bluuebunny/crossref_metadata_2025_split huggingface dataset:
330 Electrophysiologically-defined Parameterization of Intracranial Neuromodulation to Define DBS Settings for Treatment-resistant Depression
Authors: Metzger Brian , Adkinson Joshua , Oswalt Denise , Xiao Jiayang , Allawala Anusha , Goodman Wayne , Pouratian Nader , Sheth Sameer A. , Bijanki Kelly R. 
Published: March 2022

INTRODUCTION:
Deep brain stimulation settings for treatment resistant depression are typically selected through a process of behaviorally-defined trial-and-error, which is prone to substantial variability in treatment response.

METHODS:
Intracranial EEG (iEEG) was collected concurrently with 426 unique DBS configurations varied along 5 dimensions: DBS target, segmented DBS configuration, frequency, amplitude, pulse width. Multiple sessions of baseline resting-state iEEG were also recorded, from which sessions associated with the lowest and highest depression scores were selected as desired and undesired target patterns, respectively. After decomposing iEEG data into frequency bands of interest, we created correlation matrices across the spatial/spectral space of stimulation-evoked changes in power, and rank-ordered the output in terms of similarity for each stimulation configuration to the template patterns. Iterative model fitting then determined which parameter components contributed most to the matching score.

RESULTS:
To validate the approach, we compared rank-order for desired state to undesired state and found a negative correlation between them (r = -0.45, p < 0.0001), suggesting that high-ranking stimulation parameters matched to the desired state are low-ranking when matched to the undesired state. In application of these stimulation settings for therapeutic stimulation, we saw a substantial reduction in depressive symptoms compared with the patient’s pre-DBS baselines (pre-DBS vs template-matching defined stimulation: MADRS 36 vs. 9; HAM-D 24 vs. 6).

CONCLUSION:
We have implemented spatiotemporal template matching by searching a set of 426 unique stimulation parameter sets for evoked neural states recapitulating the neural signature of a desired state in a patient with TRD. Preliminary data demonstrate that particular spatiotemporal neural signatures can be defined and matched to stimulation-evoked states.
331 Role of Functional Network Formation in Epilepsy
Authors: Boddeti Ujwal , Bachani Muznbanu , Moyer Mitchell , Owotade Jemima , Serra Riccardo , Zaveri Hitten , Ksendzovsky Alexander 
Published: March 2022

INTRODUCTION:
Despite surgical resection of a defined epileptogenic focus (EF), about 50% of patients go on to have refractory seizures. Recently, focal epilepsy is being redefined as a network disorder and studies have demonstrated that resection of nodes outside the EF may contribute to better surgical outcomes. Additionally, our group has shown higher interictal connectivity between nodes involved in seizure onset in a cohort of epilepsy patients, further suggesting the presence of an underlying distributed epileptogenic network in focal epilepsy.

METHODS:
Primary mixed cultures of cortical neurons from P1 rat pups were cultured on 96-well multi-electrode array (MEA) plates with eight active electrodes per well for stimulation and recording. We developed an in vitro stimulation model of cortical epilepsy to study epilepsy network formation using a biphasic tetanic stimulation at 50 or 100 Hz, 500 μV, 250 μA applied for one hour daily for ten days.

RESULTS:
Four-days of daily in vitro stimulation demonstrated significant increases in neuronal baseline bursting, modeling kindled seizures. Tetanic stimulation with 50 Hz had the highest elevation in neuronal busting. In order to compare distributed network connectivity, we calculated and ranked coherences (13-32 Hz) across all electrode pairs (n = 24) and identified the top 15% for comparison to control. The average coherence across the top connected pairs was significantly higher in stimulated wells compared to controls (0.27 vs. 0.17, p = 0.0002). Furthermore, coherence across the highest-ranking electrode pair was strengthened with daily stimulation. This was not seen in control wells.

CONCLUSION:
Similar to human data, this in vitro model suggests an elevated interictal coherence among electrode pairs involved in seizure formation. Next, we aim to characterize the structure of this network quantifying axonal boutons and dendritic spines. Ultimately, our work aims to enable a better understanding of network formation in epilepsy that will inform future epilepsy surgery decision making.
337 Neural Network Changes with Loss of Consciousness in Parkinson's Disease
Authors: DiCesare Jasmine A. T. , Malekmohammadi Mahsa , Toker Daniel , Sparks Hiro , Hudson Andrew , Monti Martin , Pouratian Nader 
Published: March 2022

INTRODUCTION:
Consciousness is likely mediated by multiple parallel yet interacting cortico-subcortical recurrent networks. The pallidocortical circuit is of particular interest given the putative role of pallidum in consciousness, according to the mesocircuit model, though this has not been well studied.

