Bilateral Pallidal Stimulation with Directional Leads for Primary Focal Lingual Dystonia

Abstract

There have been limited studies regarding stereotactic and functional neurosurgery for lingual dystonia. Here, we report a patient with primary lingual dystonia who showed significant improvement after bilateral deep brain stimulation (DBS). A 42-year-old woman presented with a 5- to 6-year history of tongue protrusion; however, she lacked a significant medical or medication history before onset. She presented with gradually worsening symptoms and was diagnosed with idiopathic lingual dystonia. Her tongue was injected with botulinum toxin on 6 occasions; however, it had a limited effect. Oral medications were ineffective. She underwent DBS since her involuntary tongue movements were causing nocturnal breathing problems. Directional leads were bilaterally inserted into the internal segment of the globus pallidus (GPi). The directional part of each lead was inserted at the GPi bottom on both sides. The posteromedial contacts were used to deliver stimulation. After 1.5 years, the patient’s Burke-Fahn-Marsden dystonia rating scale score improved from 9 to 1.5 and 2 to 1 for movement and disability, respectively. This case demonstrated the effectiveness of bilateral GPi-DBS. Placing the directional part of the lead in the GPi bottom could improve the stimulation effects.

Directional electrodes in deep brain stimulation: Results of a survey by the European Association of Neurosurgical Societies (EANS)

“…Most experts believed that mainly patients with well-established indications, such as PD, tremor and dystonia would benefit most from directionality. This is very much in line with the literature so far, where most published studies are on PD and tremor ( Bruno et al, 2021 ; Shao et al, 2020 ; Rebelo et al, 2018 ; Schnitzler et al, 2022 ), with only a small number of case reports or small case series on dystonia, pain or psychiatric diseases ( Abel et al, 2021 ; Asahi et al, 2021 ; Krüger et al, 2021c ; Coenen et al, 2022 ; Lopez et al, 2021 ), and no studies on depression or epilepsy.…”

Neurophysiological Basis of Deep Brain Stimulation and Botulinum Neurotoxin Injection for Treating Oromandibular Dystonia

“…Currently, only three published case reports have discussed bilateral GPi-DBS for OMD, all of which were categorized as lingual dystonia. Chung et al [20] and Asahi et al [22] reported symptomatic improvements in lingual dystonia following bilateral GPi-DBS in two cases and one case, respectively. In patients with OMD, the unique neuroanatomical characteristics of bilateral innervation in each side of the stomatognathic system may complicate the application of conventional DBS compared to that in patients with focal dystonia of the limbs, as previous studies have reported that sufficient effects are sometimes difficult to obtain with interventions targeting the unilateral hemisphere.…”

“…Several case reports from the past two decades have described the use of DBS of the bilateral Gpi for the treatment of lingual dystonia [19][20][21][22]. This bilateral approach is based on the neurophysiological principle that tongue movements are regulated by the bilateral central regions through the corticobulbar tract, which differs from the contralateral regulation of the limbs (Figure 1).…”