基于EEG的多因素认知任务脑力负荷研究

目的研究不同类型、不同难度的认知任务组合情况下,脑力负荷变化情况的精细表征。方法设计一种基于逻辑运算、工作记忆和运动执行的脑力负荷诱发范式,利用该范式开展24名男性受试者参与的实验,采集受试者主观量表评分、任务绩效和脑电图(EEG)信号,并计算EEG信号多个频带的功率特征。结果主观量表和任务绩效分析表明,计算难度、N-back等级均能诱发出不同等级的脑力负荷;EEG信号分析表明,脑力负荷的增加伴随着前额叶theta波增强和alpha波的减弱;利用支持向量机(SVM)构建脑力负荷分类模型,能实现平均75%单因素三分类正确率和81.7%的脑力负荷三分类正确率;利用逐步回归模型可实现对脑力负荷的预测。结论 EEG信号的频域特征能够反映多因素认知任务的脑力负荷变化情况,可以对认知因素水平和脑力负荷进行分类和连续预测。     

自适应多维N-back认知负荷模型下的脑网络研究

目的弥补传统N-back实验只考察单一维度工作记忆内容的不足,设计多样化的脑力负荷任务,从多方位深入研究脑疲劳及认知负荷。方法从位置、颜色、形状3个维度划分3个等级,并根据反应正确率自动调节等级,构成自适应多维N-back认知负荷新范式,研究新范式下受试者的行为绩效、脑电频谱特征及脑网络变化。结果在1-back与2-back任务中,随着认知任务维度升级、脑力负荷增加,脑电alpha/beta功率比下降,PDC脑网络中各脑区之间的信息流增强且不同维度任务的信息流向与当前任务紧密相关。结论自适应多维N-back实验范式比传统单一维度N-back任务能多方位充分调动大脑认知功能、加速消耗脑力资源并影响其行为绩效,有望为更深层次研究脑认知与脑疲劳提供新思路。     

脑力负荷评定指标敏感性的比较研究

目的 比较常用脑力负荷评定指标的敏感性。方法 记录分析了受试者完成了１１种不同难度任务时的主任务绩效,附任务绩效,主观评分和心理生理指标共２５种脑力负荷评定指标。结果追踪误差,反７尖时,正确率,类别量表评分,多级估量量表评分,多维量表评分,Ｐ３潜伏期,逐次心跳间期,逐次呼吸间期和眨眼率在不同任务之间有显著差异,ＣＳ,ＭＥＳ和ＭＤＳ对任务总负荷,Ｅ,ＲＬＡＴ,ＩＢＩ和ＩＲＩ对主任务负荷,ＲＴ和ＣＲ对     

利用fNIRs研究噪声环境下脑力负荷变化规律

目的研究噪声环境下操作者的脑力负荷(mental workload,MWL)变化规律。方法采用功能性近红外光谱技术(functional near-infrared spectroscopy,fNIRs)、心电、皮肤电和脉搏波多种生理测量手段结合脑力负荷敏感脑区的氧合血红蛋白幅值变化、主观量表评价和脑力负荷评估模型输出来评估噪声刺激下操作者的MWL变化。选用16名参试者完成中性图片N-back任务,分为噪声组和对照组,噪声环境采用(80±3)d B,对照组的外界声源控制为45 d B以下。结果在同一任务负荷状态下,噪声环境中参试者的脑力负荷水平高于对照组,其中噪声组2-back任务诱发的脑力负荷水平等同于对照组3-back任务诱发的脑力负荷水平,但其在3-back任务阶段脑力负荷仅略高于对照组的同等任务阶段。结论参试者在噪声环境下执行同等工作记忆任务时脑力负荷水平可以提高,但任务难度较高时提升幅度降低;利用fNIRs监测大脑前额叶皮层血氧生理参数方法能够有效评估噪声环境下的脑力负荷变化,值得进一步深入研究。     

