Psychological stress recognition from heart rate variability parameters based on field programmable gate arrays.

Psychological stress is a big threat to people's health. Early detection of psychological stress is important. The design of a stress recognition device based on the ECG (electrocardiograph) signal is presented in this paper. The device features intelligence, precision, portability, fast response, and low power consumption. In the design, the ECG signals are acquired by the AD8232 ECG module and processed by a low power consumption FPGA (Field Programmable Gated Array) development board PYNQ-Z2. Meanwhile, a modified Deep Forest model named Aw-Deep Forest (Adaptive Weight Deep Forest) is proposed. The Aw-Deep Forest has better performance than the Deep Forest model because it improves the fitting quality of the forests. By implementing the Aw-Deep Forest model on the FPGA, the device can assess people's state of psychological stress by analyzing the HRV (heart rate variability) parameters from ECG data. This paper mainly introduces the detailed process of ECG signal collecting, filtering, analog signal to digital signal conversion, HRV parameter analysis, and psychological stress recognition with Aw-Deep Forest. The final accuracy is 81.39%.

Short-time speaker verification with different speaking style utterances.

In recent years, great progress has been made in the technical aspects of automatic speaker verification (ASV). However, the promotion of ASV technology is still a very challenging issue, because most technologies are still very sensitive to new, unknown and spoofing conditions. Most previous studies focused on extracting target speaker information from natural speech. This paper aims to design a new ASV corpus with multi-speaking styles and investigate the ASV robustness to these different speaking styles. We first release this corpus in the Zenodo website for public research, in which each speaker has several text-dependent and text-independent singing, humming and normal reading speech utterances. Then, we investigate the speaker discrimination of each speaking style in the feature space. Furthermore, the intra and inter-speaker variabilities in each different speaking style and cross-speaking styles are investigated in both text-dependent and text-independent ASV tasks. Conventional Gaussian Mixture Model (GMM), and the state-of-the-art x-vector are used to build ASV systems. Experimental results show that the voiceprint information in humming and singing speech are more distinguishable than that in normal reading speech for conventional ASV systems. Furthermore, we find that combing the three speaking styles can significantly improve the x-vector based ASV system, even when only limited gains are obtained by conventional GMM-based systems.

Cortical neural modulation by previous trial outcome differentiates fast- from slow-learning rats on a visuomotor directional choice task.

To better understand the neural cortical underpinnings that explain behavioral differences in learning rate, we recorded single-unit activity in primary motor (M1) and secondary motor (M2) areas while rats learned to perform a directional (left or right) operant visuomotor association task. Analysis of neural activity during the early portion of the cue period showed that neural modulation in the motor cortex was most strongly associated with two task factors: the previous trial outcome (success or error) and the current trial's directional choice (left or right). Furthermore, the fast learners, defined as those who had steeper learning curves and required fewer learning sessions to reach criterion performance, encoded the previous trial outcome factor more strongly than the directional choice factor. Conversely, the slow learners encoded directional choice more strongly than previous trial outcome. These differences in task factor encoding were observed in both the percentage of neurons and the neural modulation depth. These results suggest that fast learning is accompanied by a stronger component of previous trial outcome in the modulation representation present in motor cortex, which therefore may be a contributing factor to behavioral differences in learning rate. NEW & NOTEWORTHY We chronically recorded neural activity as rats learned a visuomotor directional choice task from a naive state. Learning rates varied. Single-unit neural modulation of two motor areas revealed that the fast learners encoded previous trial outcome more strongly than directional choice, whereas the reverse was true for slow learners. This finding provides novel evidence that rat learning rate is strongly correlated with the strength of neural modulation by previous trial outcome in motor cortex.

Decoding arm speed during reaching.

Neural prostheses decode intention from cortical activity to restore upper extremity movement. Typical decoding algorithms extract velocity-a vector quantity with direction and magnitude (speed) -from neuronal firing rates. Standard decoding algorithms accurately recover arm direction, but the extraction of speed has proven more difficult. We show that this difficulty is due to the way speed is encoded by individual neurons and demonstrate how standard encoding-decoding procedures produce characteristic errors. These problems are addressed using alternative brain-computer interface (BCI) algorithms that accommodate nonlinear encoding of speed and direction. Our BCI approach leads to skillful control of both direction and speed as demonstrated by stereotypic bell-shaped speed profiles, straight trajectories, and steady cursor positions before and after the movement.

