脑电非线性分析在认知功能研究中的应用

目的　探讨在不同认知作业状态下脑电非线性动力学特性的变化规律、脑电非线性动态分析在认知过程研究中的作用。方法　我们用关联维数 (D2 )、点关联维数 (PD2 )对 30名健康成年人四种状态下的脑电数据进行了分析 :安静闭眼、安静睁眼、闭眼心算作业和睁眼图形推理作业。结果　认知作业过程相对于安静状态 ,D2 和PD2 有明显的升高。闭眼和心算 ,睁眼和图形推理状态之间差异有显著意义 (D2 分别为 3 93和 4 33,P <0 0 1;4 4 7和 4 98,P <0 0 1)。D2 和PD2 随时间存在时高时低的现象。结论　动态的、短时程的非线性动力学分析方法 ,更适合研究认知过程中大脑功能活动的变化规律。以D2 和PD2 地形图为基础的动态分析 ,可以清晰地展示认知过程中D2 和PD2的分布情况及与认知作业相关的大脑部位活跃顺序和活跃程度的变化 ,有助于我们了解认知过程中大脑的工作机制。     

不同思维状态下脑电近似熵的变化规律*

背景：近似熵是一种描述信号复杂性和规律性的非线性动力学方法,只需较少数据就能度量信号的复杂性。 目的：探讨不同思维状态下脑电近似熵的变化规律,以及近似熵在认知过程中的作用。 方法：用近似熵对20名健康成年人在安静闭眼、安静睁眼、闭眼记忆、闭眼心算和图片识别 5 种状态下的脑电数据进行分析。 结果与结论：近似熵值在闭眼计算和闭眼记忆思维状态高于安静闭眼状态,在图片识别状态下高于安静睁眼状态(P < 0.01);近似熵在安静闭眼和安静睁眼状态下各导联处于较低水平,在闭眼心算和闭眼记忆思维状态下各导联处明显增加。说明不同思维状态和不同导联部位对近似熵均有影响;近似熵在认知作业过程下较安静状态增高,并且不同思维状态下大脑功能活动的复杂性不同。因此脑电近似熵分析适用于认知过程脑功能活动变化规律研究,有助于了解大脑的工作机制。 关键词：近似熵;脑电;认知功能;思维状态;数字化医学     

脑电近似熵分析对帕金森病患者认知功能障碍的评估作用

目的:观察帕金森病(PD)患者与对照者的脑电近似嫡的差异,并探讨其对PD认知功能障碍的评估作用.方法:对31例PD患者和31例对照组进行简易精神状态检查量表(MMSE)测试、蒙特利尔认知评估量表(MoCA)测试、事件相关电位(ERP)检测P300波潜伏期(P3PL),采集安静闭眼、闭眼心算、安静睁眼三种状态下的脑电信号...     

发作间期癫(癎)患者脑电非线性分析

目的:通过比较癫(癎)发作间期不同发作类型患者与正常对照组之间脑电非线性特点,探讨非线性脑电图在发作间期癫(癎)患者脑功能评价中的意义及应用价值.方法:对发作间期36例癫(癎)发作患者(其中21例强直阵挛发作患者和15例复杂部分性发作)和32例健康对照组分别行安静闭眼、闭眼心算、安静睁眼3种脑功能活动状态下的脑电图检查...     

长期住院男性精神分裂症患者认知功能调查

目的：探讨长期住院男性精神分裂症患者的认知功能。方法：采用数字划消测验、空间广度测验评定57例男性长期住院精神分裂症患者（患者组）和57名正常对照者（正常对照组）的认知功能。结果：患者组在数字划消测验的完成时间、漏划个数以及空间广度测验的总分、顺行得分、逆行得分上明显差于正常对照组（t=8．21,t=3．47,t=4．72,t=2．36,t=5．88;P〈0．05或P〈0．001）。相关分析显示,患者的病程、服药时间与数字划消测验的完成时间呈显著正相关（r=0．41,P〈0．01;r=0．30,P〈0．05）。结论：长期住院男性精神分裂症患者的认知功能明显受损,且与患者的病程和服药时间相关。     

