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Accuracy of two dipolar inverse algorithms applying reciprocity for forward calculation

COMPUTERS AND BIOMEDICAL RESEARCH 2000年第3期33卷 172-185页

作者： Laarne, P Hyttinen, J Dodel, S Malmivuo, J Eskola, H Tampere Univ Technol Ragnar Granit Inst FIN-33101 Tampere Finland Max Planck Inst Fluid Dynam D-37073 Gottingen Germany

Two inverse algorithms were applied for solving the EEG inverse problem assuming a single dipole as a source model. For increasing the efficiency of the forward computations the lead field approach based on the reciprocity theorem was applied. This method provides a procedure to calculate the computationally heavy forward problem by a single solution for each EEG lead. A realistically shaped volume conductor model with five major tissue compartments was employed to obtain the lend fields of the standard 10-20 EEG electrode system and the scalp potentials generated by simulated dipole sources. A least-squares method and a probability-based method were compared in their performance to reproduce the dipole source based on the reciprocal forward solution. The dipole localization errors were 0 to 9 mm and 2 to 22 mm without and with added noise in the simulated data, respectively. The two different inverse al algorithms operated mainly very similarly. The lead field method appeared applicable for the solution of the inverse problem and especially useful when a number of sources, e.g., multiple EEG time instances, must be solved. (C) 2000 Academic Press.

关键词：算法脑/解剖学和组织学脑/生理学计算机脑电描记术/统计学和数值数据电生理学模型神经学人类

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Important factors for the 10-year mortality rate in patients with acute chest pain or other symptoms consistent with acute myocardial infarction with particular emphasis on the influence of age

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AMERICAN HEART JOURNAL 2001年第4期142卷 624-632页

作者： Herlitz, J Karlson, BW Lindqvist, J Sjölin, M Sahlgrens Univ Hosp Div Cardiol S-41345 Gothenburg Sweden

Objective Our purpose was to describe the mortality rate and mode of death over 10 years and factors associated with death among patients admitted to the emergency department with acute chest pain or other symptoms consistent with acute myocardial infarction (AMI). Methods All patients who come to the emergency department of Sahlgrenska University Hospital in Goteborg, Sweden, with acute chest pain or other symptoms consistent with AMI during a 21-month period were studied. Results In all, 5362 patients were registered, for whom information on 10-year mortality was available in 5158 (96.2%). In all, there were 2126 deaths (41.2%). Fifty-two percent of patients were less than or equal to 65 years old. Independent predictors of death registered on admission to hospital during the subsequent 10 years were age (relative risk 1.08, 95% Cl 1.07-1.09), male sex (1.38, 1.25-1.52), initial degree of suspicion of AMI (1.13, 1.06-1.19), a pathologic initial electrocardiogram (1.76, 1.56-1.98), symptoms of congestive heart failure (1.66, 1.39-1.98), "other" nonspecific symptoms (1.22, 1.07-1.39), a history of diabetes mellitus (1.65, 1.44-1.88), a history of congestive heart failure (1.42, 1.26-1.60), a history of previous myocardial infarction (1.26, 1.12-1.40), and a history of hypertension (1.14, 1.03-1.26). For all these predictors there was a strong interaction with age, thus a much more marked influence on outcome among patients less than or equal to 65 years old than among patients > 65 years old. When the above risk indicators were simultaneously considered, development of AMI during the first 3 days after hospital admission was still an independent predictor of death (1.63, 1.43-1.86). Conclusion For patients admitted to the emergency department with acute chest pain or other symptoms consistent with AMI, several predictors based on clinical history and clinical presentation are related to the 10-year prognosis. They are more strongly associated with outcome among pati

关键词：急性病年龄因素死亡原因胸痛/诊断胸痛/流行病学胸痛/死亡率脑电描记术/统计学和数值数据急诊室医院/统计学和数值数据住院/统计学和数值数据高血压/诊断高血压/流行病学心肌梗死/诊断心肌梗死/流行病学心肌梗死/死亡率预后危险性别因素瑞典/流行病学老年人女(雌)性人类男(雄)性中年人

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Electroencephalogram confirmatory rate in neonatal seizures

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PEDIATRIC NEUROLOGY 1999年第1期20卷 27-30页

作者： Sheth, RD Univ Wisconsin Dept Neurol Madison WI 53792 USA

The electroencephalogram (EEG) is confirmatory in 70% of children and adults with seizures, although gestation- and etiology-specific EEG confirmatory rates in neonates have not been well defined. All neonates treated for seizures and who underwent EEG were identified from 4,575 neonates admitted between 1985 and 1996 to a neonatal intensive care unit. The relationship between EEG findings (epileptiform discharges and background abnormalities) and gestation, mortality rate, and seizure etiology was examined using the Student t test. One hundred eighty-three neonates treated for seizures underwent a total of 352 EEGs: 144 of these neonates (79%) had an abnormal EEG (epileptiform discharges in 113 (60%) and non-epileptiform background abnormalities in 31). The EEG confirmatory rate increased with gestation (63% at 28 weeks vs 77% at term, P < 0.02). Etiology for seizures also influenced the EEG confirmatory rate: central nervous system (CNS) infection 95% (P < 0.05), hypoxic-ischemic encephalopathy 80% (P < 0.05), germinal matrix-intraventricular hemorrhage 65%, and CNS malformations 65%. The EEG confirmatory rate was predictive of neonatal mortality (19% vs 6%, P < 0.03). The EEG was directly confirmatory (epileptiform discharges) in 60% and supportive (non-epileptiform background abnormalities) in a further 17% of neonates with seizures. Gestation and etiology influence the EEG confirmatory rate in neonatal seizures. (C) 1999 by Elsevier Science Inc. All rights reserved.

