BACKGROUND: Models have been developed for predicting ideal contact and amplitude for subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson disease (PD). Pulse-width is generally varied to modulate the size of the energy field produced. Effects of varying frequency in humans have not been systematically evaluated. OBJECTIVE: To examine how altered frequencies affect blood oxygen level-dependent activation in PD. METHODS: PD subjects with optimized DBS programming underwent functional magnetic resonance imaging (fMRI). Frequency was altered and fMRI scans/Unified Parkinson Disease Rating Scale motor subunit (UPDRS-III) scores were obtained. Analysis using DBS-OFF data was used to determine which regions were activated during DBS-ON. Peak activity utilizing T-values was obtained and compared. RESULTS: At clinically optimized settings (n = 14 subjects), thalamic, globus pallidum externa (GPe), and posterior cerebellum activation were present. Activation levels significantly decreased in the thalamus, anterior cerebellum, and the GPe when frequency was decreased (P < .001). Primary somatosensory cortex activation levels significantly decreased when frequency was increased by 30 Hz, but not 60 Hz. Sex, age, disease/DBS duration, and bilaterality did not significantly affect the data. Retrospective analysis of fMRI activation patterns predicted optimal frequency in 11/14 subjects. CONCLUSION: We show the first data with fMRI of STN DBS-ON while synchronizing cycling with magnetic resonance scanning. At clinically optimized settings, an fMRI signature of thalamic, GPe, and posterior cerebellum activation was seen. Reducing frequency significantly decreased thalamic, GPe, and anterior cerebellum activation. Current standard-of-care programming can take up to 6 mo using UPDRS-III testing alone. We provide preliminary evidence that using fMRI signature of frequency may have clinical utility and feasibility.

Background Deep brain stimulation (DBS) is a well-accepted treatment of Parkinson's disease (PD). Motor phenotypes include tremor-dominant (TD), akinesia-rigidity (AR), and postural instability gait disorder (PIGD). The mechanism of action in how DBS modulates motor symptom relief remains unknown. Objective Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to determine whether the functional activity varies in response to DBS depending on PD phenotypes. Materials and Methods Subjects underwent an fMRI scan with DBS cycling ON and OFF. The effects of DBS cycling on BOLD activation in each phenotype were documented through voxel-wise analysis. For each region of interest, ANOVAs were performed using T-values and covariate analyses were conducted. Further, a correlation analysis was performed comparing stimulation settings to T-values. Lastly, T-values of subjects with motor improvement were compared to those who worsened. Results As a group, BOLD activation with DBS-ON resulted in activation in the motor thalamus (p < 0.01) and globus pallidus externa (p < 0.01). AR patients had more activation in the supplementary motor area (SMA) compared to PIGD (p < 0.01) and TD cohorts (p < 0.01). Further, the AR cohort had more activation in primary motor cortex (MI) compared to the TD cohort (p = 0.02). Implanted nuclei (p = 0.01) and phenotype (p = <0.01) affected activity in MI and phenotype alone affected SMA activity (p = <0.01). A positive correlation was seen between thalamic activation and pulse-width (p = 0.03) and between caudate and total electrical energy delivered (p = 0.04). Conclusions These data suggest that DBS modulates network activity differently based on patient motor phenotype. Improved understanding of these differences may further our knowledge about the mechanisms of DBS action on PD motor symptoms and to optimize treatment.

BACKGROUND: Chronic pain occurs in 83% of Parkinson disease (PD) patients and deep brain stimulation (DBS) has shown to result in pain relief in a subset of patients, though the mechanism is unclear. OBJECTIVE: To compare functional magnetic resonance imaging (MRI) data in PD patients with chronic pain without DBS, those whose pain was relieved (PR) with DBS and those whose pain was not relieved (PNR) with DBS. METHODS: Functional MRI (fMRI) with blood oxygen level-dependent activation data was obtained in 15 patients in control, PR, and PNR patients. fMRI was obtained in the presence and absence of a mechanical stimuli with DBS ON and DBS OFF. Voxel-wise analysis using pain OFF data was used to determine which regions were altered during pain ON periods. RESULTS: At the time of MRI, pain was scored a 5.4 1.2 out of 10 in the control, 4.25 +/- 1.18 in PNR, and 0.8 +/- 0.67 in PR cohorts. Group analysis of control and PNR groups showed primary somatosensory (SI) deactivation, whereas PR patients showed thalamic deactivation and SI activation. DBS resulted in more decreased activity in PR than PNR (P < .05) and more activity in anterior cingulate cortex (ACC) in PNR patients (P < .05). CONCLUSION: Patients in the control and PNR groups showed SI deactivation at baseline in contrast to the PR patients who showed SI activation. With DBS ON, the PR cohort had less activity in SI, whereas the PNR had more anterior cingulate cortex activity. We provide pilot data that patients whose pain responds to DBS may have a different fMRI signature than those who do not, and PR and PNR cohorts produced different brain responses when DBS is employed.

