Online Detection of Fetal Acidemia during Labour by Testing Synchronization of EEG and Heart Rate: A Prospective Study in Fetal Sheep

Severe fetal acidemia during labour can result in life-lasting neurological deficits, but the timely detection of this condition is often not possible. This is because the positive predictive value (PPV) of fetal heart rate (FHR) monitoring, the mainstay of fetal health surveillance during labour, to detect concerning fetal acidemia is around 50%. In fetal sheep model of human labour, we reported that severe fetal acidemia (pH<7.00) during repetitive umbilical cord occlusions (UCOs) is preceded ∼60 minutes by the synchronization of electroencephalogram (EEG) and FHR. However, EEG and FHR are cyclic and noisy, and although the synchronization might be visually evident, it is challenging to detect automatically, a necessary condition for bedside utility. Here we present and validate a novel non-parametric statistical method to detect fetal acidemia during labour by using EEG and FHR. The underlying algorithm handles non-stationary and noisy data by recording number of abnormal episodes in both EEG and FHR. A logistic regression is then deployed to test whether these episodes are significantly related to each other. We then apply the method in a prospective study of human labour using fetal sheep model (n = 20). Our results render a PPV of 68% for detecting impending severe fetal acidemia ∼60 min prior to pH drop to less than 7.00 with 100% negative predictive value. We conclude that this method has a great potential to improve PPV for detection of fetal acidemia when it is implemented at the bedside. We outline directions for further refinement of the algorithm that will be achieved by analyzing larger data sets acquired in prospective human pilot studies.     

A New Method to Derive Fetal Heart Rate from Maternal Abdominal Electrocardiogram: Monitoring Fetal Heart Rate during Cesarean Section

BackgroundMonitoring of fetal heart rate (FHR) is important during labor since it is a sensitive marker to obtain significant information about fetal condition. To take immediate response during cesarean section (CS), we noninvasively derive FHR from maternal abdominal ECG.MethodsWe recruited 17 pregnant women delivered by elective cesarean section, with abdominal ECG obtained before and during the entire CS. First, a QRS-template is created by averaging all the maternal ECG heart beats. Then, Hilbert transform was applied to QRS-template to generate the other basis which is orthogonal to the QRS-template. Second, maternal QRS, P and T waves were adaptively subtracted from the composited ECG. Third, Gabor transformation was applied to obtain time-frequency spectrogram of FHR. Heart rate variability (HRV) parameters including standard deviation of normal-to-normal intervals (SDNN), 0V, 1V, 2V derived from symbolic dynamics of HRV and SD1, SD2 derived from Poincareé plot. Three emphasized stages includes: (1) before anesthesia, (2) 5 minutes after anesthesia and (3) 5 minutes before CS delivery.ResultsFHRs were successfully derived from all maternal abdominal ECGs. FHR increased 5 minutes after anesthesia and 5 minutes before delivery. As for HRV parameters, SDNN increased both 5 minutes after anesthesia and 5 minutes before delivery (21.30±9.05 vs. 13.01±6.89, P < 0.001 and 22.88±12.01 vs. 13.01±6.89, P < 0.05). SD1 did not change during anesthesia, while SD2 increased significantly 5 minutes after anesthesia (27.92±12.28 vs. 16.18±10.01, P < 0.001) and both SD2 and 0V percentage increased significantly 5 minutes before delivery (30.54±15.88 vs. 16.18±10.01, P < 0.05; 0.39±0.14 vs. 0.30±0.13, P < 0.05).ConclusionsWe developed a novel method to automatically derive FHR from maternal abdominal ECGs and proved that it is feasible during CS.     

Two cases of Continuous Fetal Heart Rate Monitoring in Twins

This report describes two cases of twin pregnancy in which continuous heart rate monitoring of both twins was successfully carried out during labour. In both cases monitoring permitted early diagnosis of fetal distress and both mothers were delivered by caesarean section. Continuous fetal heart rate monitoring permits diagnosis of fetal distress in the second twin much earlier than conventional methods.     

