signal processing

信号处理
  • 文章类型: Journal Article
    股四头肌扭矩发展率(RTD)和扭矩稳定性是评估爆炸强度和在持续一段时间内控制力的能力的有价值的指标。这可以为膝关节功能的临床评估提供信息。尽管它们广泛使用,衡量这些指标的标准化方法存在显著差距,这限制了它们在比较不同研究和人群结果方面的效用。为了弥补这些差距,我们评估了采样率的影响,信号滤波,以及RTD的转矩起始检测和转矩稳定。27名具有原发性前交叉韧带重建病史的参与者(N=27(11男/16女),年龄=23±8岁,体重指数=26±4kg/m2)和32名对照参与者(N=32(13男/19女),年龄=23±7岁,身体质量指数=23±3kg/m2)进行了等轴测股四头肌强度测试,在等速测功机上以2222Hz的频率收集数据。扭矩时间信号被下采样到大约100和1000Hz,并使用低通处理,零滞后巴特沃斯滤波器的截止频率范围跨越10-200赫兹。用于检测扭矩开始的阈值定义为0.1Nm,1Nm,5nm。RTD在0到100ms之间,0和200ms,计算了40-160毫秒,以及绝对和相对转矩的稳定性。通过将所有结果与计算的“黄金标准”值进行比较来计算相对差异,采样率为2222Hz,低通滤波器的截止频率为150Hz,和1Nm的扭矩开始,并利用线性混合模型进行比较。而所有信号收集和处理参数的组合达到了统计学意义(p<0.05),这些差异在受伤和控制肢体之间是一致的。此外,临床相关差异(+/-10%)主要通过扭矩开始检测方法观察到,并且主要在0-100ms之间影响RTD.尽管RTD和扭矩稳定性的测量通常对不同的信号收集和处理参数具有鲁棒性,扭矩起始的选择应仔细考虑,尤其是在早期RTD评估中,时间较短。
    Quadriceps rate of torque development (RTD) and torque steadiness are valuable metrics for assessing explosive strength and the ability to control force over a sustained period of time, which can inform clinical assessments of knee function. Despite their widespread use, there is a significant gap in standardized methodology for measuring these metrics, which limits their utility in comparing outcomes across different studies and populations. To address these gaps, we evaluated the influence of sampling rates, signal filtering, and torque onset detection on RTD and torque steadiness. Twenty-seven participants with a history of a primary anterior cruciate ligament reconstruction (N = 27 (11 male/16 female), age = 23 ± 8 years, body mass index = 26 ± 4 kg/m2) and thirty-two control participants (N = 32 (13 male/19 female), age = 23 ± 7 years, body mass index = 23 ± 3 kg/m2) underwent isometric quadriceps strength testing, with data collected at 2222 Hz on an isokinetic dynamometer. The torque-time signal was downsampled to approximately 100 and 1000 Hz and processed using a low-pass, zero-lag Butterworth filter with a range of cutoff frequencies spanning 10-200 Hz. The thresholds used to detect torque onset were defined as 0.1 Nm, 1 Nm, and 5 Nm. RTD between 0 and 100 ms, 0 and 200 ms, and 40-160 ms was computed, as well as absolute and relative torque steadiness. Relative differences were computed by comparing all outcomes to the \"gold standard\" values computed, with a sampling rate of 2222 Hz, a cutoff frequency in the low-pass filter of 150 Hz, and torque onset of 1 Nm, and compared utilizing linear mixed models. While all combinations of signal collection and processing parameters reached statistical significance (p < 0.05), these differences were consistent between injured and control limbs. Additionally, clinically relevant differences (+/-10%) were primarily observed through torque onset detection methods and primarily affected RTD between 0 and 100 ms. Although measurements of RTD and torque steadiness were generally robust against diverse signal collection and processing parameters, the selection of torque onset should be carefully considered, especially in early RTD assessments that have shorter time epochs.