关键词：脑疾病/并发症队列研究脑电描记术/统计学和数值数据孕龄发病率婴儿早产/生理学回顾性研究农村卫生/统计学和数值数据发作/流行病学发作/病理生理学人类婴儿新生

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The polysomnogram assay: A method to represent the overnight polysomnogram in a condensed format

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COMPUTERS AND BIOMEDICAL RESEARCH 2000年第2期33卷 110-125页

作者： Bartolo, A Clymer, BD Golish, JA Burgess, RC Ohio State Univ Ctr Biomed Engn Columbus OH 43210 USA Ohio State Univ Dept Elect Engn Columbus OH 43210 USA Cleveland Clin Fdn Dept Pulm & Crit Care Med Cleveland OH 44195 USA Ohio State Univ Dept Neurol Columbus OH 43210 USA

We present the polysamnogram assay (PSGA), a new representation format for the polysomnogram (PSG), designed to assist in the interpretation of overnight PSG studies. The technique condenses the PSG record by a factor of 30 while preserving the ability to portray PSG features of diagnostic relevance, including sleep architecture, arousals, movement, leg jerks, cyclic alternating pattern, and increased breathing effort. The PSGA patterns associated with these events are described and illustrated by examples. The new format considerably reduces the effort required to evaluate sleep quality and continuity, making it more practicable for the polysomnographer to interpret the entire overnight PSG study. The compressed time scale also facilitates analysis of relatively long PSG episodes and allows assessment of signal activity surrounding critical PSG events. The PSGA appears capable of improving identification of arousals, leg jerks, and upper airway resistance, and may be especially amenable for automatic analysis of PSG data (C) 2000 Academic Press.

关键词：气道阻力觉醒生物统计学计算机制图计算机数据说明统计脑电描记术/方法脑电描记术/统计学和数值数据肌电描记术/方法肌电描记术/统计学和数值数据眼电描记术/方法眼电描记术/统计学和数值数据心率小腿运动(Movement) 血氧测定法/方法血氧测定法/统计学和数值数据氧/血液多道睡眠描记术/方法多道睡眠描记术/统计学和数值数据呼吸力学睡眠期打鼾软件人类

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Walking through a maze alters the architecture of sleep

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PERCEPTUAL AND MOTOR SKILLS 1999年第3期88卷 1141-1159页

作者： Meier-Koll, A Bussmann, B Schmidt, C Neuschwander, D Univ Konstanz Dept Psychol D-78434 Constance Germany

Human and animal studies imply that sleep is a critical period for consolidation of recent memories. Whereas the majority of researchers focussed on the procedural learning, the present human study concerns how storing of spatial information and episodic memory are linked to sleep stages. Two city mazes, a simple and a complex one, were created by means of a computer program. Local aspects of these mazes appeared as street scenes on a TV-screen. Our subjects sat in front of the screen and manoeuvered through the maze by the help of a three-button PC mouse. Thus, each subject took a 'mental walk' through an imaginary city. The task was to find various end-points and to find the way back to the starting point. Subjects of two experimental groups 'walked' through either the simple or complex city maze for eight hours. Afterwards the subjects slept in our laboratory, where their sleep stages could be measured polygraphically. Subjects who had explored the simple maze showed considerable alteration in sleep architecture. They remained significantly longer in sleep Stage 2 than subjects who had explored the complex maze. Moreover, with successful orientation in the simple maze sleep stages occurred aperiodically, whereas walking through the complex maze was associated with sleep stages in accordance with ultradian cycles, as observed in a control group. Compared to subjects of the control group who had experienced neither maze, the subjects of both experimental groups had significantly enhanced EEG sleep spindle activities. Alteration in temporal architecture of sleep and selective prolongation of sleep Stage 2 following spatial orientation point to a functional linkage between cognitive mapping of space and sleep Stage 2 with enhanced EEG spindle activity.

