Search Results (15)

Nowadays, brain–computer interface (BCI) systems are frequently used to connect individuals who have lost their mobility with the outside world. These BCI systems enable individuals to control external devices using brain signals. However, these systems have certain disadvantages for users. This paper proposes a novel approach to minimize the disadvantages of visual stimuli on the eye health of system users in BCI systems employing visual evoked potential (VEP) and P300 methods. The approach employs moving objects with different trajectories instead of visual stimuli. It uses a light-emitting diode (LED) with a frequency of 7 Hz as a condition for the BCI system to be active. The LED is assigned to the system to prevent it from being triggered by any involuntary or independent eye movements of the user. Thus, the system user will be able to use a safe BCI system with a single visual stimulus that blinks on the side without needing to focus on any visual stimulus through moving balls. Data were recorded in two phases: when the LED was on and when the LED was off. The recorded data were processed using a Butterworth filter and the power spectral density (PSD) method. In the first classification phase, which was performed for the system to detect the LED in the background, the highest accuracy rate of 99.57% was achieved with the random forest (RF) classification algorithm. In the second classification phase, which involves classifying moving objects within the proposed approach, the highest accuracy rate of 97.89% and an information transfer rate (ITR) value of 36.75 (bits/min) were achieved using the RF classifier. Full article

Vitamin E is an essential nutrient, but its poor water solubility limits food and pharmaceutical applications. The usability of vitamin E can be enhanced via modification methods such as encapsulation, which transforms the physical state of vitamin E from a liquid to a powder. This study examined the efficacy of near-infrared (NIR) and mid-infrared (MIR) spectroscopy in identifying and predicting various vitamin E derivatives in vitamin E-encapsulated powder (VEP). An MIR analysis revealed the fundamental C–H vibrations of vitamin E in the range of 2700–3250 cm⁻¹, whereas an NIR analysis provided information about the corresponding combination, first, and second overtones in the range of 4000–9000 cm⁻¹. The MIR and NIR data were analyzed using a principal component analysis to characterize the VEP. Partial least squares (PLS) regression was applied to predict the content of individual vitamin E derivatives. PLS cross-validation revealed that NIR analysis provides more reliable predictive accuracy and precision for the contents of vitamin E derivatives, achieving a higher coefficient of determination for prediction (Q²) (0.92–0.99) than MIR analysis (0.20–0.85). For test set validation, the NIR predictions exhibited a significant level of accuracy, as indicated by a high ratio of prediction to deviation (RPD) and Q². Furthermore, the PLS models developed using the NIR data had statistically significant predictive performance, with a high RPD (1.54–3.92) and Q² (0.66–0.94). Thus, NIR spectroscopy is a valuable nondestructive technique for analyzing vitamin E samples, while MIR spectroscopy serves as a useful method for confirming its presence. Full article

Brain–computer interfaces (BCIs) enable direct communication between the brain and external devices using electroencephalography (EEG) signals. BCIs based on code-modulated visual evoked potentials (cVEPs) are based on visual stimuli, thus appropriate visual feedback on the interface is crucial for an effective BCI system. Many previous studies have demonstrated that implementing visual feedback can improve information transfer rate (ITR) and reduce fatigue. This research compares a dynamic interface, where target boxes change their sizes based on detection certainty, with a threshold bar interface in a three-step cVEP speller. In this study, we found that both interfaces perform well, with slight variations in accuracy, ITR, and output characters per minute (OCM). Notably, some participants showed significant performance improvements with the dynamic interface and found it less distracting compared to the threshold bars. These results suggest that while average performance metrics are similar, the dynamic interface can provide significant benefits for certain users. This study underscores the potential for personalized interface choices to enhance BCI user experience and performance. By improving user friendliness, performance, and reducing distraction, dynamic visual feedback could optimize BCI technology for a broader range of users. Full article