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  • 文章类型: Journal Article
    目的:早产是全球新生儿和婴儿疾病负担的重要因素。宫腔电描记术(EHG)已成为预测这种情况的一种有前途的技术,由于其高度的灵敏度。尽管在预测早产方面取得了技术进步,它在临床实践中的使用仍然有限,主要障碍之一是缺乏没有专家监督的自动信号处理工具,即自动筛查EHG记录中的运动和呼吸伪影。因此,我们的主要目标是设计和验证一个自动系统,用于在EHG记录中分割和筛选子宫起源的生理部分,以实现对子宫肌电活动的强大表征。预测早产,并有助于促进EHG技术向临床实践的可转移性。
    方法:为此,我们合并了TPEHGDS数据库中的300份EHG记录和我们自己的数据库(Ci2B-LaFe)中的69份单胎妊娠女性EHG记录.该数据集用于训练和评估U-Net,U-Net++,和U-Net3+用于EHG信号的生理和伪像段的语义分割。然后通过后处理对模型的预测进行微调。
    结果:U-Net3+优于其他型号,ROC曲线下面积为91.4%,生理活动检测平均精密度为96.4%。从0.6到0.8的阈值实现了从93.7%到97.4%的精度和从81.7%到94.5%的特异性,检测高质量的生理段,同时保持召回和特异性之间的权衡。后处理通过微调生理段和损坏段,提高了模型的适应性,确保准确的伪影检测,同时保持EHG信号的生理段完整性。
    结论:由于自动分割在预测早产方面与双盲手动分割一样有效,该自动分割工具通过消除专家对双盲分割的需求,填补了现有早产预测系统工作流程中的关键空白,并促进了EHG的实际临床使用.这项工作可能有助于早期发现真正的早产妇女,并将使临床医生能够为孕产妇健康监测系统设计个体患者策略并预测不良妊娠结局。
    OBJECTIVE: Preterm delivery is an important factor in the disease burden of the newborn and infants worldwide. Electrohysterography (EHG) has become a promising technique for predicting this condition, thanks to its high degree of sensitivity. Despite the technological progress made in predicting preterm labor, its use in clinical practice is still limited, one of the main barriers being the lack of tools for automatic signal processing without expert supervision, i.e. automatic screening of motion and respiratory artifacts in EHG records. Our main objective was thus to design and validate an automatic system of segmenting and screening the physiological segments of uterine origin in EHG records for robust characterization of uterine myoelectric activity, predicting preterm labor and help to promote the transferability of the EHG technique to clinical practice.
    METHODS: For this, we combined 300 EHG recordings from the TPEHG DS database and 69 EHG recordings from our own database (Ci2B-La Fe) of women with singleton gestations. This dataset was used to train and evaluate U-Net, U-Net++, and U-Net 3+ for semantic segmentation of the physiological and artifacted segments of EHG signals. The model\'s predictions were then fine-tuned by post-processing.
    RESULTS: U-Net 3+ outperformed the other models, achieving an area under the ROC curve of 91.4 % and an average precision of 96.4 % in detecting physiological activity. Thresholds from 0.6 to 0.8 achieved precision from 93.7 % to 97.4 % and specificity from 81.7 % to 94.5 %, detecting high-quality physiological segments while maintaining a trade-off between recall and specificity. Post-processing improved the model\'s adaptability by fine-tuning both the physiological and corrupted segments, ensuring accurate artifact detection while maintaining physiological segment integrity in EHG signals.
    CONCLUSIONS: As automatic segmentation proved to be as effective as double-blind manual segmentation in predicting preterm labor, this automatic segmentation tool fills a crucial gap in the existing preterm delivery prediction system workflow by eliminating the need for double-blind segmentation by experts and facilitates the practical clinical use of EHG. This work potentially contributes to the early detection of authentic preterm labor women and will allow clinicians to design individual patient strategies for maternal health surveillance systems and predict adverse pregnancy outcomes.