BACKGROUND:Chronic pain causes a significant burden to the US health care system, is difficult to treat, and remains a significant contributor to increased opioid use in the United States. Spinal cord stimulation (SCS) has been FDA approved for the treatment of chronic pain. OBJECTIVE:To evaluate the hypothesis that SCS reduces opioid use, and alone maintains clinical outcome measures of pain and psychosocial determinants of health. METHODS:In this prospective cohort study, we evaluated 86 patients undergoing SCS surgery for the treatment of chronic pain between September 2012 and August 2015. Preoperatively and postoperatively, patients completed the Numerical Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Pain Catastrophizing Scale (PCS), Oswestry Disability Index (ODI), and Beck's Depression Inventory (BDI). VAS scores were retrospectively analyzed. RESULTS:Fifty-three patients used opioids before SCS implantation. The 33 nonusers had lower mean VAS, NRS, and ODI scores than both opioid groups at 1 yr and improved significantly at 1 yr on the VAS (P < .001), NRS (P < .001), MPQ (P = .002), PCS (P < .001), BDI (P = .04), and ODI (P = .002). After surgery, 41.5% remained opioids and 58.5% reduced/eliminated use. Discontinued (n = 29) or reduced (n = 2) use resulted in VAS, NRS, total MPQ, and ODI score reduction (P < .001, P = .002, P = .002, and P = .009 respectively). At 1 yr, survey scores in opioid users were unchanged. There was no difference between groups in revision or failure rates. CONCLUSION:Sixty-four percent of patients who were using opioids prior to SCS reduced (n = 2) or eliminated opioid use (n = 29) at 1 yr postoperatively. Patients who eliminated opioid use or never used opioids had superior clinical outcomes to those who continued use.

BACKGROUND:Newer generation deep brain stimulation (DBS) systems have recently become available in the United States. Data on real-life experience are limited. We present our initial experience incorporating newer generation DBS with Parkinson's disease (PD) and essential tremor (ET) patients. Newer systems allow for smart energy delivery and more intuitive programming and hardware modifications including constant current and directional segmented contacts.METHODS:We compared six-month outcomes between 42 newer generation and legacy leads implanted in 28 patients. Two cohorts each included 7 PD patients with bilateral subthalamic nucleus (STN) stimulation and 7 ET patients with unilateral ventral intermediate nucleus (VIM) stimulation of the thalamus. All directional leads included 6172 Infinity 8-Channel Directional leads and Infinity internal pulse generators (Abbott Neuromodulation, Plano, TX, USA) and nondirectional leads included lead 3389 with Activa SC for VIM and PC for STN (Medtronic, Minneapolis, MN, USA).RESULTS:Six-month outcomes for medication reduction and motor score improvements between new and legacy DBS systems in PD and ET patients were similar. Directionality was employed in 1/3 of patients. Therapeutic window (difference between amplitude when initial symptom relief was obtained and when intolerable side effects appeared with the contact being used) was significantly greater in new DBS systems in both PD (p = 0.005) and ET (p = 0.035) patients. The windows for new and legacy systems were 3.60 V ± 0.42 and 2.00 V ± 0.32 for STN and 3.06 V ± 0.44 and 1.85 V ± 0.28 for VIM, respectively.DISCUSSION:The therapeutic window of newer systems, whether or not directionality was used, was significantly greater than that of the legacy system, which suggests increased benefit and programming options. Improvements in hardware and programming interfaces in the newer systems may also contribute to wider therapeutic windows. We expect that as we alter workflow associated with newer technology, more patients will use directionality, and amplitudes will become lower.