孕早期胎心率意义的探讨

目的:探讨监测孕早期胎心率(fetal heartrate,FHR)对胎儿生存预后的预测价值,尤其对已有流产征兆或有重复、习惯性流产史患者的胎儿不良生存结局的预测价值.方法:收集自2003到2007年至我院门诊要求生育的正常早孕孕妇以及有先兆流产征象或重复、习惯性流产病史、孕周在5-9+6周要求生育的孕妇415例.采用超声测定孕囊(gestational sac,GS)平均直径、胚胎头臀径(crown-rump length,CRL)、FHR.如果胎儿存活,则在孕中期11-14周时测量胎儿颈项皮肤层厚度(nuchal translucency,NT).采用X检验分析孕早期胎心率与胎儿存活率及NT值的关系.结果:胎心率低时,胎儿存活率降低(P<0.05),NT值异常升高发生率增多(P<0.05).结论:孕早期胎心率测定对预测胎儿生存预后有一定的临床意义,并且胎心率减慢还与孕中期NT值异常升高相关,因此,孕早期胎心率可作为筛查和预测中晚期妊娠胎儿畸形的重点监测对象.     

心率减速力对慢性心力衰竭患者心源性死亡的预测价值

目的:探讨心率减速力(DC)对慢性心力衰竭患者心源性死亡的预测价值。方法:选择208例慢性心力衰竭(CHF)患者和80例正常对照者为研究对象,检测和比较两组DC、心率变异性(HRV)、左心室射血分数(LVEF)、左室舒张末内径(LVEDD)、C反应蛋白(CRP)和平均心率(mH R)等指标,随访6～18个月,终点事件是心源性死亡。结果:心衰患者DC较健康对照组明显下降(4.39±1.05 ms vs. 6.36±0.32 ms, P0.001),慢性心衰患者发生心源性性死亡较存活着DC明显减低(3.52±1.83 ms vs. 4.53±0.85 ms,P=0.002),单变量分析年龄≥65岁、LVEF≤30%、CRP≥11.8 mg/L、SDNN≤70 ms和平均心率(mH R)≥75次/min和DC4.5 ms等6个变量对终点事件有预测价值;多变量分析结果显示仅年龄≥65岁、LVEF≤30%、SDNN≤70 ms和DC4.5 ms对心源性死亡有预测价值(P0.05),DC相对危险度为3.14。结论:心力衰竭患者DC减低,DC是心功能慢性心力衰竭患者心源性死亡的独立危险因子。     

2型糖尿病患者心率变异性与心率减速力的相关性及其对自主神经功能的评估价值

目的:探讨2型糖尿病(T2DM)患者心率变异性(HRV)与心率减速力(DC)的相关性及其对自主神经功能的评估价值。方法:选取2018年1月～2019年12月期间合肥市第一人民医院收治的120例T2DM患者为研究对象,纳入实验组,其中单纯T2DM患者69例(单纯T2DM组),T2DM伴周围神经病变(DPN)患者51例(DPN组),另选同期在我院进行心功能检查的健康志愿者120例作为对照组。所有受试者均进行24h动态心电图检查,根据检查结果计算HRV值[总标准差(SDNN)、两个相邻RR间期互差(PNN50)、差值均方根(RMSSD)]和DC值,根据各组受试者的DC值,统计对比各组的猝死风险,并分析T2DM患者DC值与HRV各项指标的相关性。结果:对照组、单纯T2DM组、DPN组的SDNN、PNN50、RMSSD、DC值依次降低(均P0.05)。对照组、单纯T2DM组、DPN组各猝死风险等级分布整体比较差异有统计学意义(P0.05),单纯T2DM组、DPN组猝死高危比例显著高于对照组,且DPN组猝死高危比例高于单纯T2DM组(均P0.05)。经Pearson相关分析,T2DM患者的DC值与SDNN、PNN50、RMSSD呈明显的正相关(P0.05)。结论:T2DM患者的DC值、HRV指标均低于正常人群,合并DPN的T2DM患者猝死风险明显提高,DC值与HRV指标间存在明显的正相关,可作为T2DM患者自主神经功能状态评估的重要指标。     

Propofol Pharmacokinetics and Estimation of Fetal Propofol Exposure during Mid-Gestational Fetal Surgery: A Maternal-Fetal Sheep Model

Background

Measuring fetal drug concentrations is extremely difficult in humans. We conducted a study in pregnant sheep to simultaneously describe maternal and fetal concentrations of propofol, a common intravenous anesthetic agent used in humans. Compared to inhalational anesthesia, propofol supplemented anesthesia lowered the dose of desflurane required to provide adequate uterine relaxation during open fetal surgery. This resulted in better intraoperative fetal cardiac outcome. This study describes maternal and fetal propofol pharmacokinetics (PK) using a chronically instrumented maternal-fetal sheep model.