关键词：活动周期/生理学计算机模拟脑电描记术/统计学和数值数据海马/生理学行走/生理学迷宫学习/生理学记忆/生理学定向力/生理学多道睡眠描记术/统计学和数值数据睡眠期/生理学空间知觉/生理学成年人动物女(雌)性人类男(雄)性小鼠大鼠

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Effects of hypnotizability on performance of a stroop task and event-related potentials

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PERCEPTUAL AND MOTOR SKILLS 1999年第3期88卷 819-830页

作者： Nordby, H Hugdahl, K Jasiukaitis, P Spiegel, D Univ Bergen Dept Biol & Med Psychol N-5009 Bergen Norway Stanford Univ Sch Med Stanford CA 94305 USA

The effect of hypnotizability on verbal reaction times and event-related potentials during performance of a Stroop color-naming task was studied. The Stroop stimuli (colored words) were randomly presented to 5 high and 5 low hypnotizable subjects in the right and left peripheral visual fields juring both waking state and hypnotic induction conditions. Unlike studies in which the Stroop stimuli were foveally presented to the: subjects, the highly hypnotizable subjects did not show prolonged verbal reaction times in either waking or hypnotic conditions. There was a marked deterioration in performance accuracy, however, for highly hypnotizable sub jeers during hypnosis. Event-related potentials indicated that the highly hypnotizable subjects showed a reduced P3a amplitude and a decreased N2b latency to the visual stimuli in both waking and hypnotic conditions, suggesting a lack of orienting to or disengagement from peripherally occurring stimuli.

关键词：注意力色觉脑电描记术/统计学和数值数据眼电描记术诱发电位/生理学眼球运动/生理学额叶/生理学功能偏侧化/生理学催眠术神经心理学测验反应时间言语行为视野人类

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Human movement-related brain potentials preceding voluntary movements in different arousal states monitored with skin potential level

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PERCEPTUAL AND MOTOR SKILLS 2000年第1期90卷 299-306页

作者： Masaki, H Takasawa, N Yamazaki, K Natl Res Inst Police Sci Tokyo Japan Waseda Univ Sch Human Sci Tokorozawa Saitama 3591192 Japan

The present study investigated the readiness potential (RP) preceding a brisk extension of the right middle finger during different arousal states as monitored by skin potential level (SPL). The late component of the readiness potential in the medium arousal state was significantly larger than those in the low and high arousal states. This finding indicates that the RP waveform may vary as a function of arousal states, suggesting the inverse U-shaped relationship proposed in studies of the contingent negative variation.

关键词：觉醒/生理学脑/生理学脑电描记术/统计学和数值数据诱发电位皮电反应/生理学运动(Movement)/生理学人类

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P300 habituation patterns: Individual differences from ultradian rhythms

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PERCEPTUAL AND MOTOR SKILLS 1999年第3期88卷 1111-1125页

作者： Lin, E Polich, J Scripps Res Inst Dept Neuropharmacol La Jolla CA 92037 USA Univ Calif San Diego San Diego CA 92103 USA

Event-related brain potentials (ERPs) were elicited with auditory stimuli from normal subjects every 10 min, for 10 successive trial blocks to assess ultradian influences on the P300 component. Based on a theoretical analysis of the underlying relationship between background EEG activity and P300 variability, subjects were divided into two groups according to whether P300 amplitude increased or decreased initially over trial blocks. P300 amplitude habituated across trial blocks. P300 latency produced systematic cyclical variation with approximately a 90-min. period that was opposite in phase for the different subject groups. The findings suggest that ultradian rhythms contribute to P300 latency variability. The implications of the results for P300 in applied settings are discussed.

关键词：声刺激活动周期/生理学觉醒/生理学注意力/生理学脑电描记术/统计学和数值数据诱发电位/生理学诱发电位听觉/生理学习惯化心理生理学/生理学个性模型心理学反应时间/生理学成年人女(雌)性人类男(雄)性

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Hypnagogic imagery and EEG activity

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PERCEPTUAL AND MOTOR SKILLS 1999年第2期88卷 676-678页

作者： Hayashi, M Katoh, K Hori, T Hiroshima Univ Fac Integrated Arts & Sci Dept Behav Sci Higashihiroshima 7398521 Japan

The relationships between hypnagogic imagery and EEG activity were studied. 7 subjects (4 women and 3 men) reported the content of hypnagogic imagery every minute and the hypnagogic EEGs were classified into 5 stages according to Hori's modified criteria. The content of the hypnagogic imagery changed as a function of the hypnagogic EEG stages.

关键词：声刺激 α节律大脑皮质/生理学梦/生理学脑电描记术/统计学和数值数据知觉/生理学睡眠/生理学睡眠期/生理学言语行为觉醒状态/生理学女(雌)性人类男(雄)性

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Laboratory studies on the effects of temperature variations on drowsiness

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PERCEPTUAL AND MOTOR SKILLS 1999年第3期89卷 1217-1229页

作者： Landström, U Englund, K Nordström, B Stenudd, A Natl Inst Working Life S-90713 Umea Sweden

20 subjects were analysed in a laboratory study investigating the inhibition of drowsiness by altering air temperature. The EEGs of the subjects were used to measure the effect of sequences of temperature lowerings of 10 degrees for 2- and 4-min. periods. The effect upon wakefulness mas analysed through EEG recordings and subjective ratings. Results indicated that reductions of the air temperature of 10 degrees during repeated 2- and 4-min, periods significantly increased wakefulness.

关键词：空气 α节律汽车驾驶觉知/生理学脑电描记术/统计学和数值数据环境受控睡眠期/生理学温度时间因素觉醒状态/生理学青少年成年人女(雌)性人类男(雄)性中年人

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