Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their uti...Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their utility in diagnosing VM.To better understand clinical features of VM,it is necessary to understand raw saccades data.Methods:Fourteen patients with confirmed VM,45 patients with probable VM(p-VM)and 14 agematched healthy volunteers were included in this study.Clinical findings related to spontaneous nystagmus(SN),positional nystagmus(PN),head-shaking nystagmus(HSN),caloric test and vHIT were recorded.Raw saccades data were exported and numbered by their sequences,and their features analyzed.Results:VM patients showed no SN,PN or HSN,and less than half of them showed unilateral weakness(UW)on caloric test.The first saccades from lateral semicircular canal stimulation were the most predominant for both left and right sides.Neither velocity nor time parameters were significantly different when compared between the two sides.Most VM patients(86%)exhibited small saccades,around 35%of the head peak velocity,with a latency of 200e400 ms.Characteristics of saccades were similar in patients with p-VM.Only four normal subjects showed saccades,all unilateral and seemingly random.Conclusions:Small saccades involving bilateral semicircular canals with a scattered distribution pattern are common in patients with VM and p-VM.展开更多
Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This stud...Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This study aims to identify the saccades characteristics of MD and VM.Methods:75 VM patients and 103 definite unilateral MD patients were enrolled in this study.First raw saccades were exported and analyzed.The VM patients were divided into left and right based on their ears,while the MD patients were separated into affected and unaffected subgroups based on their audiograms and symptoms.Results:The MD patients have more saccades on the affected side(85%vs.69%),and saccade velocity is more consistent than the contralateral side(shown by the coefficient of variation).The saccades occurrence rates on both sides are similar in VM(77%vs.76%),as are other saccadic parameters.The MD patients have more significant inter-aural differences than the VM patients,manifested in higher velocity(p-value 0.000),earlier arriving(p-value 0.010),and more time-domain gathered(p-value 0.003)on the affected side.Conclusions:Bilateral saccades are commonly observed in MD and VM.In contrast to MD,saccades on VM are subtle,scattered,and late-arrived.Furthermore,the MD patients showed inconsistent saccadic distribution with more velocity-uniform saccades on the affected side.展开更多
Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine wheth...Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography(ECG) abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods: Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation. Results: Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the ECG patterns of patients showing syncope during tilt table testing.Conclusions: Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.展开更多
Objective To compare the performances among three different systems for video head impulse test(vHIT),and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vH...Objective To compare the performances among three different systems for video head impulse test(vHIT),and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vHIT.Methods A two-center prospective study was done.Participants were sit 1.2 m away from the wall in a noise-proved room that dedicated for vHIT experiments.During the comparison experiments,similar settings were ensured in both hospitals,with the same distance to wall and angle of staring.For each equipment,the procedures followed the developers’recommendations.The same examiner performed the comparison between two systems in one location.For the eye-position projects,targets were placed on the wall sequentially at the pre-marked lines for different angles.For the comparison projects,9 and 13 participants were recruited,respectively.Any participant with otologic or vestibular disorders was excluded.A total of 26 healthy participants were recruited in the eye-position experiments,16 of which were further involved in inter-examiner tests.Results Our evaluations of three different systems showed that a new vHIT system,VertiGoggles®ZT-VNG-I(VG)performed as good as the long-tested Otometrics®ICS impulse(Oto)and EyeSeeCam®(ESC).During the comparison,we validated 25-degree,instead of right ahead at 0 degree,is a better place to set the targets when torsion was applied at vertical semicircular canal planes.Conclusion The new VG system is good for clinical practices.Furthermore,we proposed a new protocol to set the targets 25 degrees from right ahead after tilting head 45 degrees to evaluate vertical canals during vHIT.展开更多
Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal ...Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal factors. Furthermore, to investigate the effects of the changes of BRS on VS. Methods Forty - two patients with unexplained syncope (Among the 42 patients, there were 22 patients with positive HUT and 20 patients with negative HUT respectively) and 20 healthy volunteers (with negative HUT) underwent passive head - up tilt testing, Ante-cubital vein blood samples were taken before and after HUT, or at syncope. The fasting plasma endothelin , serum nitric oxide (NO), serum NE were measured, the BRS was assessed on the basis of the linear regression slope the RR interval versus systolic arterial blood pressure during the increment in blood pressure after intravenous administration of phenylephrine. Results (1) During the syncope, the BRS significantly reduced in HUT(+) group than baseline. At the end of tilt, the level of plasma ET, serum NO in patients with positive HUT significantly increased compared with baseline or normal controls, and the plasma concentration of NE also had the trend of increase. (2) By multiple regression analysis, a significant negative correlation was found between baroreceptor sensitivity and the plasma ET, NO at the end of HUT in patients with positive HUT, but there was no relationship between BRS and NE. Conclusions During the syncope occure, the BRS in patients with VS decreased significantly compared with normal controls. The abnormal plasma ET, NO concen-tration might contribute to the mechanism of VS.展开更多
Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether s...Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether signs such as prodromal symptoms,co-morbidity,frequency of syncopal events,body length,body mass index,and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods:Data from 100 patients with histories of syncope or pre-syncope,who were diagnosed using head-up tilt table testing,were retrospectively analyzed in a cross-sectional analysis.The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation.Results:Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms,such as dizziness and sweating,significantly more often.The patients reported more injuries resulting from syncopal events and more previous syncopal events,and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing.An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension.However,patients with pathological reaction patterns during tilt table testing were significantly taller.This finding was detected for both females and males.No significant predictors were found in the electrocardiogram patterns of patients showing syncope during tilt table testing.Conclusions:Frequency of prior syncope and prodromal symptoms,and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis.In particular,if these factors are present,tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.展开更多
To investigate age and sex distribution of vasovagal syncope （VVS） patients undergoing head-up tilt table test （HUTT） at a tertiary hospital. The details of syncope patients who underwent HUTT at our department of...To investigate age and sex distribution of vasovagal syncope （VVS） patients undergoing head-up tilt table test （HUTT） at a tertiary hospital. The details of syncope patients who underwent HUTT at our department of cardiac function from January 2004 to December 2010 were reviewed. Of the 1 799 patients who underwent the HUTT, 854 tested positive, of which 558 （65.3%） were women, which were more than the women in the negative group （450, 47.6%） （p〈0.05）. VVS patients showed a bimodal age distribution between 11 and 20 years of age and in the fourth decade. In almost all age groups, mixed response was the highest compared with vasodepressor and cardioinhibitory. VVS patients who underwent HUTT indicate bimodal distribution peaking before the second decade and the fourth decade. The incidence of females was twice that of males before the sixth decade, and old age occupies a small percentage of VVS with no other comorbidities.展开更多
To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained ...To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.展开更多
This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained ...This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.展开更多
目的建立民航飞行学员视频头脉冲试验(video head impulse test,vHIT)正常参考值,为民航飞行学员前庭功能的准确评估提供参考依据。方法随机选取40例尚处于飞行理论学习阶段的民航飞行学员进行vHIT检测,对前庭-眼反射(vestibulo-ocular ...目的建立民航飞行学员视频头脉冲试验(video head impulse test,vHIT)正常参考值,为民航飞行学员前庭功能的准确评估提供参考依据。方法随机选取40例尚处于飞行理论学习阶段的民航飞行学员进行vHIT检测,对前庭-眼反射(vestibulo-ocular reflex,VOR)的平均增益值及各半规管之间的不对称比进行比较。结果40例民航飞行学员右侧水平、前、后半规管VOR增益值分别为1.05±0.07、0.92±0.13、0.81±0.09,左侧水平、前、后半规管VOR增益值分别为1.00±0.06、0.85±0.10、0.86±0.10,所有受试者均未见补偿性扫视。双侧水平、左前-右后、右前-左后半规管VOR增益值不对称比分别为5.56%±3.64%、9.65%±4.74%、8.68%±7.07%。结论本研究建立了民航飞行学员vHIT正常参考值,为民航飞行学员的选拔及前庭功能鉴定提供了客观依据。展开更多
准确预测学生答题表现是智能导学系统为学生提供个性化学习服务的先决条件.认知诊断和知识追踪作为主流的学生表现预测方法,均将学生表现仅归因于知识状态,而忽视了学生答题过程中的应试心理状态,限制了模型预测精准性的进一步提升.为此...准确预测学生答题表现是智能导学系统为学生提供个性化学习服务的先决条件.认知诊断和知识追踪作为主流的学生表现预测方法,均将学生表现仅归因于知识状态,而忽视了学生答题过程中的应试心理状态,限制了模型预测精准性的进一步提升.为此,本文将学生的应试心理状态融入以知识为中心的学生表现预测模型中,并结合认知诊断可解释与知识追踪动态预测的互补优势,提出了一种应试心理状态增强的学生表现预测模型(Test-taking psychological state enhanced Student Performance Prediction model,TSPP).该模型通过捕捉习题与学生答题行为之间的复杂高阶关系,对学生应试心理状态进行建模;同时通过提取异构知识图中丰富的节点间关系对学生动态知识状态进行建模;最后设计了一种渐进式融合门,其采用可解释渐进式的方式融合应试心理状态与知识状态,得到可解释的预测结果.在3个真实世界数据集上的大量实验结果表明,TSPP模型在AUC(Area Under the Curve)和ACC(ACCuracy)2项指标上,相较于9种对比模型的平均表现,分别提升了6.05%和7.27%,在RMSE(Root Mean Square Error)指标上降低了6.76%.此外,通过对TSPP中的应试心理状态和知识状态进行可视化分析,并探究其可解释性参数的优势,本文进一步验证了TSPP的可解释性.展开更多
文摘Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their utility in diagnosing VM.To better understand clinical features of VM,it is necessary to understand raw saccades data.Methods:Fourteen patients with confirmed VM,45 patients with probable VM(p-VM)and 14 agematched healthy volunteers were included in this study.Clinical findings related to spontaneous nystagmus(SN),positional nystagmus(PN),head-shaking nystagmus(HSN),caloric test and vHIT were recorded.Raw saccades data were exported and numbered by their sequences,and their features analyzed.Results:VM patients showed no SN,PN or HSN,and less than half of them showed unilateral weakness(UW)on caloric test.The first saccades from lateral semicircular canal stimulation were the most predominant for both left and right sides.Neither velocity nor time parameters were significantly different when compared between the two sides.Most VM patients(86%)exhibited small saccades,around 35%of the head peak velocity,with a latency of 200e400 ms.Characteristics of saccades were similar in patients with p-VM.Only four normal subjects showed saccades,all unilateral and seemingly random.Conclusions:Small saccades involving bilateral semicircular canals with a scattered distribution pattern are common in patients with VM and p-VM.