帕金森病合并抑郁患者认知功能和P300的研究

目的 探讨帕金森病（PD）合并抑郁患者认知功能和P300的改变。方法 对67例PD患者依据Zung抑郁自评量表（SDS）和汉密顿抑郁量表（HAMD）评分分为PD抑郁组（22例）和PD非抑郁组（45例），分别对两组患者进行认知功能评定和P300检测，并对结果进行比较和相关性分析。结果 本组PD患者简明智力状态量表（MMSE）评分尚在正常范围，但明显低于正常对照组（P〈0．05），PD抑郁组MMSE评分更低（P〈0.01）；与正常对照组比较，PD组P300潜伏期延长、波幅降低（均P〈0．05），PD抑郁组改变更为明显（均P〈0．01）；PD组P300潜伏期与MMSE评分呈负相关（r=-0．413，P〈0．05），波幅与MMSE评分呈正相关（r=0．398，P〈0．05）。结论 PD患者存在认知功能障碍，以记忆损害最为明显；抑郁对认知功能有负性影响，P300检测可以早期发现PD患者的认知功能障碍。     

低频重复经颅磁刺激对脑梗死失语的治疗作用及其对脑电活动的影响

目的 观察低频重复经颅磁刺激（low-rTMS）对脑梗死失语的治疗作用和其对脑电活动的影响.方法 选取左半球脑梗死后运动性失语右利手的患者15例,经ABC失语检查表评定后随机分为对照组7例和治疗组8例.对照组予常规药物和语言康复治疗;治疗组在对照组治疗基础上予low-rTMS治疗.rTMS治疗方法：频率1 Hz、强度为运动阈值80%、部位为右侧大脑半球Broca区、每序列50次脉冲、每天10个序列、序列间隔120 s,共10 d.两组在治疗前和治疗后（rTMS治疗后2周）均行ABC评分和脑电非线性分析检测.结果 两组治疗前的ABC评分值和脑电非线性分析参数均值（D2、PD2、Cx、LE、KE、ApEn）差异无统计学意义（P＞0.05）;治疗后治疗组的ABC评分和右额区脑电非线性分析参数PD2、Cx、均值比对照组显著增加,差异有统计学意义（P＜0.05）;而治疗组的左额区脑电非线性分析参数PD2、Cx、均值与对照组比较差异无统计学意义（P＞0.05）.结论 low-rTMS刺激右侧大脑半球（Broca区）对左半球脑梗死失语患者的语言有一定的康复作用.     

原发性失眠症患者认知功能的研究

目的:探讨原发性失眠症患者认知功能损害的特点。方法:采用神经心理测验包括韦氏记忆(数字累加、视觉再认、视觉再生、联想学习)、数字广度、数字划消、连线测验和威斯康辛卡片分类测验(WCST)分别对35例原发性失眠症患者(失眠组)和30名健康对照者(正常对照组)进行注意力、记忆力、执行功能等方面的测评;同时应用匹兹堡睡眠质量指数量表(PSQI)、抑郁自评量表(SDS)、焦虑自评量表(SAS)分别评定失眠及伴随的焦虑、抑郁症状的严重程度。结果:失眠组在数字累加、视觉再认、视觉再生、联想学习、数字广度测验的数字倒背、数字划消测验中的注意力失误率、连线测验B及BA完成时间和WCST测验的各项成绩(除正确应答数外)均明显差于正常对照组(F=4.646~28.224,P0.05或P0.01)。失眠组数字累加分与病程呈负相关(r=-0.558,P=0.001);联想学习分与PSQI评分呈负相关(r=-0.405,P=0.019);连线测验B-A时间与病程呈正相关(r=0.405,P=0.019);WCST持续错误百分比与SDS分呈正相关(r=0.309,P=0.045)。结论:原发性失眠症患者存在广泛认知功能损害,其病程、失眠程度以及伴随的焦虑抑郁情绪是导致认知功能损害的影响因素。     