Methods

Fetal and maternal blood samples were simultaneously collected from eight mid-gestational pregnant ewes during general anesthesia with propofol, remifentanil and desflurane. Nonlinear mixed-effects modeling was performed by using NONMEM software. Total body weight, gestational age and hemodynamic parameters were tested in the covariate analysis. The final model was validated by bootstrapping and visual predictive check.

Results

A total of 160 propofol samples were collected. A 2-compartment maternal PK model with a third fetal compartment appropriately described the data. Mean population parameter estimates for maternal propofol clearance and central volume of distribution were 4.17 L/min and 37.7 L, respectively, in a typical ewe with a median heart rate of 135 beats/min. Increase in maternal heart rate significantly correlated with increase in propofol clearance. The estimated population maternal-fetal inter-compartment clearance was 0.0138 L/min and the volume of distribution of propofol in the fetus was 0.144 L. Fetal propofol clearance was found to be almost negligible compared to maternal clearance and could not be robustly estimated.

Conclusions

For the first time, a maternal-fetal PK model of propofol in pregnant ewes was successfully developed. This study narrows the gap in our knowledge in maternal-fetal PK model in human. Our study confirms that maternal heart rate has an important influence on the pharmacokinetics of propofol during pregnancy. Much lower propofol concentration in the fetus compared to maternal concentrations explain limited placental transfer in in-vivo paired model, and less direct fetal cardiac depression we observed earlier with propofol supplemented inhalational anesthesia compared to higher dose inhalational anesthesia in humans and sheep.     

Heart Rate Variability Analysis in an Experimental Model of Hemorrhagic Shock and Resuscitation in Pigs

Background

The analysis of heart rate variability (HRV) has been shown as a promising non-invasive technique for assessing the cardiac autonomic modulation in trauma. The aim of this study was to evaluate HRV during hemorrhagic shock and fluid resuscitation, comparing to traditional hemodynamic and metabolic parameters.

Methods

Twenty anesthetized and mechanically ventilated pigs were submitted to hemorrhagic shock (60% of estimated blood volume) and evaluated for 60 minutes without fluid replacement. Surviving animals were treated with Ringer solution and evaluated for an additional period of 180 minutes. HRV metrics (time and frequency domain) as well as hemodynamic and metabolic parameters were evaluated in survivors and non-survivors animals.

Results

Seven of the 20 animals died during hemorrhage and initial fluid resuscitation. All animals presented an increase in time-domain HRV measures during haemorrhage and fluid resuscitation restored baseline values. Although not significantly, normalized low-frequency and LF/HF ratio decreased during early stages of haemorrhage, recovering baseline values later during hemorrhagic shock, and increased after fluid resuscitation. Non-surviving animals presented significantly lower mean arterial pressure (43±7vs57±9 mmHg, P<0.05) and cardiac index (1.7±0.2vs2.6±0.5 L/min/m², P<0.05), and higher levels of plasma lactate (7.2±2.4vs3.7±1.4 mmol/L, P<0.05), base excess (-6.8±3.3vs-2.3±2.8 mmol/L, P<0.05) and potassium (5.3±0.6vs4.2±0.3 mmol/L, P<0.05) at 30 minutes after hemorrhagic shock compared with surviving animals.

Conclusions

The HRV increased early during hemorrhage but none of the evaluated HRV metrics was able to discriminate survivors from non-survivors during hemorrhagic shock. Moreover, metabolic and hemodynamic variables were more reliable to reflect hemorrhagic shock severity than HRV metrics.     

Temporal Patterns in Sheep Fetal Heart Rate Variability Correlate to Systemic Cytokine Inflammatory Response: A Methodological Exploration of Monitoring Potential Using Complex Signals Bioinformatics