5种量表在测量飞行活动主观脑力负荷中的适用性比较

目的比较5种量表在飞行活动中的脑力负荷测量适用性,筛选最适用于测量飞行活动主观脑力负荷的量表。方法27名飞行员受试者每人完成1次起落航线飞行训练,训练后根据飞行过程起飞阶段、平飞巡航阶段以及降落阶段的实际体会,分别填写NASA任务负荷指数(NASA-TLX)量表、主观负荷评价技术(SWAT)量表、修正的库柏-哈柏(MCH)量表、工作负荷描述(WP)量表和多资源问卷(MRQ)。比较并分析5种量表在测量不同飞行阶段主观脑力负荷的敏感性、诊断性和可接受性。结果敏感性方面,NASA-TLX量表最高,WP量表次之,MRQ量表最低;诊断性方面,NASA-TLX量表在脑力负荷分类诊断中具有优势,而WP量表在信息加工过程不同脑力资源的使用情况诊断中具有优势;可接受性方面,MRQ量表可接受性差,表现为量表填写时间长和理解难度大。结论 NASA-TLX量表具有很好的敏感性和诊断性,可作为飞行活动脑力负荷主观测量的首选。WP量表能从信息加工过程中不同脑力资源的使用情况进行诊断,可与NASA-TLX量表相结合测量飞行活动的脑力负荷。     

多级估量量表在脑力负荷主观评定中的应用

为探讨多级估量量表在脑力负荷主观评定中的意义，用基于模糊集的多级估量量表（ＭＥＳ）对三种不同难度视觉追踪任务的脑力负荷进行主观评量，并与追踪误差及传统类别量表（ＣＳ）的评定结果相比较。结果表明：（１）任务难度增加，追踪误差增大，各任务之间均有显著差异；（２）任务难度中，两量表评分变大，其中ＭＥＳ评分值任务间均有显著差异，ＣＳ评分值任务１和任务３之间、任务２任务３之间有显著差异，任务１和任务２之间无     

认知训练对“蛟龙号”模拟驾驶作业脑力负荷影响评估

目的研究认知训练对"蛟龙号"模拟驾驶作业脑力负荷影响,为潜航员的实际训练提供参考。方法实验采用被试内设计,实验共13天,8名受试者在第1、7、13天每天进行1次模拟驾驶作业,在第2～6天与第8～12天每天进行1h的认知训练。记录受试者第1天作业前静息状态脑电图(EEG)作为对照组,并记录第1、7、13天驾驶作业中EEG与绩效数据,在每次作业后受试者填写NASA-TLX量表。结果随着认知训练的进行,Pz(顶点)、Cz(中央点)与Fz(额中点)3个测试点的受试者EEGδ波相对功率下降、β波与γ波相对功率上升,作业绩效改善,NASA-TLX量表评分降低,差异具有统计学意义(P0.05)。同时,认知训练使作业前静息状态与作业中的EEG功率谱间差异降低。结论随着认知训练的进行,受试者进行"蛟龙号"模拟驾驶作业时的脑力负荷显著降低,在潜航员的实际训练中采用认知训练具有积极意义。     

机械臂遥操作任务难度对工作负荷的影响

目的研究机械臂遥操作任务中任务难度对绩效指标、生理指标和主观工作负荷指标的影响,判断各个指标评价工作负荷的敏感性和有效性。方法招募64名受试者开展遥操作任务模拟实验,抽象化3种不同难度的机械臂任务,分别为"点对准"、"避障"、"线对准"任务,采集操作者的绩效指标、生理指标以及主观工作负荷值。结果在不同难度的机械臂遥操作任务之间,任务完成时间、操作失误次数、平移偏差、碰撞次数、扫视频率、绩效满意度和NASA-TLX量表的总负荷值存在显著性差异(P0.05)。结论机械臂遥操作任务中,绩效指标中的任务完成时间、操作失误次数、平移偏差、碰撞次数和主观工作负荷指标能够敏感地反映工作负荷的变化,可用于综合评价模型的建立。     

主观评定法用于军事作业所致脑力疲劳的研究进展

脑力疲劳可影响机体感知、注意力、记忆、判断、决策和运动控制等多方面能力,诱发信息获取和分析错误,进而导致决策失败,成为事故征候和事故发生的重要原因。科技进步和武器装备的更新换代使军事作业中体力劳动的比例下降,脑力劳动的比例上升,建立有效的脑力疲劳筛选和评估方法尤为重要。脑力疲劳的评定方法主要分为主观评定法和客观评定法。主观评定法不仅可用于脑力疲劳的评估,还可以用于多种心理表现(如脑力负荷)的评定。该文综述了斯坦福嗜睡量表、美国国家航空航天任务负荷指数量表等主观评定法测量工具用于脑力疲劳评估的相关研究进展。     

瞳孔的变化与脑力负荷关系的试验分析

目的 根据被试者瞳孔在执行不同难度任务过程中的变化,分析不同难度任务引起的脑力负荷的变化.方法 10名被试者执行不同难度等级的视觉搜索任务,通过眼动仪记录被试者的瞳孔面积数据,分析在不同脑力负荷下瞳孔面积的变化,以了解瞳孔大小与脑力负荷之间的相关性.结果 被试者之间的瞳孔面积变化既存在2种相同变化规律,又有3种不同的差异,差异表现在瞳孔增大出现在不同的等级任务下.结论 在相同的工作环境中,瞳孔面积的变化能够评价脑力负荷的不同:随着工作难度水平的增加,瞳孔缩小;而随着紧张程度的增加,瞳孔扩大;当到达一定疲劳程度之后,瞳孔开始缩小.     