METHODS:
We characterized changes in pallidocortical circuits in awake versus propofol-induced unconscious states in humans by directly and simultaneously recording from perirolandic cortices and the pallidum in twelve Parkinson Disease (PD) patients undergoing implantation of therapeutic deep brain stimulation (DBS) leads.

RESULTS:
Propofol-induced LOC resulted in power increases up to 20 Hz in globus pallidus internus (GPi), 35 Hz in globus pallidus externus (GPe), and 100 Hz in sensorimotor cortices (S1/M1). At a network level, LOC resulted in increased pallidocortical alpha coherence with increases in Granger causality (GC) in the alpha/low beta range from GPe to all other nodes. In contrast, LOC was associated with decreased network-wide beta coherence with decreased GC in the beta range from M1 to the rest of the network.

CONCLUSION:
These results not only confirm the LOC-related changes in pallidocortical circuitry, but GC results suggest that widely reported LOC-related increases in alpha band power emanate from GPe. These findings support a significant role of the GPe in modulating consciousness. Simultaneous LOC-related suppression of beta synchrony from M1 to other nodes suggests that distinct oscillatory frequencies can act independently, conveying unique network level activity. Given the pathophysiologic role of beta synchrony in PD, LOC-related suppresion of beta synchrony may be amplified in this patient population, but may also highlight a parallel network mediating LOC-related loss of motor control.
342 Long-Term Follow-up of 54 Cases of Recurrent Glioblastoma Treated with Magnetic Resonance-Guided Laser Interstitial Thermal Therapy
Authors: Jubran Jubran H. , Shaftel Kelly T. , Hendricks Benjamin , Oladokun Femi , Farhadi Dara , Smith Kris 
Published: March 2022

INTRODUCTION:
Magnetic resonance guided laser-induced thermal therapy (MRgLITT) is a novel minimally invasive procedural treatment for progressive cerebral lesions and cerebral edema related to post-radiation treatment effect.

METHODS:
We conducted a single-center retrospective study of pre-operative imaging, clinical characteristics and survival outcomes of 54 patients with previously treated (WHO Grade IV) between January 2013 to December 2020.

RESULTS:
The average age of patients was 58.7 ± 12.0 years. Patients underwent MRgLITT a median time of 21.6 ± 23.7 months from original diagnosis. 20% (n = 11) of patients had previous history of stereotactic radiosurgery, 61% (n = 33) intensity-modulated radiation therapy, and 80% (n = 43) chemotherapy. There was an average of 1.2 ± 0.7 prior surgical resections before MRgLITT was performed. 41% (n = 22) of patients were on dexamethasone at the time of treatment. The median pre-operative enhancing lesion volume on T1 gadolinium-enhanced magnetic resonance imaging (MRI) was 9.7 cm3 (standard error [SE], 2.0 cm3) and 27.0 cm3 (SE, 5.6 cm3) on T2 fluid-attenuated inversion recovery MRI. The pathology of the biopsies taken during MRgLITT confirmed tumor recurrence in 61% (n = 33) of patients, and treatment effect or reactive changes in 37% (n = 20) of patients. 67% (n = 28) experienced radiographic evidence of progression of the previously treated lesion, while 21% (n =9) and 12% (n = 5) experienced progression of a new lesion or both, respectively. Progression-free survival after MRgLITT was 3.5 months (standard error [SE], 0.6; 95% CI, 2.4-4.6). At the time of the study, 78% (n = 42) of patients were deceased. Mean overall survival time was 29.9 months (SE, 4.3; 95% CI, 21.4-38.3). Mean survival time after MRgLITT was 8.3 months (SE, 1.2; 95% CI, 5.9-10.6. Of the 12 remaining living patients, 36% (n = 4) had a decline in their clinical status at the time of last follow up, while 64% (n = 7) and 9% (n = 1) were stable or improved, respectively. Patients were followed for a mean time interval of 9.25 ± 12.2 months from MRgLITT.

CONCLUSION:
MRgLITT may be a viable, minimally invasive option for patients with glioblastoma but is associated with relatively short post-treatment progression-free survival.
343 Machine Learning Using Multiparametric MRI Radiomic Feature Analysis to Predict Ki-67 in Meningiomas
Authors: Khanna Omaditya , Kazerooni Anahita F. , Farrell Christopher J. , Baldassari Michael , Alexander Tyler , Karsy Michael , Garcia Jose , Sako Chiharu , Evans James J. , Judy Kevin D. , Andrews David W. , Sharan Ashwini D. , Shi Wenyin , Davatzikos Christos 
Published: March 2022

INTRODUCTION:
Although WHO grade I meningiomas are considered ‘benign’ tumors, an elevated Ki-67 is one crucial factor that has been shown to influenceclinical outcomes. Machile learning using radiomic analysis can help predict tumor pathology and model outcomes.

METHODS:
A retrospective analysis was performed for a cohort of 306 patients that underwent surgical resection of WHO grade I meningiomas. MRI was used to perform radiomic feature extraction followed by machine learning using a support vector machine (SVM) through nested cross-validation on a discovery cohort (N = 230), to stratify tumors based on Ki-67. The final model was independently tested on a replication cohort (N = 76).

RESULTS:
The mean and median Ki-67 of tumor specimens were 4.84 ± 4.03% (range: 0.3 – 33.6) and 3.7% (Q1: 2.3%, Q3: 6%), respectively. Meningiomas with Ki-67=5% were larger in volume compared to tumors with Ki-67 < 5% (mean 38.65 ± 19.19 and 20.97 ± 35.57 cm3, respectively; p < 0.001), which held true in sub-group analysis of both skull base and non-skull base tumors. Similarly, meningiomas with Ki-67 = 5% had significantly larger peritumoral edema volumes compared to tumors with Ki67 < 5% (mean 22.11 ± 40.12 and 40.16 ± 42.34 cm3, respectively; p = 0.002). An area under the receiver operating curve (AUC) of 0.84 (95% CI: 0.78-0.90) with a sensitivity of 84.1% and specificity of 73.3% was achieved in the discovery cohort. When this model was applied to the replication cohort, a similar high performance was achieved, with an AUC of 0.83 (95% CI: 0.73-0.94), sensitivity and specificity of 82.6% and 85.5%, respectively. The model demonstrated similar efficacy when applied to skull base and non-skull base tumors.

CONCLUSION:
Our proposed radiomic feature analysis can be used to stratify meningiomas based on Ki-67 with excellent accuracy and can be applied to skull-base and non-skull base tumors.
353 Comprehensive Evaluation of Telehealth Service Effectiveness in the Neurosurgical Patient Population During the COVID-19 Pandemic
Authors: Sorour Omar , Slavin Justin 
Published: March 2022

INTRODUCTION:
In recent years, remote access for medical care is increasingly being utilized. However its efficacy for neurosurgical patients is not widely studied, especially in the setting of a global pandemic.

METHODS:
A HIPAA-compliant survey was created via RedCap addressing satisfaction and utility of telehealth (televideo or telephone) in patients from 03/2020 – Present. Out of 246 currently emailed patients, 22 responses were recorded (televideo, n=11; telephone, n=11).

RESULTS:
Telephone users found the phone call a suitable method, with no preference for video format. However, 3 of these phone respondents (27.3%) still required an in-person visit. For televideo service, no user reported finding difficulty in accessing their appointment. Interestingly, 45.5% of televideo users (n=5) reported that the attending physician displayed multimedia tools, such as radiographic imaging, during the visit. When examining both telephone and televideo cohorts, 95.5% of respondents (n=21) felt satisfied overall with telehealth’s ability to meet their needs. Despite this high satisfaction rate, 22.7% of all respondents were either ambivalent (n=4) or strongly disagreed (n=1) that telehealth improved access to healthcare services.

CONCLUSION:
Our study illustrates the importance of differentiating between satisfaction—which can expectedly be high in a “stay-at-home” service—and efficacy in providing neurosurgical care. We suggest that telehealth is a technologically robust tool given its reported ease of use. Yet, preliminary results show that telehealth’s comprehensiveness may hold up less for patients who still require in-person evaluation for certain diagnoses and examinations. Almost a quarter of respondents believed that telehealth did not improve access to healthcare services, arguing that telehealth visits may be less useful for some.
367 Development of Machine Learning Based Models to Predict Treatment Response to Spinal Cord Stimulation
Authors: Hadanny Amir , Pilitsis Julie G. 
Published: March 2022

INTRODUCTION:
Despite spinal cord stimulation’s (SCS) proven efficacy, failure rates are high with no clear understanding of which patients benefit long-term. Currently, patient selection for SCS is based on the subjective experience of the implanting physician.

METHODS:
A combined unsupervised (clustering) and supervised (classification) ML techniques was applied on a prospectively collected cohort of 151 patients which included 31 features. Clusters identified using unsupervised K-means clustering were fitted with individualized predictive models of logistic regression, random forest and XGboost.

