BB2 Revision13 Flashcards
DBS has NICE approval (NHS funded) for which three diseases? [3]
- Parkinson’s disease (Hypokinetic movement disorder)
- Essential Tremor (Hyperkinetic movement disorder)
- Dystonia (Hyperkinetic movement disorder)
What frequency is typically used for DBS? [1]
exam q
100 Hz
Whats the difference between essential tremor and dystonia? [2]
Essential tremor: A brain disorder causing part of your body (esp. head and forearms) to tremor uncontrollably.
Dystonia: A brain disorder with sustained or repetitive muscle contractions resulting is twisting and repetitive movements or abnormal fixed postures.
Criteria in DBS for Parkinson’s disease
What type of PD makes you elligible for DBS? [1]
What are the 4 classic symptoms for this? [4]
Idiopathic PD: with 4 classical symptoms: tremor, bradykinesia, rigidity, postural instability.
Criteria in DBS for Parkinson’s disease
Which treatment does Ptx need to have been treated withand still responsive to? [1]
Levodopa
A man sits down with his hands resting still in his lap. When he tries to grab a glass of water he begins to tremor. What is his diagnosis? [1]
Intentional tremor
DBS for PD
DBS directly impacts which two symptoms? [2]
DBS improves which symptom due to less drug being required? [1]
Directly decreases bradykinesia and rigidity
Improves dyskinesia as less L-DOPA required.
Reduced but not totally eliminated
Brain regions for DBS
Which areas of the brain targeted for tremor? [3]
Which areas of the brain targeted for Dystonia? [1]
Tremor:
* Zona incerta
* Subthalamic nucleus
* GPin
Dystonia:
* GPin
Which type of tremor indicates Parkinsons Disease unless proven otherwise?
Reemergent tremor
Resting tremor
Intentional tremor
Postural tremor
Which type of tremor indicates Parkinsons Disease unless proven otherwise?
Reemergent tremor
Resting tremor
Intentional tremor
Postural tremor
Which structures are the arrows pointing to? [5]
Label A-C
A: PAG
B: substantia nigra
C: red nucleus
FYI Method of DBS
Using MRI scan to work out the target site.
Connect a stereotaxic frame on patient’s head.
Drill a 4 cm hole into the skull, then insert the microelectrode tip to the presumptive target site.
Once target site has been located, microelectrode is removed and the stimulating electrode is inserted.
Cap hole, close wound, MRI scan to check electrode at correct site, then general anaesthesia for neuro-stimulator implant.
Return home next day, then 1 month later return to clinic to
programme DBS and adjust drug dosage.
State the effect (% of patients is effective for) of DBS on:
- Epilepsy [1]
- Chronic neuropathic pain [1]
Epilepsy:
* Reduce NOT eliminate seizures frequency
* Benefit for 50-60% patients (exam Q)
Chronic neuropathic pain
* Benefit 15-50% pain patients.
* Only reduce NOT eliminate pain experience.
Name 3 risks of DBS
- 2-3% risk of brain haemorrhage
- small risk of cerebrospinal fluid leakage
- 15% risk of temporary problems with transplantation (e.g. infection, allergy to implant).
Mechanisms of DBS
Explain the inhibition hypothesis [2]
Theory: PD due to overactive basal ganglia neurons in the STN and/or GPi.
DBS can block this and remove spontaneous discharge from GPi neurones
Mechanisms of DBS
Explain the excitation hypothesis [2]
DBS can excite afferent axons antidromically resulting in ‘jamming’ the spontaneous activity
DBS inhibits the local neuronal firing removing the spontaneous discharge from subthalamic nucleus
Mechanisms of DBS
Explain the excitation hypothesis [2]
DBS can excite afferent axons antidromically resulting in ‘jamming’ the spontaneous activity
DBS inhibits the local neuronal firing removing the spontaneous discharge from subthalamic nucleus
Mechanisms of DBS
Explain the disruption hypothesis
DBS in GPi can activate axon terminals causing extensive release of NTs (i.e. GABA & glutamate)
DBS dissociates inputs and outputs in the stimulated nucleus, thus disrupting/blocking the abnormal information flow through the GPi.
DBS disrupts abnormal information flow through the GPi
Targeting which area of the brain may help Tourette Syndrome?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help Tourette Syndrome?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix