Saccades of video head impulse test in Meniere's disease and Vestibular Migraine: What can we learn from?

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.

Analysis of video head impulse test saccades data in patients with vestibular migraine or probable vestibular migraine

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.

AB055.Eye movements in the dark:saccades to non-visual targets

Background:Saccades are rapid and abrupt eye movements that allow us to change the point of fixation very quickly.Saccades are generally made to visual points of interest,but we can also saccade to non-visual objects that attract our attention.While there is a plethora of studies investigating saccadic eye movements to visual targets,there is very little evidence of how eye movement planning occurs when individuals are performing eye movements to non-visual targets across different sensory modalities.Methods:Fifteen adults with normal,or corrected to normal,vision made saccades to either visual,auditory,tactile or proprioceptive targets.In the auditory condition a speaker was positioned at one of eight locations along a circle surrounding a central fixation point.In the proprioceptive condition the participant’s finger was placed at one of the eight locations.In the tactile condition participants were touched on their right forearm in one of four eccentric location,left and right of a central point.Eye movements were made in complete darkness.Results:We compared the precision and accuracy of the eye movements to tactile,proprioceptive,and auditory targets in the dark.Overall,both precision and accuracy of movements to non-visual targets were significantly lower compared to visual targets.Conclusions:These differences emphasize the central role of the visual system in saccade planning.

基于扫视路径速度的隧道入口驾驶舒适性分析

为了更准确地评价公路隧道入口段驾驶员的视觉舒适性,以隧道入口段的驾驶员视觉特性为研究对象,在云南上鹤高速公路的野鸭塘1号、2号和3号隧道开展实车试验,采集驾驶员的注视与扫视时间、视点位置、瞳孔直径等眼动参数,并依次对20名驾驶员进行问卷调查。基于试验数据和问卷调查结果,提出扫视路径速度指标并验证其合理性。结果表明:扫视路径速度能够有效地对隧道入口段的驾驶视觉舒适性进行评价;当隧道照明条件相同时,新型蓄能反光发光材料能够使驾驶员的平均扫视路径速度降低50.62%,峰值扫视路径速度降低40.32%。通过对视觉舒适指标的关联性分析,进一步表明:扫视路径速度与驾驶员的视觉舒适性呈反比关系;随着隧道入口光环境质量的提高,驾驶员的扫视时间占比增加,进而扫视所用时间变长,扫视路径速度减慢,此时驾驶员的视觉舒适性较高有利于安全行驶,反之则不利于行车安全。

非典型帕金森综合征的异常眼球运动

非典型帕金森综合征(APS)是一组类似于帕金森病(PD)的神经退行性疾病,包括多系统萎缩(MSA)、路易体痴呆(DLB)、进行性核上性麻痹(SP)、皮质基底节变性(CBD)等。随着人口老龄化进程的加剧,APS等神经退行性疾病的发病率不断上升。目前,APS的诊断取决于“危险信号”被识别的可能性,包括早期频繁跌倒、早期认知障碍、进展更快、对左旋多巴反应差等。近年来,随着研究的进展,发现APS患者的眼球运动有着不同程度的障碍,且眼动评估具有非侵入性的优势,对于APS有一定的辅助诊断价值。故本文将对APS的眼球运动障碍方面进行系统性综述。

眼跳间隙效应的解释机制——来自眼动实验的研究

采用间隙效应的经典实验范式,考察人类被试在不同实验条件(实验一)和不同间隙时间(实验二)下的眼跳潜伏期,研究眼跳间隙效应的解释机制.结果显示,在经典间隙时间(200 ms)下,间隙条件下的眼跳潜伏期最短,信号警报条件次之,基线条件下最长;其他间隙时间下的实验结果与经典间隙时间下的结果并不一致.实验结果表明,眼跳间隙效应的解释机制受间隙时间长短的影响.

视频头脉冲测试中扫视波参数的重要性分析

本综述旨在全面讨论视频头脉冲中扫视波(catch-up saccades,CS)的参数、机制以及其与前庭功能和相关疾病的联系,从而验证CS在临床评估前庭功能及相关疾病中的关键作用。本文详细描述了CS的参数特征、生理机制以及产生的条件,并深入分析其在前庭-眼反射以及颈眼反射的角色。借助头脉冲抑制模型中的CS,结合动态视敏度以及步态和平衡功能,进一步探讨CS与前庭功能的紧密联系。此外,本文还从不同年龄段、前庭功能损伤、梅尼埃病及前庭性偏头痛等角度,剖析了CS的表现及其在各种疾病背景下的重要性。总之,CS对于维持视觉的稳定性,评估前庭功能的损伤程度以及前庭康复阶段均具有重要价值。

Modeling perisaccadic time perception

There is an impressive scarcity of quantitative models of the clock patterns in the brain. We propose a mesoscopic approach, i.e. neither a description at single neuron level, nor at systemic level/too coarse granularity, of the time perception at the time of the saccade. This model uses functional pathway knowledge and is inspired by, and integrates, recent findings in both psychophysics and neurophysiology. Perceived time delays in the perisaccadic window are shown numerically consistent with recent experimental measures. Our model provides explanation for several experimental outcomes on saccades, estimates popu-lation variance of the error in time perception and represent a meaningful example for bridging psychophysics and neurophysiology. Finally we found that the insights into information processing during saccadic events lead to considerations on engineering exploitation of the underlying phenomena.

