Effects of Dexmedetomidine on Activity in the Subthalamic Nucleus

Study Overview
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Brief Summary
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The purpose of this research study is to find out whether dexmedetomidine changes brain cell activity in the subthalamic nucleus (STN).

Detailed Description
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In order to find whether dexmedetomidine is optimal for sedation during Deep brain stimulation surgery, we will measure the electrical activity in the STN during Deep brain stimulation surgery, and measure how this activity is changed during administration of Dexmedetomidine. We hypothesize that dexmedetomidine does not change the firing rate and pattern in the STN.

Official Title
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Effects of Dexmedetomidine on Neuronal Activity in the Subthalamic Nucleus During Deep Brain Stimulation (DBS) Electrode Implantation Surgery

Conditions
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Parkinson's Disease, Deep Brain Stimulation Surgery

Intervention / Treatment
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* Drug: Dexmedetomidine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients scheduled to undergo bilateral STN electrode implantation surgery with Micro-electrode recording for the treatment of Parkinson's disease. Exclusion Criteria: Hypersensitivity to dexmedetomidine Bradycardia: Sinus rhythm slower than 50 bpm Known or suspected obstructive sleep apnea Suspected difficult intubation Pregnancy Under 18 years of age or over 85 years of age Cognitive disability impairing understanding the experiment or signing the informed consent form

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexmedetomidine during MER<br>The study is performed in patients undergoing DBS electrode implantation to their STN for the treatment of parkinson's disease. Microelectrode recording (MER) is performed as part of STN electrode implantation surgery, to increase the precision of the stimulating electrode placement. The study includes administration of dexmedetomidine while recording electrical activity at a single location to evaluate the effects of this drug on the MER. | Drug: Dexmedetomidine<br>* Dexmedetomidine infusion will be started with a loading dose of 1 mcg/Kg over ten to 20 minutes followed by a maintenance infusion of 0.7 mcg/Kg/hr until stable sedation is achieved.<br>* Other names: Precedex;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Average Population Spiking Activity | We calculated the root mean square (RMS) of the high frequency electrical activity. This is a common measure for the spiking rate of the population of neurons in the vicinity of the electrode tip. This Measure has been previously described as a useful measure to determine the target location during deep brain stimulation (DBS) procedures. We calculated the change in RMS inside the STN between baseline and peak sedation. For each subject we normalized the RMS to the RMS of the electrical activity outside the nucleus. This is done to eliminate the effects of noise and variability in electrode resistance. Thus, the normalized RMS is a pure number with no units. | 20-35 minutes following drug administration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Average Firing Pattern in the STN | We've used total power in the Beta range (13-30Hz) to evaluate change in firing pattern and oscillation frequency. | 20-35 minutes following drug administration | 
| Time to Recovery | The time it takes for the patient to become alert after drug administration is stopped. | 20-60 minutes after stopping drug administration | 
| Portion of Participants With Timely Return of the Neuronal Activity to Baseline | The portion of patients in which neuronal activity returned to baseline within 30 after stopping sedation. | 30 minutes after stopping drug administration | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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SubThalamic Nucleus, Microelectrode recording, Deep Brain Stimulation Electrode implantation