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1.
目的探讨失眠症患者在不同认知作业状态下脑电非线性动力学的初步特点。方法应用日本光电1518K脑电图和地形图系统,以及关联维数(D2)、点关联维数(PD2)方法对75例失眠症和64名正常成人在安静闭眼、安静睁眼、闭眼心算作业、睁眼记忆和数字划消五种状态下的脑电数据进行了分析。结果 (1)在D2和PD2上,正常和失眠症睁闭眼实验中差异均未达到显著性。(2)在D2上,与正常对照组比较,失眠症在心算和数字划消两个认知心理测试中均见降低。(3)在PD2上,与正常对照组比较,失眠症在心算、汉字记忆和数字划消三个认知心理测试中也见降低(P〈0.05或P〈0.01)。结论非线性动力学分析为临床提供了一种处理分析脑电信号的新思路,有助于进一步了解失眠症认知过程中大脑的工作机制。  相似文献   

2.
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  相似文献   

3.
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...  相似文献   

4.
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...  相似文献   

5.
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。  相似文献   

6.
探讨事件刺激处理时心理活动的脑电生理改变。方法应用脑电地形图的检测技术对30例正常人安静状态及在两种作业难度下脑电功率值的变化进行观察。结果(1)事件刺激后α2频带功率值降低,β、α1频带功率值增高,变化以枕区,顶区,后颞区的功率值最为显著;(2)随作业难度的的增加α2频带功率呈梯度降低,β频带功率则呈梯度增高;(3)在心算过程中,安静状态下呈现的两侧半球电位值差异消失。结论:心算期间大脑皮层出现  相似文献   

7.
众所周知,临床脑电图描记,一般都是在清醒、安静、闭眼状态下进行,此时在两半球后部的基本电活动为8~13次/秒的α节律。而在描记过程进行时,还要睁眼10秒钟左右,然后再闭眼,观察在睁眼状态下脑电图的变化。一般的注意力都集中在α节律的变化,因为睁眼时,α节律消失,而为低幅β波所替  相似文献   

8.
目的 探讨脑电非线性分析在急性一氧化碳中毒(ACMP)疗效评估中的价值. 方法 选取川北医学院附属医院神经内科自2010年11月至2011年3月收治的ACMP患者21例,分别于入院时、入院治疗2周及入院治疗4周时采集脑电信号,将3个时间点获取的脑电信号行非线性分析(D2、Cx、ApEn、C-ApEn、Dm、PD2、LE和KE)并分别与21例正常对照者比较. 结果 ACMP组D2、Cx、ApEn、C -ApEn、Dm值随治疗时间的延长有逐步增高的趋势,而PD2、LE和KE值与治疗周期无相关性.入院时ACMP组D2、Cx、ApEn、C-ApEn、Dm平均值与对照组比较差异具有统计学意义(P<0.05);入院治疗2周及入院治疗4周的ACMP组脑电非线性参数(LE、PD2、D2、Dm、Cx、ApEn及C-ApEn)平均值与对照组相比差异均无统计学意义(P>0.05). 结论 脑电非线性参数(D2、DM、Cx、ApEn、C-ApEn)在ACMP治疗初期能较同步客观地反映脑功能的恢复情况,具有一定的评估疗效价值.  相似文献   

9.
目的研究早期帕金森病(Parkinson disease,PD)患者姿势稳定性的变化并分析相关影响因素。方法收集2019年2月至2019年6月作者医院收治的早期未治疗PD患者30例及同期招募的健康对照者20名。完成基于惯性加速度器的姿势摆动度的测定,选取急动度(Jerk)和均方根加速度(root mean square acceleration,RMS)为度量指标,分别在前后方向(antero-posterior,AP)、中侧(medio-1ateral,ML)方向及总矢量方向上进行测定。比较不同视觉状态下PD与健康对照姿势摆动指标的差异,比较不同视觉状态下PD治疗前后姿势摆动指标的差异。结果 (1)在睁眼和闭眼状态下,除RMS(ML)外,PD组Jerk(AP)、Jerk、Jerk(ML)、RMS(AP)、RMS均较对照组高(均P0.05);(2)除RMS(ML)外,闭眼状态下PD组及对照组的Jerk(AP)、Jerk、RMS(AP)、RMS较睁眼状态下高(P0.05或P0.01);PD组和对照组由睁眼状态至闭眼状态各摆动指标恶化率比较无统计学差异(P0.05)。(3)在睁眼状态下,PD患者初始左旋多巴治疗前后摆动指标比较差异均无统计学意义(P0.05),而在闭眼状态下,除PD患者治疗后RMS(ML)较治疗前高(P=0.047)外,余指标比较均无统计学差异(均P0.05)。结论早期PD患者亦存在姿势不稳,且闭眼状态下明显;初始常规剂量左旋多巴治疗则未明显影响姿势稳定性。  相似文献   

