Propofol Anesthesia Precludes LFP-Based Functional Mapping of Pallidum during DBS Implantation

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.

Neurophysiological Characterization of Posteromedial Hypothalamus in Anaesthetized Patients

“…However, the exact degree of the effect remains unclear. Nevertheless, the mean frequency and other electrophysiological properties, such as local field potentials [ 32 , 33 ], are modified by anesthesia. Therefore, it is reasonable to identify lower values of frequency discharge in anaesthetized versus awake patients.…”

Neurophysiological Characterization of Thalamic Nuclei in Epileptic Anaesthetized Patients

“…From a methodological viewpoint, it is important to consider that all patients were under general anesthesia, and this condition can modify neuronal discharge features and perhaps the synaptic functions of some thalamic nuclei [32], but the exact degree of the effect remains to be elucidated. However, it is known that the mean frequency discharge (a useful variable during MERs) [16,17,18,33] and other electrophysiological properties, such as local field potentials [34], are affected by anesthesia. However, there is evidence in a study of DBS of the subthalamic nucleus (STN) that localization with MER and patient comfort can be achieved with equal effectiveness in patients under generalized anesthesia compared with that in awake patients [35].…”

Neural Circuit and Clinical Insights from Intraoperative Recordings During Deep Brain Stimulation Surgery

“…General anesthesia is widely accepted to be associated with a decreased neuronal spiking rate in the STN of DBS patients, although this has been debated [129,130]. LFP appear to be more susceptible to anesthesia, as a recent study by Malekmouhammadi et al has demonstrated diminished relative power differences in beta oscillation and high-frequency oscillation in LFP recorded from the GPi of asleep patients compared to awake patients [131]. Authors reported that the differences in LFP between the GPe and GPi were all but obliterated under general anesthesia, severely limiting the potential of LFP as an aid in intraoperative targeting [131].…”