Cognitive demands in automation

As the nature of a task changes with increasing automation, so do the cognitive demands on the human operator. The present study examines the implications of such changes on subjective workload and automation design issues. A variety of tasks (continuous flight control, discrete target acquisition, and decision making) was used to tax the different cognitive systems. Each task could be performed alone or in combination with other tasks. Performance and subjective workload ratings, obtained by three workload scales, were examined as a function of the level of automation. Results demonstrated the usefulness of the multiple resource approach to task analysis. All three workload scales were found to be sensitive to the task demands. The Bedford scale was particularly impressive in distinguishing the different types of resources in demand. Both the multiple resource model's performance predictions and the subjective workload ratings were shown to be invaluable for decisions on how and what to automate.     

EEG and ECG changes during simulator operation reflect mental workload and vigilance

BACKGROUND: Performing mission tasks in a simulator influences many neurophysiological measures. Quantitative assessments of electroencephalography (EEG) and electrocardiography (ECG) have made it possible to develop indicators of mental workload and to estimate relative physiological responses to cognitive requirements. OBJECTIVE: To evaluate the effects of mental workload without actual physical risk, we studied the cortical and cardiovascular changes that occurred during simulated flight. METHODS: There were 12 pilots (8 novices and 4 experts) who simulated a flight composed of 10 sequences that induced several different mental workload levels. EEG was recorded at 12 electrode sites during rest and flight sequences; ECG activity was also recorded. Subjective tests were used to evaluate anxiety and vigilance levels. RESULTS: Theta band activity was lower during the two simulated flight rest sequences than during visual and instrument flight sequences at central, parietal, and occipital sites (p < 0.05). On the other hand, rest sequences resulted in higher beta (at the C4 site; p < 0.05) and gamma (at the central, parietal, and occipital sites; p < 0.05) power than active segments. The mean heart rate (HR) was not significantly different during any simulated flight sequence, but HR was lower for expert subjects than for novices. The subjective tests revealed no significant anxiety and high values for vigilance levels before and during flight. CONCLUSIONS: The different flight sequences performed on the simulator resulted in electrophysiological changes that expressed variations in mental workload. These results corroborate those found during study of real flights, particularly during sequences requiring the heaviest mental workload.     

基于脑电功率谱特征的脑力疲劳分析

目的 研究连续数学运算对脑力疲劳的影响,探讨脑电的功率谱特征与脑力疲劳之间的关系,寻找脑力疲劳程度评价的客观指标.方法 对连续数学运算前后以及休息后3种状态下脑电的功率谱重心频率以及功率谱熵进行了分析,并采用主观评价和行为学方法对3种状态进行对照分析.结果 连续数学运算后脑电功率谱重心频率以及功率谱熵显著降低,主观感觉疲劳程度、数学运算及PVT测试的平均反应时间显著增加;休息后脑电功率谱特征、主观感觉疲劳程度及反应时间的变化规律相反.结论 脑电功率谱重心频率以及功率谱熵与脑力疲劳有较强的相关性,随着脑力疲劳程度的增加,脑电功率谱重心频率以及功率谱熵降低.同时脑电功率谱特征与主观评价和行为学分析结果有较强的一致性,有望成为衡量脑力疲劳程度的客观指标.     

不同旋转速度背景及认知负荷对视认知早期加工的影响

目的研究不同转速旋转背景条件下,完成不同认知负荷视觉认知任务过程中的视认知早期加工的变化。方法受试者为20名健康右利手大学生,视觉背景分为白色背景与不同转速的模拟星空背景。要求受试者完成不反应、选择区分和选择心算任务,同时记录12导脑电数据。结果各种负荷任务中中央区的P1潜伏期最短,峰值波幅最高;与白色背景相比,各种速度旋转背景下,反应时及P1潜伏期缩短;与白色背景相比,不同旋转背景下完成选择区分及选择心算任务的P1峰值波幅升高。结论不同速度星空旋转背景加速了视觉认知的感知,在高负荷任务下增加启动效应。星空旋转不同角速度主要对区分反应的主动抑制加工过程产生影响。     