Interaction between microRNA expression and classical risk factors in the risk of coronary heart disease.

The aim of this study was to identify the synergistic effect of microRNA expression with classical risk factors of coronary heart disease (CHD) and to explore their diagnostic value for coronary stenotic lesions in subjects with CHD. Plasma samples were obtained from 66 subjects with CHD and from 58 control individuals. A quantitative reverse-transcription PCR (RT-qPCR) assay was conducted to confirm the relative expressions of the known CHD-related miRNAs. The severity of coronary atherosclerosis was based on the Gensini scoring system. The expression of miR-125b in plasma of the CHD group was lower than that of the non-CHD group (0.14 ± 0.09 vs. 0.18 ± 0.10, p = 0.055), and the miR-125b levels significantly decreased following an increasing Gensini score (P = 0.037). Spearman correlation analyses indicated the Gensini score was negatively associated with miR-125b (r = -0.215, p = 0.017). Of all the miRNAs, miR-125b showed the lowest AUC (0.405; 95% CI: 0.305 ~ 0.506, p = 0.070). We found several synergistic effects between miR-125b and classical risk factors, such as age, sex, CR, FBG and HDL-C; the proportion of CHD attributable to the interaction of miR-125b and age was as high as 80%. Therefore, miR-125b was shown to play an important role in individual's susceptibility to developing CHD.

Improved discriminability of spatiotemporal neural patterns in rat motor cortical areas as directional choice learning progresses.

Animals learn to choose a proper action among alternatives to improve their odds of success in food foraging and other activities critical for survival. Through trial-and-error, they learn correct associations between their choices and external stimuli. While a neural network that underlies such learning process has been identified at a high level, it is still unclear how individual neurons and a neural ensemble adapt as learning progresses. In this study, we monitored the activity of single units in the rat medial and lateral agranular (AGm and AGl, respectively) areas as rats learned to make a left or right side lever press in response to a left or right side light cue. We noticed that rat movement parameters during the performance of the directional choice task quickly became stereotyped during the first 2-3 days or sessions. But learning the directional choice problem took weeks to occur. Accompanying rats' behavioral performance adaptation, we observed neural modulation by directional choice in recorded single units. Our analysis shows that ensemble mean firing rates in the cue-on period did not change significantly as learning progressed, and the ensemble mean rate difference between left and right side choices did not show a clear trend of change either. However, the spatiotemporal firing patterns of the neural ensemble exhibited improved discriminability between the two directional choices through learning. These results suggest a spatiotemporal neural coding scheme in a motor cortical neural ensemble that may be responsible for and contributing to learning the directional choice task.

Cortical neural responses to previous trial outcome during learning of a directional choice task.

The outcomes that result from previous behavior affect future choices in several ways, but the neural mechanisms underlying these effects remain to be determined. Previous studies have shown that the lateral (AGl) and medial (AGm) agranular areas of the rat frontal cortex are involved in the learning and selection of action. Here we describe the activity of single neurons in AGl and AGm as rats learned to perform a directional choice task. Our analysis shows that single-cell activity in AGl and AGm was modulated by the outcome of the previous trial. A larger proportion of neurons encoded the previous trial's outcome shortly after cue onset than during other time periods of a trial. Most of these neurons had greater activity after correct trials than after error trials, a difference that increased as behavioral performance improved. The number of neurons encoding the previous trial's outcome correlated positively with performance accuracy. In summary, we found that neurons in both AGl and AGm encode the outcome of the immediately preceding trial, information that might play a role in the successful selection of action based on past experience.

Hemoglobin A1c risk score for the prediction of coronary artery disease in subjects with angiographically diagnosed coronary atherosclerosis.

