Transcranial Magnetic Resonance-Guided Focused Ultrasound in X-Linked Dystonia-Parkinsonism

Abstract

X-linked dystonia-parkinsonism (XDP) is a neurodegenerative condition found among males with maternal ancestry from Panay Island, Philippines. The treatment options are limited. We report on our experience of three XDP patients who underwent transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) pallidothalamic tractotomy. The three patients were all genetically confirmed XDP, with a mean XDP-Movement Disorder Society of the Philippines (MDSP) Scale score of 68.7/200. All patients were on stable doses of their oral medications and their last botulinum toxin injection was 12 months prior to study. Two patients complained of moderate to severe arm pain 2–7 months after the procedure. There was an overall improvement in the XDP-MDSP Scale score of 36.2% (18.7 vs. 15) at 6 months and 30.1% (68.7 vs. 45.5) at 1 year. Notably, there was worsening of the nonmotor subscale (part IIIB, nonbehavioral aspect) by 350% at 1 year. While these numbers are encouraging, there is a need to do a larger study on the safety and efficacy of tcMRgFUS on XDP.

Unilateral Transcranial Magnetic Resonance-guided Focused Ultrasound Pallidothalamic Tractotomy in X-linked Dystonia-parkinsonism: A Case Report

“…This was better than the reported outcome (30.1%) in a recent publication. 10 There was a significant improvement in our patient's pain sensation involving the right arm dystonia. In PD, the pain has been reported to be the only one that improved after pallidothalamic tractotomy.…”

“…Only three patients with XDP have undergone unilateral tcMRgFUS. 10 Our patient underwent left pallidothalamic tractotomy. The PTT connects the globus pallidus internus with the ventroanterior/ventrolateral thalamus.…”

“…8 There have been reports on the utility of transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) for dystonia, including XDP. 9,10 Given the limited options for patients with XDP, we considered pallidothalamic tractotomy for our patients. Here, we report a patient with XDP who underwent a unilateral tcMRgFUS pallidothalamic tractotomy with 1-year follow-up.…”

Update in the clinical application of focused ultrasound

“…One patient presented mild dysarthria at 12 months and 3 reported dystonia recurrence. Anecdotally, three cases of genetically confirmed X-Linked Dystonia-Parkinsonism improved with ultrasound pallidothalamic tractotomy [53], and one case of genetically confirmed spinocerebellar ataxia showed a reduction of tremor after CTT ablation [54].…”

Dystonia: Still a Mysterious Syndrome

“…In addition to medication therapy, pallidal deep brain stimulation (DBS) surgery is a promising treatment for medically intractable primary dystonia, which involves the cortico–basal ganglia–thalamocortical motor loop in its pathogenesis [ 16 , 17 ]. Jamora et al showed the efficacy of lesioning the pallidothalamic tract using focused transcranial MR-guided ultrasound in dystonia patients with DYT3/XDP-TAF1, suggesting the involvement of the cortico–basal ganglia–thalamocortical loop in the pathogenesis of DYT3/XDP-TAF1 dystonia [ 18 ]. Goto et al proposed a striatal compartmental hypothesis in the pathogenesis of dystonia, which may affect the cortico–basal ganglia–thalamocortical loop [ 19 ].…”