Cognitive outcomes after focused ultrasound thalamotomy for tremor: Results from the COGNIFUS (COGNitive in Focused UltraSound) study

Clinical neurophysiology in the treatment of movement disorders: IFCN handbook chapter

In this review, different aspects of the use of clinical neurophysiology techniques for the treatment of movement disorders are addressed. First of all, these techniques can be used to guide neuromodulation techniques or to perform therapeutic neuromodulation as such. Neuromodulation includes invasive techniques based on the surgical implantation of electrodes and a pulse generator, such as deep brain stimulation (DBS) or spinal cord stimulation (SCS) on the one hand, and non-invasive techniques aimed at modulating or even lesioning neural structures by transcranial application. Movement disorders are one of the main areas of indication for the various neuromodulation techniques. This review focuses on the following techniques: DBS, repetitive transcranial magnetic stimulation (rTMS), low-intensity transcranial electrical stimulation, including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), and focused ultrasound (FUS), including high-intensity magnetic resonance-guided FUS (MRgFUS), and pulsed mode low-intensity transcranial FUS stimulation (TUS). The main clinical conditions in which neuromodulation has proven its efficacy are Parkinson's disease, dystonia, and essential tremor, mainly using DBS or MRgFUS. There is also some evidence for Tourette syndrome (DBS), Huntington's disease (DBS), cerebellar ataxia (tDCS), and axial signs (SCS) and depression (rTMS) in PD. The development of non-invasive transcranial neuromodulation techniques is limited by the short-term clinical impact of these techniques, especially rTMS, in the context of very chronic diseases. However, at-home use (tDCS) or current advances in the design of closed-loop stimulation (tACS) may open new perspectives for the application of these techniques in patients, favored by their easier use and lower rate of adverse effects compared to invasive or lesioning methods. Finally, this review summarizes the evidence for keeping the use of electromyography to optimize the identification of muscles to be treated with botulinum toxin injection, which is indicated and widely performed for the treatment of various movement disorders.

Staged magnetic resonance-guided focused ultrasound thalamotomy for the treatment of bilateral essential tremor and Parkinson's disease related tremor: a systematic review and critical appraisal of current knowledge

Introduction

Essential tremor (ET) and Parkinson's Disease (PD) are debilitating neurodegenerative disorders characterized by tremor as a predominant symptom, significantly impacting patients' quality of life. Magnetic Resonance-guided Focused Ultrasound (MRgFUS) Thalamotomy is an innovative therapeutic option for the treatment of unilateral medically refractory tremor with fewer adverse effects compared to traditional surgical interventions. A recent CE approval allows appropriate patients to have their second side treated.

Objective

The objective of this systematic review was to analyze available current knowledge about the use of MRgFUS for the treatment of bilateral ET and PD related tremor, to identify the effectiveness and the risks associated with bilateral treatment.

Methods

Eligible studies were identified by searching published studies in PubMed and Scopus databases from May 2014 to January 2024 and by identifying ongoing studies registered on the clinicaltrials.gov website. Data were summarized by considering the following information topics: the number of patients involved, the selected lesion target, the assessment tool used to evaluate clinical changes, the observed improvement, the reported side effects, and the time interval between the two treatments. The study was registered in PROSPERO (ID: CRD42024513178).

Results

Nine studies were eligible for this review, 7 for ET and 2 for PD. The involved population included a variable number of patients, ranging from 1 to 11 subjects for ET and from 10 to 15 subjects for PD. The main lesional targets were the ventral intermediate nucleus of the thalamus, the pallidothalamic tract and the cerebellothalamic tract bilaterally. All studies investigated the tremor relief through the Clinical Rating Scale for Tremor (CRST) in patients with ET, and through the Unified Parkinson's Disease Rating Scale (UPDRS) in patients with PD. A variable degree of improvement was observed, with all patients expressing overall satisfaction with the bilateral treatment. Adverse events were mild and transient, primarily involving gait disturbances, dysarthria, and ataxia. A standardized protocol for administering the two consecutive treatments was not identifiable; typically, the timing of the second treatment was delayed by at least 6 months.

Conclusion

Available evidence supports the effectiveness and safety of staged bilateral MRgFUS treatments for ET and PD-related tremor.

Cognitive safety of focused ultrasound thalamotomy for tremor: 1-year follow-up results of the COGNIFUS part 2 study

Introduction

In the COGNitive in Focused UltraSound (COGNIFUS) study, we examined the 6-month cognitive outcomes of patients undergoing MRgFUS thalamotomy. This study endorsed the safety profile of the procedure in terms of cognitive functions that cannot be evaluated in real-time during the procedure unlike other aspects. The aim of the COGNIFUS Part 2 study was to investigate the cognitive trajectory of MRgFUS patients over a 1-year period, in order to confirm long-term safety and satisfaction.

Methods

We prospectively evaluated the cognitive and neurobehavioral profile of patients with essential tremor (ET) or Parkinson's Disease (PD) related tremor undergoing MRgFUS thalamotomy at 1 year-follow-up following the treatment.