OBJECTIVE: To develop a risk score by incorporating Hemoglobin A1c(HbA1c) with traditional risk factors for the prediction of coronary artery disease (CAD) in Chinese subjects. METHODS: A total of 196 consecutive subjects (131 males and 65 females) aged 38-89 years who underwent coronary angiography were enrolled in this study. HbA1c risk score sheets for the prediction of CAD were developed using age, gender and HbA1c. A receiver-operating characteristic curve analysis was used to determine the optimum cut-off levels of the HbA1c risk score for predicting CAD. RESULTS: In the ROC curve analysis, the optimal cut-off value of the HbA1c score for predicting CAD was 5.1, with a sensitivity of 72.0% and a specificity of 75.5% (area under the curve 0.781, 95% confidence interval 0.709 to 0.854, p=0.000). CONCLUSIONS: The HbA1c score system is a simple and feasible method that can be used for the prediction of CAD. Large-scale studies are needed to further substantiate these results.

Evaluation of penile erection rigidity in healthy men using virtual touch tissue quantification.

BACKGROUND: The aim of the study was to describe the shear wave velocity (SWV) values of the penis by virtual touch tissue quantification (VTTQ) and to examine the clinical usefulness of this procedure in evaluation of the rigidity changes in penile erection. PATIENTS AND METHODS.: VTTQ was performed in 37 healthy volunteers. In the course of erection, SWV values of glans penis, corpus penis and radix penis were quantified and grades of erection were documented. The SWV values at different grades of erection were compared. RESULTS: The axial and radial SWV values of glans penis, corpus penis and radix penis all significantly decreased from Grade 0 to Grade 4 of erection. At Grade 4, they were less than one-third of that at Grade 0 (axial direction: 0.79 ± 0.13 vs. 2.79 ± 0.32 for glans penis, P<0.001; 0.77 ± 0.19 vs. 2.84 ± 0.30 for corpus penis, P<0.001 and 0.76 ± 0.15 vs. 2.81 ± 0.34 for radix penis, P<0.001; radial direction: 0.82 ± 0.15 vs. 2.83 ± 0.31 for glans penis, P<0.001; 0.79 ± 0.18 vs. 2.81 ± 0.27 for corpus penis, P<0.001 and 0.81 ± 0.16 vs. 2.82 ± 0.33 for radix penis, P<0.001). CONCLUSIONS: VTTQ can provide numerical measurements of penile rigidity and can effectively and sensitively indicate the axial and radial rigidity changes in penile erection, which provide a new approach to assessing the erectile function.

A comparison of virtual touch tissue quantification and digital rectal examination for discrimination between prostate cancer and benign prostatic hyperplasia.

BACKGROUND: Virtual touch tissue quantification (VTTQ) is a new, promising technique for detecting the stiffness of tissues. The aim of this study is to compare the performance of VTTQ and digital rectal examination (DRE) in discrimination between prostate cancer and benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: VTTQ was performed in 209 prostate nodular lesions of 107 patients with BPH and suspected prostate cancer before the prostate histopathologic examination. The shear wave velocity (SWV) at each nodular lesion was quantified by implementing an acoustic radiation force impulse (ARFI). The performance of VTTQ and DRE in discrimination between prostate cancer and BPH was compared. The diagnostic value of VTTQ and DRE for prostate cancer was evaluated in terms of the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. RESULTS: Prostate cancer was detected in 57 prostate nodular lesions by histopathologic examination. The SWV values (m/s) were significantly greater in prostate cancer and BPH than in normal prostate (2.37 ± 0.94, 1.98 ± 0.82 vs. 1.34 ± 0.47). The area under the receiver operating characteristic curve (AUC) for VTTQ (SWV>2.5m/s) to differentiate prostate nodules as benign hyperplasia or malignancy was 0.86, while it was 0.67 for DRE. The diagnostic sensitivity, specificity, PPV, NPV and accuracy were 71.93 %, 87.5 %, 68.33 %, 89.26 %, 83.25 %, respectively for VTTQ (SWV>2.5m/s), whereas they were 33.33 %, 81.57 %, 40.43 %, 76.54 %, 68.42 % respectively for DRE. CONCLUSIONS: VTTQ can effectively detect the stiffness of prostate nodular lesions, which has a significantly higher performance than DRE in discrimination between prostate cancer and BPH.

Reduced difference in left ventricular mass at end diastole and peak systole is a predictor of major stenosis of the left coronary artery territory.