Background: The selection of suitable patients for the surgical treatment of benign prostatic obstruction (BPO) is a challenge in persons ≥75 years of age. Methods: After a systematic literature search of PubMed, 22 articles were included in this review. Clinical and functional parameters were evaluated statistically. Results: The mean age of the patients was ≥79 years. The mean duration of postoperative catheterization ranged between 2 (d) (ThuLEP, thulium laser enucleation of the prostate) and 4.4 days (TURP, transurethral resection of the prostate). Complication rates ranged between 6% (HoLAP, holmium laser ablation of the prostate) and 34% (PVP, photoselective vaporization of the prostate); the maximum rate of severe complications was 4% (TURP). The mean postoperative maximal urinary flow (Qmax) in mL/sec. ranged between 12.9 mL/sec. (HoLAP) and 19.8 mL/sec (Hol-TUIP, holmium laser transurethral incision of the prostate). The mean quality of life (QoL) score fell from 4.7 ± 0.9 to 1.8 ± 0.7 (HoLEP), from 4.1 ± 0.4 to 1.9 ± 0.8 (PVP), from 5.1 ± 0.2 to 2.1 ± 0.2 (TURP), and from 4 to 1 (ThuVEP, thulium laser vapoenucleation of the prostate). Pearson’s correlation coefficient (r) revealed a positive linear correlation between age and inferior functional outcome (higher postoperative International Prostate Symptom Score (IPSS) [r = 0.4175]), higher overall complication rates (r = 0.5432), and blood transfusions (r = 0.4474) across all surgical techniques. Conclusions: This meta-analysis provides the summary estimates for perioperative and postoperative functional outcome and safety of endoscopic treatment options for BPO in patients ≥ 75 years of age. Of particular importance is that all surgical techniques significantly improve the postoperative quality of life of patients in this age group compared to their preoperative quality of life. Full article

Background: Optic neuritis (ON) is an inflammatory condition of the optic nerve. ON is associated with development of demyelinating diseases of the central nervous system (CNS). CNS lesions visualized by magnetic resonance imaging (MRI) and the finding of oligoclonal IgG bands (OB) in the cerebrospinal fluid (CSF) are used to stratify the risk of MS after a “first” episode of ON. However, the diagnosis of ON in absence of typical clinical manifestations can be challenging. Methods and Materials: Here we present three cases with changes in the optic nerve and ganglion cell layer in the retina over the disease course. (1) A 34-year-old female with a history of migraine and hypertension had suspect amaurosis fugax (transient vision loss) in the right eye. This patient developed MS four years later. Optical coherence tomography (OCT) showed dynamic changes of the thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) over time. (2) A 29-year-old male with spastic hemiparesis and lesions in the spinal cord and brainstem. Six years later he showed bilateral subclinical ON identified using OCT, visual evoked potentials (VEP) and MRI. The patient fulfilled diagnosis criteria of seronegative neuromyelitis optica (NMO). (3) A 23-year-old female with overweight and headache had bilateral optic disc swelling. With OCT and lumbar puncture, idiopathic intracranial hypertension (IIH) was excluded. Further investigation showed positive antibody for myelin oligodendrocyte glycoprotein (MOG). Conclusions: These three cases illustrate the importance of using OCT to facilitate quick, objective and accurate diagnosis of atypical or subclinical ON, and thus proper therapy. Full article

Purpose: Prostate cancer (PCa) and benign prostatic hyperplasia (BPH) are common in elderly men. Data on the laser-based surgery known as thulium vapoenucleation of the prostate (ThuVEP) in PCa patients are rare. Our objective was to analyse the feasibility, safety and functional outcome of ThuVEP in patients with lower urinary tract symptoms (LUTS) and PCa. Methods: Multicentre study, including 1256 men who underwent ThuVEP for LUTS. Maximum urinary flow rate (Qmax) and post-void residual volume (PVR) were measured perioperatively. The International Prostate Symptome Score (IPSS) was measured perioperatively and at follow-up (FU). Perioperative complications were captured. Reoperation rate was captured at FU. Results: Of 994 men with complete data, 286 (28.8%) patients had PCa. The most common Gleason score was 3 + 3 in 142 patients (49.7%). Most common was low-risk PCa (141 pts; 49.3%). PCa patients were older, had smaller prostates and had higher prostate-specific antigen (PSA) values (all p < 0.001). Comparing non-PCa and PCa patients, no differences occurred perioperatively. IPSS, quality of life and PVR decreased (all p < 0.001) and Qmax improved (p < 0.001) in both groups. Reoperation rates did not differ. The results of low- vs. intermediate-/high-risk PCa patients were comparable. Conclusion: ThuVEP is a safe and long-lasting treatment option for patients with LUTS with or without PCa. No differences occurred when comparing low- to intermediate-/high-risk PCa patients. Full article

