🎯 1. Globus Pallidus Internus (GPi) Most common and well-established target for dystonia
Indications:
Primary generalized dystonia (e.g., DYT1 mutation)
Segmental dystonia
Cervical dystonia
Secondary dystonias (e.g., tardive dystonia, post-stroke dystonia – with variable results)
Mechanism:
Modulates excessive inhibitory output from the basal ganglia.
Advantages:
Consistent long-term benefits
Approved by most guidelines and covered in many clinical trials
🎯 2. Subthalamic Nucleus (STN) Less commonly used in dystonia; more typical in Parkinson’s disease.
Indications:
Some studies show benefits in dystonia–parkinsonism syndromes
May be considered in selected cases of secondary dystonia or if STN is already being targeted for co-existing Parkinsonian symptoms
Potential advantage:
Less energy consumption (which can be useful for battery life)
🎯 3. Ventral Intermediate Nucleus of the Thalamus (VIM) Used occasionally, mainly in focal hand dystonia or tremor-dominant dystonia
More often a target in essential tremor, but might help specific dystonia phenotypes with tremor components
🧠Other Experimental / Rare Targets: Substantia nigra pars reticulata (SNr):
Experimental target in certain secondary dystonias
Pedunculopontine nucleus (PPN):
Occasionally explored in dystonia with axial involvement or gait issues
🧬 Target Selection Considerations Etiology: Primary (idiopathic/genetic) dystonia usually responds better than secondary dystonia.
Patient age: Pediatric cases with generalized dystonia often benefit greatly from GPi-DBS.
Imaging findings: Structural abnormalities may guide away from typical targets.
Clinical phenotype: Segmental vs focal vs generalized; presence of tremor; rate of progression.