Lecture 10: Cerebellar Disorders and Ataxia

Question 1

What are the main functions of the cerebellum?

Answer 1

• coordinates range, velocity and strength of muscle contractions to produce steady volitional movements and postures
• muscle tone regulation
• equilibrium in conjunction with vestibular system

Question 2

What is a more cognitive function of cerebellum?

Answer 2

interconnections with pre frontal cortex for non motor functions of memory, cognition, attention and executive functions

Question 3

Where do the cerebellar peduncles connect to?

Answer 3

dorsal aspect of pons, midbrain, and medulla

peduncles form 4th wall of ventricles

Question 4

What are the 3 cerebellar peduncles?

Answer 4

1. superior- connects to midbrain, carries efferent info from cerebellum
2. middle- afferents from contra cerebellum via pontine nuclei
3. inferior- connections with medulla, efferent to vestibular nuclei

Question 5

What are the 3 cerebellar nuclei?

Answer 5

1. spinocerebellum
2. cerebro-cerebellum
3. vestibulocerebellum

Question 6

What are two functional zones in spinocerebellum?

Answer 6

1. fastigal- medial descending systems
2. interposed- lateral DS

responsible for motor execution

Question 7

What is functional zone in cerebro- cerebellum?

Answer 7

denate- areas 4 and 6 (premotor and motor cortex)

for motor planning

Question 8

What is functional zone for vestibulocerebellum?

Answer 8

vestibular nuclei

for balance and eye movements

Question 9

What will result from a lesion in the vestibulocerebellum region?

Answer 9

ataxia with vertigo and nystagmus, inability to use vestibular system to control eye movements during head rotation

Question 10

What portion of the spinocerebellum is the fastigal zone located?

Answer 10

medial zone / vermis

controls posture and muscle tone, upright stance, locomotion

Question 11

What will happen if there is a lesion in the medial zone/vermis?

Answer 11

poor balance, ataxic gait, falls, hypotonia, ocular motor deficits

Question 12

What portion of the spinocerebellum is the inter posed zone located?

Answer 12

intermediate zone

controls agonist-antagonist timing in gait and limb movements

Question 13

What will happen if there is a lesion in the intermediate zone?

Answer 13

ataxic gait, intention tremor, dysdiachokinesia, dysmetria, dysarthria

Question 14

What is the function of the cerebrocerebellum?

Answer 14

denate nuclei: associated with planning movements, timing of ag and antag, cooridnation of fine finger movements, planning of complex motor actions,

Question 15

What will happen if there is a lesion in the denate nuclei?

Answer 15

limb dysmetria, decomposition of movement and dysdiacochokinesia

Question 16

What are the 3 main arteries of the cerebellum?

Answer 16

1. SCA- anterior lobe
2. PICA- posterior lobe
3. AICA- ventral anterior, and posterior lobes, flocculonodular lobe

all arise from vertebro-basilar artery

Question 17

What branch of cerebellar arteries is an infarct most common?

Answer 17

PICA

Question 18

What is clinical presentation of cerebellar infarcts?

Answer 18

N/V, vertigo, nystagmus, limb ataxia, unsteady gait, and HA

can cause swelling leading to hydrocephalus

Question 19

What are some examples of hereditary cerebellar lesions?

Answer 19

spinocerebellar ataxia, Freidrich’s ataxia, episodic, mitochondrial disease, fragile x syndrome

Question 20

What are examples of acquired cerebellar lesions?

Answer 20

CVA, tumor, arnold chiari, toxicity, MS, trauma/TBI, infection

Question 21

What is the most common hereditary cerebellar lesion?

Answer 21

Freidrich’s which is the degeneration of spinal cord, peripheral nerves and cerebellum

leads to ataxic gait, then arms and trunk, sensory loss, hyporeflexia and dysarthria

Question 22

What is age of onset for Friedrich’s?

Answer 22

5-15 years old, wheelchair bound in 10-20 years

may survive into 60-70’s

Question 23

What side will effects be seen on for cerebellar lesion if lesion is unilateral ?

Answer 23

ipsilateral as they cross at superior peduncle and then cross back at corticospinal and rubrospinal tracts

Question 24

When will a patient experience a poorer prognosis with cerebellar lesion?

Answer 24

if damage is to cerebellar output pathways are damaged, worse with SC artery, hemorrhagic, degenerative process, extracerebellar damage

Question 25

What is prognosis for an acute onset lesion such as CVA or trauma?

Answer 25

more severe sx, recovery greatest in first 4 weeks, plateau by 6 months

Question 26

What are sx of cerebellar ataxia?

Answer 26

dysmetria, dysdia, dyssynergia, tremor

Question 27

What is sensory ataxia?

Answer 27

impaired motor responses due to absent or insufficient sensory input

Question 28

What are two types of clinical tests and measures for cerebellar lesions?

Answer 28

non-equilibrium and equilibrium tests

Question 29

What are some body structure and function areas to test?

Answer 29

dysdia, dysmetria, dyssynergia, intention tremors, postural tremors, hypotonia (due to less excitation of alpha and gamma motor neurons), asthenia (general weakness), dysarthria

Question 30

What are activities that should be examined?

Answer 30

gait- ataxic gait most common finding in cerebellar lesions

balance, rolling, bed mobility, transfers, stairs

Question 31

What are two common outcome assessment measures for cerebellar lesions?

Answer 31

ICARS and SARA