帕金森病患者认知功能与脑电活动及脑影像学改变的相关性研究

目的研究帕金森病（Parkinsondisease,PD）患者认知功能、脑电活动及脑影像学的相关性。方法对70例PD患者及40例正常人进行中文版简易智能状态检查（MMSE）量表、BEAM频谱分析及脑影像学检查,对经MMSE初步测查后可疑认知功能障碍者进一步行成套神经心理学评估（FOM、RVR、DST、BD、BNT、HAMD）。结果PD痴呆组的神经心理学评估分值明显降低,痴呆组慢波（δ、θ频段）相对功率谱较非痴呆组明显增高（P〈0.01）,而快波（β1、β2频段）的相对功率谱显著降低（P〈0.05）;痴呆组额叶、颞叶的皮质萎缩及皮质下萎缩程度明显增加,且合并脑白质疏松症（LA）者明显高于非痴呆组;PD认知功能损害与额叶脑沟宽度、外侧裂宽度、三脑室宽度、脑室指数、前角指数及δ波功率值相关。结论神经心理学测验有利于发现PD患者的认知功能障碍,PD认知功能障碍与额颞叶皮质萎缩、皮质下机构萎缩程度、δ波功率及抑郁障碍密切相关,合并LA者痴呆发生率高。     

磁刺激神门穴脑电信号的非线性动力学分析

背景：中医临床已经证明针刺或电刺神门穴可以改变神经活动或者治疗神经系统疾病。磁刺激技术是一种新型生物刺激技术,鉴于其刺激强度高且无痛无创,所以可以采用经颅磁刺激技术刺激穴位替代针刺或电刺穴位。 目的：应用磁刺激刺激人肢体神门穴,分析大脑不同的功能状态与脑电信号混沌程度的关系,初步验证应用磁刺激疗法治疗疾病的可行性。 设计、时间及地点：对照观察,于2007-01/2008-05在河北工业大学河北省电磁场与电器可靠性重点实验室完成。 对象：被试选择健康右利手男性4名,无实验经历,无既往神经、精神系统病史,实验期间被试保持闭眼静息。 方法：共进行2个实验。静息实验即测量被试安静状态下的脑电信号样本,磁刺激实验即采用经颅磁刺激刺激被试肢体神门穴,并测量脑电信号样本。用非线性动力学的方法对被试在2种状态下的脑电信号样本进行分析。 主要观察指标：安静与磁刺激状态下脑电信号非线性动力学参数。 结果：磁刺激状态下被试的非线性特征指标如关联维数、Lyapunov指数和样本熵均较安静状态低(P < 0.05)。以上3个指标越低,大脑的状态越趋于平静、有序。 结论：磁刺激肢体神门穴降低了脑电信号的混沌程度,使大脑更加镇静。提示磁刺激肢体神门穴具有改善脑功能的作用,在一定程度上证明了磁刺激疗法的可行性。     

Decrease of non-linear structure in the EEG of Alzheimer patients compared to healthy controls.

OBJECTIVE: Non-linear EEG analysis can provide information about the functioning of neural networks that cannot be obtained with linear analysis. The correlation dimension (D2) is considered to be a reflection of the complexity of the cortical dynamics underlying the EEG signal. The presence of non-linear dynamics can be determined by comparing the D2 calculated from original EEG data with the D2 from phase-randomized surrogate data. METHODS: In a prospective study, we used this method in order to investigate non-linear structure in the EEG of Alzheimer patients and controls. Twenty-four patients (mean age 75.6 years) with 'probable Alzheimer's disease' (NINCDS-ADRDA criteria) and 22 controls (mean age 70.3 years) were examined. D2 was calculated from original and surrogate data at 16 electrodes and in three conditions: with eyes open, eyes closed and during mental arithmetic. RESULTS: D2 was significantly lower in the Alzheimer patients compared to controls (P = 0.023). The difference between original and surrogate data was significant in both groups, implicating that non-linear dynamics play a role in the D2 value. Moreover, this difference between original and surrogate data was smaller in the patient group. D2 increased with activation, but not significantly more in controls than in patients. CONCLUSIONS: In conclusion, we found decreased dimensional complexity in the EEG of Alzheimer patients. This decrease seems to be attributable at least partially to different non-linear EEG dynamics. Because of this, non-linear EEG analysis could be a useful tool to increase our insight into brain dysfunction in Alzheimer's disease.     