Fetal inflammation is associated with increased risk for postnatal organ injuries. No means of early detection exist. We hypothesized that systemic fetal inflammation leads to distinct alterations of fetal heart rate variability (fHRV). We tested this hypothesis deploying a novel series of approaches from complex signals bioinformatics. In chronically instrumented near-term fetal sheep, we induced an inflammatory response with lipopolysaccharide (LPS) injected intravenously (n = 10) observing it over 54 hours; seven additional fetuses served as controls. Fifty-one fHRV measures were determined continuously every 5 minutes using Continuous Individualized Multi-organ Variability Analysis (CIMVA). CIMVA creates an fHRV measures matrix across five signal-analytical domains, thus describing complementary properties of fHRV. We implemented, validated and tested methodology to obtain a subset of CIMVA fHRV measures that matched best the temporal profile of the inflammatory cytokine IL-6. In the LPS group, IL-6 peaked at 3 hours. For the LPS, but not control group, a sharp increase in standardized difference in variability with respect to baseline levels was observed between 3 h and 6 h abating to baseline levels, thus tracking closely the IL-6 inflammatory profile. We derived fHRV inflammatory index (FII) consisting of 15 fHRV measures reflecting the fetal inflammatory response with prediction accuracy of 90%. Hierarchical clustering validated the selection of 14 out of 15 fHRV measures comprising FII. We developed methodology to identify a distinctive subset of fHRV measures that tracks inflammation over time. The broader potential of this bioinformatics approach is discussed to detect physiological responses encoded in HRV measures.     

Wireless Fetal Heart Rate Monitoring in Inpatient Full-Term Pregnant Women: Testing Functionality and Acceptability

We tested functionality and acceptability of a wireless fetal monitoring prototype technology in pregnant women in an inpatient labor unit in the United States. Women with full-term singleton pregnancies and no evidence of active labor were asked to wear the prototype technology for 30 minutes. We assessed functionality by evaluating the ability to successfully monitor the fetal heartbeat for 30 minutes, transmit this data to Cloud storage and view the data on a web portal. Three obstetricians also rated fetal cardiotocographs on ease of readability. We assessed acceptability by administering closed and open-ended questions on perceived utility and likeability to pregnant women and clinicians interacting with the prototype technology. Thirty-two women were enrolled, 28 of whom (87.5%) successfully completed 30 minutes of fetal monitoring including transmission of cardiotocographs to the web portal. Four sessions though completed, were not successfully uploaded to the Cloud storage. Six non-study clinicians interacted with the prototype technology. The primary technical problem observed was a delay in data transmission between the prototype and the web portal, which ranged from 2 to 209 minutes. Delays were ascribed to Wi-Fi connectivity problems. Recorded cardiotocographs received a mean score of 4.2/5 (± 1.0) on ease of readability with an interclass correlation of 0.81(95%CI 0.45, 0.96). Both pregnant women and clinicians found the prototype technology likable (81.3% and 66.7% respectively), useful (96.9% and 66.7% respectively), and would either use it again or recommend its use to another pregnant woman (77.4% and 66.7% respectively). In this pilot study we found that this wireless fetal monitoring prototype technology has potential for use in a United States inpatient setting but would benefit from some technology changes. We found it to be acceptable to both pregnant women and clinicians. Further research is needed to assess feasibility of using this technology in busy inpatient settings.     

Preterm Birth Has Sex-Specific Effects on Autonomic Modulation of Heart Rate Variability in Adult Sheep

Introduction

Globally, 11% of infants are born preterm. In adulthood, individuals born preterm are at increased risk of cardiovascular morbidity and mortality, but the mechanistic basis of this remains unknown. Clinically overt cardiovascular disease may be preceded by altered cardiac autonomic activity characterised by increased sympathetic activity and/or reduced parasympathetic activity. Thus, altered cardiac autonomic activity in survivors of preterm birth may underlie later cardiovascular risk.

Objective

To investigate the impact of gestational age on cardiac autonomic activity in juvenile and adult sheep.

Methods and Results

Singleton-bearing ewes were randomised antenatally to spontaneous term birth (TC; n=73) or corticosteroid induced preterm birth (PT; n=60). Cardiac autonomic modulation was assessed using heart rate variability analysis in juvenile and adult offspring. Preterm birth in adult males was associated with altered sympatho-vagal modulation (LFnu: PT 64±4 vs. TC 49±4, p<0.05; LogLF/HF: PT 1.8±0.1 vs. TC 1.5±0.1, p<0.05) and reduced parasympathetic modulation (LogRMSSD: PT 2.9±0.2 vs. TC 3.4±0.1, p<0.05; LogNN50: PT 0.3±0.4 vs. TC 1.6±0.4, p<0.05). Within the range of term birth, each one-day increment in gestational age was associated with a decrement in LFnu in juvenile females and with a decrement in LFnu and LF/HF ratio, but an increment in RMSSD and NN50 in adult females.

