6- Motor Disorders

Question 1

What are the signs of cerebellar disease? (mnemonic= DANISH)

Answer 1

D-dysdiadochokinesia 
A-ataxia
N-nystagmus
I-intention tremor
S-slurred speech (dysarthria)
H-hypotonia

Question 2

What is nystagmus?

Answer 2

Flickering eye movement due to malcoordination of extra-ocular muscles

Question 3

What is dysarthria?

Answer 3

Slurred speech from malcoordination of muscles of larynx and tongue

Question 4

What is dysdiadochokinesia?

Answer 4

Difficulty with rapidly alternating movements

Question 5

What is an intention tremor?

Answer 5

A tremor that worsens as target is approached

Question 6

What is the cause of Parkinson’s disease?

Answer 6

Degeneration of dopaminergic neurones in substantial nigra pars compacta

Question 7

What are some signs and symptoms of Parkinson’s disease?

Answer 7

Tremor, rigidity, bradykinesia, dementia, depression

Question 8

What other symptoms of Parkinson’s are caused by the bradykinesia?

Answer 8

Hypophonia- quiet speech from bradykinesia of larynx and tongue muscles
Decreased facial movement
Micrographia- small handwriting from bradykinesia of hands

Question 9

Why does bradykinesia occur in Parkinson’s disease?

Answer 9

Due to loss of cortical excitation

Question 10

What is the inheritance pattern of Huntington’s chorea?

Answer 10

Autosomal dominant

Question 11

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

Answer 11

30-50 years old

Question 12

What is the cause of the hyperkinetic features of Huntington’s chorea?

Answer 12

Loss of inhibitory projections from striatum to Globus pallidus externa

Question 13

What are some features of Huntington’s chorea?

Answer 13

Chorea, dystonia, loss of co-ordination

Question 14

What is hemiballismus?

Answer 14

Rare condition causing involuntary unilateral explosive movements

Question 15

What is the basic sections of the cerebellum?

Answer 15

Two lateral hemispheres with midline vermis between them

Question 16

Which areas of the brain stem do the cerebellar peduncles (superior, middle, inferior) communicate with?

Answer 16

Superior- Midbrain
Middle- Pons
Inferior- Medulla

Question 17

Where does the cerebellum receive sensory information from?

Answer 17

Ipsilateral spinal cord and contralateral sensory cortices (via corticopontocerebellar pathway)

Question 18

Which structure together form the striatum?

Answer 18

Caudate and putamen

Question 19

How does an increase in thalamic activity affect cortical activity?

Answer 19

Increase in thalamic activity will cause an increase in cortical activity

Question 20

Via which structure do the basal ganglia communicate with the motor cortex?

Answer 20

Thalamus

Question 21

What roles do the basal ganglia and cerebellum have in performing a task like picking up a cup?

Answer 21

Basal ganglia- determine appropriate movements to perform task
Cerebellum- determines appropriate sequence of these movements to perform the task

Question 22

By which receptors does dopamine exert an inhibitory effect on the indirect pathway?

Answer 22

D2

Question 23

By which receptors does dopamine exert an excitatory effect on the direct pathway?

Answer 23

D1 receptors

Question 24

Stimulation of the indirect pathway has what effect on thalamic activity and therefore also on cortical activity?

Answer 24

Decreased thalamic and cortical activity

Question 25

Stimulation of the direct pathway has what effect on thalamic activity and therefore also on cortical activity?

Answer 25

Increased thalamic and therefore increased cortical activity