Imaging and surgery of movement disorders

Question 1

What is the aim of surgical intervention and is considerations

Answer 1

• change in function
• Improve quality of life
• minimal risk of inflicting morbidity and mortality

Question 2

Symptoms and their brain targets

Answer 2

STN :
- can help improve with dopamine responsive symptoms
- improve motor fluctuations
- reduction in medication
SIDE EFFECTS
- such articulation

PALLIDUM:
-effective for dyskinesia/ dystonia
- leads likely to interfere in psychology
BAD
- does not improve slowness as much as STN

MOTOR THALAMUS (VIM) / ZONA INCERTA (ZI)
- useful in tremor

Question 3

Explain pros, cons and methods of deep brain stimulation

Answer 3

Electric connected to pacemaker in brain, electrode stimulation block activity)
Lesioning (not dbs)| comparison
- cheap
- no implanted hardwear
(Irreversible)

High frequency stimulation
-more social acceptable
- relatively reversible
(Expensive)
(Labour intensive)
(Hardware problems - infections ex)

Question 4

Explain the mechanisms of DBS

Answer 4

Similar clinical effect to lesioning.
Effect increases with rate, plateaus at >100-130Hz

Physiological effect:
- depolarisation blockade on v gated channels)
- DBS activates inhibitory axons (synaptic inhibition)
- transmitter depletion (synaptic depression)
- disruption of network activity (desynchronisation) (abnormal synchronisation (strong but wrong prediction) disrupted

Question 5

DBS

Answer 5

MRI guided DBS

MRI verified DBS

Question 6

Those involved in the multidisciplinary teams and those at the core

Answer 6

Patient, carer, family

• general neurologist/psychiatrist
• neuroradiologist
• specialist nurse
• patient support groups
• physiotherapist
• speech and language therapist
• functional neurosurgeon / functional neurologist

Question 7

Methods and benefits of DBS

Answer 7

• implantation of impulse generator (pacemaker) (tunnel wire into pacemaker in chest)
• strong evidence base for efficacy and cost efficacy

Common target
STN (sensorimotor zone in dorsolateral STN)
STN - PD
Vim/cZi - tremor

Non motor effects:
- euphoria, laughter, mania
- depression, anxiety
- aggressive behaviour

Side effects:
Limbic = study found change in artistic expression

Question 8

Role of imaging in functional neurosurgery

Answer 8

MRI :
- method of compensating for geometric distortion
- raises the possibility of acquiring the target on the first pass though the brain in the major of cases (safety implications.

Focussed ultrasound:
- piezoelectricity and buzzy crystals
- converting mechanical energy into electrical energy and vice versa

Question 9

DBS: conditions and their use

Answer 9

Dystonia

PD - tremor

Question 10

Methods of structural connectivity in functional neurosurgery

Answer 10

Connectivity scans important for identifying target and related effect

• Visualising the VIM nucleus- FA T1 map (Akram)
• Focussed ultrasound: piezoelectricity and buzzy crystals
  Applications;
  -speakers
• microphone
• lighter

Non invasive method for discussing ultrasound through skull:
- Hydrophone-Phased (phase correction to compensate for the skull thickness) (transducer (elements)

1. Sonication <-
2. Temp check |
3. Location check |
4. Correction if necessary |
5. Neurology check ->

Question 11

How might neurosurgery be applied to mental health disorders ?

Answer 11

Medication refractory patients only

OCD
Depressed mood
Cognitive inflexibility

^ all reduced in severity from baseline

Question 12

What is the future of imaging

Answer 12

Advances in imaging:
- focussed ultrasound (overlapping of energy beams)

Applications:
- Cluster headaches
- Depression
- Neural correlates of emotions eg love hate