OBJECTIVES: To evaluate the feasibility of using the difference in left ventricular (LV) mass at end diastole and peak systole as determined by area-length calculation methods to detect major stenosis of the left coronary artery territory by 2-dimensional echocardiography. METHODS: The LV mass at end diastole, LV mass at peak systole, and LV mass difference between end diastole and peak systole were measured and compared between 39 healthy participants and 40 patients with coronary artery disease (CAD) referred for coronary angiography. The mass difference was compared to the mean percent stenosis diameter by linear correlation analysis, and its performance in discrimination between the patients with CAD and the healthy participants was analyzed. RESULTS: Compared to the healthy participants, the patients with CAD had significantly higher LV mass at peak systole (mean ± SD, 101.97 ± 30.34 versus 89.87 ± 28.71 g; P< .05) and a lower mass difference between end diastole and peak systole (21.36 ± 17.55 versus 40.12 ± 14.37 g; P < .01). The mass difference correlated significantly with the mean percent stenosis diameter (r = -0.71; P < .001) in patients with CAD . With the use of the mass difference as the criterion to distinguish patients with CAD from healthy participants, the area under the receiver operating characteristic curve was 0.81 (P < .05). The sensitivity, specificity, and accuracy for the prediction of major stenosis (>70%) of the left coronary artery were 82.35%, 70.37%, and 75% respectively for a mass difference of less than 30.2 g. CONCLUSIONS: The LV mass difference between end diastole and peak systole can effectively reflect the diameter changes of the left coronary artery, and a reduced mass difference is a sensitive and specific predictor of major stenosis of the left coronary artery territory.

Coalition of DNA polymorphisms of ApoB and ApoAI genes is related with coronary artery disease in Kazaks.

OBJECTIVE: To explore the relationship between polymorphisms of XbaI and MspI loci of apolipoprotein B (ApoB) gene and -75 bp, +83 bp loci of apolipoprotein AI (ApoAI) gene and coronary heart disease (CHD) in Kazaks of Xinjiang Uyghur Autonomous Region, China. METHODS: These loci were analyzed by PCR-restriction fragment length polymorphism (PCR-PFLP). Two hundred and five patients with CHD and two hundred and thirty six controls were involved. RESULTS: There were significant distinctions among low-density lipoprotein cholesterol (LDL-C), triglyceride (TG) and the ApoAI/ApoB ratio between the two groups, but no significant distinction among the polymorphism frequencies of the four sites between the two groups. The polymorphism coalition frequency of X(--)/Ms(++)/M(1) (+-)/M(2) (++) (named Coalition 11) was significantly higher in CHD compared to the control group (14.6% vs. 7.2%, P < 0.05). The level of total cholesterol (TC) in Coalition 11 was significantly higher and the level of the ApoAI/ApoB ratio in Coalition 11 was significantly lower than Coalition 1∼10 in CHD patients. The level of the ApoAI/ApoB ratio of Coalition 11 was significantly lower than the Coalition 1∼10 in control group. The levels of ApoAI/ApoB ratio of Coalition 3 were significantly higher compared to Coalition 11 in the two groups, respectively. The level of LDL-C of Coalition 3 was significantly lower than in the Coalition 11 in control group. The level of TC of Coalition 5 was significantly higher than Coalition 3 in the CHD group. The level of the ApoAI/ApoB ratio of Coalition 5 was significantly lower than in Coalition 3 or Coalition 1∼10 of the two groups, respectively. The level of LDL-C of Coalition 5 was significantly higher than in Coalition 3 in control group. The ratio of ApoAI/ApoB was negatively related to TC, LDL-C and was positively related to HDL-C, both in CHD and control groups. CONCLUSION: Coalition 11 of the 4 loci polymorphisms of the ApoB and ApoAI genes was correlated with CHD in Kazaks, and perhaps the ratio of ApoAI/ApoB was the most diagnostic parameter related with CHD among all lipid parameters. CHD may also be associated with Coalition 5, and, perhaps, Coalition 3 may have been confirmed as a protection factor against CHD, if more samples were enrolled.