Background: Most fMRI studies on pain perception utilized thermal stimuli due to the lack of a non-metallic reliable, reproducible mechanical stimulus. We explored 2 potential MR compatible mechanical devices and validated one that induced changes on fMRI. Purpose: To validate a noxious mechanical stimulus MR compatible device in a healthy cohort and a chronic pain cohort. Further to ensure this device caused changes on fMRI compared to a pressure device. Methods: Two-healthy controls underwent fMRI scans in the presence/absence of mechanical noxious stimuli using different devices. A paradigm for administering the stimuli with the most robust responses on fMRI was developed. Reproducibility of the device was confirmed in 10 chronic pain patients and age/gender-matched healthy controls. Comparisons of patient demographics including age, sex, and numerical rating scale (NRS) scores between the cohorts were performed using a two-sample t-test. Reproducibility was assessed through repeated-measures ANOVA. Results: Both devices, when administered at 15 seconds on, 30 seconds off induced primary somatosensory cortex (SI) activation on fMRI. The device affecting the nail bed induced consistent discomfort and was subsequently validated. Specifically, a mean pressure of 15.7 ± 0.05 psi induced discomfort that remained consistent over repeated trials (p=0.74). Further, in healthy controls, there was a significant correlation between pressure applied and NRS scores in controls(p<0.01). In chronic pain patients, a mean pressure of 15.3 ± 0.10 psi provided discomfort during a single trial. This pressure did not differ than that found in healthy controls (p=0.26). Conclusion: We have developed and validated a novel pressure device which is MRI compatible and provides for improved accuracy. We have demonstrated increased reproducibility compared to existing devices in literature and documented feasibility in pilot fMRI studies. Future work will focus on demonstrating its use in fMRI studies in chronic pain patients.

BackgroundThe majority of Parkinson's disease patients with deep brain stimulation (DBS) use a monopolar configuration, which presents challenges for EEG and MRI studies. The literature reports algorithms to convert monopolar to bipolar settings.Purpose/HypothesisTo assess brain responses of Parkinson's disease patients implanted with DBS during fMRI studies using their clinical and presumed equivalent settings using a published conversion recipe.Study TypeProspective.SubjectsThirteen DBS patients.Field Strength/Sequence1.5T and 3T, fMRI using gradient echo‐planar imaging.AssessmentPatients underwent 30/30sec ON/OFF DBS fMRI scans using monopolar and bipolar settings. To convert to a bipolar setting, the negative contact used for the monopolar configuration remained constant and the adjacent dorsal contact was rendered positive, while increasing the voltage by 30%. fMRI activation/deactivation maps and motor Unified Parkinson's Disease Rating Scale (UPDRS‐III) scores were compared for patients in both configurations.Statistical Tests T‐tests were used to compare UPDRS scores and volumes of tissue activated (VTA) diameters in monopolar and bipolar configurations.ResultsThe patterns of fMRI activation in the monopolar and bipolar configurations were generally different. The thalamus, pallidum, and visual cortices exhibited higher activation using the patient's clinical settings than the presumed equivalent settings. VTA diameters were lower (7 mm vs. 6.3 mm, P = 0.047) and UPDRS scores were generally higher in the bipolar (33.2 ± 16) than in the monopolar configuration (28.3 ± 17.4), without reaching statistical significance (P > 0.05).Data ConclusionMonopolar and bipolar configurations result in different patterns of brain activation while using a previously published monopolar–bipolar conversion algorithm. Clinical benefits may be achieved with varying patterns of brain responses. Blind conversion from one to the other should be avoided for purposes of understanding the mechanisms of DBS.Level of Evidence: 1Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2018.

INTRODUCTION:Preoperative work-up for spinal cord stimulation (SCS) includes a psychological assessment; however, no one psychological factor has correlated with poor outcomes across studies. We developed a Psychological Evaluation Tool for Spinal Cord Stimulation Candidacy (PETSCSC), which includes all factors in the literature found to correlate with outcomes. In this study, we examine whether PETSCSC correlates with postoperative outcomes.METHODS:Patients undergoing SCS were prospectively enrolled in this study. PETSCSC scores were obtained preoperatively. Numeric rating scale (NRS), global impression of change (GIC), pain catastrophizing scale (PCS), McGill pain questionnaire (MPQ), Oswestry disability index (ODI), and Beck Depression Inventory were assessed preoperatively and postoperatively. Outcomes were correlated with PETSCSC scores.RESULTS:Thirty-four SCS patients had a mean follow-up of 9.88 ± 2.91 months. At latest follow-up, we observed significant improvement in NRS, PCS, MPQ, and ODI. Total PETSCSC score exhibited significant correlation with GIC (p = 0.026, r = 0.380) and improvement in PCS total (p = 0.041, r = 0.351), and MPQ affective (p = 0.002, r = 0.517) scores. The PETSCSC emotive subset significantly correlated with GIC (p = 0.020, r = 0.395). The PETSCSC depression subset significantly correlated with improvement in PCS rumination (p = 0.009, r = 0.439), PCS helplessness (p = 0.021, r = 0.393), PCS total (p = 0.021, r = 0.394), and MPQ affective (p = 0.002, r = 0.501). The PETSCSC therapy subset significantly correlated with improvement in MPQ sensory (p = 0.026, r = -0.381) and MPQ affective (p < 0.001, r = 0.583).DISCUSSION:PETSCSC scores and subscores demonstrate significant correlation with pain outcomes used in assessment of SCS efficacy. Higher PETSCSC scores correlate with greater improvement in GIC, MPQ affective, and PCS scores. Stratification of these patients based on PETSCSC total and subset scores could help with prognostication.

