Nevin Manimala

J Neural Eng. 2024 Mar 8. doi: 10.1088/1741-2552/ad31c4. Online ahead of print.

ABSTRACT

PURPOSE: Retinal implants use electrical stimulation to elicit perceived flashes of light (“phosphenes”). Single-electrode phosphene shape has been shown to vary systematically with stimulus parameters and the retinal location of the stimulating electrode, due to incidental activation of passing nerve fiber bundles. However, this knowledge has yet to be extended to paired-electrode stimulation.

METHODS: We retrospectively analyzed 3548 phosphene drawings made by three blind participants implanted with an Argus II Retinal Prosthesis. Phosphene shape (characterized by area, perimeter, major and minor axis length) and number of perceived phosphenes were averaged across trials and correlated with the corresponding single-electrode parameters. In addition, the number of phosphenes was correlated with stimulus amplitude and neuroanatomical parameters: electrode-retina and electrode-fovea distance as well as the electrode-electrode distance to (“between-axon”) and along axon bundles (“along-axon”). Statistical analyses were conducted using linear regression and partial correlation analysis.

RESULTS: Simple regression revealed that each paired-electrode shape descriptor could be predicted by the sum of the two corresponding single-electrode shape descriptors (p<.001). Multiple regression revealed that paired-electrode phosphene shape was primarily predicted by stimulus amplitude and electrode-fovea distance (p<.05). Interestingly, the number of elicited phosphenes tended to increase with between-axon distance (p<.05), but not with along-axon distance, in two out of three participants.

CONCLUSIONS: The shape of phosphenes elicited by paired-electrode stimulation was well predicted by the shape of their corresponding single-electrode phosphenes, suggesting that two-point perception can be expressed as the linear summation of single-point perception. The notable impact of the between-axon distance on the perceived number of phosphenes provides further evidence in support of the axon map model for epiretinal stimulation. These findings contribute to the growing literature on phosphene perception and have important implications for the design of future retinal prostheses.

PMID:38457841 | DOI:10.1088/1741-2552/ad31c4

J Neurosurg. 2024 Mar 8:1-9. doi: 10.3171/2024.1.JNS232560. Online ahead of print.

ABSTRACT

OBJECTIVE: Surgical intervention can be curative or palliative for drug-resistant focal epilepsy. However, if the seizure onset zone (SOZ) cannot be adequately localized via noninvasive tests, intracranial EEG (iEEG) recordings are often carried out to develop surgical plans in appropriate candidates. Stereotactic EEG (SEEG), subdural EEG (SDE), and SDE with depth electrodes (hybrid) are major tools used for investigation, but there is no class 1 or 2 evidence comparing the effectiveness of these modalities.

METHODS: The authors identified an institutional cohort of patients who underwent iEEG monitoring between 2001 and 2022. Demographic data, preoperative clinical features, iEEG intervention, and follow-up data were identified. Primary study endpoints included the following: 1) likelihood of SOZ localization; 2) likelihood of surgical treatment after iEEG; 3) seizure outcomes; and 4) complications.

RESULTS: A total of 329 patients were identified (176 in the SEEG, 60 in the SDE, and 93 in the hybrid cohort) who were followed for a median of 5.4 (IQR 6.8) years. Baseline characteristics, including demographics, mean age at epilepsy diagnosis, mean age at iEEG investigation, number of preoperative antiseizure medications, and preoperative seizure frequency, were not statistically different across the 3 cohorts. Patients in the SEEG cohort were more likely to have their SOZ localized than were the patients in the SDE group (OR 2.3) and were less likely to undergo subsequent resection (OR 0.3) or to have complications (OR 0.4), although there was no statistical difference with respect to likelihood of undergoing any subsequent neurosurgical treatment, or with respect to favorable seizure outcomes. Patients in the hybrid cohort were more likely to have SOZ localized than were patients in the SDE group (OR 3.1), but were more likely to undergo resection (OR 4.9) or any neurosurgical treatment (OR 2.5) compared to patients in the SEEG group. Patients in the hybrid cohort had better seizure outcomes compared to the SDE (OR 2.3) but not to the SEEG group.

CONCLUSIONS: Patients in the SEEG group were more likely to have their SOZ localized and patients in the SDE group were more likely to undergo resection, but they did not differ with respect to seizure outcomes.

PMID:38457804 | DOI:10.3171/2024.1.JNS232560

JMIR Nurs. 2024 Mar 8;7:e54443. doi: 10.2196/54443.