Purpose: To evaluate the radiation effect of fractionated robotic radiotherapy of benign tumors located in the parasellar region on the anterior and posterior segments of the eye. Methods: A prospective observational study based on the expanded ophthalmological examination. The pre-treatment baseline was used as a control for the post-radiotherapy follow-up examinations. The study group consists of 34 patients (68 eyes) irradiated using the CyberKnife system. There were ten patients with cavernous sinus meningioma, nine with pituitary adenoma, five with meningioma of the anterior and middle cranial fossa, five with meningioma in the region close to optic chiasm, three with craniopharyngioma, and two with meningioma of the orbit. All patients were treated using three fractions of 600–800 cGy. We assessed the impact of radiation on the eye based on changes in anatomical and functional features. The condition of the eye surface, central corneal thickness (CCT), endothelial cell density (ECD), lens densitometry, central macular thickness (CMT), and retinal nerve fiber layer (RNFL) were the anatomical features assessed. The functional tests were best-corrected visual acuity (BCVA), intraocular pressure (IOP), visual field (VF) and visual-evoked potentials (VEP). An ophthalmologic examination was performed before and 6, 12, 18, and 24 months after radiotherapy. Results: We did not observe any significant changes in BCVA, IOP, CCT, CMT, VF, and VEP, nor in the slit-lamp examination during the two-years observation. We found a significant decrease in ECD at all follow-up measurements. The drop in ECD exceeded approximated age-related physiological loss. The reduction in ECD was not large enough to disrupt corneal function and thus affect vision. We also observed a statistically significant reduction of RNFL in all observation time points. However, there was no correlation between the dose delivered to the optic pathway and the decrease in RNFL thickness. The thinning of the RNFL was not significant enough to impair visual function. Conclusion: Fractionated robotic radiotherapy of the tumors located close to the optical pathway is safe and does not impair patient’s vision. Minor changes found in optic nerve anatomy (RNFL thinning) might be related to radiation effect or tumor compression. The causal relation between low doses of radiation delivered to the cornea and the observed significant but slight decrease in ECD is uncertain. The observed changes did not cause visual disturbances perceivable by the patients. Full article

Previous research comparing traditional two-dimensional (2D) and virtual reality with stereoscopic vision (VR-3D) stimulations revealed that VR-3D resulted in higher levels of immersion. However, the effects of these two visual modes on emotional stimulus processing have not been thoroughly investigated, and the underlying neural processing mechanisms remain unclear. Thus, this paper introduced a cognitive psychological experiment that was conducted to investigate how these two visual modes influence emotional processing. To reduce fatigue, participants (n = 16) were randomly assigned to watch a series of 2D and VR-3D short emotional videos for two days. During their participation, electroencephalograms (EEG) were recorded simultaneously. The results showed that even in the absence of sound, visual stimuli in the VR environment significantly increased emotional arousal, especially in the frontal region, parietal region, temporal region, and occipital region. On this basis, visual evoked potential (VEP) analysis was performed. VR stimulation compared to 2D led to a larger P1 component amplitude, while VEP analysis based on the time course of the late event-related potential component revealed that, after 1200 ms, the differences across visual modes became stable and significant. Furthermore, the results also confirmed that VEP in the early stages is more sensitive to emotions and presumably there are corresponding emotion regulation mechanisms in the late stages. Full article

Photobiological neuromodulation and its clinical application has been investigated in recent years. The response of the gamma-oscillation to human visual stimuli is known to be both burst and resonant in nature, and the coupling between alpha and gamma oscillations may play a functional role in visual processing. To date, there is no study that examined the effects of gamma-frequency violet light (VL) stimulation on human electroencephalography (EEG). In this study, we investigated the neurophysiological changes induced by light stimulation using EEG. The purpose of this study was to evaluate the specific effects of 40 Hz gamma-frequency VL stimulation on EEG activity by comparing the effects of white light (WL) with the same condition. Twenty healthy participants (10 females: 37.5 ± 14.3 years; 10 males: 38.0 ± 13.3 years) participated in this study and the following results were observed. First, when compared with the power spectrum density (PSD) of baseline EEG, 40 Hz-WL induced significant increase of PSD in theta band. Second, compared the PSDs between EEG with 40 Hz-VL and EEG with 40 Hz-WL, 40 Hz-VL induced significantly lower enhancement in delta and theta bands than 40 Hz-WL. Third, when focused on the occipital area, negative peak of VEP with 40 Hz-VL was smaller than that of 40 Hz-WL. Fourth, 40 Hz-VL induced an increase of alpha-gamma coupling during the VEP at the F5 electrode site as well as post-EEG at the C4 electrode site, compared with baseline EEG. Thus, the present study suggested that 40 Hz-VL stimulation may induce unique photobiological neuromodulations on human EEG activity. Full article

