Evaluation of the efficacy and safety of MRI-guided focused ultrasound (MRgFUS) for focal hand dystonia: study protocol for an open-label non-randomised clinical trial

Increased functional connectivity of motor regions and dorsolateral prefrontal cortex in musicians with focal hand dystonia

BACKGROUND

Musician's dystonia is the most common form of focal task-specific dystonia and is suggested to be the result of dysfunctional communication among sensory-motor networks. Thus far, few functional connectivity studies have investigated musician's dystonia specifically, leaving its exact pathophysiological mechanisms unclear. The goal of this study was to verify connectivity findings from other task-specific dystonias on a large sample of musician's hand dystonia patients and to analyze associations with possible adverse childhood experiences, a suggested risk factor for dystonia.

METHODS

Forty professional musicians suffering from musician's hand dystonia and a matched control group of healthy musicians underwent resting-state functional magnetic resonance imaging and answered the childhood trauma questionnaire. Using a seed-to-whole brain approach, functional connectivity alterations between motor cortices, the prefrontal cortex, the basal ganglia and the thalamus were analyzed.

RESULTS

Musician's dystonia patients showed increased functional connectivity of the dorsolateral prefrontal cortex with the putamen and the pallidum, especially in right-side affected patients. Patients further displayed increased connectivity of the left thalamus and the right lateral premotor cortex. No associations between functional connectivity, duration of disorder and childhood adversity were observed.

CONCLUSION

The findings are consistent with previous research, highlighting the pathophysiological importance of the basal ganglia. Altered resting-state functional connectivity may reflect underlying neuroplastic changes in musicians with dystonia that lead to an altered flow of information, disrupting movement inhibition. Involvement of the dorsolateral prefrontal and premotor cortices further suggests that motor disturbances occur in the early planning phase of a movement. The findings indicate that a holistic re-training approach with and without the instrument could be beneficial for regaining motor control.

The Use of Focused Ultrasound Ablation for Movement Disorders

Focused ultrasound ablation achieves selective thermal lesioning of the thalamic and basal ganglia targets using real-time MR imaging guidance. It is US Food and Drug Administration-approved to treat essential tremor and Parkinson's disease tremor, fluctuations, and dyskinesias. Patients often seek focused ultrasound treatment because symptom relief is immediate, and hardware implantation is not required. This review summarizes the current and potential future application of focused ultrasound ablation to treat movement disorders. We also discuss the ongoing research optimizing the technique of focused ultrasound ablation to improve long-term efficacy and minimize the risk of side effects.

Update on musculoskeletal applications of magnetic resonance-guided focused ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive, incisionless, radiation-free technology used to ablate tissue deep within the body. This technique has gained increased popularity following FDA approval for treatment of pain related to bone metastases and limited approval for treatment of osteoid osteoma. MRgFUS delivers superior visualization of soft tissue targets in unlimited imaging planes and precision in targeting and delivery of thermal dose which is all provided during real-time monitoring using MR thermometry. This paper provides an overview of the common musculoskeletal applications of MRgFUS along with updates on clinical outcomes and discussion of future applications.