6: Motor Disorders

Question 1

What is the role of the cerebellum?

Answer 1

Motor control, balance and coordination

Question 2

How does the cerebellum communicate with the brainstem?

Answer 2

Via the cerebral peduncles

Superior attaches to midbrain, middle attaches to pons, inferior attaches to medulla

Question 3

Do cerebellar hemisphere lesions cause ipsilateral or contralateral signs?

Answer 3

Ipsilateral because tracts are ipsilateral, unlike in the cerebrum

Question 4

What are some symptoms of a cerebellar lesion and how could each symptom be tested for?

Answer 4

DANISH

dysdiadochokinesis (ask px to rapidly alternate patting hand with palm and dorsal aspect)
Ataxia (heel to toe walk, and heel to shin test)
Nystagmus (ask px to follow your finger with eyes)
Intention tremor (ask to touch finger to nose)
Slurred speech (ask px to repeat couple of phrase)
Hypotonia

Question 5

What is the basal ganglia responsible for?

Answer 5

Controlling the speed, amplitude and size of movements

Question 6

What is the output of the basal ganglia?

Answer 6

The thalamus

Question 7

What is the overall net effect of pathways in the basal ganglia?

Answer 7

Thalamic stimulation of the motor cortex

Question 8

What causes Parkinson’s disease?

Answer 8

Loss of dopaminergic neurones in the substantia nigra

Question 9

What is the triad of symptoms in Parkinson’s?

Answer 9

Bradykinesia
Cog wheel rigidity
Restinb tremor (disappears during intentional movement)

Question 10

What are some other symptoms of Parkinson’s, other than the main triad?

Answer 10

Small handwriting
Dementia
Depression
Hypophonia 
Shuffling gait
Reduced facial expression
Personality changes

Question 11

What is the inheritance pattern of Huntington’s disease?

Answer 11

Autosomal dominant

Question 12

What is the average age of onset of Huntington’s?

Answer 12

30 to 40

Question 13

What is Huntington’s Disease and how does it present?

Answer 13

Autosomal dominant disorder
Due to cell loss in the basal ganglia and the cortex
Presents with chorea (uncontrollable limb movements), cognitive impairment, behavioural difficulties, dysphagia, dysarthria, abnormal eye movements, neuropsychiatric manifestations

Question 14

Which basal ganglia pathway out of the direct and indirect pathway promote movement and how does dopamine affect these?

Answer 14

Direct pathway promotes movement
Indirect pathway inhibits movement

Dopamine stimulate direct pathway
Dopamine inhibits indirect pathway

So overall dopamine Acts to promote movement