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  • 文章类型: Journal Article
    在不确定的环境中,表型多样性可能有利于生存。然而,随着环境不确定性的减少,具有不同表型的相对优势降低。这里,我们展示了大肠杆菌种群如何整合多种化学信号来调节感官多样性,以响应环境中每种配体患病率的变化。测量单个细胞中的激酶活性,我们量化了不同背景刺激混合物中对各种化学引诱物的敏感性分布。我们发现当配体无竞争性结合时,人口独立地调整每个信号的感官多样性,当信号的环境浓度增加时,多样性降低。然而,在竞争性配体中,种群一次只能减少一个配体的感觉多样性。数学建模表明,感觉多样性调节有利于大肠杆菌种群,通过调节多少细胞随着其患病率的变化而按比例跟踪每个信号。
    In uncertain environments, phenotypic diversity can be advantageous for survival. However, as the environmental uncertainty decreases, the relative advantage of having diverse phenotypes decreases. Here, we show how populations of E. coli integrate multiple chemical signals to adjust sensory diversity in response to changes in the prevalence of each ligand in the environment. Measuring kinase activity in single cells, we quantified the sensitivity distribution to various chemoattractants in different mixtures of background stimuli. We found that when ligands bind uncompetitively, the population tunes sensory diversity to each signal independently, decreasing diversity when the signal\'s ambient concentration increases. However, among competitive ligands, the population can only decrease sensory diversity one ligand at a time. Mathematical modeling suggests that sensory diversity tuning benefits E. coli populations by modulating how many cells are committed to tracking each signal proportionally as their prevalence changes.
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  • 文章类型: Journal Article
    背景:睡眠呼吸暂停综合征,以睡眠期间呼吸的反复停止(呼吸暂停)或减少(呼吸不足)为特征,是术后呼吸抑制的主要危险因素。睡眠呼吸暂停评估中的挑战导致了从氧合血红蛋白饱和度(SpO2)得出的替代指标的提议。例如氧饱和度下降指数(ODI)和SpO2低于90%的累积睡眠时间百分比(CT90),作为术后呼吸抑制的预测因子。然而,它们的性能受到限制,ODI曲线下面积为0.60,CT90曲线下面积为0.59。我们的目标是提出术前过夜SpO2的新特征,这些特征与睡眠呼吸暂停严重程度相关,并可预测术后呼吸抑制。
    方法:对235例手术患者的术前SpO2信号进行回顾性分析,得出7个特征来表征睡眠呼吸暂停严重程度。特征包括SpO2信号的熵和标准偏差;低于平均负荷,表征平均SpO2下的面积;平均,标准偏差,和去饱和负担的熵;以及总体夜间去饱和负担。使用Pearson相关性分析评估提取的特征与睡眠呼吸暂停严重程度之间的关联。采用Logistic回归评估特征在识别术后呼吸抑制方面的预测性能。
    结果:我们的研究结果表明,在评估睡眠呼吸暂停严重程度方面,所提出的特征与常规呼吸暂停低通气指数(AHI)相似。曲线下平均面积为0.77至0.81。值得注意的是,隔夜SpO2信号的熵和标准偏差以及低于平均负荷显示出与AHI相当的预测能力,但计算要求和个人负担最小,使它们有希望用于筛查目的。我们基于性别的分析表明,与熵和标准差相比,低于平均水平的负担在检测呼吸抑制方面,女性比男性表现出更高的灵敏度。
    结论:本研究强调了术前SpO2特征作为AHI预测术后呼吸的替代指标的潜力。
    BACKGROUND: Sleep apnea syndrome, characterized by recurrent cessation (apnea) or reduction (hypopnea) of breathing during sleep, is a major risk factor for postoperative respiratory depression. Challenges in sleep apnea assessment have led to the proposal of alternative metrics derived from oxyhemoglobin saturation (SpO2), such as oxygen desaturation index (ODI) and percentage of cumulative sleep time spent with SpO2 below 90% (CT90), as predictors of postoperative respiratory depression. However, their performance has been limited with area under the curve of 0.60 for ODI and 0.59 for CT90. Our objective was to propose novel features from preoperative overnight SpO2 which are correlated with sleep apnea severity and predictive of postoperative respiratory depression.
    METHODS: Preoperative SpO2 signals from 235 surgical patients were retrospectively analyzed to derive seven features to characterize the sleep apnea severity. The features included entropy and standard deviation of SpO2 signal; below average burden characterizing the area under the average SpO2; average, standard deviation, and entropy of desaturation burdens; and overall nocturnal desaturation burden. The association between the extracted features and sleep apnea severity was assessed using Pearson correlation analysis. Logistic regression was employed to evaluate the predictive performance of the features in identifying postoperative respiratory depression.