基金supported by grants from National Key Research and Development Program of China-part3(2020YFC2005203)Capital's Funds for Health Improvement and Research(No.2022-1-2023).
文摘Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This study aims to identify the saccades characteristics of MD and VM.Methods:75 VM patients and 103 definite unilateral MD patients were enrolled in this study.First raw saccades were exported and analyzed.The VM patients were divided into left and right based on their ears,while the MD patients were separated into affected and unaffected subgroups based on their audiograms and symptoms.Results:The MD patients have more saccades on the affected side(85%vs.69%),and saccade velocity is more consistent than the contralateral side(shown by the coefficient of variation).The saccades occurrence rates on both sides are similar in VM(77%vs.76%),as are other saccadic parameters.The MD patients have more significant inter-aural differences than the VM patients,manifested in higher velocity(p-value 0.000),earlier arriving(p-value 0.010),and more time-domain gathered(p-value 0.003)on the affected side.Conclusions:Bilateral saccades are commonly observed in MD and VM.In contrast to MD,saccades on VM are subtle,scattered,and late-arrived.Furthermore,the MD patients showed inconsistent saccadic distribution with more velocity-uniform saccades on the affected side.
文摘Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography(ECG) abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods: Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation. Results: Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the ECG patterns of patients showing syncope during tilt table testing.Conclusions: Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.
基金supported by grants from the National Science Foundation for Outstanding Young People(No.81922018)the Transformation and Industrialization of Scientific and Technological Achievements in Shanghai(No.18441904000)+3 种基金the National Natural Science Foundation of China(No.81771011)the National Natural Science Foundation of China Young Investigator Program(No.81800907)the Development Fund for Shanghai Talents(No.2017046)the Excellent Personnel Training Plan for the Shanghai Health System(No.2017Q003).
文摘Objective To compare the performances among three different systems for video head impulse test(vHIT),and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vHIT.Methods A two-center prospective study was done.Participants were sit 1.2 m away from the wall in a noise-proved room that dedicated for vHIT experiments.During the comparison experiments,similar settings were ensured in both hospitals,with the same distance to wall and angle of staring.For each equipment,the procedures followed the developers’recommendations.The same examiner performed the comparison between two systems in one location.For the eye-position projects,targets were placed on the wall sequentially at the pre-marked lines for different angles.For the comparison projects,9 and 13 participants were recruited,respectively.Any participant with otologic or vestibular disorders was excluded.A total of 26 healthy participants were recruited in the eye-position experiments,16 of which were further involved in inter-examiner tests.Results Our evaluations of three different systems showed that a new vHIT system,VertiGoggles®ZT-VNG-I(VG)performed as good as the long-tested Otometrics®ICS impulse(Oto)and EyeSeeCam®(ESC).During the comparison,we validated 25-degree,instead of right ahead at 0 degree,is a better place to set the targets when torsion was applied at vertical semicircular canal planes.Conclusion The new VG system is good for clinical practices.Furthermore,we proposed a new protocol to set the targets 25 degrees from right ahead after tilting head 45 degrees to evaluate vertical canals during vHIT.
