Mahsa Malekmohammadi1, Hiro Sparks1, Nicholas AuYong1, Andrew Hudson2, Nader Pouratian1,3,4. 1. Department of Neurosurgery, University of California, Los Angeles, California, USA. 2. Department of Anesthesiology, University of California, Los Angeles, California, USA. 3. Neuroscience Interdepartmental Program, University of California, Los Angeles, California, USA. 4. Brain Research Institute, University of California, Los Angeles, California, USA.
Abstract
BACKGROUND/AIMS: There are reports that microelectrode recording (MER) can be performed under certain anesthetized conditions for functional confirmation of the optimal deep brain stimulation (DBS) target. However, it is generally accepted that anesthesia affects MER. Due to a potential role of local field potentials (LFPs) in DBS functional mapping, we characterized the effect of propofol on globus pallidus interna (GPi) and externa (GPe) LFPs in Parkinson disease (PD) patients. METHODS: We collected LFPs in 12 awake and anesthetized PD patients undergoing DBS implantation. Spectral power of β (13-35 Hz) and high-frequency oscillations (HFOs: 200-300 Hz) was compared across the pallidum. RESULTS: Propofol suppressed GPi power by > 20 Hz while increasing power at lower frequencies. A similar power shift was observed in GPe; however, power in the high β range (20-35 Hz) increased with propofol. Before anesthesia both β and HFO activity were significantly greater at the GPi (χ2 = 20.63 and χ2 = 48.81, p < 0.0001). However, during anesthesia, we found no significant difference across the pallidum (χ2 = 0.47, p = 0.79, and χ2 = 4.11, p = 0.12). CONCLUSION: GPi and GPe are distinguishable using LFP spectral profiles in the awake condition. Propofol obliterates this spectral differentiation. Therefore, LFP spectra cannot be relied upon in the propofol-anesthetized state for functional mapping during DBS implantation.
BACKGROUND/AIMS: There are reports that microelectrode recording (MER) can be performed under certain anesthetized conditions for functional confirmation of the optimal deep brain stimulation (DBS) target. However, it is generally accepted that anesthesia affects MER. Due to a potential role of local field potentials (LFPs) in DBS functional mapping, we characterized the effect of propofol on globus pallidus interna (GPi) and externa (GPe) LFPs in Parkinson disease (PD) patients. METHODS: We collected LFPs in 12 awake and anesthetized PDpatients undergoing DBS implantation. Spectral power of β (13-35 Hz) and high-frequency oscillations (HFOs: 200-300 Hz) was compared across the pallidum. RESULTS:Propofol suppressed GPi power by > 20 Hz while increasing power at lower frequencies. A similar power shift was observed in GPe; however, power in the high β range (20-35 Hz) increased with propofol. Before anesthesia both β and HFO activity were significantly greater at the GPi (χ2 = 20.63 and χ2 = 48.81, p < 0.0001). However, during anesthesia, we found no significant difference across the pallidum (χ2 = 0.47, p = 0.79, and χ2 = 4.11, p = 0.12). CONCLUSION:GPi and GPe are distinguishable using LFP spectral profiles in the awake condition. Propofol obliterates this spectral differentiation. Therefore, LFP spectra cannot be relied upon in the propofol-anesthetized state for functional mapping during DBS implantation.