Conclusions

Cardiac autonomic function in adult sheep is affected in a sex-specific manner by gestational age at birth, even within the term range. Altered cardiac autonomic function may contribute to increased later cardiovascular morbidity in those born preterm.     

Evaluation of an Exercise Field Test Using Heart Rate Monitors to Assess Cardiorespiratory Fitness and Heart Rate Recovery in an Asymptomatic Population

Purpose

Measures of cardiorespiratory fitness (CRF) and heart rate recovery (HRR) can improve risk stratification for cardiovascular disease, but these measurements are rarely made in asymptomatic individuals due to cost. An exercise field test (EFT) to assess CRF and HRR would be an inexpensive method for cardiovascular disease risk assessment in large populations. This study assessed 1) the predictive accuracy of a 12-minute run/walk EFT for estimating CRF () and 2) the accuracy of HRR measured after an EFT using a heart rate monitor (HRM) in an asymptomatic population.

Methods

Fifty subjects (48% women) ages 18–45 years completed a symptom-limited exercise tolerance test (ETT) (Bruce protocol) and an EFT on separate days. During the ETT, was measured by a metabolic cart, and heart rate was measured continuously by a HRM and a metabolic cart.

Results

EFT distance and sex independently predicted. The average absolute difference between observed and predicted was 0.26±3.27 ml·kg⁻¹·min⁻¹ for our model compared to 7.55±3.64 ml·kg⁻¹·min⁻¹ for the Cooper model. HRM HRR data were equivalent to respective metabolic cart values during the ETT. HRR at 1 minute post-exercise during ETT compared to the EFT had a moderate correlation (r = 0.75, p<0.001).

Conclusion

A more accurate model to estimate CRF from a 12-minute run/walk EFT was developed, and HRR can be measured using a HRM in an asymptomatic population outside of clinical settings.     

子宫收缩对胎儿心率变异性非线性的影响

目的对不同子宫收缩状态下,分析胎儿心率变异性的非线性混沌强度。方法采用非线性滴定方法,计算胎儿心率变异性的噪声极限,即非线性混沌强度;另用近似熵方法计算宫缩状态下胎儿心率变异性的复杂性。结果统计结果表明宫缩频率越高,计算所得到的噪声极限越大。说明随着外加刺激的增强,胎儿心率变异性的非线性混沌强度是增大的。但是近似熵方法不能反映相似的结果,宫缩反而使胎儿心率变异性的复杂性降低。     

Heart Rate Variability Is Associated with Exercise Capacity in Patients with Cardiac Syndrome X

Heart rate variability (HRV) reflects the healthiness of autonomic nervous system, which is associated with exercise capacity. We therefore investigated whether HRV could predict the exercise capacity in the adults with cardiac syndrome X (CSX). A total of 238 subjects (57±12 years, 67.8% men), who were diagnosed as CSX by the positive exercise stress test and nearly normal coronary angiogram were enrolled. Power spectrum from the 24-hour recording of heart rate was analyzed in frequency domain using total power (TP) and spectral components of the very low frequency (VLF), low frequency (LF) and high frequency (HF) ranges. Among the study population, 129 subjects with impaired exercise capacity during the treadmill test had significantly lower HRV indices than those with preserved exercise capacity (≥90% of the age predicted maximal heart rate). After accounting for age, sex, and baseline SBP and heart rate, VLF (odds ratio per 1SD and 95% CI: 2.02, 1.19–3.42), LF (1.67, 1.10–2.55), and TP (1.82, 1.17–2.83) remained significantly associated with preserved exercise capacity. In addition, increased HRV indices were also associated with increased exercise duration, rate-pressure product, and heart rate recovery, independent of age, body mass index, and baseline SBP and heart rate. In subgroup analysis, HRV indices demonstrated similar predictive values related to exercise capacity across various subpopulations, especially in the young. In patients with CSX, HRV was independently associated with exercise capacity, especially in young subjects. The healthiness of autonomic nervous system may have a role in modulating the exercise capacity in patients with CSX.     

