Abstract This experiment was to study the feasibility from direct observation of muscle contraction of the lower extremity fromelectrical stimulation threshold of nerve fascicle in identifying the Iα intrafusal afferent fibers during selective posterior rhizotomy (SPR) and to investigate the clinical relationship between the muscle spasm and the electrical stimulation of nerve fascicles. The electrical stimulation threshold of all nerve fascicles in 36 cases during SPR were analysed statistically. The results showed that there was a significant difference between the electrical stimulation threshold of the severed nerve fascicles and intact nerve fascicles no matter the nerve root or each posterior nerve rootlet was examined. It was simple and reliable for surgeons to identify correctly the Iα intrafusal afferent fibers intraoperatively from direct observation of the electrical stimulation threshold of nerve fascicle.
The brain-computer interface (BCI) systems used in practical applications require as few electroencephalogram (EEG) acquisition channels as possible. However, when it is reduced to one channel, it is difficult to remove the electrooculogram (EOG) artifacts. Therefore, this paper proposed an EOG artifact removal algorithm based on wavelet transform and ensemble empirical mode decomposition. Firstly, the single channel EEG signal is subjected to wavelet transform, and the wavelet components which involve EOG artifact are decomposed by ensemble empirical mode decomposition. Then the predefined autocorrelation coefficient threshold is used to automatically select and remove the intrinsic modal functions which mainly composed of EOG components. And finally the ‘clean’ EEG signal is reconstructed. The comparative experiments on the simulation data and the real data show that the algorithm proposed in this paper solves the problem of automatic removal of EOG artifacts in single-channel EEG signals. It can effectively remove the EOG artifacts when causes less EEG distortion and has less algorithm complexity at the same time. It helps to promote the BCI technology out of the laboratory and toward commercial application.
Objective To introduce the multivariate random effects model (MREM) in the meta-analysis of diagnostic tests with multiple thresholds. Methods This paper expanded and extended the bivariate random effects model (BREM) to develop the MREM, and implemented it in the SAS Proc NLMIXED procedure. Results The MREM could obtain the study specific ROC curve for each study through empirical Bayes estimation, and the summary ROC curve located in between all study specific ROC curves evenly, while the BREM couldn’t obtain the study specific ROC curve. In addition, in the aspect of parameters estimation, the MREM didn’t depend on the choice of the diagnosis threshold and the type of SROC. The MREM could get only one SROC curve and its AUC was between the AUC of the 5 types of SROC from BREM, so it could avoid overestimation or underestimation. Conclusion The MREM can fully exploit the data, obtain stable and reliable results, and have a good application value in meta-analysis of diagnostic tests with multiple thresholds.
Central serous chorioretinopathy (CSC) is a common macular disease, which can lead to the loss of central vision in young patients. Although the disease is self-limited to some extent, there is no shortage of patients with prolonged course and recurrent attacks, eventually leading to irreversible visual impairment. Therefore, taking reasonable treatment in a certain period is particularly important for the visual prognosis of patients. Although thermal laser photocoagulation of leakage points and photodynamic therapy (PDT) have achieved good effects, there are risks of retinal damage and retinal pigment epithelium atrophy. Subthreshold micropulse laser (SMLP) is a kind of subthreshold short pulse laser, which does not cause visible damage to the retina and is safer. In the era of lack of PDT drugs, SMLP has gradually become an important means of clinical treatment for CSC, especially for patients with no obvious leakage point or subfoveal leakage point. An in-depth understanding of the mechanism of action of SMLP and its efficacy and safety in the treatment of CSC is helpful for the promotion and application of SMLP in the clinical treatment of CSC.
The paper introduces a training system for foot ulcer patients based on three axis accelerometer, which uses three axis accelerometer and Apple mobile phone platform to guide foot ulcer patients to carry out a variety of lower limb muscle tissues training. The acceleration values of three directions for the foot training is obtained by analog-to-digital conversion and transmitted to the Apple mobile phone via its Bluetooth low energy. The Apple mobile phone accomplishes acceleration data preprocessing, numerical filtering and adaptive dual-threshold processing by our developed application program, so as to achieve the purpose of foot gesture recognition. The experimental result shows that the design can effectively present the training situation and effect of patients, encourage patients to adhere to the training, and provide some reference data for doctors and patients.