Results

The sample consists of 50 patients (male 76%; mean age ± SD 69.0 ± 8.56; mean disease duration ± SD 12.13 ± 12.59; ET 28, PD 22 patients). A significant improvement was detected at the 1 year-follow-up assessment in anxiety and mood feelings (Hamilton Anxiety rating scale 5.66 ± 5.02 vs. 2.69 ± 3.76, p ≤ <0.001; Beck depression Inventory II score 3.74 ± 3.80 vs. 1.80 ± 2.78, p = 0.001), memory domains (Rey Auditory Verbal Learning Test, immediate recall 31.76 ± 7.60 vs. 35.38 ± 7.72, p = 0.001 and delayed recall scores 5.57 ± 2 0.75 vs. 6.41 ± 2.48), frontal functions (Frontal Assessment Battery score 14.24 ± 3.04 vs. 15.16 ± 2.74) and in quality of life (Quality of life in Essential Tremor Questionnaire 35.00 ± 12.08 vs. 9.03 ± 10.64, p ≤ 0.001 and PD Questionnaire -8 7.86 ± 3.10 vs. 3.09 ± 2.29, p ≤ 0.001).

Conclusion

Our study supports the long-term efficacy and cognitive safety of MRgFUS treatment for ET and PD.

Efficacy and safety of magnetic resonance-guided focused ultrasound for Parkinson's disease: a systematic review and meta-analysis

Objective

Magnetic resonance imaging-guided focused ultrasound (MRgFUS) is a novel noninvasive treatment for drug-resistant Parkinson's disease (PD) related tremor. This study aims to evaluate MRgFUS's efficacy and safety in PD through a systematic review and meta-analysis, examining pre-and post-treatment MDS-UPDRSIII and/or CRST scores and associated adverse events.

Materials and methods

We conducted an extensive literature search across PubMed, Embase, Web of Science, and Cochrane Library databases, screening studies based on set criteria and analyzing MDS-UPDRSIII, CRST, and adverse events pre- and post-MRgFUS treatment.

Results

Out of 468 retrieved articles, 20 studies involving 258 patients, spanning 2014-2023, were included.17 studies indicated significant MDS-UPDRSIII score reductions post-MRgFUS treatment, while 3 showed significant CRST score declines. In the "on" medication state, pooled MDS-UPDRSIII scores at 1, 3, 6, and 12 months were 12.18 (95% CI: 5.83-18.52), 12.10 (95% CI: 8.22-15.97), 14.85 (95% CI: 9.28-20.41), and 20.65 (95% CI: 12.15-29.14) respectively. In the "off" state, scores were 11.45 (95% CI: -3.50-26.40), 14.71 (95% CI: 4.95-24.46), 21.52 (95% CI: 19.28-23.75), and 22.28 (95% CI: 15.26-29.30). Adverse events were typically mild and transient, with speech disturbances, ataxia, and sensory abnormalities being common post-operative neurological complications.

Conclusion

MRgFUS offers an effective and relatively safe treatment option for patients with drug-resistant PD-related tremor.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, No. CRD42023428332.

Magnetic Resonance-guided Focused Ultrasound thalamotomy for refractory neuropathic pain: a systematic review and critical appraisal of current knowledge

Background

Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is an innovative therapeutical approach for medically refractory tremor. It is currently under investigation for other neurological diseases including refractory neuropathic pain (NP).

Objective

The objective of this systematic review is to analyze available evidence about the effectiveness and safety profile of MRgFUS in the treatment of refractory NP.

Methods

Eligible studies were identified by searching published studies in PubMed and Scopus databases from inception to December 2022 and by identifying ongoing studies registered on the clinicaltrials.gov website. The study was registered in PROSPERO (ID: CRD42021277154).

Results

We found three published observational studies and nine ongoing studies. In published studies, the involved population ranged from 8 to 46 patients with overall 66 patients being included with NP or trigeminal neuralgia. The target lesion was in the posterior part of the central lateral nucleus of the thalamus, bilaterally. Outcomes were assessed at different times through the Visual Analog Scale, showing a variable degree of improvement. Adverse events were rare, mild, and transient (vertigo, paresthesias, and dysesthesias) with intracerebral bleeding being reported as major adverse event in one case only. Among ongoing studies, we found three prospective, randomized, sham-controlled, crossover trials (RCTs) and six observational studies. Inclusion criteria are previous failure of more than three pharmacological treatments and NP duration longer than 6 months. The thalamus is the main proposed target and measured outcomes are accuracy of the procedure and pain relief, with a follow-up period ranging from 1 week to 1 year.

Conclusion

This systematic review suggests that, although high-quality studies are lacking, available evidence endorses the effectiveness and safety of MRgFUS in the management of NP. Ongoing RCTs will provide more robust data to understand benefits and risks of the procedure.

Registration

PROSPERO (ID: CRD42021277154).