Parkinson's Disease

Question 1

Origin

Answer 1

first described by Parkinson in 1817

Question 2

Morbidity rate

Answer 2

~1% of the UK and US population of age 50 or older, more common in men

Question 3

Major symptoms (1)

Answer 3

1) motor impairments including rigidity, resting tremor and poor balance

Question 4

Other symptoms (7)

Answer 4

1) stooped posture
2) slow movements
3) reduced movement initiation
4) reduced facial expressions
5) slow speech
6) decreased voice amplitude
7) decreased blink rate

Question 5

Diagnosis

Answer 5

reduced levels of dopamine

PET scan of fluorescent dye Fluoro-dopa

Question 6

4 major findings that contribute to the neural basis of Parkinson’s Disease

Answer 6

1) PD patients show a degeneration of the substantia nigra
2) PD is characterised by the occurrence of Lewy bodies
3) neurons within the substantia nigra contain dopamine
4) dopamine levels are reduced in PD patients
- injection of 6-Hydroxydopamine (destroys dopamine) produces PD-like symptoms in controls
- substantia nigra directs to motor areas and the striatum

Question 7

Substantia nigra

Answer 7

“black substance”, found at the base of the brain stem

Question 8

Lewy bodies

Answer 8

cells filled with filaments

Question 9

Causes?

Give further details

Answer 9

1) some genetic influences but not inheritable
- mutations on chromosome 4, which produces alpha-synuclein (regulates dopamine release)
- mutations on chromosome 6, which produces the Parkin gene (results in loss of motor function)

Question 10

Drug treatment with L-dopa

Answer 10

Dopamine itself cannot cross the blood brain barrier.

Injection of dopamine precursor L-dopa has 65% success rate, but some side effects (nausea, sweating, confusion)

Question 11

Other drugs than L-dopa used for treatment

Answer 11

Can use either drugs that mimic dopamine or block the reuptake of dopamine into the cells

Question 12

Problems with drug treatment

Answer 12

many drugs don’t cross the blood brain barrier and cause side effects in the liver
drug therapy cannot stop the degeneration of cells

Question 13

Alternatives to drug treatment

Answer 13

Stem cell research looks promising but it is a controversial topic
Surgery can be performed to remove the globus pallidus or the sub-thalamic nucleus

Question 14

Globus pallidus (connections, normal function and PD malfunction)

Answer 14

Located between the striatum and the motor cortex
Function: inhibition of the motor cortex
Without the substantia nigra in PD it overreacts and over-inhibits the motor cortex

Question 15

Sub-thalamic nucleus (connections, function)

Answer 15

Connected to the globus pallidus

Activates the globus pallidus

Question 16

Problems with pallidotomy

Answer 16

The globus pallidus is located right beside the optic tract, so surgery can cause damage and thus blindness

Question 17

Improved surgery procedure

Answer 17

The patient’s head is kept still with a stereotoxic frame.
After determining the location for invasion with a CT scan, an electrode is inserted under constant assessment of the patient’s vision and motor abilities.