What is Deep Brain Stimulation?
Procedure in which stimulating electrodes are placed stereotactically into certain deep brain structures
Which 3 movement disorders can DBS be used to treat (NICE approved - NHS funded)?
- Parkinson’s disease
- Essential tremor
- Dystonia
What is a resting tremor?
Tremor present when at rest e.g. hands rested on the table
What is a postural tremor?
Tremor present when in a position against gravity, e.g. arms lifted in the air
What is an intentional tremor?
Tremor present when trying to do something, e.g. when writing/reaching to pick up a glass
What is an essential tremor?
Brain disorder causing part of the body (esp. head and forearms) to tremor uncontrollably
What is dystonia?
Brain disorder with sustained or repetitive muscle contractions resulting in twisting and repetitive movements or abnormal fixed postures
What brain regions can be targeted with DBS for tremor?
- Zona incerta
- Subthalamic nucleus
- Globus pallidus internal
What brain region can be targeted with DBS for dystonia?
- Globus pallidues internal
Which brain region can be targeted with DBS for depression?
- Broadmann area 25
Advantages of DBS
- Safe
- Can improve tremors that are L-dopa resistant
- Reversible effects
- Provides continuous symptom control
- Allows a decrease in medication
Disadvantages of DBS
- Small risks (brain haemorrhage, CSF leakage)
- May experience tingling
- Migration of electrode
What are the 4 mechanisms of DBS?
- Inhibition hypothesis
- Excitation hypothesis
- Disruption hypothesis
- Neuro-network modulation hypothesis
What is the inhibition hypothesis of DBS?
- Theory: PD due to overactive basal ganglia neurons in the STN and/or GPi
- DBS can block this and remove spontaneous discharge from GPi neurons
- This hypothesis agrees with anatomical lesioning and pharmacological intervention (e.g. GABA agonist)
What is the excitation hypothesis of DBS?
- DBS can excite efferent axons antidromically resulting in ‘jamming’ the spontaneous activity