Objective: Pain is a prevalent and debilitating nonmotor symptom of Parkinson's disease (PD) that is often inadequately managed. Deep brain stimulation (DBS) has been shown to relieve pain in PD but an effective method of identifying which types of PD pain respond to DBS has not been established. We examine the effects of DBS on different types of PD pain using the King's Parkinson's disease pain scale (KPDPS), the only validated scale of PD pain. Methods: We prospectively followed 18 PD patients undergoing subthalamic nucleus (STN) or Globus pallidus interna (GPi) DBS. Subjects completed the KPDPS, low back disability index (LBDI), and McGill pain questionnaire (MPQ), preoperatively and at six months postoperatively. Subjects underwent the unified Parkinson's disease rating scale-III (UPDRS-III) with preoperative scores ON medication and postoperative scores ON medication/DBS stimulation. Results: Of the 18 patients, a total of 12 subjects had STN DBS and 6 had GPi DBS. As a group, subjects showed improvement in total KPDPS score at six-month postoperative follow-up (p = 0.004). Fluctuation and nocturnal pain were most significantly improved (p = 0.006, 0.01, respectively). Significant improvements were found in fluctuation-related pain domain following GPi DBS. Conclusions: In this pilot study, we are the first group to employ KPDPS to monitor pain relief following DBS in PD patients. We demonstrate that fluctuation-related pain and nocturnal pain significantly improve with DBS. Use of the KPDPS in the future will allow better understanding of how STN and GPi DBS treat PD pain over time.

Objective: To assess the utility of salivary cortisol measurements as a biomarker for depression in patients with Parkinson disease. Background: Parkinson disease (PD) causes several non-motor symptoms that negatively impact quality of life including depression. Due to symptom overlap, diagnosis may be delayed or missed and treatment is often ineffective. A useful biomarker for depression in PD could be of great utility. Salivary cortisol (SC) has been explored as a biomarker for depression in the general population but not in PD. Design/Methods: Over a period of one year, 3 subject groups were recruited: PD patients with depression (PDD), PD patients without depression (PDND), and healthy age-matched controls (C). Depression was identified by a score ≥1 on UPDRS part 1 and Beck Depression Inventory (BDI) ≥14. An State Trait Anxiety Inventory (STAI-T) score above the mean for our subject population identified positive anxiety symptoms. Subjects collected a morning and evening SC sample on three non-consecutive days. Subjects recorded their exercise, medications, and caffeine intake on days samples were taken. Results: 47 subjects participated: for the PDD group (n=20), mean SC levels were AM=0.533 mg/dL (±0.089 mg/dL), PM= .154 mg/dL (±0.042 mg/dL). PDND group (n=16), mean AM SC levels =0.511 mg/dL (±0.044 mg/dL), PM =0.086 mg/dL (±0.009 mg/dL). C group (n=11), mean AM SC levels=0.337 mg/dL (±0.054 mg/dL), PM =0.076 mg/dL (±0.015 mg/dL). No statistically significant group difference was found (F(2,44)=1.270, p=0.290). Similarly, treatment with antidepressants had no significant effect on AM or PM SC levels. Mean STAI-T scores were significantly higher in PDD=42.526 (±2.534) vs PDND=26.933 (±1.485), (t(32)=4.952, p=0.008), but presence of anxiety did not influence AM or PM SC levels. Conclusions: In this pilot study, SC samples collected by subjects at home did not correlate with depression or depression medication in a PD population. This is contrary to what has been reported regarding depression in a general population and may be due to the small sample size. Disclosure: Dr. Sweeney has nothing to disclose. Dr. Prusik has received research support from Jazz Pharmaceuticals. Dr. Molho has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Nerocrine Biosciences, Acadia Pharmaceuticals. Dr. Molho has received research support from Biotie, Civitas Therapeutics, Biogen, Kyowa Hakko Kirin.

