Deep brain stimulation 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)
DBS has NICE approval (Individual funding requests) for which two diseases [2]
- Epilepsy
- Chronic neuropathic pain
What frequency is typically used for DBS? [1]
exam q
100 Hz
Parkinson’s Disease
What is the difference between resting, postural and intentional tremors? [3]
Resting tremor: occurs when voluntary muscle activity is absent
Postural tremor: occurs when holding a body part motionless agaisnt a force of gravity
Intentional tremor: occurs with a goal-directed movement and worsens as approaching the target
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
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
Criteria in DBS for Parkinson’s disease
What other factors need make you elligible for DBS?
No mental disorders.
Physically fit for surgery.
DO NOT have sensory issues
DO NOT get weakness or hyperreflexia
Age? (Younger patients (29 yr) benefit more from DBS,
What type of symptoms does DBS treat? [1]
DBS can ONLY treat the ‘Motor symptoms’ and NOT the non-motor symptoms (e.g. gait or balance,
cognitive problems, depression)
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.
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 structure is the line pointing at? [1]
Red nucleus
Explain how DBS effects this graph (effect of levodopa on dyskinesia and bradykinesia)
The DBS increase the baseline so that you have less bradykinesia phase: so require less levodopa.
(If your tremor was moderate, then DBS will reduce it done by 70% and slight tremor. If have severe tremor, DBS can reduce it down to mild tremor)
Targeting which area of the brain may help alleviate addiction?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help elleviate addiction?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help alleviate anorexia?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help alleviate anorexia?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help AD?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help AD?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help treatment resistant deppression?
Brodmann area 25 (Subcallosal cingulate)
Hypothalamus
Thalamic centromedian/parafascicular complex
Nucleus Accumbens
Anterior of the fornix
Targeting which area of the brain may help treatment resistant deepression?
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
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
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.
Treating epilepsy with DBS: where is the electrode impanted? [1]
Electrode implanted into the anterior nucleus of the
thalamus (ANT)
Treating therapy-refractory obsessive-compulsive disorder with DBS: where is the electrode impanted? [2]
- nucleus accumbens
- ventral striatum
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
Which potential mechansim for DBS is depicted by the figure?
1- Inhibition hypothesis
2- Excitation hypothesis
3- Disruption hypothesis
4- Neuro-network modulation hypothesis
3- Disruption hypothesis
DBS activates axon terminals in the stimulated nucleus, induces extensive release of neurotransmitters, such as GABA and glutamate (Glu), and dissociates inputs and outputs in the stimulated nucleus
‘Deep brain stimulation also excites afferent axons antidromically’
Which of the following best describes this theory of how DBS works
1- Inhibition hypothesis
2- Excitation hypothesis
3- Disruption hypothesis
4- Neuro-network modulation hypothesis
‘Deep brain stimulation also excites afferent axons antidromically’
Which of the following best describes this theory of how DBS works
1- Inhibition hypothesis
2- Excitation hypothesis
3- Disruption hypothesis
4- Neuro-network modulation hypothesis