Behavioral activation of human hippocampal EEG: Relationship to recent memory

Behaviorally activated EEG was recorded from each hippocampus in 17 epilepsy surgery patients with unilateral (11 left, 6 right) mesial temporal lobe (MTL) seizure onset and correlated with preoperative material-specific memory test performances. Whole-band power (1–30 Hz) was recorded and subjected to spectral analysis under three conditions: (a) eyes closed resting, (b) eyes open with a verbal task, and (c) eyes open with a nonverbal task. Significantly less EEG desynchronization was observed in the epileptogenic hippocampus during the verbal activation condition but not during the eyes-open nonverbal task. Decreased EEG reactivity in the left hippocampus during verbal activation was correlated significantly with verbal memory test impairment among patients with left MTL seizure onset. However, similar relationships were not obtained between right seizure focus patients and performance on a visuospatial learning test. Results confirm the association of left MTL structures with verbal memory functions and emphasize the difficulty in demonstrating a consistent relationship between right MTL structures and visuospatial memory performance.     

无痴呆型血管性认知障碍患者执行功能损害特征分析

目的探讨无痴呆型血管性认知障碍（VCIND）患者执行功能损害的特征。方法采用语义与语音流畅试验、数字符号编码测验、连线测验、画钟测验和Stroop色词测验对43例VCIND患者和35名性别、年龄和文化程度相匹配的正常对照进行测试。结果与正常对照组相比,VCIND组患者计时类测验明显低于正常对照组（P＜0.01）,计分类测验中数字符号编码测验、语义与语音流畅试验低于正常对照组（P＜0.01）,其中Stroop色词测验计分（P＜0.05）。与正常对照组比较,VCIND组画钟测验评分无统计学意义（P〉0.05）。结论VCIND患者执行功能损害主要表现为转换障碍、工作记忆损害、知觉运动与信息处理速度减慢。     

Long-term cognitive and behavioural follow-up in three patients with eye closure-triggered paroxysmal activity.

PURPOSE: To study clinical, EEG, neuropsychological and behavioural evolution of three patients presenting with epileptic activity triggered by eye closure (EC) over a mean 10-year follow-up period. METHODS: All patients were studied at the time of the first observation (T0) and after a long follow-up period (T1). At both T0 and T1, each patient underwent: 1) traditional and specific activation techniques during prolonged video-EEG monitoring to detect possible inducing factors; 2) neuropsychological evaluations during video-EEG monitoring either with eyes closed or eyes open to detect any transient cognitive impairment (TCI); 3) detailed neuropsychological assessment without simultaneous EEG recording, to detect any stable cognitive impairment (SCI). RESULTS: EEG recordings showed transient, generalized paroxysms in one case and a continuous epileptic activity triggered by eye closure in the other two cases, at both T0 and T1. In all patients, no particular epileptiform discharge-induced factors were identified except for eye blinking (spontaneous, voluntary or induced by corneal reflex). The results of neuropsychological assessment while eyes were closed as compared to performances with eyes open, showed no significant differences at T0 or at T1 in two cases, thus possibly indicating the absence of TCI. Wechsler Intelligence Scales showed a decrease in performance at T1 in the two patients with eye closure-induced, continuous epileptiform activity. Detailed neuropsychological assessment without EEG recordings demonstrated an impairment of facial recognition ability in all three patients at T1. CONCLUSIONS: The lack of any differences between the results of neuropsychological tests performed with eyes open and eyes closed in two patients might suggest that not all eye-closure-triggered paroxysms are associated with TCI. On the other hand, our data highlight that EC-triggered, EEG epileptic discharges can produce long-lasting neuropsychological and behavioural effects, and also indicate that EEG discharges recurring over time might exert a disruptive effect on cognitive functions. Our three patients showed extreme variability across the neuropsychological tasks except for a facial recognition deficit that was evident in all cases, thus suggesting a possible dysfunction of temporo-occipital brain structures and/or of the fusiform face area as recently demonstrated by combined fMRI/EEG studies in patients with fixation-off sensitivity.     

Abnormal EEG complexity in patients with schizophrenia and depression.