ObjectiveTo investigate the time relationship of the change, and diagnostic accuracy and sensitivity between retinal light threshold fluctuations (LTF) and retinal nerve fiber layer (RNFL) and ganglion cell complex(GCC) thickness on high-risk primary open-angle glaucoma (POAG). MethodsTotally 319 patients (319 eyes) with high-risk in POAG from the First Affiliated Hospital of Kunming Medical Universityand during December 2009 and December 2017, 50 healthy individuals (50 eyes) as control were collected in this longitudinal cohort study. Visual field and OCT were reviewed every 6 months on the high-risk group and every 12 months on the control group. High-risk groups inclusion criteria: vertical C/D≥0.6; early visual field defect (according to glaucoma visual field damage GSS2 quantitative grading standards, mean deviation and pattern standard deviation of central field exceeds the border as an early visual field defect); continuous repeatable results. The first field and OCT results in the absence of visual field defects and C/D≥0.6, which were conformed reliability indicators and removed learning effects as a baseline. When patients achieve POAG diagnosis criteria first time which was recorded as a turning point. And they were divided into early group meanwhile were ended of follow-up. After the last follow-up, the inspection data was segmented counted in yearly interval. The changes of LTF, thickness of RNFL and GCC during the follow-up period in the early POAG group and the control group were observed. The loss rate and change rate in each period were compared for the assessment of their trends with time. Followed by calculation of the area under receiver operating curves (AUC) to compare the predicted value of POAG and the sensitivity at 95% specificity in each period. ResultsAfter last follow-up, totally 67 patients 67 eyes (early POAG group, 37 males and 30 females) were entered the turning point. The mean follow-up of the early POAG group and the control group were 6.6 and 6.4 years. The average RNFL thickness was 79.05±8.09 μm, GCC thickness was 71.58±8.41 μm, LTF was −6.05±7.02 dB in early POAG group. The average RNFL thickness was 93.49±6.24 μm, GCC thickness was 79.72±6.32 μm, LTF was −0.31±0.58 dB in the control group. The differences of LTF and the thickness of RNFL and GCC were statistically significant (t=−5.97, −10.42, −5.60; P＜0.001). The AUC of RNFL, GCC thickness and LTF increased with time in the early POAG group. The sensitivity was gradually increased at 95% specificity: 5th year before to at turning point, RNFL thickness AUC was 0.15, 0.65, 0.71, 0.77, 0.85, 0.92, and sensitivity was 20%, 56%, 61%, 65%, 70%, 76%, respectively; GCC thickness AUC was 0.12, 0.53, 0.69, 0.74, 0.82, 0.90, and sensitivity was 14%, 53%, 69%, 74%, 82%, 90%, respectively; the AUC of LTF was 0.10, 0.21, 0.33, 0.75, 0.86, 0.91, and sensitivity was 7%, 17%, 44%, 65%, 78%, 87%, respectively. ConclusionsThe earliest time of structural functional damage of POAG is at the 4th year before confirmed, simultaneous RNFL diagnosis accuracy and sensitivity are better than GCC and LTF. The earliest time of visual functional damage of POAG is at the 2th year before confirmed, simultaneous LTF diagnosis accuracy and sensitivity are better than RNFL and GCC.
The limitation of resource of blood and risk of transfusion-transmitted infections contribute to development and generalization of restrictive transfusion strategy. However, advanced evidences of clinical trials indicated a restrictive transfusion threshold after cardiac surgery was not superior to a liberal threshold with respect to morbidity or health care costs. It is time to optimize patient blood management but not free-transfusion and increase of risk of patients. The duration of red-cell storage was not associated with significant differences in the mortality and morbidity of patients. Three new pathogen-reduction technologies and pharmaceutical intervenes may provide safe of transfusion and improvement of outcomes.
Aiming at the defects that the traditional pulse transit time (PTT) detection methods are sensitive to changes in photoplethysmography (PPG) signal and require heavy computation, we proposed a new algorithm to detect PTT based on waveform time domain feature and dynamic difference threshold. We calculated the PTT by using dynamic difference threshold method to detect the R-waves of electrocardiogram (ECG), shortening the main peak detection range in PPG signal according to the characteristics of the waveform time domain, and using R wave to detect the main peak of PPG signal. We used the American MIMIC database and laboratory test data to validate the algorithm. The experimental results showed that the proposed method could accurately extract the feature points and detect PTT, and the PTT detection accuracies of the measurements and the database samples were 99.1% and 97.5%, respectively. So the proposed method could be better than the traditional methods.
