Motor Disorders

Question 1

Where is the cerebellum located within the cranium?

Answer 1

Posterior cranial fossa

Question 2

How is the cerebellum separated from the occipital and parietal lobes?

Answer 2

By the tentorium cerebelli

Question 3

How is the cerebellum separated by the pons?

Answer 3

4th ventricle

Question 4

The cerebellum consists of the _____ and two _________ ___________

Answer 4

Vermis

Lateral hemispheres

Question 5

The Vermis regulates which structures?

Answer 5

Trunk musculature

Question 6

Lateral cerebral hemispheres regulate which structures?

Answer 6

Distal structures i.e. limbs

Question 7

Are tracts in the cerebellum contralateral or ipsilateral?

Answer 7

Ipsilateral

Question 8

Which structure attaches the cerebellum to the midbrain?

Answer 8

Superior cerebellar peduncle

Question 9

Which structure attaches the cerebellum to the pons?

Answer 9

Middle cerebellar peduncle

Question 10

Which structure attaches the cerebellum to the medulla?

Answer 10

Inferior cerebellar peduncle

Question 11

Midline cerebellar lesions can cause what clinical presentations?

Answer 11

Truncal ataxia

Abnormal gait

Question 12

Extension of cerebellar midline lesions can cause what?

Answer 12

4th cranial nerve lesions

Ipsilateral arm tremors

Compression of 4th ventricle

Obstruction of CSF flow—> Hyrdocephalus

Question 13

Do cerebellar lesions cause ipsilateral or contrlateral symptoms?

Answer 13

Ipsilateral symptoms

Question 14

What are the 6 symptoms of cerebellar pathology?

Answer 14

Disdiadochokinesis - abnormal repetitive movement

Ataxia - abnormal movement

Intention tremor

Slurred speech

Hypotonia- decreased muscle tone compared to normal, floppy

“DANISH”

Question 15

What is the name of the area of the brain known to be involved in motor function?

Answer 15

Basal Ganglia

Question 16

Name three important overall structures of the basal ganglia.

Answer 16

Caudate

Lentiform nucleus

Substantia nigra

Question 17

The lentiform nucleus is made up of what?

Answer 17

Putamen

Globus pallidus externa

Blobus pallidus interna

Question 18

Substantia nigra can be separated into which two parts?

How do they differ?

Answer 18

Pars compacta - dorsal, dopaminergic nerurones

Pars reticularis - ventral

Question 19

Output of the basal ganglia is to the cerebral cortex via _________.

Answer 19

The thalamus

Question 20

The caudate nucleus and the putamen make up what?

Answer 20

Striatum

Question 21

What is the overall net effect of direct and indirect pathways in the basal glanglia with regard to the motor cortex.

Answer 21

Thalamic stimulation of the motor cortex

Question 22

Disorders will present in the same or different side of the body to the affected basal ganglia?

Answer 22

Same side as the abnormal basal ganglia

Question 23

What 4 features might imply disorders of the basal ganglia?

Answer 23

Abnormal motor control

Altered posture

Muscle tone

Dyskinesia

Question 24

What is Parkinson’s disease?

How is the disease characterised (triad of features)?

Answer 24

Chronic, progressive movement disorder characterised by a triad of bradykinesia, tremor and rigidity

Question 25

Parkinson's disease is caused by what?

Answer 25

Degeneration of substantia nigra pars compacta which causes deficiency in dopamine production

Question 26

Using reference to both the direct and the indirect pathways, explain why Parkinson's disease presents as it does when the substantia nigra pars compacta is degenerated.

Answer 26

Without dopamine, the direct pathway is stimulatory and therefore inhibits the thalamus---\> Causes bradykinesia Without dopamine, the indirect pathway is inhibitory and therefore---\> Further causes bradykinesia

Question 27

Besides the three cardinal signs, what are some other associated features of Parkinson's disease

Answer 27

Hypophonia Reduced facial expression Micrographia Dementia Depression

Question 28

What is Huntington's disease? At what age does it usually present?

Answer 28

An autosomal, dominant, progressive disorder Associated with cell loss within the basal ganglia and cortex 30-50 years

Question 29

Give some defining symptoms of Huntington's disease.

Answer 29

Chorea - abnormal, jerky movements of the body Dystonia - repetitive muscle cramping Incoordination Cognitive decline Behavioural difficulties

Question 30

Describe the pathogenesis of Huntington's disease.

Answer 30

Loss off GABAergic neurones from the **putamen** of the basal ganglia. Lose inhibiton of globus pallidus externa which in turn leads to less inhibtion of the subthalamic nucleus ---\> less stimulation of the globus pallidus interna. The globus pallidus interna is usually responsible for inhibition of the **thalamus, loss of this inhibition**. This explains the **excessive, jerky, uncoordinated movements**.

Question 31

The cerebellum can be divided into how many functional lobes?

Answer 31

3 - Anterior - Posterior - Flocculonodular

Question 32

Give some examples of conditions that may cause cerebellar signs.

Answer 32

**P**osterior fossa tumour **A**lcohol **M**S **T**rauma **R**are **I**nherited **E**pilepsy medication **S**troke "PASTRIES"