    RESULTS: Our findings indicated a similar performance of the proposed features to the conventional apnea-hypopnea index (AHI) for assessing sleep apnea severity, with average area under the curve ranging from 0.77 to 0.81. Notably, entropy and standard deviation of overnight SpO2 signal and below average burden showed comparable predictive capability to AHI but with minimal computational requirements and individuals\' burden, making them promising for screening purposes. Our sex-based analysis revealed that compared to entropy and standard deviation, below average burden exhibited higher sensitivity in detecting respiratory depression in women than men.
    CONCLUSIONS: This study underscores the potential of preoperative SpO2 features as alternative metrics to AHI in predicting postoperative respiratory.
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  • 文章类型: Journal Article
    目前的指南建议在神经肌肉阻断剂给药期间进行定量神经肌肉阻滞监测。使用表面肌电图(EMG)的监测器确定复合运动动作电位(cMAP)振幅或曲线下面积(AUC)。缺乏对这些方法的互换性的严格评估,但对于临床和研究保证EMG对神经肌肉阻滞深度的解释不受方法的影响是必要的。
    在两项已发表的研究中,研究了48例罗库溴铵患者的数字化EMG波形。EMG振幅和AUC由通过目视检查分类为有效的所有cMAP成对计算。使用重复措施Bland-Altman分析比较了服用罗库溴铵(T1c)之前的第一次抽搐(T1)与对照T1的比率和四组比率(TOFR)。
    在平均T1/T1c≤0.2的2419个配对T1/T1c差异中,有8个(0.33%)超出了预设的临床一致性范围(-0.148至0.164)。在平均TOFR≥0.8的1781个配对TOFR差异中,有70个(3.93%)超出了预定的临床协议范围((-0.109至0.134)。在所有7286个T1/T1c配对差异中,平均偏倚为0.32(95%置信区间0.202-0.043),在所有5559个配对的TOFR差异中,平均偏倚为0.011(95%置信区间0.0050~0.017).在配对的T1/T1c和TOFR差异中,Lin的一致性相关系数分别为0.98和0.995。T1/T1c和TOFR的重复性系数<0.08,方法间无差异。
    当使用cMAP振幅或AUC计算时,定量评估神经肌肉阻滞深度在临床上是可互换的。
    UNASSIGNED: Current guidelines recommend quantitative neuromuscular block monitoring during neuromuscular blocking agent administration. Monitors using surface electromyography (EMG) determine compound motor action potential (cMAP) amplitude or area under the curve (AUC). Rigorous evaluation of the interchangeability of these methods is lacking but necessary for clinical and research assurance that EMG interpretations of the depth of neuromuscular block are not affected by the methodology.
    UNASSIGNED: Digitised EMG waveforms were studied from 48 patients given rocuronium during two published studies. The EMG amplitudes and AUCs were calculated pairwise from all cMAPs classified as valid by visual inspection. Ratios of the first twitch (T1) to the control T1 before administration of rocuronium (T1c) and train-of-four ratios (TOFRs) were compared using repeated measures Bland-Altman analysis.
    UNASSIGNED: Among the 2419 paired T1/T1c differences where the average T1/T1c was ≤0.2, eight (0.33%) were outside prespecified clinical limits of agreement (-0.148 to 0.164). Among the 1781 paired TOFR differences where the average TOFR was ≥0.8, 70 (3.93%) were outside the prespecified clinical limits of agreement ((-0.109 to 0.134). Among all 7286 T1/T1c paired differences, the mean bias was 0.32 (95% confidence interval 0.202-0.043), and among all 5559 paired TOFR differences, the mean bias was 0.011 (95% confidence interval 0.0050-0.017). Among paired T1/T1c and TOFR differences, Lin\'s concordance correlation coefficients were 0.98 and 0.995, respectively. Repeatability coefficients for T1/T1c and TOFR were <0.08, with no differences between methods.
    UNASSIGNED: Quantitative assessment neuromuscular block depth is clinically interchangeable when calculated using cMAP amplitude or the AUC.