Recent research has demonstrated frontal cortical involvement to co-occur with visual re-organization, suggestive of top-down modulation of cross-modal mechanisms. However, it is unclear whether top-down modulation of visual re-organization takes place in mild hearing loss, or is dependent upon greater degrees of hearing loss severity. Thus, the purpose of this study was to determine if frontal top-down modulation of visual cross-modal re-organization increased across hearing loss severity. We recorded visual evoked potentials (VEPs) in response to apparent motion stimuli in 17 adults with mild-moderate hearing loss using 128-channel high-density electroencephalography (EEG). Current density reconstructions (CDRs) were generated using sLORETA to visualize VEP generators in both groups. VEP latency and amplitude in frontal regions of interest (ROIs) were compared between groups and correlated with auditory behavioral measures. Activation of frontal networks in response to visual stimulation increased across mild to moderate hearing loss, with simultaneous activation of the temporal cortex. In addition, group differences in VEP latency and amplitude correlated with auditory behavioral measures. Overall, these findings support the hypothesis that frontal top-down modulation of visual cross-modal re-organization is dependent upon hearing loss severity. Full article

In kidney transplant recipients (KTRs), uraemia-induced central nervous system damage partly subsides, while the long-lasting exposure to tacrolimus may cause pathologic visual evoked potentials (VEP) findings, which have not been investigated yet. Thus, the aim of the present study was to assess the effect of tacrolimus maintenance treatment on bioelectrical function of optic nerves in stable KTRs. Sixty-five stable KTRs were enrolled, including 30 patients treated with twice-daily (Prograf) and 35 patients treated with prolonged once-daily (Advagraf) tacrolimus formulation. In all patients, pattern and flash VEP measurements were performed. Tacrolimus dosing and exposure were also analyzed. Overall, 129 eyes were analyzed. In pattern VEP, both (1°) and (15′) latencies of P100 waves were significantly longer, whereas (1°) and (15′) amplitudes were lower in the Advagraf group as compared with the Prograf group. Multivariate regression analyses revealed that the use of Advagraf (vs. Prograf) was independently associated with longer (1°) and (15′) P100 latencies and lower corresponding amplitudes, whereas log tacrolimus daily dose was only related to amplitudes in a whole study group. In flash VEP, log tacrolimus trough level was associated with negative changes in P2 wave amplitude irrespective of tacrolimus formulation, whereas its association with P2 latency was observed only in the Prograf group. Both the type of tacrolimus formulation and drug exposure influenced the VEP parameters in stable KTRs. Full article

Contemporary minimally invasive surgical (MIS) treatment options of patients with male Lower Urinary Tract Symptoms (LUTS) in men with prostate glands >80 mL include Holmium Laser Enucleation Prostate (HoLEP), Thulium laser VapoEnucleation Prostate (ThuVEP), and Laparoscopic (LSP) or Robotic-Assisted Simple Prostatectomy (RASP). Implementing new laser technologies is costly, and the steep learning curve of these laser techniques limit their wide range use. This promoted the use of LSP and RASP in centers with readily established laparoscopy or robotic surgery programs. The aim of this study is to review case and comparative series of RASP. We systematically reviewed published data from 2008 to 2020 on RASP and have identified 26 non-comparative and 9 comparative case series. RASP has longer operation time but less time spent in hospital and less blood loss. The outcomes of improvements in symptom score, post-voiding residual urine (PVR), postoperative PSA decline, complications, and cost are similar when compared to open and laser enucleation techniques. These outcomes position RASP as a viable MIS treatment option for patients with male LUTS needing surgical treatment for enlarged prostates. Nevertheless, prospective, randomized controlled trials (RCTs) with multicenter and large sample size are needed to confirm the findings of this systematic review. Full article