ABSTRACT

BACKGROUND: In nursing education, bridging the gap between theoretical knowledge and practical skills is crucial for developing competence in clinical practice. Nursing students encounter challenges in acquiring these essential skills, making self-efficacy a critical component in their professional development. Self-efficacy pertains to individual’s belief in their ability to perform tasks and overcome challenges, with significant implications for clinical skills acquisition and academic success. Previous research has underscored the strong link between nursing students’ self-efficacy and their clinical competence. Technology has emerged as a promising tool to enhance self-efficacy by enabling personalized learning experiences and in-depth discussions. However, there is a need for a comprehensive literature review to assess the existing body of knowledge and identify research gaps.

OBJECTIVE: The aim of this study is to systematically map and identify gaps in published studies on the use of technology-supported guidance models to stimulate nursing students’ self-efficacy in clinical practice.

METHODS: This scoping review followed the framework of Arksey and O’Malley and was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR). A systematic, comprehensive literature search was conducted in ERIC, CINAHL, MEDLINE, Embase, PsycINFO, and Web of Science for studies published between January 2011 and April 2023. The reference lists of the included papers were manually searched to identify additional studies. Pairs of authors screened the papers, assessed eligibility, and extracted the data. The data were thematically organized.

RESULTS: A total of 8 studies were included and four thematic groups were identified: (1) technological solutions for learning support, (2) learning focus in clinical practice, (3) teaching strategies and theoretical approaches for self-efficacy, and (4) assessment of self-efficacy and complementary outcomes.

CONCLUSIONS: Various technological solutions were adopted in the guidance models to stimulate the self-efficacy of nursing students in clinical practice, leading to positive findings. A total of 7 out of 8 studies presented results that were not statistically significant, highlighting the need for further refinement of the applied interventions. Nurse educators play a pivotal role in applying learning strategies and theoretical approaches to enhance nursing students’ self-efficacy, but the contributions of nurse preceptors and peers should not be overlooked. Future studies should consider involving users in the intervention process and using validated instruments tailored to the studies’ intervention objectives, ensuring relevance and enabling comparisons across studies.

PMID:38457802 | DOI:10.2196/54443

J Neurosurg Spine. 2024 Mar 8:1-9. doi: 10.3171/2024.1.SPINE231137. Online ahead of print.

ABSTRACT

OBJECTIVE: The purpose of this retrospective study was to evaluate the relationship between bone mineral density (BMD), as assessed with dual-energy x-ray absorptiometry (DEXA), and Hounsfield units (HU) measured in volumes of interest (VOIs) and regions of interest (ROIs) on lumbar spine CT.

METHODS: A retrospective analysis was performed on data of lumbar vertebrae obtained from patients who underwent both DEXA and lumbar spine CT scan within a 6-month period. Vertebrae with a history of compression fracture, infectious spondylitis, cement reinforcement, or lumbar surgery were excluded. HU measurements were performed in the VOI and ROI (midaxial, midcoronal, and midsagittal sections) with CT, whereas BMD was assessed with DEXA. Statistical analyses, including correlation assessments and receiver operating characteristic (ROC) curve analyses, were performed.

RESULTS: This analysis included 712 lumbar vertebrae, with a median patient age of 72.0 years. BMD values and HU measurements in the VOI increased sequentially from L1 to L4, whereas HU values in the ROI did not show a consistent pattern. HU values in the VOI consistently showed a stronger correlation with BMD than those in the ROI. ROC analysis revealed patient-level cutoff values for the diagnosis of osteoporosis at different lumbar vertebral levels with high sensitivity and specificity, as well as an excellent area under the curve.

CONCLUSIONS: This is the first study to introduce a novel approach using the HU value in the VOI to assess bone health at the lumbar spine. There is a strong correlation between the HU value in the VOI and BMD, and the HU value in the VOI can be used to predict osteoporosis.

PMID:38457796 | DOI:10.3171/2024.1.SPINE231137

J Neurosurg. 2024 Mar 8:1-11. doi: 10.3171/2023.12.JNS231542. Online ahead of print.

ABSTRACT

OBJECTIVE: Meningiomas are the most common primary brain tumors in adults and a subset are aggressive lesions resistant to standard therapies. Laser interstitial thermal therapy (LITT) has been successfully applied to other brain tumors, and recent work aims to explore the safety and long-term outcome experiences of LITT for both new and recurrent meningiomas. The authors’ objective was to report safety and outcomes data of the largest cohort of LITT-treated meningioma patients to date.

METHODS: Eight United States-based hospitals enrolled patients with meningioma in the Laser Ablation of Abnormal Neurological Tissue Using Robotic NeuroBlate System (LAANTERN) prospective multicenter registry and/or contributed additional retrospective enrollments for this cohort study. Demographic, procedural, safety, and outcomes data were collected and analyzed using standard statistical methods.

