Cerebellar Dysfunction

Question 1

Vestibulocerebellum, spinocerebellar, cerebrocerebellum

Answer 1

V- floculonodular lobe
S - vermis/paravermal hemispheres
C - lateral hemisphere

Question 2

Superior cerebellar peduncle connection to brainstem

Answer 2

• Attaches to midbrain

- Contains cerebellar efferent fibers

Question 3

Middle cerebellar peduncle connection to brainstem

Answer 3

• Attaches to the pons

- Contains afferent fibers from cerebral cortex

Question 4

Inferior cerebellar peduncle connection to brainstem

Answer 4

• Attaches to the medulla
• Contains afferent fibers from the brain stem and SC
• ALSO contains efferent fibers from the vestibular and reticular nuclei

Question 5

Pathways: IPSI or BIL

Answer 5

Most are ipsilateral except vestibulocerebellum has bilateral control

Question 6

Input fibers

Answer 6

• Mossy fibers (information)

- Climbing fibers (timing)

Question 7

Output fibers

Answer 7

• Purkinje cells

Question 8

Vestibulocerebellum function and inputs

Answer 8

• Function: Regulates equilibrium

- Inputs: Vestibular nuclei and superior colliculus (eye and head position/movement)

Question 9

Vestibulocerebellum outputs and deep cerebellar nucleus

Answer 9

• Outputs: Med vestibular nuclei ( VOR) +
  lat vestibular nuclei, reticulospinal system, PMC (postural reactions)
• DCN: Fastigial

Question 10

Spinocerebellum function and inputs

Answer 10

• Function: Regulates gross limb movement

- Inputs: Spinocerebellar tracts

Question 11

Spinocerebellum outputs and deep cerebellar nucleus

Answer 11

• Outputs: Vestibulospinal + reticulopinal tracts, motor cortex + red nucleus
• DCN: Emboliform, globose

Question 12

Cerebrocerebellum function and inputs

Answer 12

• Function: Regulates distal limb voluntary movements, motor planning, and timing
• Inputs: Cerebral cortex via pontine nuclei

Question 13

Cerebrocerebellum outputs and deep cerebellar nucleus

Answer 13

• Outputs: Motor + premotor cortices via thalamus, red nucleus to activate rubrospinal tract
• DCN: Dentate

Question 14

Wernicke-Korsakoff syndrome

Answer 14

Vitamin B/thiamine deficiency due to alcohol abuse

Question 15

Pharmacological agents that can cause ataxia

Answer 15

• Anti-convulsants
• Anti-neoplastics
• Lithium (BIPOLAR)

Question 16

Drugs that can cause ataxia

Answer 16

Cocaine + heroine

Question 17

Infections that can cause ataxia

Answer 17

Chickenpox is most common

Question 18

Endocrine issues that can cause ataxia

Answer 18

• Hypothroidism (reversible with thyroid replacement therapy)
• Hashimoto’s (no responsive to thyroid replacement therapy)

Question 19

Nutrition issues that can cause ataxia

Answer 19

GLUTEN

Question 20

Spinocerebellar ataxia

Answer 20

• Degenerative condition that is based on autosomal dominant or recessive genes

Question 21

Friederich’s ataxia

Answer 21

• Age of onset 8-15 years
• Presents as clumsiness with gait
• Common to have scoliosis and gait deformities
• Eventually dies of heart failure

Question 22

Dandy-Walker syndrome

Answer 22

• Congenital malformation characterized by enlarged 4th ventral and complete/partial absence of vermis
• Intellectual problems common due to hydrocephalus

Question 23

Dyssynergia

Answer 23

Impairments in ability to coordinate multi-joint movements

Question 24

Motor control and learning impairments

Answer 24

• Cerebellum plays an important role in motor memory formation of coordination tasks
• Important for shifting movement performance to more automatic state
• Cerebellar dysfunction can hinder learning and cause slower rate of learning
• Disrupts feedforward but doesn’t effect feedback

Question 25

Error-based vs reinforcement learning

Answer 25

- Reinforcement learning provides greater retention - Reinforcement learning is intact in individuals with cerebellar damage but greater variability with performance (poor retention with error-based learning)

Question 26

Compensatory approaches to ataxia

Answer 26

- Simple, single joint movements - Visual/verbal cues to improve gait - Assistive devices for posture/balance/mobility - Compression garments - Cooling a limb may have temp benefit

Question 27

Recovery approaches to ataxia

Answer 27

- Biofeedback via EMG activity of mm activation/postural sway with computer game - Strengthening/balance/ocular exercises to improve postural stability - Locomotor training

Question 28

PT + rTMS and ataxia

Answer 28

- Amplitude of lateral head and body sway reduced = improved dynamic balance in earlier stages of disease - No effect on gait speed

Question 29

Scale for the Assessment and Rating of Ataxia (SARA)

Answer 29

- Provides quantitative assessment of impairments related to cerebellar ataxia * Also used in ataxic stroke - Evaluates gait, stance, sitting, speech, and various limb coordination tasks

Question 30

SARA cut-off scores

Answer 30

- Gait: <8 = independent; <11.5 = quad cane; <12.25 = walker - ADL dependence: <5.5 = independent; <10 = Min A; <14.25= Mod A; >23 = Max A

Question 31

International Cooperative Ataxia Rating Scale (ICARS)

Answer 31

- Evaluates impairment as a result of hereditary ataxia with regard to postural/gait disturbance, limb ataxia, dysarthria, oculomotor disorders - Higher the score = greater impairment (0-100) - No cut-off scores

Question 32

Friedereich's Ataxia Rating Scale (FARS)

Answer 32

- Assess ataxia and impairment based on diagnosis by same name - 3 subscales: ataxia, ADLs, neuro eam - Higher the score = greater impairment (0-159) - No cut-off scores

Question 33

Push and Release Test

Answer 33

- Assesses postural instability by ability to regain balance - Lean posteriorly into examiner's hands and hands are removed, number of steps is score - No cut-off scores

Question 34

Push and Release Test scoring

Answer 34

0 - Recovers ind with 1 step 1 - 2 to 3 steps required but able to recovers ind 2 - 4 or more steps required but recovers ind 3 - Able to step but requires assist to prevent fall 4 - Falls without attempting to step/unable to stand without assistance

Question 35

Retropulsive Pull Test

Answer 35

- Assesses nonvestibular-related balance impairment (PD) | - Examiner stands behind subject and pulls subject's shoulders backwards

Question 36

Retropulsive Pull Test scoring

Answer 36

0 - recovers independent with 1-2 steps or ankle reaction 1 - Recovers independent with 3+ steps 2 - Requires assistance to prevent fall 3 - Very unstable; loses balance spontaneously 4- Unable to stand without assist