ObjectiveTo observe the safety and effectiveness of targeted navigation laser with continuous wave threshold power in the treatment of chronic central serous chorioretinopathy (CCSC).MethodsA retrospective clinical study. From November 2018 to June 2020, 28 eyes of 28 patients with CCSC diagnosed in the Eye Hospital of Nanjing Medical University were included in the study. Among them, there were 17 males with 17 eyes and 11 females with 11 eyes; all of them had a monocular disease. The average age of the patients was 36.24±5.14 years, and the average course of the diseases was 4.7±1.3 months. All affected eyes underwent best corrected visual acuity (BCVA), fluorescein fundus angiography, fundus autofluorescence, frequency domain optical coherence tomography and angiography, multifocal electroretinogram (mf-ERG) and micro field inspection. BCVA was carried out using the international standard visual acuity chart, which was converted into the logarithmic minimum angle of resolution (logMAR) visual acuity during statistics. A targeted navigation laser system was used for continuous wave power therapy under the threshold. Two weeks and 1, 3 months after treatment, the same equipment and methods as before treatment were used to perform related examinations to observe the BCVA, subfoveal choroidal thickness (SFCT), foveal retinal thickness (CMT), the mean light sensitivity (MS) in the 10° range of the macular center, and the amplitude density of P1 wave at ring 1 and 2. The t test was used to compare CMT, SFCT, retinal amplitude density and MS before and after treatment.ResultsBefore treatment and 2 weeks, 1 and 3 months after treatment, the average logMAR BCVA of the eyes were 0.74±0.16, 0.57±0.16, 0.22±0.05, 0.21±0.06, and the average CMT was 512.33±31.56, 350.40±36.61, 256.49±22.38, 253.45±23.65 μm respectively, the average SFCT was 462.82±25.38, 462.37±39.54, 461.51±29.36, 461.25±34.55 μm, the average MS was 16.32±5.41, 17.53±4.23, 19.52±4.12, 21.35±2.77 dB respectively. At different times before and after treatment, BCVA (t=6.52, 5.71, 6.01; P=0.00, 0.00, 0.00), CMT (t=3.08, 6.57, 4.90; P=0.01, 0.00, 0.00), SFCT (t=7.01, 6.54, 4.85; P=0.08, 0.07, 0.17), MS (t=6.17, 4.25, 5.46; P=0.02, 0.00, 0.00), the difference was statistically significant. The amplitude density of P1 wave at ring 1 in the affected eye was 64.37±18.25, 85.31±13.98, 98.35±14.52, 98.40±22.17 nV/deg2, and the amplitude density of P1 wave at ring2 was 36.12±18.32, 44.02±17.15, 62.35±14.85, 63.17±15.79 nV/deg2. The amplitude density of P1 wave at ring 1 (t=5.11, 9.03, 4.27; P=0.03, 0.00, 0.00) and ring 2 (t=5.11, 9.03, 4.27; P=0.03, 0.00, 0.00) before and after treatment showed statistical significance.ConclusionTargeted navigation laser continuous wave threshold power treatment for CCSC can increase the BCVA, macular retinal amplitude density and macular foveal MS, and reduce CMT and SFCT.
At present, fatigue state monitoring of upper limb movement generally relies solely on surface electromyographic signal (sEMG) to identify and classify fatigue, resulting in unstable results and certain limitations. This paper introduces the sEMG signal recognition and motion capture technology into the fatigue state monitoring process and proposes a fatigue analysis method combining an improved EMG fatigue threshold algorithm and biomechanical analysis. In this study, the right upper limb load elbow flexion test was used to simultaneously collect the biceps brachii sEMG signal and upper limb motion capture data, and at the same time the Borg Fatigue Subjective and Self-awareness Scale were used to record the fatigue feelings of the subjects. Then, the fatigue analysis method combining the EMG fatigue threshold algorithm and the biomechanical analysis was combined with four single types: mean power frequency (MPF), spectral moments ratio (SMR), fuzzy approximate entropy (fApEn) and Lempel-Ziv complexity (LZC). The test results of the evaluation index fatigue evaluation method were compared. The test results show that the method in this paper has a recognition rate of 98.6% for the overall fatigue state and 97%, 100%, and 99% for the three states of ease, transition and fatigue, which are more advantageous than other methods. The research results of this paper prove that the method in this paper can effectively prevent secondary injury caused by overtraining during upper limb exercises, and is of great significance for fatigue monitoring.