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  • 文章类型: Journal Article
    背景:心电图(ECG)对于诊断心脏病至关重要,但是在左心室辅助装置(LVAD)患者中获得清洁信号会受到电磁干扰(EMI)的阻碍。传统的过滤器具有有限的功效。目前需要一种简单有效的方法。
    方法:从5例LVAD患者获得的原始ECG数据。LVAD类型包括HeartMateII,III在多个叶轮速度下,还有HeartMateIII和ProtekDuo的案子.检查ECG频谱图,以确保研究中存在各种类型的EMI。然后用四种去噪技术处理ECG:移动平均滤波器,有限脉冲响应滤波器,快速傅里叶变换,和离散小波变换。
    结果:离散小波变换被证明是最有前途的方法。它提供了一个适合所有人的解决方案,以最少的用户输入实现自动处理,同时保留关键的高频组件并减少LVADEMI伪影。
    结论:我们的研究证明了离散小波变换在LVAD患者中获得高保真ECG的实用性和有效性。该方法可以增强临床诊断和监测。
    BACKGROUND: Electrocardiograms (ECGs) are vital for diagnosing cardiac conditions but obtaining clean signals in Left Ventricular Assist Device (LVAD) patients is hindered by electromagnetic interference (EMI). Traditional filters have limited efficacy. There is a current need for an easy and effective method.
    METHODS: Raw ECG data obtained from 5 patients with LVADs. LVAD types included HeartMate II, III at multiple impeller speeds, and a case with HeartMate III and a ProtekDuo. ECG spectral profiles were examined ensuring the presence of diverse types of EMI in the study. ECGs were then processed with four denoising techniques: Moving Average Filter, Finite Impulse Response Filter, Fast Fourier Transform, and Discrete Wavelet Transform.
    RESULTS: Discrete Wavelet Transform proved as the most promising method. It offered a one solution fits all, enabling automatic processing with minimal user input while preserving crucial high-frequency components and reducing LVAD EMI artifacts.
    CONCLUSIONS: Our study demonstrates the practicality and efficiency of Discrete Wavelet Transform in obtaining high-fidelity ECGs in LVAD patients. This method could enhance clinical diagnosis and monitoring.
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  • 文章类型: Journal Article
    超声脉冲回波技术被广泛用于测量由于管道腐蚀而导致的壁厚减小。超声波监测是非侵入性的,可以在线进行,以评估管道的结构健康。虽然超声波是一种强大的技术,它提出了两个主要困难引起的温度变化在介质被监测:机械组件必须具有高稳定性和超声波传播速度必须考虑到温度变化。在本文中,提出了一种详细的策略来补偿温度变化时传播速度的变化。该方法被认为是自补偿的,因为校准数据是从使用评估中的管道捕获的超声信号中获得的。分析了温度补偿中的系统误差,首先考虑给出参考初始管道厚度,第二,当给出参考声速时。该技术是在实验室条件下通过使用含有沙子的连续流盐水加速腐蚀的闭环进行评估的。在这个测试中,将超声结果与用于确定腐蚀损失的传统试片法进行比较。结果表明,自补偿方法能够对温度波动进行补偿,并且通过超声技术测量的总厚度损失接近通过试样测量的值。最后,测量系统在暴露于阳光下的生产管道中进行了测试。结果表明,自补偿方法可以减少厚度损失读数中的振荡,由温度波动引起的,但是大的温度变化不能完全补偿。该实验还显示了低机械稳定性的影响,这导致了完全无效的结果。
    The ultrasonic pulse-echo technique is widely employed to measure the wall thickness reduction due to corrosion in pipelines. Ultrasonic monitoring is noninvasive and can be performed online to evaluate the structural health of pipelines. Although ultrasound is a robust technique, it presents two main difficulties arising from the temperature variation in the medium being monitored: the mechanical assembly must have high stability and the ultrasonic propagation velocity must take into account the temperature variation. In this paper, a detailed strategy is presented to compensate for changes in the propagation velocity whenever the temperature changes. The method is considered self-compensated because the calibration data is obtained from the ultrasonic signals captured using the pipe under evaluation. The analysis of systematic errors in the temperature compensation is presented, first considering that a reference initial pipe thickness is given, and second when a reference sound velocity is given. The technique was evaluated under laboratory conditions using a closed loop with accelerated corrosion through the use of continuous flow saline water containing sand. In this test, the ultrasonic results were compared with the traditional coupon method used to determine corrosion loss. The results show that the self-compensated method was able to compensate for temperature fluctuations, and the total thickness loss measured by the ultrasound technique was close to the value measured by the coupons. Finally, the measurement system was tested in a production pipeline exposed to sunlight. The results show that the self-compensated method can reduce the oscillations in the thickness loss readings, caused by temperature swings, but large temperature variations cannot be completely compensated for. This experiment also shows the effects of low mechanical stability, which caused completely invalid results.