OBJECTIVE: Schizophrenics are usually unable to perform well on cognitive tasks due to disturbances in cortical information processing that are observable as abnormalities in electroencephalogram (EEG) signals. However, whether such cortical disturbances can be assessed by quantitative EEG analysis remains unclear. The purpose of this study was to characterize EEG disturbances, using the Lempel-Ziv complexity (LZC), in the subjects with schizophrenia at rest or while performing mental arithmetic tasks. The results were compared to those from the subjects with depression and with healthy controls. METHODS: The subjects included 62 schizophrenia patients, 48 depression patients and 26 age-matched healthy controls. EEG was recorded under two conditions: (i) resting with eyes closed, and (ii) a mentally active condition wherein the subjects were asked to subtract 7 from 100 iteratively with their eyes closed. EEG signals were analyzed by LZC and conventional spectral methods. RESULTS: In all the groups, LZC of EEG decreased during the mental arithmetic compared with those under the resting conditions. Both the schizophrenia and the depression groups had a higher LZC (p<0.05) than the controls. Also, the schizophrenia group had a lower LZC (p<0.05) than the depression group during the mental arithmetic task as well as during the resting state. Significant differences in LZC, at some symmetrically located loci (FP1/FP2, F7/F8), between the two hemispheres were found in all the patient groups only during the arithmetic task. CONCLUSIONS: Compared with conventional spectral analysis, LZC was more sensitive to both the power spectrum and the temporal amplitude distribution. LZC was associated with the ability to attend to the task and adapt the information processing system to the cognitive challenge. Thus, it would be useful in studying the disturbances in the cortical information processing patients with depression or schizophrenia. SIGNIFICANCE: LZC of EEG is associated with mental activity. Thus, LZC analysis can be an important tool in understanding the pathophysiology of schizophrenia and depression in future studies.     

卒中后抑郁的长程脑电图研究

目的 探讨卒中后抑郁患者长程脑电图的特点。方法 选取卒中后抑郁患者101例,行长程脑电图,计算睁闭眼实验后第一个10 sec内脑电图δ、θ、α、β波的时间,以及整夜S1、S2、S3、S4睡眠阶段和快动眼睡眠（rapid eye movement sleep,REM）占总睡眠时间的比例,与健康对照组脑电图结构进行比较。结果 卒中后抑郁组较对照组脑电图上慢波（δ和θ波）明显增加（δ波P＝0.001,θ波P＝0.005）,α波明显减少（P＝0.008）,β波无显著差异。和正常对照组睡眠结构比较,卒中后抑郁组睡眠S2、S3和S4阶段比例减少（P值分别为0.008、0.004）,睡眠S1阶段和REM比例增加（P值分别为0.001和0.006）。结论 卒中后抑郁症患者脑电背景慢波增多;卒中后抑郁症患者浅睡眠多,而中到深度睡眠减少。     

Withdrawal of visual feedback improves micrographia in Parkinson's disease.

Micrographia is a common, often presenting feature of Parkinson's disease. We assessed a simple writing paradigm in 40 PD patients "off" medications, 40 different PD patients "on" medications, and 64 age- and sex-matched controls. Patients wrote "Today is a nice day" with both eyes open and eyes closed to assess the effects of visual withdrawal (eyes closure). The order (eyes open vs. eyes closed) was alternated. In the "off" medicine group, eye closure increased the writing length by 14.0 +/- 10.1% (P < 0.05) from a mean of 69.1 to 77.7 mm [range -14% to +73%]. The percentage increase was larger in the 20 subjects with the smallest baseline writing size (worse micrographia), compared to the 20 with relatively larger writing (19.5% vs. 7.9%, P < 0.05). Neither the "on" medicine group, nor the control group changed. Simple eye closure significantly increased writing size in "off" PD patients to a similar or greater amount as levodopa. This data suggests that micrographia is not a pure motor hypokinetic feature but is affected by PD similar to other superlearned tasks such as walking. Furthermore, some patients have adapted this simple eye closing strategy when writing, especially signatures.     

Fractal dimension analysis of static stabilometry in Parkinson's disease and spinocerebellar ataxia.

The static stabilometry patterns associated with Parkinson's disease (PD, n = 15) and spinocerebellar ataxia (SCA, n = 15) were compared with those of normal control (n = 15) by measuring the fractal dimensions. Fractal dimensions were estimated using the modified pixel dilation (mPD) method. The fractal dimensions with closed eyes showed a significant correlation with Environmental area for SCA group (p < 0.05). The fractal dimension for SCA group was significantly higher with closed eyes than that with open eyes (p < 0.05). The fractal dimension with closed eyes was significantly higher in PD and SCA groups than that in normal group (p < 0.05). The fractal dimension with closed eyes was higher when the clinical stage was more severe with PD and SCA group while Environmental and Longitude/Environmental areas were not. These findings suggest that the fractal dimension is more sensitive than traditional stabilometric analysis in an evaluation of postural instability in PD and SCA.