RESULTS: Twenty adult patients (12 prospective and 8 retrospective) with LITT-targeted meningiomas were accrued. Patients underwent LITT for new (6 patients) and recurrent (14 patients) tumors (ranging from the 1st to 12th recurrence). The 30-day complication rate was 10%. Twenty percent of patients (4/20) had exhausted all other treatment options. Median length of follow-up was 1.3 years. One-third of new (2/6) and one-half of recurrent (7/14) meningiomas had disease progression during follow-up. One-year estimated local control (LC), progression-free survival, and overall survival rates were 55.3%, 48.4%, and 86.3%, respectively. In the 12 patients who had ≥ 91% ablative coverage, 1-year estimated LC was 61.4%. The complication rate was 10% (2/20), with 1 complication being transient and resolving postoperatively.

CONCLUSIONS: This cohort study supports the safety of the procedure for this tumor type. LITT can offer a much-needed treatment option, especially for patients with multiply recurrent meningiomas who have limited remaining alternatives.

PMID:38457795 | DOI:10.3171/2023.12.JNS231542

J Neurosurg Spine. 2024 Mar 8:1-8. doi: 10.3171/2023.12.SPINE231251. Online ahead of print.

ABSTRACT

OBJECTIVE: Biomechanical factors in lumbar fusions accelerate the development of adjacent-segment disease (ASD). Stiffness in the fused segment increases motion in the adjacent levels, resulting in ASD. The objective of this study was to determine if there are differences in the reoperation rates for symptomatic ASD (operative ASD) between anterior lumbar interbody fusion plus pedicle screws (ALIF+PS), posterior lumbar interbody fusion plus pedicle screws (PLIF+PS), transforaminal lumbar interbody fusion plus pedicle screws (TLIF+PS), and lateral lumbar interbody fusion plus pedicle screws (LLIF+PS).

METHODS: A retrospective study using data from the Kaiser Permanente Spine Registry identified an adult cohort (≥ 18 years old) with degenerative disc disease who underwent primary lumbar interbody fusions with pedicle screws between L3 to S1. Demographic and operative data were obtained from the registry, and chart review was used to document operative ASD. Patients were followed until operative ASD, membership termination, the end of study (March 31, 2022), or death. Operative ASD was analyzed using Cox proportional hazards models.

RESULTS: The final study population included 5291 patients with a mean ± SD age of 60.1 ± 12.1 years and a follow-up of 6.3 ± 3.8 years. There was a total of 443 operative ASD cases, with an overall incidence rate of reoperation for ASD of 8.37% (95% CI 7.6-9.2). The crude incidence of operative ASD at 5 years was the lowest in the ALIF+PS cohort (7.7%, 95% CI 6.3-9.4). In the adjusted models, the authors failed to detect a statistical difference in operative ASD between ALIF+PS (reference) versus PLIF+PS (HR 1.06 [0.79-1.44], p = 0.69) versus TLIF+PS (HR 1.03 [0.81-1.31], p = 0.83) versus LLIF+PS (HR 1.38 [0.77-2.46], p = 0.28).

CONCLUSIONS: In a large cohort of over 5000 patients with an average follow-up of > 6 years, the authors found no differences in the reoperation rates for symptomatic ASD (operative ASD) between ALIF+PS and PLIF+PS, TLIF+PS, or LLIF+PS.

PMID:38457789 | DOI:10.3171/2023.12.SPINE231251

J Neurosurg Spine. 2024 Mar 8:1-8. doi: 10.3171/2024.1.SPINE231010. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the correlation between radiological indices of shoulder balance (SB) and cosmetic indices of shoulder deformity in patients with Lenke type 2 adolescent idiopathic scoliosis (AIS) and to determine the extent to which patient-reported outcomes (PROs) correlate with these measurements. Current management decisions and outcomes for SB in AIS are primarily based on radiological measurements. It is crucial to understand how these radiological parameters and cosmetic indices relate to patient satisfaction.

METHODS: The authors analyzed the preoperative radiological and photographic indices of SB, along with PROs, in patients with Lenke type 2 AIS. Lateral SB parameters included the radiological shoulder height (RSH) and clavicle angle, while medial SB parameters included the first rib angle and T1 tilt angle. Photographic indices included the shoulder height angle (SHA), axilla height angle (AHA), and the left/right trapezius angle (LRTA) ratio. The authors assessed the self-image, mental health, and total score domains of the Korean version of the 22-item Scoliosis Research Society questionnaire.

RESULTS: In their analysis of Lenke type 2 patients, the authors found that correlation coefficients between radiological measurements and photographic indices ranged from -0.25 to 0.47, among which only lateral SB including clavicle angle and RSH showed a significant correlation with anterior and posterior photographic indices. No statistically significant correlations were found between radiological measurements and PROs. Anterior photographic indices including SHA and AHA significantly correlated with all three PROs (p < 0.05).

