title: Subthalamic local field potentials in Parkinson's disease and isolated dystonia: An evaluation of potential biomarkers.
abstract: Local field potentials (LFP) recorded from the subthalamic nucleus in patients with Parkinson's disease (PD) demonstrate prominent oscillations in the beta (13-30 Hz) frequency range, and reduction of beta band spectral power by levodopa and deep brain stimulation (DBS) is correlated with motor symptom improvement. Several features of beta activity have been theorized to be specific biomarkers of the parkinsonian state, though these have rarely been studied in non-parkinsonian conditions. To compare resting state LFP features in PD and isolated dystonia and evaluate disease-specific biomarkers, we recorded subthalamic LFPs from 28 akinetic-rigid PD and 12 isolated dystonia patients during awake DBS implantation. Spectral power and phase-amplitude coupling characteristics were analyzed. In 26/28 PD and 11/12 isolated dystonia patients, the LFP power spectrum had a peak in the beta frequency range, with similar amplitudes between groups. Resting state power did not differ between groups in the theta (5-8 Hz), alpha (8-12 Hz), beta (13-30 Hz), broadband gamma (50-200 Hz), or high frequency oscillation (HFO, 250-350 Hz) bands. Analysis of phase-amplitude coupling between low frequency phase and HFO amplitude revealed significant interactions in 19/28 PD and 6/12 dystonia recordings without significant differences in maximal coupling or preferred phase. Two features of subthalamic LFPs that have been proposed as specific parkinsonian biomarkers, beta power and coupling of beta phase to HFO amplitude, were also present in isolated dystonia, including focal dystonias. This casts doubt on the utility of these metrics as disease-specific diagnostic biomarkers.
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA. Electronic address: Doris.Wang@ucsf.edu.
authors.forename: Doris D
authors.initials: DD
authors.lastname: Wang
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA. Electronic address: Coralie.Dehemptinne@ucsf.edu.
authors.forename: Coralie
authors.initials: C
authors.lastname: de Hemptinne
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, CA, USA. Electronic address: Svjetlana.Miocinovic@ucsf.edu.
authors.forename: Svjetlana
authors.initials: S
authors.lastname: Miocinovic
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA. Electronic address: Salman.Qasim@columbia.edu.
authors.forename: Salman E
authors.initials: SE
authors.lastname: Qasim
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA. Electronic address: Andrew.Miller@ucsf.edu.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Miller
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, CA, USA. Electronic address: Jill.Ostrem@ucsf.edu.
authors.forename: Jill L
authors.initials: JL
authors.lastname: Ostrem
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, CA, USA. Electronic address: Nicholas.Galifianakis@ucsf.edu.
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Galifianakis
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, CA, USA. Electronic address: Marta.SanLucianoPalenzuela@ucsf.edu.
authors.forename: Marta
authors.initials: M
authors.lastname: San Luciano
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA. Electronic address: Philip.Starr@ucsf.edu.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Starr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001611:Beta Rhythm; D015415:Biomarkers; D058256:Brain Waves; D004421:Dystonia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted; D020531:Subthalamic Nucleus / Q000503:physiopathology*
chemical_list: D015415:Biomarkers
keywords: Beta oscillation; Cross frequency interaction; Deep brain stimulation; Electrophysiology; Phase amplitude coupling