OBJECTIVE:Spinal cord stimulation (SCS) has been shown to be effective in treating chronic pain in patients with varying etiologies. However, the impact of pharmacological treatment on augmenting response to SCS has not been previously studied.METHODS:We enrolled 108 patients who had undergone SCS surgery and documented their pain preoperatively and at 12 months postoperatively using the Numeric Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Oswestry Disability Index (ODI), Pain Catastrophizing Scale (PCS), and Global Impression of Change (GIC). Pain outcomes were compared between patients receiving SCS alone and in addition to duloxetine.RESULTS:At 1-year follow-up, patients receiving duloxetine and SCS (n = 41) had better pain relief in the affective component of MPQ (p < 0.05) than those receiving SCS alone (n = 71). Patients on duloxetine with SCS also were significantly more willing to receive SCS again (p < 0.01). This willingness appeared to be duloxetine dose dependent (p < 0.05). Patients receiving pregabalin or gabapentin with SCS did not have significantly more pain relief than patients receiving SCS alone.CONCLUSION:This study shows the combination therapy to be an effective strategy to provide more holistic pain relief and further improve the quality of life of SCS patients.

IntroductionSpinal cord stimulation (SCS) is an established, effective method of treating chronic pain. High frequency stimulation (HFS) is an alternative SCS waveform that has been shown to alleviate pain but also necessitates more frequent recharging. The purpose of this pilot study is to evaluate efficacy of alternating conventional stimulation and HFS (termed “shuffle” stimulation) in improving SCS outcomes.MethodsShuffle stimulation was designed to deliver conventional stimulation in upright positions with relative HFS in lying positions, automated through accelerometer technology. In this 13-week cross-over study, patients were randomized to receiving conventional and shuffle stimulation in four-week blocks. Pain outcomes and sensory testing were compared from preoperative baseline and at the conclusion of each study period.ResultsTwelve patients completed this study. Two patients showed no change from baseline visual analogue scale (VAS) with either type of stimulation and were excluded from statistical analysis of pain outcomes. Mean numerical rating scale (NRS) scores assessing current pain were significantly lower in shuffle stimulation (4.0 ± 1.6) compared to conventional stimulation (5.8 ± 2.3) (p = 0.024). In the total cohort, 7 of 11 patients preferred shuffle over conventional stimulation.ConclusionsThis study generated preliminary evidence showing improved NRS current pain scores in shuffle stimulation compared to conventional stimulation. More patients preferred shuffle stimulation compared to conventional stimulation. Optimizing stimulation when patients are recumbent may increase patient satisfaction and pain control. The potential advantages of shuffle stimulation may warrant further investigation.

Objectives: Spinal Cord Stimulation (SCS) is an effective treatment for chronic pain. How often pain remission follows SCS has not been evaluated. This is a retrospective analysis of patients who underwent an implantation of spinal cord stimulators for various chronic pain conditions. The objective of the study was to elucidate characteristics and features of patients with pain relief greater than 80% after one year of treatment. Methods: A total of 86 patients with thoracic SCS and 12-month follow-up data were identified. Patients were divided into a remission group (>80% improvement in Numeric Pain Rating Scale [NRS] pain scale), average responders (20-80% improvement) and a non-responder group (less than 20% improvement). These patient groups were compared via the following outcome measures: NRS, Oswestry Disability Index (ODI), Pain Catastrophizing Scale (PCS), McGill Pain Questionnaire (MPQ), and Insomnia Severity Index (ISI). Correlations with age, body mass index (BMI), tobacco and alcohol usage, patient satisfaction with SCS, disability status, and opioid usage were assessed. Results: Nineteen of 86 patients (22%) were remitters at one year follow-up, including 17 patients who had an NRS50 at that time. Upon analyzing the three patient groups (non-responders, average responders, and remitters), remitter patients showed the greatest change over the one-year post-operative period in ODI (F(2) 58.101, p<0.01) and PCS (F(2) = 7.607, p<0.01). Moreover, remission was less likely when the patients were on disability prior to implant (chi(2) (2) = 6.469, p<0.05) and on opioids pre-operatively (chi(2) (2) = 17.688, p < 0.01). Conclusions: Our study demonstrates a remission rate of 22% with SCS at one-year follow with a total of 19.8% of our total patient cohort having an NRS of 0. Greater decreases in PCS and ODI correlate with remission. Further, pre-operative disability and opioid use correlate with lower likelihood of remission.