Distortion of Space and Time during Saccadic Eye Movements

The space-time distortion perceived subjectively during saccadic eye movements is an associative phenomenon of a transient shift of observer’s visual frame of reference from one position to another. Here we report that the lines of subjective simultaneity defined as two spatially separated flashes perceived during saccades were nearly uniformly tilted along the physical time-course. The causality of the resulting space-time compression may be explained by the Minkowski space-time diagram in physics.

基于CornerNet-Saccade的手部分割模型

手部分割技术受手部形态、分割背景等因素的影响,分割效率难以提高。在CornerNet-Saccade模型基础上构造一种基于扫视机制的分割模型。通过模拟人眼观察物体时先扫视再仔细观察的行为特征,降低待处理图像的像素数量并在初步判断手部位置后将掩码分支添加到不同尺度特征图中,完成精细分割任务。在此基础上,引入线性瓶颈结构完成模型轻量化操作以降低模型复杂度。实验结果表明,该模型在Egohands数据集上平均交并比高达88.4%,优于RefinNet、U-Net等主流模型,轻量化处理后其平均交并比虽降低了2.2个百分点,但参数量仅为原模型的44.9%。

Simulate Human Saccadic Scan-Paths in Target Searching

Human saccade is a dynamic process of information pursuit. There are many methods using either global context or local context cues to model human saccadic scan-paths. In contrast to them, this paper introduces a model for gaze movement control using both global and local cues. To test the performance of this model, an experiment is done to collect human eye movement data by using an SMI iVIEW X Hi-Speed eye tracker with a sampling rate of 1250 Hz. The experiment used a two-by-four mixed design with the location of the targets and the four initial positions. We compare the saccadic scan-paths generated by the proposed model against human eye movement data on a face benchmark dataset. Experimental results demonstrate that the simulated scan-paths by the proposed model are similar to human saccades in term of the fixation order, Hausdorff distance, and prediction accuracy for both static fixation locations and dynamic scan-paths.

THE PEAK LATENCY OF ORBITAL PRESACCADIC SPIKE POTENTIAL WITH HORIZONTAL EYE MOVEMENTS

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AB073.Correlations between control of saccadic eye movements and performance in other cognitive tasks in younger adults,older adults and patients with Parkinson’s disease

Background:Cognitive control is defined as the ability to act flexibly in the environment by either behaving automatically or inhibiting said automatic behaviour and it can be measured using an interleaved pro/anti-saccade task.Decline in cognitive control has been attributed to normal aging and neurological illnesses such as Parkinson’s disease(PD)as well as decline in other cognitive abilities.This parallel might highlight the role played by cognitive control in information processing and working memory.However,little is known about the relationship between cognitive control and other cognitive processes such as visual memory,decision making,and visual search.We thus propose to correlate the incidence of impaired cognitive control with deficits in visual memory,decision making and visual search in three groups:younger adults,older adults and patients with idiopathic PD.Methods:Seventy-one participants,namely 34 adults(M=22.75,SD=3.8),22 older adults(M=67.4,SD=8.3),and 20 PD patients(M=65.59,SD=8.2)performed four tasks:interleaved pro/anti-saccade,visual memory,decision making,and serial and pop-out visual search.Results:Results show that within each group,anti-saccade error rate(ER)were significantly and negatively correlated with visual memory ER(ryounger=−0.378,P=0.036;rolder=−0.440,Polder=0.046;rPD=−0.609,P=0.016).On the other hand,correct decision-making reaction times(RT)were significantly correlated with anti-saccade ER,and RTs only in older adults(rER=0.529,P=0.014;rRT=0.512,P=0.018)and PD patients(rER=0.727,P=0.012;rRT=0.769,P=0.001).For visual search,PD patients showed a significant relationship between RTs for correct pro-saccades and pop-out(r=0.665,P=0.007),and serial(r=0.641,P=0.010)search RTs.Furthermore,there was a significant correlation between MoCA scores and anti-saccade RTs(r=−0.559,P=0.030)and ER(r=−0.562,P=0.029)in PD patients.Taken together,these results support the hypothesis of PD patients’reliance on bottom-up processes as top-down processes decline.For younger adults,there was a significant correlation between serial search performance and both anti-saccade ER(r=0.488,P=0.005),and correct pro-saccade ER(r=0.413,P=0.021).In older adults,this relationship was absent,but anti-saccade ER significantly correlated with pop-out search times(r=0.473,P=0.030).Conclusions:We found significant relationships between cognitive tasks and cognitive control as measured through the interleaved pro/anti-saccade task across and within participant groups,providing evidence of the appropriateness of the use of the interleaved pro/anti-saccade task as a measure of overall cognitive control.