Deceleration Trauma to the Heart and Great Vessels after Road-traffic Accidents

Four young men involved in high-speed car crashes developed cardiovascular trauma. Two patients had aortic aneurysms, one rupture of the mitral valve, and one ventricular septal defect; successful surgical correction was undertaken in all. The importance of considering the possibility of cardiovascular trauma in these circumstances is emphasized, and x-ray films (repeated if necessary) should be taken even when there are no external signs of trauma.     

Dose-Finding in the Development of an LPS-Induced Model of Synovitis in Sheep

Models of transient synovitis that can be controlled with antiinflammatory and analgesic drugs have been used to study pain amelioration. To this end, we aimed to determine the dose of intraarticularly administered E. coli LPS that induced signs of synovitis without systemic signs in clinically healthy male castrated sheep (n = 14). In phase 1, a single dose of LPS (0.5, 1.0, 1.5, or 2.0 ng in a total volume of 0.5 mL) was administered into the right stifle joint. In phase 2, a dose of LPS (1.0 or 2.0 μg) in 0.3 mL was administered to 4 naïve sheep. In phase 3, 4 sheep from phase 1 were inoculated after a 60 d washout period with either 0.5 or 1.0 μg of LPS. During the first 48 h after LPS administration, the following were performed: assessment of clinical parameters; scoring for lameness, pain on limb flexion, and local swelling; and ultrasonography of the joints were performed. The doses tested during phase 1 produced subtle signs. During phase 2, mild to moderate lameness with no evidence of systemic signs occurred at both doses. In phase 3, clinical responses were similar between the 0.5- and 1-µg doses. Signs of swelling were not observed at any time. Therefore, we consider the 0.5-µg to be the most appropriate for this model, because it was the lowest dose tested capable of causing lameness without signs of systemic inflammation in all animals.

As an experimental model for the study of arthropathies, the aseptic administration of small doses of endotoxin in the joint induces mild to moderate inflammation and the development of clinical signs similar to those of the naturally occurring disease.⁶ Some studies have used models of transient synovitis to determine whether the associated pain can be controlled with antiinflammatory and analgesic drugs. The use of an LPS-induced model of synovitis to evaluate the analgesic effect of various therapeutic protocols has mainly been reported for horses.^9,16,27,28 However, sheep are an important model species in biomedical research, particularly in orthopedic studies,^15,20,32 due to their similarity in weight, size, and joint and bone structure with humans, and in cardiovascular^7,11 studies, because they are good models of cardiac anatomy and physiology. Consequently, the development of analgesia protocols for acute pain conditions is greatly needed.Animal experiments are under increasing focus regarding their ethical and legal aspects. In vivo studies are permitted when methods consistent with the 3Rs principals (replacement, refinement, and reduction) are considered and implemented.²⁶ This means that experiments have to be performed without animals when possible (replacement) or with as few animals as possible (reduction) and with as little pain and distress as possible (refinement). In this context, species-specific analgesia is considered an important refinement method applicable to the majority of research.²⁵ However, few studies have been conducted to determine analgesia protocols for different pain conditions in sheep. The standardization of animal pain models is necessary for the reliable evaluation of efficient and different drug protocols.^10,19,24To guide standardization of the dose of E. coli LPS for intraarticular administration, with the aim of developing a pain model for studies of analgesia in sheep, we here assessed the ability of various intraarticular doses of LPS to trigger synovitis. Our hypothesis was that the dose established for use in horses (0.5 ng/joint) would trigger similar effects in sheep.     

Association of Saccade Duration and Saccade Acceleration/Deceleration Asymmetry during Visually Guided Saccade in Schizophrenia Patients

Objective

To examine the difference between schizophrenia patients and normal controls on velocity and acceleration of saccade, by using the basic visually guided saccade (VGS) paradigm.

Methods

Eighteen schizophrenia outpatients and fourteen normal controls participated in the VGS task. Multiple indicators, including amplitude, duration, velocity, latency, accuracy rate, acceleration, and deceleration were analyzed. Asymmetric acceleration index (AAI) was introduced to describe the difference between peak acceleration and peak deceleration. The correlation coefficient (R_AD) of AAI and duration was computed to examine the difference between schizophrenia patients and normal controls.

Results

No significant difference between patients and normal controls was found on amplitude, duration, latency, and accuracy rate. However, R_AD values of schizophrenia patients were significantly lower than the control group.

Conclusion

Compared to normal controls, association of saccade duration and saccade acceleration/deceleration asymmetry during visually guided saccade was lower in schizophrenia patients.