RESULTS:
Two distinct clusters were found and patients in the cohorts significantly differed in age, duration of chronic pain, pre-operative numeric rating scale (NRS) and pre-operative pain catastrophizing scale scores. Using the 10 most influential features, logistic regression predictive models with a nested cross-validation demonstrated the highest overall performance with area under the curve (AUC) of 0.757 and 0.708 for each respective cluster.

CONCLUSION:
This combined unsupervised-supervised learning approach yielded high predictive performance, suggesting advance ML-derived approaches have potential to be utilized as a functional clinical tool to improve long-term SCS outcomes.
401 Risk Factors for Increased Mortality in Patients with ICH and COVID-19: Timing Matters
Authors: Selner Ashley , Arslan Danial , McGuire Laura S. , Mehta Ankit I. 
Published: March 2022

INTRODUCTION:
Intracerebral hemorrhage (ICH) has been reported with comorbid COVID-19 infection and is associated with significant morbidity and mortality.

METHODS:
The NIH N3C national database was used to retrospectively analyze COVID-19 infected patients within 1 month of ICH admitted after March 11, 2020. The primary endpoint was death during admission, and the cohort of patients who suffered fatalities were compared to those discharged from admission. Additional analyses compared patients diagnosed with ICH after COVID-19 infection versus those presenting with ICH and subsequent COVID infection.

RESULTS:
1614 ICH-COVID patients from 55 sites were identified, 351 of which suffered fatalities. In the ICH-COVID fatality cohort versus those discharged, there was a significantly higher proportion of prior comorbid obesity (36.2% vs 28.3%), diabetes (48.1% vs 40.1%), atrial fibrillation (35.0% vs 24.8%), and heart failure (30.8% vs 23.8%). Racial and ethnic differences were not significant across the two cohorts. Of note, higher rates of hypertension and smoking were not observed. Increased complications of MI (18.2% vs 11.0%), PE (14.2% vs 9.5%), and DVT (19.7% vs 14.9%) were observed. The fatality cohort showed an increased proportion of patients presenting with ICH prior to COVID-19 infection compared to those diagnosed with ICH after COVID-19 infection. Analyses comparing the timing of ICH and COVID diagnoses regardless of outcome confirmed higher rates of mortality (28.4% vs 20.3%) in those with ICH followed by COVID-19 infection. To account for confounding non-survivable ICH in respective cohorts, fatalities within 2 days of ICH diagnosis were excluded and this finding remained significant.

CONCLUSION:
Fatalities from ICH and concurrent COVID-19 infection were increased for those with history of obesity, diabetes, atrial fibrillation and heart failure, and higher rates of MI, PE, and DVT were observed compared to non-fatal cases. Patients who presented with ICH and subsequently became COVID infected had higher mortality rate than those who suffered ICH after COVID.
427 Use of Antibacterial Envelopes for Prevention of Infection in Neuromodulation
Authors: Persad Amit R. L. , Ahmed Syed U. , Mercure-Cyr Rosalie , Waterhouse Karen , Vitali Aleksander 
Published: March 2022

INTRODUCTION:
Neuromodulation is effective but carries a historic infection rate as high as 12%. TYRX antibacterial envelopes (Medtronic Inc., Minneapolis, MN), which are absorbable mesh envelopes that elute minocycline and rifampin, have been used in implantable cardiac devices with substantial risk reduction for infection.

METHODS:
We conducted a retrospective cohort study of consecutive implantable pulse generator (IPG) and intrathecal pump unit implantation with a TYRX antibacterial envelope© at our center between October 2014 and December 2019. This cohort was then compared to a historical cohort of consecutive patients undergoing IPG or pump placement or revision prior to the use of the envelopes (between October 2007 and April 2015).

RESULTS:
In the pre-envelope cohort of 151 IPGs placed in 116 patients, there was an infection rate of 18/151 (11.9%). In the antibacterial envelope cohort of 233 IPGs placed in 185 patients, there were 5 infections (2.1%). The absolute risk reduction of the antibacterial envelope was 4.6% (95% CI, 0.045-0.048), with a relative risk reduced by 77% (odds ratio, 0.23; 95% CI 0.05-1.08; P = 0.065). The NNT was 21 (95% CI 20.8-22.4). The pre-envelope cohort of 41 pumps placed in 39 patients, the infection rate was 6/41 (14.6%). In the antibacterial envelope cohort of 59 pumps in 54 patients, there was 1 infection (1.7%). The absolute risk reduction of the antibacterial envelope was 12.9% (95% CI 1.6-24.3), with a relative risk reduction of 88% (odds ratio, 0.13; 95% CI, 0.02-1.11; P = 0.04). The NNT was 7.7 (95% CI 4.4-32.3).

