Appearance of frontal midline theta rhythm and personality traits

The distinct theta rhythm in the frontal midline area during a performance of mental tasks has been called Fm theta. However, Fm theta shows individual differences in its appearance. The relationship between the appearance of Fm theta and the subject personality was investigated in the present study. Forty male university students performed an arithmetic addition test for 5 min daily during three consecutive days and their EEGs were recorded during the test. They also completed the Maudsley Personality Inventory (MPI) and the Taylor Manifest Anxiety Scale (MAS) after the EEG recording on the last day. The subjects who obtained low scores on the anxiety scale of MAS, high scores on the extraversion scale of MPI and low scores on the neuroticism scale of MPI showed larger amounts of Fm theta. On the other hand, those subjects who showed high scores on the anxiety scale, low scores on the extraversion scale and high scores on the neuroticism scale showed smaller amounts of Fm theta or none. These results suggest that the appearance of Fm theta is closely related to the subject personality traits.     

A physiological marker for assessing anxiety level in humans: frontal midline theta activity

The distinct theta rhythm in the frontal midline area during performance of mental tasks has been designated as Fm theta. Sixteen male university students who failed to show any appearance of Fm theta in 3 consecutive days were given diazepam 5 mg, amobarbital 80 mg, methylphenidate 15 mg and placebo, in a double-blind, crossover design. Scores were made on the state anxiety scale of STAI; EEGs were recorded before and during performance of an arithmetic addition. The test was repeated twice: before and one hr after drug administration. Fm theta appeared following the drug administration even in those who had never shown the appearance of Fm theta, and the appearance time of Fm theta increased in the following order: diazepam greater than amobarbital greater than placebo greater than methylphenidate. The scores of STAI decreased in the same order. The speed of performed tasks was increased by methylphenidate and placebo, but decreased by amobarbital and diazepam. These results suggest that relief from anxiety might be reflected in the appearance of Fm theta and that Fm theta might be a useful tool to measure the anxiety level in humans.     

Moving potential field of frontal midline theta activity during a mental task

The movement of potential field (potential flow) of frontal midline theta activity (Fmθ) was examined by using optical flow detection techniques in image processing in 6 normal subjects. Electroencephalograms (EEGs) over the fronto-central region were recorded from 13 electrodes around F_z. The potential flow of Fmθ was estimated on a frame which consisted of a square grid of 19 × 19 points in which each of the 13 electrodes was positioned with F_z at the center of grid. The peak-to-trough amplitude distribution was rounded or oval with a maximum just anterior to F_z. In each hemisphere, potential field moved medially in a region anterior to F_z, posteriorly near or at the midline and laterally in a region posterior to F_z. In the temporal sequence of potential field, at each point velocity directions tended to change progressively clockwise or counterclockwise. In the whole frame, a rotary movement of potential flow was found with a center at the middle on each side. Our findings suggested that a potential maximum at the midline may be due to overlapping of fields of opposite direction over the frontal scalp, arising from sources of similar orientation in both hemispheres. It can be assumed that Fmθ propagates in a clockwise direction in the left hemisphere and in a counterclockwise direction in the right hemisphere.     

Effects of centrally acting drugs on the frontal midline theta activity in man

The frontal midline theta activity which appears during a performance of mental tasks has been designated as Fm theta. Sixteen male university students who showed the appearance of Fm theta in 3 consecutive days were given 4 centrally acting drugs, i.e., diazepam 5 mg, amobarbital 80 mg, methylphenidate 15 mg and placebo, in a double-blind, crossover design. Scores were made on the state anxiety scale of Spielberger's State Trait Anxiety Inventory (STAI), and EEGs were recorded monopolarly before and during the performance of an arithmetic addition. The test was done twice, before and one hour after the drug administration. Placebo increased the appearance time of Fm theta, decreased the STAI scores and increased the tasks. Diazepam increased the appearance of Fm theta and decreased the state of anxiety but did not influence the amount of tasks. Amobarbital changed neither the appearance of Fm theta nor STAI scores but decreased the tasks slightly. Methylphenidate failed to influence the appearance of Fm theta but increased both the STAI scores and performed tasks. These results suggest that the appearance of Fm theta is influenced by the drugs and that the relief from anxiety might be involved in the appearance of Fm theta.     

Medial prefrontal cortex generates frontal midline theta rhythm

Frontal midline theta rhythm (Fm theta) is a distinct theta activity of EEG in the frontal midline area that appears during concentrated performance of mental tasks in normal subjects and reflects focused attentional processing. To tomographically visualize the source current density distributions of Fm theta, we recorded Fm theta by using a 64-channel whole-head MEG system from four healthy subjects, and applied a new analysis method, synthetic aperture magnetometry (SAM), an adaptive beam forming method. Fm theta was observed in the MEG signals over the bilateral frontal regions. SAM analysis showed bilateral medial prefrontal cortices, including anterior cingulate cortex, as the source of Fm theta. This result suggests that focused attention is mainly related to medial prefrontal cortex.     

