Intraoperative Localization of the Subthalamic Nucleus Using Long-Latency Somatosensory Evoked Potentials.

BACKGROUND: Target localization for deep brain stimulation (DBS) is a challenging step that determines not only the correct placement of stimulation electrodes, but also influences the success of the DBS procedure as reflected in the desired clinical outcome of a patient. OBJECTIVE: We report on the feasibility of DBS target localization in the subthalamic nucleus (STN) by long-latency somatosensory evoked potentials (LL-SSEPs) (>40 msec) in Parkinson's disease (PD) patients. METHODS: Micro-macroelectrode recordings were performed intraoperatively on seven PD patients (eight STN hemispheres) who underwent DBS treatment. LL-SSEPs were elicited by ipsi- and contralateral median nerve stimulation to the wrist. RESULTS: Four distinctive LL-SSEP components were elicited ("LL-complex" consisting of P80, N100, P140, and N200). The P80 appeared as the most visible and reliable intraoperative component. Localization of the "LL-complex" within the target was approved with typical microelectrode firing activity patterns, atlas visualization of recording electrodes, and postoperative CT-based visualization of final DBS electrodes. CONCLUSIONS: LL-SSEPs represent a promising approach for DBS target localization in the STN, provided deeper understanding on their anesthesia effect is obtained. This approach is advantageous in that it does not require the patient's participation in an intraoperative setting.

Correction: Long-Latency Somatosensory Evoked Potentials of the Subthalamic Nucleus in Patients with Parkinson's Disease.

[This corrects the article DOI: 10.1371/journal.pone.0168151.].

Long-Latency Somatosensory Evoked Potentials of the Subthalamic Nucleus in Patients with Parkinson's Disease.

Somatosensory evoked potentials (SSEPs) are a viable way to measure processing of somatosensory information. SSEPs have been described at the scalp and the cortical level by electroencephalographic, magnetoencephalographic and intracranial cortical recordings focusing on short-latency (SL; latency<40 ms) and long-latency (LL; latency>40 ms) SSEPs as well as by deep brain stimulation (DBS) electrode studies targeting SL-SSEPs. Unfortunately, LL-SSEPs have not been addressed at the subcortical level aside from the fact that studies targeting the characteristics and generators of SSEPs have been neglected for the last ten years. To cope with these issues, we investigated LL-SSEPs of the subthalamic nucleus (STN) in twelve patients with Parkinson's disease (PD) that underwent deep brain stimulation (DBS) treatment. In a postoperative setting, LL-SSEPs were elicited by median nerve stimulation (MNS) to the patient's wrists. Ipsilateral or contralateral MNS was applied with a 3 s inter-stimulus interval. Here, we report about four distinctive LL-SSEPs ("LL-complex" consisting of P80, N100, P140 and N200 component), which were recorded by using monopolar/bipolar reference and ipsi/contralateral MNS. Phase reversal and/or maximum amplitude provided support for the generation of such LL-SSEPs within the STN, which also underscores a role of this subcortical structure in sensory processing.

Local field potential oscillations of the globus pallidus in cervical and tardive dystonia.

BACKGROUND: Reports about neural oscillatory activity in the globus pallidus internus (GPi) have targeted general (GD) and cervical dystonia (CD), however to our knowledge they are nonexistent for tardive dystonia (TD). METHODS: Local field potentials (LFPs) from seven CD and five TD patients were recorded intraoperatively. We compared LFP power in thetadelta, alpha and beta band during rest and sensory palmar stimulation (SPS) in patients with general anesthesia and local/analgo sedation. RESULTS: We found prominent LFP power activity in thetadelta for both CD and TD. Unlike TD, a significant difference between rest and SPS was revealed for CD. CONCLUSIONS: Our data support the presence of LFP oscillatory activity in CD and TD. Thetadelta power modulation in the GPi is suggested as a signature for sensory processing in CD.