Deep brain stimulation of the ventrolateral thalamic base and posterior subthalamic area in dystonic head tremor

Dystonic head tremor (DHT) is characterized by head tremor associated with cervical dystonia (CD). Deep brain stimulation (DBS) can be considered when local treatment with botulinum toxin or oral medication has failed. However, there is lack of data regarding the optimal target structure for surgery in DHT. DBS of the ventrolateral (VL) thalamus is an established treatment option for medically refractory tremor. Tremor suppression is described as being most effective when stimulating at the inferior thalamic base and within the posterior subthalamic area (PSA). Moreover, there is surgical evidence from the pre-DBS era that both lesions and high-frequency stimulation of the PSA improve CD. Based on these observations, we performed DBS in three patients with DHT, placing the proximal contacts of the electrodes into the inferior base of VL thalamic nuclei and the distal contacts into the adjacent PSA. Chronic stimulation improved not only head tremor but also CD. These findings suggest that DBS at the base of VL thalamus and the adjacent PSA should undergo further investigation as a potential target for patients with DHT.