Focused ultrasound ventro-oral thalamotomy alters cortical excitability and motor control in focal hand dystonia
Abstract
Focal hand dystonia is a disabling disorder characterized by task-specific abnormal involuntary movements that disrupt motor control. While the aetiology is unknown, abnormalities in sensory processing, sensorimotor organization, and maladaptive plasticity are thought to contribute to pathogenesis, with both genetic and environmental factors implicated. Current first-line treatments may provide only partial or transient relief. High-intensity focused ultrasound offers a means of focally ablating the target pathways implicated in dystonia. The ventro-oral complex, a relay within the motor thalamus, represents a key node in the corticobasal gangliathalamocortical circuit involved in directing motor output. Surgical radiofrequency lesioning of the Vo-complex confers sustained benefit in focal hand dystonia however the mechanisms that underlie this improvement remain unexplored. Pallidal intervention, via deep brain stimulation, has been shown to modify abnormal cortical motor plasticity in individuals with generalized dystonia, and this modification has been correlated with symptom improvement. It has been hypothesized that, to obtain long-term symptom improvement in focal hand dystonia, similar permanent network or circuit-based modification is required. In this prospective single-arm interventional study, we analysed the clinical and neurophysiological correlates of 11 individuals who underwent high-intensity focused ultrasound ventro-oral complex thalamotomy during 12 months follow-up. These measurements allowed us to identify the immediate and delayed impacts of ventro-oral thalamotomy on symptom burden, motor performance, motor cortex excitability, spatial specificity, and associative plasticity in individuals with focal hand dystonia. These findings were compared to 10 age and sex-matched healthy control participants. Consistent with our hypothesis, ventro-oral complex thalamotomy was associated with symptomatic improvement in focal hand dystonia as measured by standardized rating scales. There was no long-term loss of strength or motor dexterity in the treated limb, although adverse events were common and persisted in two participants. Inducible abnormalities in motor cortex excitability were attenuated following treatment and the spatial specificity of motor cortical responses shifted towards control values. Stimulus response curve analysis demonstrated modification of neuroplastic gain, echoing effects previously reported for pallidal stimulation in generalized dystonia. We concluded that ventro-oral complex thalamotomy may be associated with symptom improvement in focal hand dystonia and is associated with identifiable changes in motor cortex excitability. This work presents an opportunity for further studies to build on the identified mechanistic insights into single target lesioning, and advance the field of personalized circuit-informed strategies for the treatment of movement disorders.
Related
- High Intensity Focused Ultrasound (HIFU) Thalamotomy as a Safe and Effective Treatment of Essential Tremor (ET) in Older Populations and those with Comorbidities
- iTBS induces a suppression-rebound pattern in human cortical excitability
- The effects of TMS stimulus direction on corticospinal and cortico‐cortical excitability of the lower limb in healthy adults
- Effects of prolonged local vibration superimposed to muscle contraction on motoneuronal and cortical excitability
- Urinary and Sexual Function Outcomes After Ultrasound-Guided High-Intensity Focused Ultrasound for Uterine Fibroids: Associations of Lower Urinary Tract Symptoms with Fibroid Location and Uterine Morphology
BibTeX
@article{maamary2026focused,
title = {{Focused ultrasound ventro-oral thalamotomy alters cortical excitability and motor control in focal hand dystonia}},
author = {Joel Maamary and James Peters and Isabelle Osborne and Kain Kyle and Nicholas Olsen and Diane Ruge and Benjamin Jonker and Yael Barnett and Stephen Tisch},
journal = {Brain Communications},
year = {2026},
month = oct,
doi = {10.1093/braincomms/fcag403},
url = {https://doi.org/10.1093/braincomms/fcag403},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Focused ultrasound ventro-oral thalamotomy alters cortical excitability and motor control in focal hand dystonia
AU - Joel Maamary
AU - James Peters
AU - Isabelle Osborne
AU - Kain Kyle
AU - Nicholas Olsen
AU - Diane Ruge
AU - Benjamin Jonker
AU - Yael Barnett
AU - Stephen Tisch
PY - 2026
DA - 2026/10/23
JO - Brain Communications
DO - 10.1093/braincomms/fcag403
UR - https://doi.org/10.1093/braincomms/fcag403
AB - Focal hand dystonia is a disabling disorder characterized by task-specific abnormal involuntary movements that disrupt motor control. While the aetiology is unknown, abnormalities in sensory processing, sensorimotor organization, and maladaptive plasticity are thought to contribute to pathogenesis, with both genetic and environmental factors implicated. Current first-line treatments may provide only partial or transient relief. High-intensity focused ultrasound offers a means of focally ablating the target pathways implicated in dystonia. The ventro-oral complex, a relay within the motor thalamus, represents a key node in the corticobasal gangliathalamocortical circuit involved in directing motor output. Surgical radiofrequency lesioning of the Vo-complex confers sustained benefit in focal hand dystonia however the mechanisms that underlie this improvement remain unexplored. Pallidal intervention, via deep brain stimulation, has been shown to modify abnormal cortical motor plasticity in individuals with generalized dystonia, and this modification has been correlated with symptom improvement. It has been hypothesized that, to obtain long-term symptom improvement in focal hand dystonia, similar permanent network or circuit-based modification is required. In this prospective single-arm interventional study, we analysed the clinical and neurophysiological correlates of 11 individuals who underwent high-intensity focused ultrasound ventro-oral complex thalamotomy during 12 months follow-up. These measurements allowed us to identify the immediate and delayed impacts of ventro-oral thalamotomy on symptom burden, motor performance, motor cortex excitability, spatial specificity, and associative plasticity in individuals with focal hand dystonia. These findings were compared to 10 age and sex-matched healthy control participants. Consistent with our hypothesis, ventro-oral complex thalamotomy was associated with symptomatic improvement in focal hand dystonia as measured by standardized rating scales. There was no long-term loss of strength or motor dexterity in the treated limb, although adverse events were common and persisted in two participants. Inducible abnormalities in motor cortex excitability were attenuated following treatment and the spatial specificity of motor cortical responses shifted towards control values. Stimulus response curve analysis demonstrated modification of neuroplastic gain, echoing effects previously reported for pallidal stimulation in generalized dystonia. We concluded that ventro-oral complex thalamotomy may be associated with symptom improvement in focal hand dystonia and is associated with identifiable changes in motor cortex excitability. This work presents an opportunity for further studies to build on the identified mechanistic insights into single target lesioning, and advance the field of personalized circuit-informed strategies for the treatment of movement disorders.
SN - 2632-1297
ER -