文摘Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal factors. Furthermore, to investigate the effects of the changes of BRS on VS. Methods Forty - two patients with unexplained syncope (Among the 42 patients, there were 22 patients with positive HUT and 20 patients with negative HUT respectively) and 20 healthy volunteers (with negative HUT) underwent passive head - up tilt testing, Ante-cubital vein blood samples were taken before and after HUT, or at syncope. The fasting plasma endothelin , serum nitric oxide (NO), serum NE were measured, the BRS was assessed on the basis of the linear regression slope the RR interval versus systolic arterial blood pressure during the increment in blood pressure after intravenous administration of phenylephrine. Results (1) During the syncope, the BRS significantly reduced in HUT(+) group than baseline. At the end of tilt, the level of plasma ET, serum NO in patients with positive HUT significantly increased compared with baseline or normal controls, and the plasma concentration of NE also had the trend of increase. (2) By multiple regression analysis, a significant negative correlation was found between baroreceptor sensitivity and the plasma ET, NO at the end of HUT in patients with positive HUT, but there was no relationship between BRS and NE. Conclusions During the syncope occure, the BRS in patients with VS decreased significantly compared with normal controls. The abnormal plasma ET, NO concen-tration might contribute to the mechanism of VS.
文摘Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether signs such as prodromal symptoms,co-morbidity,frequency of syncopal events,body length,body mass index,and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods:Data from 100 patients with histories of syncope or pre-syncope,who were diagnosed using head-up tilt table testing,were retrospectively analyzed in a cross-sectional analysis.The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation.Results:Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms,such as dizziness and sweating,significantly more often.The patients reported more injuries resulting from syncopal events and more previous syncopal events,and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing.An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension.However,patients with pathological reaction patterns during tilt table testing were significantly taller.This finding was detected for both females and males.No significant predictors were found in the electrocardiogram patterns of patients showing syncope during tilt table testing.Conclusions:Frequency of prior syncope and prodromal symptoms,and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis.In particular,if these factors are present,tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.
基金Supported by the National Natural Science Foundation of China (30972954)
文摘To investigate age and sex distribution of vasovagal syncope （VVS） patients undergoing head-up tilt table test （HUTT） at a tertiary hospital. The details of syncope patients who underwent HUTT at our department of cardiac function from January 2004 to December 2010 were reviewed. Of the 1 799 patients who underwent the HUTT, 854 tested positive, of which 558 （65.3%） were women, which were more than the women in the negative group （450, 47.6%） （p〈0.05）. VVS patients showed a bimodal age distribution between 11 and 20 years of age and in the fourth decade. In almost all age groups, mixed response was the highest compared with vasodepressor and cardioinhibitory. VVS patients who underwent HUTT indicate bimodal distribution peaking before the second decade and the fourth decade. The incidence of females was twice that of males before the sixth decade, and old age occupies a small percentage of VVS with no other comorbidities.
文摘To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.
基金supported by a grant from the Wuhan Science and Technology Program of China(No.2014060101010032)
文摘This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.
文摘目的建立民航飞行学员视频头脉冲试验(video head impulse test,vHIT)正常参考值,为民航飞行学员前庭功能的准确评估提供参考依据。方法随机选取40例尚处于飞行理论学习阶段的民航飞行学员进行vHIT检测,对前庭-眼反射(vestibulo-ocular reflex,VOR)的平均增益值及各半规管之间的不对称比进行比较。结果40例民航飞行学员右侧水平、前、后半规管VOR增益值分别为1.05±0.07、0.92±0.13、0.81±0.09,左侧水平、前、后半规管VOR增益值分别为1.00±0.06、0.85±0.10、0.86±0.10,所有受试者均未见补偿性扫视。双侧水平、左前-右后、右前-左后半规管VOR增益值不对称比分别为5.56%±3.64%、9.65%±4.74%、8.68%±7.07%。结论本研究建立了民航飞行学员vHIT正常参考值,为民航飞行学员的选拔及前庭功能鉴定提供了客观依据。
文摘准确预测学生答题表现是智能导学系统为学生提供个性化学习服务的先决条件.认知诊断和知识追踪作为主流的学生表现预测方法,均将学生表现仅归因于知识状态,而忽视了学生答题过程中的应试心理状态,限制了模型预测精准性的进一步提升.为此,本文将学生的应试心理状态融入以知识为中心的学生表现预测模型中,并结合认知诊断可解释与知识追踪动态预测的互补优势,提出了一种应试心理状态增强的学生表现预测模型(Test-taking psychological state enhanced Student Performance Prediction model,TSPP).该模型通过捕捉习题与学生答题行为之间的复杂高阶关系,对学生应试心理状态进行建模;同时通过提取异构知识图中丰富的节点间关系对学生动态知识状态进行建模;最后设计了一种渐进式融合门,其采用可解释渐进式的方式融合应试心理状态与知识状态,得到可解释的预测结果.在3个真实世界数据集上的大量实验结果表明,TSPP模型在AUC(Area Under the Curve)和ACC(ACCuracy)2项指标上,相较于9种对比模型的平均表现,分别提升了6.05%和7.27%,在RMSE(Root Mean Square Error)指标上降低了6.76%.此外,通过对TSPP中的应试心理状态和知识状态进行可视化分析,并探究其可解释性参数的优势,本文进一步验证了TSPP的可解释性.