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  • 文章类型: Journal Article
    GNSS信号容易受到欺骗和干扰,这对关键国家基础设施的安全构成威胁。缺乏具有欺骗和干扰的GNSS数据集,阻碍了GNSS反欺骗和抗干扰技术的研究。本数据文章提供了一个由低成本传感器记录的数据集,该传感器部署在云南大学科学厅5楼的阳台上(25°3\'26\'\'N,102°41\'55\'\'E)。传感器套件包括GNSS天线,u-bloxGNSS接收器和嵌入式计算机。在实验中,使用SDRHackRFOne和商业干扰器不规则地发射包括欺骗和干扰在内的干扰,分别。接收器收集的数据集由两部分组成:(1)原始数据;(2)处理后的数据。原始数据的类型包括硬件信息,卫星信息和GPS接收机参数,Campass,伽利略,GLONASS和QZSS系统。从原始数据中提取处理后的数据,包括信号,多普勒频移,伪距观测,载波相位,位置(纬度,经度,和高度),卫星方位角和仰角,等。提供的数据集对GNSS安全性很有趣,基于科学界的抗干扰和反欺骗机制。
    GNSS signals are vulnerable to spoofing and interference, which poses a threat to the security of critical national infrastructure. GNSS data sets with spoofing and jamming are lacking, which hinders the research of GNSS anti-spoofing and anti-interference techniques. This data article presents a dataset recorded by a low-cost sensor deployed on the balcony at the 5th floor of the Science Hall of Yunnan University (25°3\'26\'\' N, 102°41\'55\'\' E). The sensor suite includes a GNSS antenna, a u-blox GNSS receiver and an embedded computer. In the experiment, interferences including spoofing and jamming were irregularly emitted using a SDR HackRF One and a commercial jammer, respectively. The dataset collected by the receiver consists of two parts: (1) raw data; (2) processed data. The types of the raw data include hardware information, satellite information and receiver parameters of GPS, Campass, Galileo, GLONASS and QZSS systems. The processed data are extracted from the raw data, including the signals, Doppler shift, pseudorange observations, carrier phase, position (latitude, longitude, and altitude), satellite azimuth and elevation angles, etc. The provided datasets are interesting for the GNSS security, anti-jamming and anti-spoofing mechanisms based scientific communities.