The acronym EEP, coding for transurethral Endoscopic Enucleation of the Prostate, was introduced in 2016 by the European Association of Urology (EAU) guidelines panel on management of non-neurogenic male lower urinary tract symptoms (LUTS) and benign prostatic obstruction (BPO). Since then, a laser-based treatment, Holmium Laser Enucleation of the Prostate (HoLEP), and the current-based treatment of bipolar enucleation of the prostate (BipoLEP) are equally appreciated as valuable options for the management of benign prostatic obstruction (BPO). This was mainly inspired by the results of two meta-analyses on randomized controlled trials, comparing open prostatectomy with either Holmium Laser Enucleation of the Prostate (HoLEP) or bipolar enucleation of the prostate (BipoLEP). Prior to that, HoLEP was embraced as the only valid option for transurethral enucleation, although evidence for equivalence existed as early as 2006, but was not recognized due to a plethora of acronyms for bipolar energy-based treatments and practiced HoLEP-centrism. On the other hand, the academic discourse focused on different (other) laser approaches that came up, led by Thulium:Yttrium-Aluminum-Garnet (Tm:YAG) Vapoenucleation (ThuVEP) in 2009 and, finally, transurethral anatomical enucleation with Tm:YAG support (thulium laser enucleation of the prostate, ThuLEP) in 2010. Initially, the discourse on lasers focused on the different properties of lasers rather than technique or surgical anatomy, respectively. In and after 2016, the discussion ultimately moved towards surgical technique and accepting anatomical preparation as the common of all EEP techniques (AEEP). Since then, the unspoken question has been raised, whether lasers are still necessary to perform EEP in light of existing evidence, given the total cost of ownership (TCO) for these generators. This article weighs the current evidence and comes to the conclusion that no evidence of superiority of one modality over another exists with regard to any endpoint. Therefore, in the sense of critical importance, AEEP can be safely and effectively performed without laser technologies and without compromise. Full article

Bleeding is the most common complication of transurethral resection of the prostate and simple open prostatectomy, especially in men on antiplatelet/anticoagulant therapy. The present study aimed to evaluate the safety and effectiveness of thulium laser vapoenucleation of the prostate (ThuVEP) for benign prostatic hyperplasia in patients on chronic antithrombotic medications. Between January 2015 and December 2019, 88 men underwent the procedure under antithrombotic agents in our center. The mean age was 74.7 ± 6.1 years. Median prostate volume was 66.5 mL. Patients on oral anticoagulants were bridged to low-molecular-weight heparin (n = 35). Aspirin (n = 39), clopidogrel (n = 10), and ticlopidine (n = 4) were maintained. Of the patients, 69.3% had an American Society of Anesthesiologists score ≥ 3. Blood loss at 24 h was comparable in all groups. Median catheterization length and postoperative stays were 2 and 3 days respectively. Acute cardiovascular events occurred in 2 patients (2.3%). Of the patients, 4 required prolonged bladder irrigation, 2 required blood transfusions, 1 required a cystoscopy for bleeding control, and 1 required a suprapubic cystostomy for blood clot evacuation. No patients died within 30 days of being discharged. Late complications occurred in 3 (3.8%) patients (1 optical urethrotomy and 1 bladder neck incision for stenosis; 1 acute myocardial infarction). All follow-up visits (1, 6, and 12-month) showed a significant improvement in all urinary parameters compared to baseline. ThuVEP appears to be a feasible surgical option in high-risk patients on antithrombotic regimens, with acceptable postoperative morbidity, good functional outcome, and low incidence of medium-term reoperation rate. Full article

The self-priming pump as an essential energy conversion equipment is widely used in hydropower and thermal power plants. The energy losses in the internal flow passage of the pump directly affect its work efficiency. Therefore, it is important to improve the internal flow characteristic of the pump. In the present work, a novel self-priming pump which starts without water is proposed; this pump can reduce the energy consumption as well as the time needed to start its operation. The spatial structure of the vortices in the pump is investigated by employing the Q criterion with the numerical solution of the vorticity transport equation. Based on the morphology, the vortices can be separated into three categories: Trailing Edge Vortex (TEV), Leading Edge Vortex (LEV) and Gap Leakage Vortex (GLV). Generally, the morphology of the TEV is more disorderly than that of LEV and GLV, and the intensity of TEV is significantly higher than that of the other two vortices. To determine the magnitude and distribution of energy loss in the pump, entropy production analysis is employed to study the influence of blade thickness on energy characteristics of the pump. It is found that with an increase in the flow rate, the location of energy loss transfers from the trailing edge to the leading edge of the blade, and viscous entropy production (VEP) and turbulence entropy production (TEP) are the dominant factors which influence the energy conversion in the pump. More importantly, employing the blade with a thin leading edge and a thick trailing edge can not only significantly reduce the impact of incoming flow under over-load condition (flow rate higher than the design condition) but can also increase the efficiency of the pump. Thus, an increase in thickness of the blade from the leading edge to the trailing edge is beneficial for improving the pump performance. The results of this paper can be helpful in providing guidelines for reducing the energy loss and in improving the performance of a self-priming pump. Full article