CONCLUSION:
Usage of an antibacterial envelope with device placement for neuromodulation therapy has resulted in a lower infection rate at our center. Based on these results, we can recommend the use of envelopes for infection prophylaxis.
428 The Lumbar Tap Trial Experience: An Analysis of Outcomes in 133 Adult Normal Pressure Hydrocephalus Patients Undergoing 2-Day Lumbar Tap Trial at a Single Center
Authors: Cunningham Coby , Leonardo Jody 
Published: March 2022

INTRODUCTION:
Lumbar Tap Trial (LTT) with high volume cerebrospinal fluid (CSF) removal is one of the primary adjunct testing modalities at a neurosurgeon’s disposal in the diagnosis of normal pressure hydrocephalus (NPH). Patients responsive to LTT may receive permanent fluid diversion by way of shunt placement.

METHODS:
Retrospective review of the electronic medical records of 133 patients that underwent a 2-day LTT by a single surgeon at our adult hydrocephalus center was conducted. Each patient has been closely followed at our hydrocephalus clinic from the time of symptomatic presentation through LTT, eventual shunt placement (if performed), and frequent post-operative assessments. Assessment of improvement during LTT and following shunt placement includes a timed 25 ft. walk test at our clinic.

RESULTS:
From 2016 – present, 133 patients have undergone 136 completed LTTs. During initial LTT, no major complications such as death, infection, hemorrhage, or nerve-root injury were seen. Minor complications included post-tap low back pain, headache, and transient nerve-root irritation. Average improvement during timed 25 ft. walk test was 6.6 sec following LTT. Average improvement in timed walk test in patients receiving shunt placement was 13.9 sec compared to post LTT walk time.

CONCLUSION:
In patients with suspected NPH, high-volume LTT was found to be an effective and safe diagnostic tool in our patient population. Patients demonstrating significant objective improvement during a timed walk test are frequently recommended for shunting. Patients undergoing shunt placement following improvement on LTT continued to improve with a mean decrease in walk time post-operatively, highlighting the effectiveness of LTT in predicting symptomatic response to shunt placement.
439 A Colloidal Polymethyl-Methacrylate (PMMA) Microsphere-Based Treatment for Patients with Symptomatic Discogenic Disease: A Safety and Feasibility Clinical Trial
Authors: Brown Nolan J. , Shahrestani Shane , Lien Brian , Yang Chen Y. , Ton Emily , Diaz-Aguilar Luis D. , Sahyouni Ronald , Wali Arvin R. , Abraham Mickey E. , Taylor Sandra , Taylor William R. 
Published: March 2022

INTRODUCTION:
Low Back Pain (LBP) is a global healthcare issue, and first line therapy for patients with LBP include physical therapy, oral pain relievers, and steroid injections. If unsuccessful, surgical procedures are indicated. Non-surgical second-line treatments for LBP are warranted, and one example is DiscSeal, a colloidal form of viscous gel composed of polymethyl-methacrylate microspheres and aqueous buffered sodium hyaluronate.

METHODS:
Six participants were enrolled. The study population comprised of males/females between the ages of 18 and 70, diagnosed with chronic LBP of six months or more prior to enrollment determined to be predominantly caused by discogenic disease of the lumbar spine who failed at least six weeks of conservative management. Participants completed visits at 7, 14, 42, 90, and 180 days.

RESULTS:
The mean age of participants was 38.8 ± 10.0 years. The mean DiscSeal volume administered was 1.62 ± 0.35 mL with a range between 1.1-2.0 mL. The mean procedure time was 10.8 minutes. Mean LBP visual analog scale (VAS) percentage changes from baseline were -27.0% at 90 days and -42.3% at 180 days, with 50.0% of participants maintaining LBP VAS scores <4 at 90- and 180-days post treatment with DiscSeal. Similarly, mean leg pain VAS percentage changes from baseline were -47.0% at 90 days and -36.6% at 180 days. Overall, participants' average improvement, assessed by Patient Rating Overall Health Status, was 55.2% at 90 days and 67.8% at 180 days.

CONCLUSION:
The results from this first-in-man trial suggest a favorable safety and efficacy profile for the continued study of DiscSeal. Future studies evaluating DiscSeal as a minimally invasive therapy for chronic discogenic LBP are warranted.