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  • 文章类型: Journal Article
    目的:多发性硬化症(MS)是一种影响中枢神经系统(CNS)的神经炎症性疾病,免疫系统瞄准并破坏围绕神经纤维的保护性髓鞘,抑制轴突信号传输。脱髓鞘性视神经炎(ON),常见的MS症状,涉及视神经损伤.我们开发了NeuroVEP,一个便携式的,无线诊断系统,通过耳机中的智能手机提供视觉刺激,并使用自定义脑电图电极从头皮测量视觉皮层的诱发电位。
    方法:使用短2.5分钟全视野视觉诱发电位(ffVEP)测试评估受试者的视力,随后是12.5分钟的多焦点VEP(mfVEP)测试。ffVEP通过分析每只眼睛的P100成分来评估视觉通路的完整性,而mfVEP评估了36个视野区域的异常。广泛的信号处理,特征提取方法,并探索了机器学习算法来分析mfVEP。根据一组视力正常的受试者收集的数据,对患者ffVEP结果的关键指标进行了统计评估。使用具有模拟缺陷的自定义视觉刺激来验证mfVEP结果,该结果产生了91%的分类准确性。
    结果:20名受试者,用NeuroVEP装置和仅递送ffVEP刺激的护理标准(SOC)VEP测试装置测试10个对照和10个具有MS和/或ON的对照。在91%的案例中,NeuroVEP和SOC装置的ffVEP结果一致.如有,NeuroVEPmfVEP结果与Humphrey自动视野检查视野分析非常吻合.从mfVEP数据推断的病变位置与磁共振成像和光学相干断层扫描结果一致。
    结论:这项初步研究表明,NeuroVEP有可能成为一种可靠的,便携式,用于神经视觉障碍的电生理和视野分析的客观诊断装置。
    OBJECTIVE: Multiple sclerosis (MS) is a neuro-inflammatory disease affecting the central nervous system (CNS), where the immune system targets and damages the protective myelin sheath surrounding nerve fibers, inhibiting axonal signal transmission. Demyelinating optic neuritis (ON), a common MS symptom, involves optic nerve damage. We\'ve developed NeuroVEP, a portable, wireless diagnostic system that delivers visual stimuli through a smartphone in a headset and measures evoked potentials at the visual cortex from the scalp using custom electroencephalography electrodes.
    METHODS: Subject vision is evaluated using a short 2.5-min full-field visual evoked potentials (ffVEP) test, followed by a 12.5-min multifocal VEP (mfVEP) test. The ffVEP evaluates the integrity of the visual pathway by analyzing the P100 component from each eye, while the mfVEP evaluates 36 individual regions of the visual field for abnormalities. Extensive signal processing, feature extraction methods, and machine learning algorithms were explored for analyzing the mfVEPs. Key metrics from patients\' ffVEP results were statistically evaluated against data collected from a group of subjects with normal vision. Custom visual stimuli with simulated defects were used to validate the mfVEP results which yielded 91% accuracy of classification.
    RESULTS: 20 subjects, 10 controls and 10 with MS and/or ON were tested with the NeuroVEP device and a standard-of-care (SOC) VEP testing device which delivers only ffVEP stimuli. In 91% of the cases, the ffVEP results agreed between NeuroVEP and SOC device. Where available, the NeuroVEP mfVEP results were in good agreement with Humphrey Automated Perimetry visual field analysis. The lesion locations deduced from the mfVEP data were consistent with Magnetic Resonance Imaging and Optical Coherence Tomography findings.
    CONCLUSIONS: This pilot study indicates that NeuroVEP has the potential to be a reliable, portable, and objective diagnostic device for electrophysiology and visual field analysis for neuro-visual disorders.
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  • 文章类型: Journal Article
    随着万物互联(IoE)的出现,完全互连系统的概念已经成为现实,不同工业系统之间的无缝通信和互操作性的需求比以往任何时候都更加紧迫。为了应对海量数据流量带来的挑战,我们展示了工业制造过程中语义信息处理的潜力,然后提出了一个简短的工业网络语义处理和通信系统框架。特别是,该方案具有任务导向和协作处理的特点。为了说明其适用性,我们提供了时间序列和图像的例子,作为典型的工业数据源,对于实际任务,如生命周期估计和表面缺陷检测。仿真结果表明,语义信息处理实现了一种更有效的信息处理和交换方式,与传统方法相比,这对于处理未来互联工业网络的需求至关重要。
    With the advent of the Internet of Everything (IoE), the concept of fully interconnected systems has become a reality, and the need for seamless communication and interoperability among different industrial systems has become more pressing than ever before. To address the challenges posed by massive data traffic, we demonstrate the potentials of semantic information processing in industrial manufacturing processes and then propose a brief framework of semantic processing and communication system for industrial network. In particular, the scheme is featured with task-orientation and collaborative processing. To illustrate its applicability, we provide examples of time series and images, as typical industrial data sources, for practical tasks, such as lifecycle estimation and surface defect detection. Simulation results show that semantic information processing achieves a more efficient way of information processing and exchanging, compared to conventional methods, which is crucial for handling the demands of future interconnected industrial networks.
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