VIM DBS Respiratory Modulation: N-of-1 Trial

Study Overview
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Brief Summary
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Research from our group has demonstrated modulation of PEFR in patients with STN and PAG stimulation. However, the effect of VIM (motor thalamus) stimulation remains to be investigated. Our group has also been involved in research that indicates that VIM stimulation may reduce perception of breathlessness. However, methodological factors limit the conclusions that can be drawn from this prior work. N-of-1 trials, organised as a randomised multiphase crossover design, are uniquely well suited for DBS research where stimulation can be switched ON and OFF, and with simple tests that can be done quickly, multiple times. PEFR and breath-holding are simple tests that we will test in this way. Other respiratory tests will be carried out along side, as optional, in a single phase design. We aim to offer this study to a continuous cohort of patients scheduled to undergo VIM (ET/DT) DBS at our institution. We will establish a pre-operative baseline of respiratory function, and then perform the n-of-1 trial post-operatively, soon after the patient returns to hospital to receive their DBS programming.

Official Title
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Respiratory Modulation by VIM Deep Brain Stimulation: N-of-1 Trial of Breath-holding and Peak Expiratory Flow

Conditions
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Essential Tremor, Dystonic Tremor

Intervention / Treatment
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* Procedure: VIM DBS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled for VIM DBS Diagnosis of ET or DT Exclusion Criteria: None

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ET VIM DBS patients<br>Essential tremor patients scheduled for VIM DBS | Procedure: VIM DBS<br>* Stereotactic deep brain stimulation of ventral intermediate nucleus of thalamus<br>|
| DT VIM DBS patients<br>Dystonic tremor patients scheduled for VIM DBS | Procedure: VIM DBS<br>* Stereotactic deep brain stimulation of ventral intermediate nucleus of thalamus<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Breath-hold (urge to breath) | Time from start of breath-hold to urge to breathe | 3 months post-operative, ON and OFF: randomised, cross over, 5-phase design | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Breath-hold (break point) | Time from start of breath-hold to breakpoint | 3 months post-operative, ON and OFF: randomised, cross over, 5-phase design | 
| Peak Expiratory Flow Rate | Maximum PEFR of three trials | 3 months post-operative, ON and OFF: randomised, cross over, 5-phase design | 
| Dyspnoea-12 Questionnaire | Difference in D12 score | Baseline and 3 months post-operative | 
| Oscillometry | Difference in airway resistance | Baseline and 3 months post-operative ON and OFF | 
| Maximum inspiratory pressure | Best MIP of three trials | Baseline and 3 months post-operative ON and OFF |