
complete loss of ability to associate movements for complex movements
What is dysdiadochokinesia?
- deficit in coordination between agonist-antagonist muscle pairs elicted during voluntary rapid alternating movements
- excessive slowness, inconsistency in range of RAMs (worsens as movement continues)
- manifests as rigid movements, compensatory bradykinesia of limbs
- can impact speech and swallow muscles - dysarthria and dyshagia
What is hypotonia?
- In particular, decreased extensor tone necessary for holding body upright against gravity
- can see effects in limbs, EOMS, speech muscles
- typically more problematic in more severe cerebellar lesions or in the acute stages of cerebellar injury only
- usually resolves w/time
What is a cerebellar tremor?
- an oscillatory and predictable tremor that is due to insufficient ability to anticipate the effects of movements and excessive reliance on sensory feedback loops
- typcially an action tremor
- postural
- intentional/kinetic
- typcially an action tremor
What does imbalance from cerebellar lesion typically look like?
- increased postural sway
- impaired postural responses to perturbations
- titubation → abnormal oscillation of head/neck
- disequilibrium
- midline disorientation → lateral pulsion towards side of lesion
What types of occulomotor deficits may be observed with cerebellar lesions? (include general regions impacted)
- Spinocerebellar
- impaired smooth pursuit
- impaired saccades
- Vestibulocerebellar
- Nystagmus may be present (most common = gaze-evoked)
- Loss of VOR suppression
What types of speech deficits may be present after a cerebellar lesion?
- Ataxic dysarthria:
- impaired articulation
- impaired prosody
- slowed speech
- volume variability
- staccato voice
How is motor control impacted by a cerebellar lesion?
- loss of real-time integration of feedback from peripheral systems
- anticipated movement vs actual movment
- delayed or absent adjustments to inaccurate motor programs
How is motor learning impaired following a cerebellar lesion?
- impaired ability to store adapted movement patterns after repeated exposure
- Impaired automatic processes involved w/rapidly adjusting movements for new, predictable demands
- becomes inefficient and difficult, high cog load