10.
阿尔茨海默病(AD)早期诊断常是困难的,基因、影像等手段可发现一些生物学标记物,但临床上仍缺乏客观、简便易于普及的检测手段。近年来定量脑电图在认知功能障碍方面研究日益受到关注。通过定量分析可以获得脑电的频率、相位、网络相关性及复杂度、子波熵等定量信息,揭示大脑电活动的动力学机制,从而帮助我们发现可能的AD脑电相关的生物标记物。定量脑电不仅可以显示安静状态下的脑电信息,也可以检测不同认知任务下脑电的定量演变,观察药物使用后脑电的定量变化。定量脑电图作为认知功能障碍研究的新方法,显示了良好的研究前景。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
In this paper, a time series complexity analysis of dense array electroencephalogram signals is carried out using the recently introduced Sample Entropy (SampEn) measure. This statistic quantifies the regularity in signals recorded from systems that can vary from the purely deterministic to purely stochastic realm. The present analysis is conducted with an objective of gaining insight into complexity variations related to changing brain dynamics for EEG recorded from the three cases of passive, eyes closed condition, a mental arithmetic task and the same mental task carried out after a physical exertion task. It is observed that the statistic is a robust quantifier of complexity suited for short physiological signals such as the EEG and it points to the specific brain regions that exhibit lowered complexity during the mental task state as compared to a passive, relaxed state. In the case of mental tasks carried out before and after the performance of a physical exercise, the statistic can detect the variations brought in by the intermediate fatigue inducing exercise period. This enhances its utility in detecting subtle changes in the brain state that can find wider scope for applications in EEG based brain studies.  相似文献   

14.
In a pilot study, we investigated the topography of 11 continuous MEG measures for the eyes-opened and eyes-closed condition together with three simple mental tasks (mental arithmetic, visual imagery, word generation). One-minute recordings for each condition from 16 right-handed subjects were analyzed. The electrophysiological measures consisted of 6 spectral band measures together with spectral edge frequency and spectral entropy, plus the time-domain-based entropy of amplitudes (ENA) and the nonlinear measures correlation dimension D2 and Lyapunov exponent L1. In summary, our results indicate a pronounced task-dependent difference between the anterior and the posterior region, but no lateralization effects. Although the nonlinear measures ranged in the middle field with respect to the number of significant contrasts, they were the only ones to be partially successful in discriminating the mental tasks from each other. The most efficient measure turned out to be the ENA. Under mental activation the ENA was larger than in both no task conditions (eyes opened and eyes closed). This finding reflects lower variations of the maximum amplitude during performance of mental tasks than during no task states.  相似文献   

15.

Background

In spite of the large number of studies on schizophrenia, a full understanding of its core pathology still eludes us. The application of the nonlinear theory of electroencephalography (EEG) analysis provides an interesting tool to differentiate between physiologic conditions (e.g., resting state and mathematical task) and normal and pathologic brain activities. The aim of the present study was to investigate nonlinear EEG activity in patients with schizophrenia.

Methods

We recorded 19-lead EEGs in patients with stable schizophrenia and healthy controls under 4 different conditions: eyes closed, eyes open, forward counting and backward counting. A nonlinear measure of complexity was calculated by means of correlation dimension (D2).

Results

We included 17 patients and 17 controls in our analysis. Comparing the 2 populations, we observed greater D2 values in the patient group. In controls, increased D2 values were observed during active states (eyes open and the 2 cognitive tasks) compared with baseline conditions. This increase of brain complexity, which can be interpreted as an increase of information processing and integration, was not preserved in the patient population.

Limitations

Patients with schizophrenia were taking antipsychotic medications, so the presence of medication effects cannot be excluded.

Conclusion

Our results suggest that patients with schizophrenia present changes in brain activity compared with healthy controls, and this pathologic alteration can be successfully studied with nonlinear EEG analysis.  相似文献   

16.
This study aimed at assessing the effects of cognitive activity and mental task load on the correlation dimension of the human electroencephalogram (EEG). Three experimental conditions were created: a baseline condition and two cognitive task conditions, a calculation task and a time estimation task. The calculation task was supposed to induce a higher mental load than the time estimation task, which is regarded as a less complex one. This was verified by a subjective rating scale. All conditions differed significantly in subjective estimated task load. The correlation dimension appeared to be higher in both task conditions compared to the baseline condition. A comparison of the two tasks indicated that the difference in correlation dimension between calculation and time estimation was also significant, with the highest value for calculation. It is concluded that cognitive and mental activity is associated with a higher correlation dimension in the EEG. This implies that the correlation dimension is a sensitive parameter in the analysis of electrical brain activity.  相似文献   

17.
18.
Patients with Parkinson's disease (PD) are impaired when performing cognitive tasks such as mental operations and working memory paradigms, which engage frontal lobe regions. These impairments may reflect degeneration of either nigrostriatal or mesocortical dopaminergic projections. D2 receptor antagonist 11C-raclopride (RAC) with positron emission tomography (PET) now provides an in vivo approach for investigating dopaminergic transmission by monitoring changes in synaptic dopamine levels during task performance, Our RAC PET study suggests that the capacity to release dopamine during a working memory task is impaired in the striatum but relatively preserved in the medial prefrontal cortex in patients with PD. This pattern of dopamine release is in accordance with our previous H2(15)O PET findings showing hypoactivity of the striatum during a mental operation task in PD. These PET findings support a view that degeneration of nigrostriatal dopaminergic projection causing disruption of the cortico-basal ganglia circuit contributes to the cognitive impairments observed in PD. The findings also implicates that mesocortical dopaminergic function may be preserved in PD. Since excessive stimulation of dopamine receptors in the frontal cortex can rather deteriorate its function, the benefit in the striatum and the risk in the frontal cortex should be properly evaluated for dopamine replacement therapy.  相似文献   

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