AB014.Impaired anti-saccade production in posterior parietal cortex damaged patients

Background:Performing an anti-saccade relies on two mechanisms:(I)inhibiting an automatic saccade to a target,and(II)generating,instead,a voluntary saccade to a location other than this visual target.It remains unclear where and how these two processes are implemented to ensure the production of correct anti-saccades.Previous research in optic ataxia has implicated the posterior parietal cortex(PPC)in anti-pointing,implying a possible role of the PPC in anti-saccade production.Methods:Here,we tested how three patients with unilateral or bilateral damage to the PPC,as well as six neurologically intact controls,perform different types of anti-saccade:classic anti-saccades(180°rotation)or mirror saccades(90°rotation)across and within hemi-fields.Results:We showed that PPC damaged patients were impaired in anti-saccade production for their contralesional visual fields.This was reflected in a longer period of erroneous pro-saccades,longer latencies associated with correct anti-saccades to the contralesional visual field and more imprecise anti-saccades.Conclusions:Our results thus suggest that PPC damage results in delayed and prolonged competing saccade planning processes between two locations(i.e.,visual target and saccade goal location).Taken together,our results provide evidence for a crucial role of the PPC in parallel mechanisms underlying anti-saccade performance.

AB048.Pre-saccadic attentional facilitation is influenced by irrelevant post-saccadic changes

Background:Many studies have shown that attention is shifted toward the goal of the upcoming saccade.It has been suggested that the purpose of this attentional shift is to aid in trans-saccadic integration by acting as a‘pointer’(Cavanagh,Hunt,Afraz&Rolfs,2010)for remembering,processing and updating objects across saccadic eye movements(Rolfs,Jonikaitis,Deubel&Cavanagh,2011).We tested this hypothesis that pre-saccadic attentional facilitation acts as a pointer for trans-saccadic integration by investigating how irrelevant post-saccadic changes influenced pre-saccadic attentional discrimination.On one hand,if pre-saccadic attentional facilitation is an independent process involved only in enhancing peripheral information before the saccade,then manipulating visual information(absence or shift)after the saccade should have no influence on discrimination.On the other hand,if pre-saccadic attentional facilitation is involved in trans-saccadic integration,changes in visual information should influence discrimination of the pre-saccadic information.Methods:We tested different conditions involving different post-saccadic changes.In the baseline condition,participants made a saccade at the appearance of an arrow and discriminated a symbol(DS)that was presented briefly before the saccade at one of six peripheral locations.The symbol was masked thereafter with a figure 8,which remained till the end of the trial.Importantly,the DS was always presented while participants were fixating at center,and only the figure 8 was present at the end of the saccade.Participants were instructed to make the saccade then report the identity of the DS(4AFC).We then tested how blanking post-saccadic information[blanking of the saccade goal(SG)location,DSOff condition;of the entire visual scene including or excluding the SG location,AllOff and DSOnly conditions]and how displacement of the figure 8s after the saccade would affect performance.Results:We observed that discrimination performance was significantly lower when the SG location disappeared during the saccade and was no longer present when the saccade was completed(DSOff,-6.9%).This decrease in performance cannot be attributed to changes in the visual scene that may have drawn attention,as this was the case for all conditions;performance was not different when the entire visual scene was blanked(AllOff,-0.0%)or when only the DS remained(DSOnly,-1.6%).We also found that the performance decreased as a function of the displacement of the figure 8 from the SG location,particularly if it was displaced outside of the saccade landing zone.Conclusions:Based on these pattern of results,we suggest that pre-saccadic attentional facilitation is indeed involved in trans-saccadic integration by acting as a location marker or pointer.The lack of a visual target at the saccade goal,even if it is irrelevant to the pre-saccadic discrimination task,disrupted performance.