Relationship between brachial-ankle pulse wave velocity and cardiovascular risk factors: a multi-ethnic study.

OBJECTIVE: The objective of the present multi-ethnic study was to explore whether an association exists between brachial-ankle pulse wave velocity (baPWV) and cardiovascular risk factors in China. METHODS: Two hundred sixty-four adult subjects (152 subjects were of Han nationality, 70 subjects were from Uygur, 19 subjects were from Kazakh, 15 subjects were from Hui, and 8 subjects were of other nationalities.) aged 30-82 years were enrolled in the present study. The subjects' anthropometric, baPWV and laboratory measurements were recorded. RESULTS: Age (p=0.000), systolic blood pressure (p=0.000), diastolic blood pressure (p=0.002), fasting blood glucose (p=0.000), and hemoglobin (p=0.019) differed significantly among the subjects in the baPWV quartile. Spearman correlation analyses indicated that baPWV was significantly and positively associated with age (r=0.584, p=0.000), systolic blood pressure (r=0.396, p=0.000), diastolic blood pressure (r=0.217, p=0.000), and fasting blood glucose (r=0.231, p=0.000). baPWV was significantly and negatively associated with erythrocyte number (r=-0.181, p=0.003) and hemoglobin (r=-0.192, p=0.002) levels. Multiple regression analyses suggested that age (ß=0.573, p=0.000), systolic blood pressure (ß=0.181, p=0.003), triglycerides (ß=0.160, p=0.008), and cholesterol (ß=0.132, p=0.020) were independently associated with baPWV. CONCLUSION: Age, SBP, triglycerides, and cholesterol levels are independently and positively associated with baPWV.

Reduced antegrade flow in the coronary sinus is a predictor of coronary artery stenosis in hypertensive patients.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of assessing blood flow in the coronary sinus by transthoracic Doppler echocardiography for detecting coronary artery stenosis in hypertensive patients. METHODS: Flow in the coronary sinus was studied in 105 participants who all had undergone coronary angiography: 35 nonhypertensive patients, 34 hypertensive patients without coronary artery disease (CAD), and 36 hypertensive patients with CAD. The antegrade phase of flow in the coronary sinus was analyzed and compared among the groups. Multivariate analysis for blood flow and coronary artery stenosis was done. RESULTS: Compared with the nonhypertensive patients, the hypertensive patients without CAD had significantly higher blood flow (9.36 ± 5.94 vs 5.84 ± 2.91 mL/stroke and 584.45 ± 177.32 vs 327.68 ± 125.48 mL/min, respectively; P < .001) in the coronary sinus. Compared with the hypertensive patients without CAD, those with CAD had significantly lower blood flow (5.18 ± 0.72 vs 9.36 ± 5.94 mL/stroke and 352.51 ± 156.18 vs 584.45 ± 177.32 mL/min; P < .001) and a lower velocity time integral (13.14 ± 2.51 vs 19.85 ± 4.89 cm; P < .01). Stepwise multiple regression analysis indicated that the coronary sinus diameter, velocity time integral, and heart rate significantly correlated with the blood flow per minute in the coronary sinus in each group, and the flow per minute was the independent determinant of the percent stenosis diameter. The sensitivity, specificity, and accuracy for the prediction of severe stenosis (>70%) in the left coronary artery were 91.07%, 87.76%, and 88.49% for blood flow of less than 220 mL/min in the coronary sinus. CONCLUSIONS: Transthoracic Doppler echocardiography can effectively depict blood flow changes in the coronary sinus, and reduced antegrade flow is a sensitive and specific predictor of coronary artery stenosis in hypertensive patients.

A novel and simple approach to distinguish chronic prostatitis/ chronic pelvic pain syndrome IIIb from IIIa using virtual touch tissue quantification.