CONCLUSIONS: Radiological shoulder parameters did not accurately reflect the perceived SB. Anterior photographic indices were reliable for evaluating clinical SB in patients with Lenke type 2 AIS and correlated with PROs. Spine surgeons may benefit from paying more attention to anterior photographic indices when making surgical decisions regarding clinical SB.

PMID:38457786 | DOI:10.3171/2024.1.SPINE231010

J Clin Oncol. 2024 Mar 8:JCO2301507. doi: 10.1200/JCO.23.01507. Online ahead of print.

ABSTRACT

PURPOSE: The phase III Cancer and Leukemia Group B (CALGB)/SWOG 80405 trial found no difference in overall survival (OS) in patients with metastatic colorectal cancer receiving first-line chemotherapy in combination with either bevacizumab or cetuximab. We investigated the potential prognostic and predictive value of HER2 amplification and gene expression using next-generation sequencing (NGS) and NanoString data.

PATIENTS AND METHODS: Primary tumor DNA from 559 patients was profiled for HER2 amplification by NGS (FoundationOne CDx). Tumor tissue from 925 patients was tested for NanoString gene expression using an 800-gene panel. OS and progression-free survival (PFS) were the time-to-event end points.

RESULTS: High HER2 expression (dichotomized at median) was associated with longer PFS (11.6 v 10 months, P = .012) and OS (32 v 25.3 months, P = .033), independent of treatment. An OS benefit for cetuximab versus bevacizumab was observed in the high HER2 expression group (P = .02), whereas a worse PFS for cetuximab was seen in the low-expression group (P = .019). When modeled as a continuous variable, increased HER2 expression was associated with longer OS (hazard ratio [HR], 0.83 [95% CI, 0.75 to 0.93]; adjusted P = .0007) and PFS (HR, 0.82 [95% CI, 0.74 to 0.91]; adjusted P = .0002), reaching a plateau effect after the median. In patients with HER2 expression lower than median, treatment with cetuximab was associated with worse PFS (HR, 1.38 [95% CI, 1.12 to 1.71]; adjusted P = .0027) and OS (HR, 1.28 [95% CI, 1.02 to 1.59]; adjusted P = .03) compared with that with bevacizumab. A significant interaction between HER2 expression and the treatment arm was observed for OS (P_intx = .017), PFS (P_intx = .048), and objective response rate (P_intx = .001).

CONCLUSION: HER2 gene expression was prognostic and predictive in CALGB/SWOG 80405. HER2 tumor expression may inform treatment selection for patients with low HER2 favoring bevacizumab- versus cetuximab-based therapies.

PMID:38457761 | DOI:10.1200/JCO.23.01507

Phys Rev Lett. 2024 Feb 23;132(8):088301. doi: 10.1103/PhysRevLett.132.088301.

ABSTRACT

We study the dynamics of micron-sized particles on a layer of motile cells. This cell carpet acts as an active bath that propels passive tracer particles via direct mechanical contact. The resulting nonequilibrium transport shows a crossover from superdiffusive to normal-diffusive dynamics. The particle displacement distribution is distinctly non-Gaussian even at macroscopic timescales exceeding the measurement time. We obtain the distribution of diffusion coefficients from the experimental data and introduce a model for the displacement distribution that matches the experimentally observed non-Gaussian statistics. We argue why similar transport properties are expected for many composite active matter systems.

PMID:38457713 | DOI:10.1103/PhysRevLett.132.088301

Phys Rev Lett. 2024 Feb 23;132(8):085201. doi: 10.1103/PhysRevLett.132.085201.

ABSTRACT

The breakdown of scale invariance in turbulent flows, known as multifractal scaling, is considered a cornerstone of turbulence. In solar wind turbulence, a monofractal behavior can be observed at electron scales, in contrast to larger scales where multifractality always prevails. Why scale invariance appears at electron scales is a challenging theoretical puzzle with important implications for understanding solar wind heating and acceleration. We investigate this long-standing problem using direct numerical simulations of three-dimensional electron reduced magnetohydrodynamics. Both weak and strong kinetic Alfvén waves turbulence regimes are studied in the balanced case. After recovering the expected theoretical predictions for the magnetic spectra, a higher-order multiscale statistical analysis is performed. This study reveals a striking difference between the two regimes, with the emergence of monofractality only in weak turbulence, whereas strong turbulence is multifractal. This result, combined with recent studies, shows the relevance of collisionless weak KAW turbulence to describe the solar wind at electron scales.

PMID:38457708 | DOI:10.1103/PhysRevLett.132.085201