Parkinson's Disease

Question 1

what are the common symptoms of Parkinson’s disease?

Answer 1

• Dyskinesia (involuntary, erratic, writhing movements of the face, arms, legs or trunk)
• Rigidity
• Slow Shuffle
• Tremor

Question 2

what part of the brain is most affected in Parkinson’s?

Answer 2

basal ganglia, particular the substania nigra pars compacta

Question 3

what is the substania nigra pars compacta?

Answer 3

the source of the important nigrostriatal dopamine pathway

+ motor movement

Question 4

what is the basal ganglia responsible for?

Answer 4

a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.

Question 5

what happens to the basal ganglia and substance nigra par compact in Parkinson’s?

Answer 5

dopamine secreting neurones begin to die and break down affecting the basal ganglia system

Question 6

how does dopamine neurons beginning to die affect an individual?

Answer 6

• voluntary movements primarily affected
• all about control and timing of movements -> issues with starting and initiating movement

Question 7

neuropathy of parkinson’s

Answer 7

• nigro-striatal pathway degeneration leading to a depletion of striata dopamine
• some degeneration of other dopamine pathways too - midbrain affected too

Question 8

what is the striatum?

Answer 8

a cluster of interconnected nuclei that form a part of the basal ganglia. It is involved in decision making functions, such as motor control, emotion, habit formation, and reward

Question 9

what would happen if you cut open the main brain area?

Answer 9

generally black because of the melanin

Question 10

what were the treatment options prior to 1960?

Answer 10

no effective treatment available

Question 11

what did they realise when Parkinson’s was an attribute of dopamine involvement?

Answer 11

lead to the use of drugs which increase brain dopamine levels

Question 12

what is the issue with dopamine, itself?

Answer 12

cannot cross blood-brain barriers

Question 13

How we ensure that the brain gets dopamine?

Answer 13

precursor, L-Dopa, enters the brain and is converted into dopamine

Question 14

what are issues with dopamine?

Answer 14

causes severe side effects (dyskinetic movements, psychotism)

Question 15

what treatment may be given if an individual is younger?

Answer 15

dopamine agonist

Question 16

how much deep brain stimulation help Parkinson’s disease?

Answer 16

lesions of the sub thalamic nucleus (STN) or internal segment of globus pallidus effectively reduce Parkinson’s signs by respectively normalising or eliminating abnormal and excessive inhibitory output from the internal pallidal segment

Question 17

how efficient is DBS?

Answer 17

• Improvement on slowness
• Complete elimination of tremors
• Improved facial expressiveness
• Better balance

Question 18

what are the side effects of DBS?

Answer 18

• Neuropsychiatric
• Displacement
• Complications from surgery
• Risk of infection and bleeding during and after surgery (something common with all surgeries anyways)

Question 19

Dopaminergic circuits in the basal ganglia are involved in the…

Answer 19

timing and readout of movements

Question 20

dysfunction of dopaminergic circuits can lead to..

Answer 20

hyper or hypokinesias

Question 21

an imbalance in the dopamine system is often associated with other cognitive problems -> what are these generalised executive dysfunction with reduction / impairment

Answer 21

• Cognitive flexibilityspeed
• Abstract thinking
• Working memory
• Cognitive speed
• Recall and perception
• Estimation of time
• Dementia vs. hallucinations

Question 22

An imbalance in the dopamine system is often associated with other cognitive problems as well as

Answer 22

Dementia vs. hallucinations

Lack of motivation vs. risk seeking behaviours

Question 23

dementia with lewy bodies vs. parkinson’s

Answer 23

both have movement and cognitive deficits, but they are still different conditions

Question 24

what is dementia with Lewy bodies usually misdiagnosed as and what is the problem with this?

Answer 24

Alzheimer’s but they have different medications, one that may not be as effective for either of the other diseases

Question 25

why might timing mechanisms that are affected in parkinson’s give rise to cognitive problems?

Answer 25

Dopamine system can also cause hallucinations as well as motor issues (loads of other symptoms that go along with parkinsons that can affect individuals just as much)

Question 26

Dopaminergic neurotransmitter involved in Parkinson’s syndrome is used by many brain systems, which other neural systems use this transmitter?

Answer 26

Dopamine is responsible for the reward circuit (with a loss of inhibition leading to: compulsive gambling, risk seeking behaviour and suicide (inability to regulate reward))

Question 27

Any problems that might be caused with deep brain stimulation?

Answer 27

• Device malfunction perhaps, headaches, bradykinesia (slowness of movement and speed)
• Can generate other movement-related disorders (i.e. a lot more involuntary movements)
• Strokes and seizures
• Invasive brain surgery may cause problems
• Unaccounted for changes in behaviour, mood or cognition caused by DBS might result in personal identity changes

Question 28

Deep Brain Stimulation

Answer 28

• brain treatment acting on the basal ganglia
• motor control improves quite a bit, individual is able to have more control over their movement, is able to talk in longer strides without long interval pauses, able to catch oneself when pulled backwards
• hand movements have improved, less tremour, can pull facial movements
• can move and turn without difficult -> initiate movement voluntarily
• better ability to catch oneself when pulled backwards

Question 29

what neurotransmitter system is affected in Parkinson’s disease?

Answer 29

dopamine
(potential motor region in the brain)

Question 30

can you think of another condition affecting this brain system where the opposite problem is found and movement is freely created even when not intended?

Answer 30

Tourette’s Syndrome - participants move freely, usually very quickly, even when not intended to

Hellabiliusm: involved the arm and leg on one side, normally rotating continously (contorting on one side of the body) (usually from a CBA issue)

ISSUE WITH STOPPING THE MOVEMENT - But same dopamine system is involved, just in a slightly different way!