Table 3.
Stimulation-induced side effects
| Direction of current spread | Side effect | Structures involved | |
|---|---|---|---|
| STN | Lateral or anterolateral |
Contralateral muscle contractions Facial or tongue pulling Dysarthria Eyelid opening apraxia Contralateral gaze deviation |
Internal capsule |
| Anteromedial | Autonomic changes/vegetative side effects (nausea, heat sensation, sweating) | Lateral hypothalamic area | |
| Medioventral |
Disconjugate gaze Diplopia |
Oculomotor nerve | |
| Posterior | Paresthesias | Medial lemniscus | |
| Dorsal or ventral |
Bradykinesia worseninga Levodopa effect reduction Mood changes (mania, depression, or apathy) |
Zona incerta/thalamus Substantia nigra |
|
| Scarcely localizable |
Impulsivity Hypophonia |
– | |
| GPi | Medial | Contralateral muscle contractions | Internal capsule |
| Posterior | Bradykinesia worseninga | ||
| Dorsal | Dyskinesia | Globus pallidus pars externa | |
| Ventral | Phosphenes | Optic tract | |
|
Lateral Anterior |
No side effects | Globus pallidus pars externa |
GPi globus pallidus pars interna, STN subthalamic nucleus
aIn spite of rigidity improvement