Cognitive load of walking in people who are blind: Subjective and objective measures for assessment

BackgroundAlthough walking without vision seems to carry a high cognitive cost, few studies have measured the cognitive load involved in this activity in blind people. The aim of this study was to assess the cognitive load of walking in blind people, using gait analysis, a dual task paradigm and a subjective assessment of cognitive load.MethodsIn a quantitative quasi-experimental design, 25 blind adults walked 40 meters. In one trial, participants walked normally (control condition). In another, they walked while performing an auditory simple reaction time task, and in the third trial they walked, performed the simple reaction time task and avoided obstacles. In addition to the simple reaction time task performance, walking speed was recorded, and participants provided a subjective assessment of cognitive load after each trial. Performance of participants aged less than 60 years were compared with those aged over than 60 years.ResultsWalking significantly reduced performance of the simple reaction time task; carrying out the simple reaction time task while walking significantly reduced walking performance and increased the subjective assessment of cognitive load; and simple reaction time task performance decreased and subjective assessment increased when obstacles were present. Few significant age effects were found.SignificanceWalking without vision involves a cognitive load that increases when the environment becomes complex. Each of the three methods used is relevant when assessing the cognitive load involved in walking in blind people, and could be useful in rehabilitation intervention. The results obtained allowed recommendations to be suggested for the design of technological mobility devices.     

状态相关脑波复杂度分析方法的研究

目的 建立状态相关脑波复杂度（Ｃｓ）分析方法，探讨安静状态及心算作业时的脑波复杂度及心算引起Ｃｓ改变的规律。方法 记录１０名２６～３０岁男性安静及心算状态的１６导ＥＥＧ，用自行编制的状态相关脑波复杂度分析程序进行处理，分析两种状态下的Ｃｓ及其与脑功能状态相关的变化。结果 心算作业使Ｃｓ显著改变：Ａ类（８名）安静时Ｃｓ较低，心算作业时Ｃｓ在全脑均呈上升趋势或显著上升，且以左右颞及枕顶区最显著；Ｂ类（     

视觉记忆负荷对EEG的事件相关同步化与事件相关去同步化的影响

目的：研究视觉空间记忆和抽象几何图形记忆的工作记忆负荷对脑电事件相关同步化和去同步化的影响。方法：采用n-back范式，取n分别等于1、2、3为3种负荷水平下完成视觉空间匹配和抽象几何图形匹配两类记忆任务，并记录其脑电。结果：theta波的ERS总是伴随着alpha波的ERD出现。随着任务难度的增大，6-8Hz的theta波的ERS下降，alpha波的ERD增大，图形匹配任务引出的thetaERS和alphaERD均大于空间位置匹配任务。任务难度和任务类型的效应大多出现在CZ和FZ电极，这与任务所包含的注意和记忆的加工主要激活额叶和顶叶皮层的观点相符合。结论：EEG的ERD（或ERS）随视觉记忆负荷变化，因此可作为反映视觉记忆负荷的有效指标。     

The role of spatial alignment in posture-cognition dual task interaction

BackgroundA range of cognitive tasks can interfere with postural control, particularly in older adults. In the case of spatial tasks, the spatial alignment between the task and postural control can incur dual-task costs separately from task load. It has been suggested that spatial tasks incur dual-task costs because accessing the visuospatial sketchpad component of working memory reduces the capacity to utilize external visual information for postural control.Research questionWe investigated whether the spatial alignment between a cognitive and a postural control task can affect postural stability even when visual perception is not involved in either task and task load does not differ between aligned and non-aligned conditions. We predicted that any such effect would be greater in older people and in a more challenging stance.MethodsFifty healthy adults (27 aged 20–35, 23 aged 59–88) with no history of balance or cognitive difficulties performed a mental navigation task while standing in open or closed stance with eyes closed. The mental navigation task was presented in a reference plane that was either aligned or non-aligned to the horizontal reference plane in which the posture control system controlled the position of the body’s center of gravity. Task performance was measured as accuracy and response time and postural sway as anteroposterior (AP) and mediolateral (ML) sway velocity.ResultsThe older group were less accurate in the mental navigation task, and both groups had higher AP and ML sway velocity in closed stance. When standing in the more challenging stance, the older group had higher AP sway velocity while performing the mental navigation task in the non-aligned than the aligned reference plane condition.SignificanceThe spatial configuration compatibility between a cognitive task and postural control can affect postural stability even when visual information is not being used for either task and task load is unchanged.