Abstract Details

Title Subthalamic Nucleus DBS Sub-harmonic Oscillatory Activity Reflect Presence or Absence of DBS Responsiveness

Topic Movement Disorders

Presentation(s) P1 - Poster Session 1 (8:00 AM-9:00 AM)

Poster/Presentation
Number 3-013

Objective To correlate DBS sub-harmonics with patient responsiveness and investigate neurophysiological mechanisms subserving DBS induced sub-harmonics.

Background DBS induced sub-harmonics have been observed in multiple studies, but the relationship of sub-harmonics to clinical outcomes and underlying neurophysiology is ill-defined.

Design/Methods Electrophysiological recordings and MDS-UPDRS III were performed in two DBS patients without dyskinesia biweekly during a 10-week exercise program. Testing was conducted under four conditions (Levodopa/DBS both ON and OFF) during baseline and final visits and ON/ON in the sessions between.

Results

P009 showed stimulation responsiveness in MDS-UPDRS III scores (55 OFF levodopa/OFF stimulation, 43 ON/OFF, 29 OFF/ON, 25 ON/ON), whereas P010 showed a similar response to medication but was less responsive to stimulation (57, 43, 45, 46). During baseline recordings, P009 (DBS 145 Hz) displayed increased spectral power in two subharmonic frequencies: ~108 Hz (¾ subharmonic, mean-0.086, SD-0.118) and ~72 Hz (½ subharmonic, mean-0.058, SD-0.079) OFF/ON levodopa/DBS. Increased spectral power at ~72 Hz (mean-0.025, SD-0.034) persisted in OFF/OFF. Increased spectral power at DBS sub-harmonic frequencies was not present under any condition in patient P010 (DBS 180 Hz)(mean-0.025, SD-0.0003).

P009 showed increased spectral power at ~108 Hz and ~72 Hz during sessions 1-4. Before session 5, DBS was clinically adjusted to 165 Hz. Increased spectral power was then present at the new subharmonic frequencies (~123 Hz and ~82 Hz) as well as at ~72 Hz (½ original DBS frequency). During the final session, increased spectral power was present at ~123 Hz and ~72 Hz with the patient OFF/OFF.

Conclusions DBS induced persistent oscillatory neural activity at DBS sub-harmonic frequencies that may serve as a biomarker for patient responsiveness to DBS therapy. DBS may activate natural resonance frequencies in the STN, or establish persistent oscillatory activity in neural circuitry through neural plasticity.

Authors/Disclosures
Bradley Greger, PhD PRESENTER	The institution of Prof. Greger has received research support from DoD. Prof. Greger has received intellectual property interests from a discovery or technology relating to health care.
Markey C. Olson, PhD-C (Barrow Neurological Institute)	Ms. Olson has nothing to disclose.
Sydney Felsen	No disclosure on file
Baltazar Zavala (Barrow Neurological Institute)	No disclosure on file
Sankardas Kariparambil Sudheesh	No disclosure on file
Holly A. Shill, MD, FAAN (Barrow Neurology Clinics)	Dr. Shill has received personal compensation in the range of $0-$499 for serving as a Consultant for Boston Scientific. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biovie. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sumitomo. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Encora. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Movement Disorders Society. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbvie. Dr. Shill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Guideline Central.
Francisco Ponce (Barrow Neurological Institute)	No disclosure on file
Sana Aslam, DO (University of Colorado)	Dr. Aslam has nothing to disclose.

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