Spinal cord stimulation (SCS) is an efficacious therapy used to treat chronic pain. The type of SCS programming is important in improving patients' quality of life and overall satisfaction. In this study, 19 patients who underwent SCS with traditional devices were given between 4 and 6 programs including programs with stimulation below sensory threshold and above sensory threshold. Usage patterns and preferences were assessed.

OBJECTIVE Chronic pain is a major distressing symptom of Parkinson's disease (PD) that is often undertreated. Subthalamic nucleus (STN) deep brain stimulation (DBS) delivers high-frequency stimulation (HFS) to patients with PD and has been effective in pain relief in a subset of these patients. However, up to 74% of patients develop new pain concerns while receiving STN DBS. Here the authors explore whether altering the frequency of STN DBS changes pain perception as measured through quantitative sensory testing (QST). METHODS Using QST, the authors measured thermal and mechanical detection and pain thresholds in 19 patients undergoing DBS via HFS, low-frequency stimulation (LFS), and off conditions in a randomized order. Testing was performed in the region of the body with the most pain and in the lower back in patients without chronic pain. RESULTS In the patients with chronic pain, LFS significantly reduced heat detection thresholds as compared with thresholds following HFS (p = 0.029) and in the off state (p = 0.010). Moreover, LFS resulted in increased detection thresholds for mechanical pressure (p = 0.020) and vibration (p = 0.040) compared with these thresholds following HFS. Neither LFS nor HFS led to changes in other mechanical thresholds. In patients without chronic pain, LFS significantly increased mechanical pain thresholds in response to the 40-g pinprick compared with thresholds following HFS (p = 0.032). CONCLUSIONS Recent literature has suggested that STN LFS can be useful in treating nonmotor symptoms of PD. Here the authors demonstrated that LFS modulates thermal and mechanical detection to a greater extent than HFS. Low-frequency stimulation is an innovative means of modulating chronic pain in PD patients receiving STN DBS. The authors suggest that STN LFS may be a future option to consider when treating Parkinson's patients in whom pain remains the predominant complaint.

BackgroundIntraoperative neuromonitoring (IONM) through electromyography (EMG) studies has been shown to be a safe, effective way to determine the laterality of the spinal cord and guide electrode placement during spinal cord stimulation (SCS). However, the use of IONM to predict post-operative energy requirements and midline has not been examined and offers a new avenue to streamline programming and device selection. Further, the impact of cerebrospinal fluid (CSF) thickness on intraoperative and post-operative amplitudes is understood but has not been explicitly characterized.MethodsA total of 24 patients undergoing SCS implantation for chronic pain had intraoperative EMG studies performed to determine physiologic midline. The intraoperative midline was compared to the midline determined on post-operative day 1 based on paresthesia patterns during programming. For patients who had thoracic leads placed, the amplitudes needed to induce abdominal and extremity lateralization during SCS placement were compared with the intensities needed to induce therapy at post-operative day 1. Additionally, we examined whether CSF thickness, body mass index, diabetes, drug use, and smoking correlated with intraoperative and post-operative amplitudes.ResultsIntraoperative EMG was able to predict post-operative paresthesia-based midline in 70.83% of patients. There was a statistically significant relationship between the intraoperative intensity needed to induce extremity lateralization with the post-operative intensity to induce therapy (p=0.009) as well as the intraoperative intensity needed to stimulate abdominals with the post-operative intensity (p=0.033). There was also a relationship seen between CSF thickness and the post-operative energy requirements in patients (p=0.039).DiscussionEMG accurately predicts post-operative energy requirements and midline in SCS patients. While 29.17% of patients did not have a match between their intraoperative and post-operative midlines, EMG testing was still valuable in guiding electrode placement and providing information to predict post-operative intensities. Additionally, CSF thickness correlated with amplitude settings on the first post-operative day.

To assess the impact of synchronization errors between the assumed functional MRI paradigm timing and the deep brain stimulation (DBS) on/off cycling using a custom electrocardiogram‐based triggering system