Electrocortical Activity Differences Related to Saccadic Movements between Bipolar Patients and Healthy Subjects

Objective: The present study aimed to investigate and to compare the electrophysiological changes in bipolar patients and healthy subjects during the execution of a saccade task. Materials and Methods: The subjects had to respond to a fixed visual stimulus presented by a LEDs bar. We executed an ANOVA (one-way) and post hoc Scheffé test to examine the difference of absolute alpha power and reaction time among four groups: control, depression, manic and euthymic. We observed the frontal, parietal and occipital regions. The paired t test was realized on each electrode and group to compare the pre and post moment in the task. Results: We observed a statistical difference among the groups for the behavioral variable—saccade reaction time. For the electrophysiological variable—absolute alpha power, we did not find significant difference between the moments (pre and post stimulus presentation) for none of the electrodes of each bipolar group. However, the results pointed out to a difference between the moments for F3, P3, O1 and O2 electrodes for control group. Conclusion: We cannot affirm that the task influences the cortical activity of the patients. It is possible that the method used to analyze the data is not the adequate. The time-frequency analysis could be better to analyze the present data. We also observed that the absolute alpha power could be considered a marker of bipolar disorder, but not of the different states (i.e., mania, depression, euthymia).

融合时空上下文信息的强化学习小目标快速搜索

人眼在搜索目标时,先基于此前的扫视经验粗略扫视,找到可能有目标的位置,再进行详细搜索.前者的扫视可称为基于时间上下文信息的扫视,后者可称为基于位置上下文信息的搜索.受人眼这种目标搜索模式启发,本文提出一种结合强化学习的时空上下文目标搜索方法.该方法基于强化学习搜索策略构建时间上下文模块,获得时间上下文信息;再通过构建一个自适应多尺度窗口提取位置上下文信息,两种信息在目标搜索过程中交替配合,完成目标搜索.实验结果表明,该方法在MS COCO数据集上较基准方法提升了2.9%,且可在5个搜索次数内找到目标.

急性有氧运动影响抑制控制:手动任务与眼动任务敏感性的差异

目的:比较手动和眼动两种任务范式测量急性中等强度有氧运动对大学生抑制控制影响中敏感性的差异。方法:将60名大学生分成3个运动干预组,进行不同持续时间(15分钟、30分钟、45分钟)的中等强度自行车运动,并于运动前、后使用停止信号任务和撤销眼跳任务对参与者的抑制控制能力进行评估。结果:采用混合实验设计的重复测量方差分析发现,测量时间点(运动前、后)在撤销眼跳任务中的眼跳潜伏期、眼跳幅度和兴趣区总注视时间上的主效应均显著,即运动干预后的眼跳潜伏期短,眼跳幅度小,兴趣区总注视时间少。运动时长和测量时间点在停止信号手动任务中的主效应均不显著。结论:在运动认知效益研究中,手动任务和眼动任务在评估抑制控制能力的差异时,眼跳潜伏期、眼跳幅度和兴趣区总注视时间等眼动指标更敏感且优越。

基于扫视变化特性的城市隧道驾驶紧张情绪分析

为分析城市隧道出入口段及中间段驾驶人的紧张情绪,选取重庆市向黄隧道、真武山隧道、长冲隧道和八一隧道为研究对象,利用照度计、光透过率检测仪、眼动仪等试验设备开展现场实车试验,采集照度、光透过率、扫视幅度等参数,同时开展紧张情绪问卷调查。基于所得数据,分析扫视速度在不同时间及空间下的分布特性,建立明暗适应段的扫视速度与照度变化率,中间段的扫视速度与照度、光透过率的函数关系模型。结合问卷调查等级,采用3σ准则划分明暗适应段及中间段的扫视速度分级区间,并与问卷调查结果进行对比验证。最后通过函数关系模型,反向求解得到紧张情绪在明暗适应段变化较小时所需的照度变化率控制范围。结果表明:扫视速度能反映驾驶人在明暗适应段和中间段紧张情绪的变化;当明暗适应段的照度变化率增大或中间段的照度、光透过率减小时,扫视速度提高,此时驾驶人紧张情绪加剧,反之则降低。

非痴呆型血管性认知障碍患者的记忆扫视研究

目的研究非痴呆型血管性认知障碍(VCIND)患者的记忆扫视(MGS)特征,探讨MGS对该类患者认知功能的检测价值。方法选取2022年1月至2023年2月在濮阳市人民医院神经内科就诊的44例VCIND患者作为病例组,同时选取80例健康受试者作为对照组。应用视频眼震电图仪对两组进行经典MGS检查,比较检验结果。观察指标包括左右向10°、15°、20°(共6个角度)的MGS速度、潜伏期、精确度。结果两组MGS速度差异无统计学意义(P>0.05),病例组MGS潜伏期延长(左向15°的P=0.094,余各方向各角度P<0.05),MGS精确度降低(右向10°的P=0.079,余各方向各角度P<0.05)。结论VCIND患者MGS异常,主要表现为潜伏期延长及精确度下降,MGS提供了客观的电生理指标,具有一定的辅助诊断价值。