Virtual touch tissue quantification (VTTQ) is a new, promising technique for detecting the stiffness of tissues. To evaluate the performance of VTTQ in discrimination between chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS) IIIa and IIIb, VTTQ was performed in 147 patients with clinical definite CP/CPPS. The shear wave velocity (SWV) at inner gland and outer gland was quantified by implementing an acoustic radiation force impulse. The performance of different ratios of SWV at outer gland and inner gland in discrimination between CP/CPPS IIIa and IIIb was compared. CP/CPPS IIIb and IIIa was detected in 69 and 78 patients, respectively. The SWV values of outer gland in the patients with CP/CPPS IIIa were significantly greater than that of inner gland, while there were no significant difference between outer gland and inner gland in the patients with CP/CPPS IIIb. The area under the receiver operating characteristic curve for the ratio one (<1.5) of SWV at outer gland and inner gland to distinguish CP/CPPS IIIb from IIIa was 0.72, while it was 0.88 for the ratio two (<1.1). The diagnostic sensitivity, specificity and accuracy for CP/CPPS IIIb were 100%, 69.2%, 83.7%, respectively for the ratio one and 100%, 84.6%, 91.8%, respectively for the ratio two. These data suggested that CP/CPPS IIIa and IIIb have different SWV values in inner gland and outer gland, and VTTQ can effectively distinguish CP/CPPS IIIb from CP/CPPS IIIa using the ratio of SWV at outer gland and inner gland.

The tissue velocity imaging and strain rate imaging in the assessment of interatrial electromechanical conduction in patients with sick sinus syndrome before and after pacemaker implantation.

Tissue velocity imaging (TVI) and strain rate imaging (SRI) were recently introduced to quantify myocardial mechanical activity in patients receiving cardiac resynchronization therapy. To clear whether atrial-demand-based (AAI) (R) atrial pacing can fully simulate the electromechanical conduction of physiological state and to clarify which one is more appropriate for the assessment of electromechanical activity of the heart between TVI and SRI, 30 normal subjects and 31 patients with sick sinus syndrome (SSS) before and after AAI(R) pacemaker implantation (PI) were investigated in this study. The results showed that the time intervals (ms), P-SRa assessed by SRI (not P-Va assessed by TVI) prolonged step by step from the lateral wall of the right atrium (RA), the interatrial septum (IAS) and the left atrium (LA) in normal subjects(5.01±0.62, 17.05±3.54 and 45.09±12.26, p<0.01). P-Va and P-SRa did not differ at the RA, IAS and LA in patients with SSS before PI (p>0.05), and they were significant longer than those of normal subjects (p<0.01). However, they shortened to normal levels in patients with SSS after PI and P-SRa showed again the trend of gradually prolonging from the RA, IAS to LA. At the same time, the peak velocities and the peak strain rates during atrial contraction also returned to normal values from lower levels. These data suggested that AAI(R) atrial pacing can successfully reverse the abnormal interatrial electromechanical conduction in patients with SSS, and SRI is more appropriate for the assessment of the electromechanical activity of atrial wall than TVI.

A novel approach to assessing changes in prostate stiffness with age using virtual touch tissue quantification.

OBJECTIVES: Virtual touch tissue quantification is a promising new implementation of the acoustic radiation force impulse ultrasound technique. The purposes of this study were to describe the normal shear wave velocity values of the prostate by virtual touch tissue quantification and to examine the clinical usefulness of this procedure in evaluation of age-related shear wave velocity changes in the prostate. METHODS: One hundred twenty healthy volunteers were involved in this study. They were divided into 3 groups (40 participants per group): young (<30 years), middle aged (30-60 years), and old (>60 years). The shear wave velocity was measured at the inner and outer glands of the prostate at the maximum depth (~5.5 cm) in each participant. RESULTS: The mean shear wave velocities ± SD at the inner gland of the prostate in the young, middle-aged, and old groups were 0.86 ± 0.21, 1.17 ± 0.42, and 1.82 ± 0.61 m/s, respectively, whereas the velocities at the outer gland in the respective groups were 0.85 ± 0.32, 1.15 ± 0.49, and 1.87 ± 0.75 m/s. The shear wave velocities did not differ between the inner and outer glands in any age group. They were all significantly greater in the old group than in the young and middle-aged groups (P < .05). Moreover, the shear wave velocities at the inner and outer glands all correlated significantly with age. CONCLUSIONS: Virtual touch tissue quantification can provide numerical measurements of prostate stiffness and can effectively and objectively indicate age-related changes in prostate stiffness by measuring shear wave velocity values.