Cerebellar Disease

Question 1

Roles of cerebellum

Answer 1

Receives and modulates inputs relating to
1- Balance (vestibulospinal nerves)
2- Reticular formation ( relates to neuron excitability and gravity opposing muscles)
3- Motor planning ( thalamus)

Question 2

Afferents to cerebellum + type

Answer 2

1 - Vestibular nuclei ( Balance + head and neck movements)
2- DSCT ( Proprioception)
3- Premotor cortex ( Motor planning)

Question 3

Cerebellum Efferents:

Answer 3

1- Lateral vestibular nucleus to LMN
2- Reticular formation to LMN
3- Red nuceli to LMN
4- UMN via thalamus

Question 4

Features of cerebellum disease

Answer 4

1- Ataxia
2- Dysarthria
3- Dysphagia
4- Visual symptoms ( Oscillopsia and dilopia)
+/- Vertigo
+/- nausea and vomiting
5- Abnormal eye movments (Nystagmus and squarewave jerks)

Question 5

Which motor systems are typically affected by ataxia due to cerebellar disease

Answer 5

Can affect multiple motor systems

• Orobucal = Speach and swallowing difficulties
• Limbs= clumsiness
• Truncal= Problems sitting
• Gait = unsteadiness

Question 6

Characteristics of dysarthria

Answer 6

Laboured/ slurred speach : Emphasis given to each word.
Difficulties in being understood
Stacatto (pauses between words)
Rapid tongue movements slowed

Question 7

What eye movements would be observed in a patient with cerebellar disease

Answer 7

1- Nystagmus: Rhytmic oscillatory eye movements. (Voluntary gaze which appears as a twitching movement of the eyes due to a slow and fast phase).
2- Square wave jerks: Eyes jump on and off target leading to a square motion of the eye

Question 8

Describe the motions of nystagmus

Answer 8

Fast + slow phase :

• Abnormality is the slow phase, the eyes drift off the target.
• The fast phase brings the eye back to the target
• Indication of cerebellar disease.

Question 9

Features of limb ataxia

Answer 9

Intention tremor: Limb/ finger motion gets worse the closer to the target. Caused by the inability of the cerebellum to gage the distance to the target and leads to overcorrection and overshoot.

• Dysmensia/ Past pointing
• Dysdiadochokinesia: Impaired rapid alternating movements.

Question 10

Features of Truncal and gait ataxia

Answer 10

• May be the only sign of cerebellar disease when only the vermis is affected due to toxins such as alcohol
• Broad based gait
  -Sways to either side (wobbling while standing)
  -Irregular steps in time and distance
  Exaggerated with heel-toe walking

Question 11

Signs of cerebellar disease

Answer 11

No muscle weakness
Tone can be normal or reduced
Reflexes are normal
Sensation is normal

Question 12

Causes of cerebellar disease

Answer 12

Metabolic/ toxins (alcohol)
Congenital malformations (arnold chiari/ where tissue extends into the spinal canal)
Vascular disease (stroke)
Inflammation/ demyelination (MS)
Tumours
Infection
degenerative diseases of the cerebellum. (usually genetic causes)

Question 13

Features or signs of multiple sclerosis

Answer 13

Unilateral ataxia
Perivenular inflammation and patches of demyelination
Commonly affects cerebellar peduncles

Question 14

What needs to be considered when dealing with possible cerebellar disease

Answer 14

Less obvious finding but cerebellar disease may be suspected when symptoms are greater than weakness would suggest

• Symptoms like clumsiness of the hand without any changes in muscle strength
• Accompanying symptoms such as double vision or swallowing difficulties.