Rationale: Deep brain stimulation (DBS) is an effective treatment for essential tremor and Parkinson's disease. The effect of DBS relies on the modulation of dysfunctional motor brain networks and on average 50% motor improvement is achieved, using standardized motor evaluation scores. However, approximately 20% of treated patients show insufficient benefit, with less than 30% improvement. To improve outcomes through better electrode placement and selection of DBS electrical parameter programming, more advanced visualization of motor networks is needed; both anatomical (7-Tesla MRI) and functional (magnetoencephalography, MEG). Current DBS implantations are based on 1.5- or 3- Tesla MR scans. The resolution of these scans is not sufficient to visualize brain networks, preventing electrode placement directed at motor parts within the brain nucleus. In addition to the 7-Tesla MRI guided electrode placement, by applying MEG, programming will be directed at influencing the cortical motor areas, resulting in an overall decrease in dysfunctional network activity.
Objective: Primary objective of the study is to determine whether brain network visualization using 7T MRI and MEG improves motor symptoms as measured by the disease-specific Unified Parkinson's Disease Rating Scale (UPDRS-III) and Tremor Assessment Rating Scale (TETRAS); and quality of life as measured by the Parkinson's Disease Questionnaire 39 (PDQ-39). Secondary outcomes are: disease related daily functioning, adverse effects, operation time, quality of life (QUEST), patient satisfaction with treatment outcome and patient evaluation of treatment burden.
Study design: Single-center, prospective study with repeated measures; standardized assessments of motor skills and quality of life (UPDRS-III, TETRAS, PDQ-39) after DBS placement will be compared with scores after adjustments based on network analyses.
Study population: Enrollment will be ongoing from April 2024.
Intervention (if applicable): Patients with DBS for a minimum of six months will undergo an additional MEG scan. Application of 7T MRI for DBS is standard care and outcome scores used will be readily accessible from the already existing advanced electronic DBS database.
Main study parameters/endpoints: The co-primary outcome measures are the change in motor symptoms (measured by the UPDRS-III,TETRAS) and quality of life (measured by the PDQ-39). This is measured as part of standard care. The secondary outcome measures are the Amsterdam Linear Disability Score for functional health status, Starkstein apathy scale, Quality of Life Questionnaire in Essential Tremor (QUEST), patient satisfaction with the treatment, patient evaluation of treatment burden, operating time, hospitalization time, change of tremor medication, side effects and complications. The primary and secondary outcome scores are already stored in our advanced electronic DBS database.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The 7-Tesla MRI and MEG protocols (including stimulation parameters) already developed by our group and reported in (five) studies will be applied. After selecting the best DBS programming, the aim is to optimize DBS outcome by: a) increasing the mean improvement in motor function and quality of life by at least 10% and b) achieving a minimum of 30% improvement in motor function for each patient (measured by standardized assessment of motor function and quality of life). The proposed research project involves treatment options that are non-invasive and/or part of standard care in daily practice. The therapies will not be combined with other research products. Participation in this study constitutes negligible risk according to NFU criteria for human research.
Age > 18 years;
Idiopathic PD/ET with at least six months of DBS
Underwent a preoperative 7-Tesla MRI scan
Legally incompetent adults;
No written informed consent.
A spinal stimulation or deep brain stimulation system is not compatible with 7-Tesla MRI
There a no implants inadmissible in the MEG, although patients will be questioned for possible (non-removable) implants such as pacemakerand/or dental as they may interfere with the magnetic signals
Single group
magnetoencephalography
Other intervention500 patients with Parkinson's disease and essential tremor will undergo magnetoencephalography
Essential Tremor Rating Assessment Scale (TETRAS)
The amount of decrease in motor symptoms indicated by change in the disease-specific Essential Tremor Rating Assessment Scale (TETRAS) after six months of deep brain stimulation. The TETRAS scores are between 0 and 64; higher scores indicating worse (more severe) tremor symptoms.
Unified Parkinson's Disease Rating Scale (UPDRS-III)
The amount of decrease in motor symptoms indicated by change in the disease-specific Unified Parkinson's Disease Rating Scale (UPDRS-III) after six months of deep brain stimulation. The UPDRS-III scores are between 7 and 86; higher scores indicating worse (more severe) motor symptoms.
Parkinson's disease questionnaire-39
The Parkinson's Disease Questionnaire (PDQ-39) assesses how often people with Parkinson's experience difficulties across 8 dimensions of daily living including relationships, social situations and communication. It also assesses the impact of Parkinson's on specific dimensions of functioning and wellbeing. The scores are between 0 and 100 (the sum of all 39 items), higher score indicating more health problems.
The Amsterdam Linear Disability Score for functional health status
The Amsterdam Linear Disability Score (ALDS) is a generic itembank which measures disability, as expressed by the ability to perform activities of daily living. These scores are linearly transformed into values between 0 and 100. Lower scores indicate more disability.
Starkstein apathy scale
The 14-item Starkstein Apathy Scale (SAS) is used to measure the severity of apathetic symptoms in Parkinson disease. The scores are between 0 and 42. Higher scores indicating worse apathy.
Quality of Life in Essential Tremor Questionnaire
The Quality of Life in Essential Tremor Questionnaire (QUEST) is a 30-item scale developed specifically for patients with essential tremor to measure items impacting perceived quality of life (QOL) that generic QOL measures do not effectively capture, including activities of daily living that are affected by essential tremor. The QUEST was made to be relatively brief and easy for patients to use.
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