EEG sleep studies in patients with generalized anxiety disorder

Sleep polygraphic recordings were performed during 3 consecutive nights in 12 inpatients with generalized anxiety disorder (GAD) in comparison with age- and sex-matched groups of patients with major depressive disorder (MDD) and normal subjects. GAD patients differed significantly from those with MDD. A lower number of awakenings and stage shifts in night 1 and the mean of the 3 nights and a shorter rapid eye movement (REM) duration in night 1 but longer REM latency in the mean of the 3 nights were observed in GAD in comparison to MDD. GAD patients also showed a significantly longer sleep onset latency and shorter duration of total sleep time and Stage 2 than control subjects. Electroencephalographic sleep recordings, as well as other laboratory tests, may help the clinician to differentiate anxiety from depressive disorders.     

Noradrenergic function in generalized anxiety disorder: effects of yohimbine in healthy subjects and patients with generalized anxiety disorder

There is extensive preclinical and clinical support for the hypothesis that hyperactivity of noradrenergic neuronal systems is related to the pathophysiology of some forms of human anxiety. In the present investigation, the behavioral, biochemical, and cardiovascular responses to the alpha 2-adrenergic receptor antagonist, yohimbine, was determined in 20 patients with generalized anxiety disorder (GAD) and 20 healthy subjects. The responses to yohimbine were generally similar in the two groups except there was a trend for the yohimbine-induced increase in plasma 3-methoxy-4-hydroxyphenylglycol to be less in the GAD patients. These findings contrast with previous studies of the effects of yohimbine in panic disorder patients and, thereby, support a neurobiological distinction between these two disorders.     

Auditory stimulus intensity responses and frontal midline theta rhythm

The influence of stimulus intensity on the N1 component of auditory evoked potentials recorded at fronto-central sites was investigated in respect to the spectral components of the EEG recorded at Cz, Fz and Oz. The study was performed on 14 healthy adult subjects. The only EEG frequency bandwidth that was strongly correlated with the N1 amplitude-intensity slope was the theta rhythm, particularly the 5–7 Hz frequencies recorded at Cz and Fz. This frequency bandwidth corresponds to the previously described frontal midline theta rhythm related to performance of tests that require continuous concentration of attention. Our results show that the steeper the slope, the greater the amount of Fmθ. This suggests that the interindividual differences in the N1 amplitude/intensity slope could be related to interindividual differences in attentional readiness toward the auditory stimuli, even when delivered in “passive” conditions.     

Neuroactive steroid levels in patients with generalized anxiety disorder

Serum levels of allopregnanolone, pregnenolone sulfate, and dehydroepiandrosterone sulfate were measured in 8 male patients with generalized anxiety disorder (GAD) and 8 healthy control subjects. Results suggest that patients with GAD have significantly lower levels of pregnenolone sulfate than control subjects.     

Psychiatric comorbidity in Greek patients with generalized anxiety disorder

From a total sample of 1,448 psychiatric outpatients, 81 (5.6%) received a diagnosis of generalized anxiety disorder (GAD) according to DSM-III-R criteria. Fifty-three (65%) of them had another Axis I diagnosis, while this percentage increased to 78% (63/81) when lifetime psychiatric diagnoses were recorded. The most frequent comorbid diagnoses were panic disorder, dysthymia, major depression and social phobia. Forty-three (53%) of the GAD patients met the criteria for personality disorder. They manifested obsessive-compulsive, avoidant personality and personalities of cluster C in general significantly more frequently than the rest of the total sample. The presence of a personality disorder was related to a significantly higher score on almost all the Minnesota Multiphasic Personality Inventory clinical and research scales, to a worse level of functioning and to an earlier age of onset of GAD. The results of the present study (1) support previous findings of high rates of comorbidity of clinical syndromes in GAD, (2) indicate that GAD co-occurs frequently with cluster C personality disorders, mainly avoidant and obsessive-compulsive, and (3) that the presence of a concomitant personality disorder is related to severer psychopathology and to a worse level of functioning. Copyright Copyright 1999 S. Karger AG, Basel     

Orienting response and frontal midline theta activity: a somatosensory spectral perturbation study.

OBJECTIVE: Brain electric activity in the theta frequency band has been associated with the encoding of new, and the retrieving of previously stored, information. We studied the time course of stimulus-to-stimulus changes of theta activity under repetitive somatosensory stimulation. MATERIALS AND METHODS: Twelve healthy subjects participated in the study. Repetitive electric stimuli, grouped into 48 stimulus trains, were applied to the left index finger. The stimulus trains contained 27 stimuli (0.9 Hz, 2.5 times sensory threshold). Each stimulus train of 30 s was followed by a stimulus-free break of 30 s. This stimulation paradigm allowed the separate estimation of effects for each position of the stimulus in the train and an analysis of stimulus-to-stimulus changes. Multichannel EEG recordings allowed a topographic analysis of the event-related spectral perturbation effects in the theta frequency band. The brain electric novelty response triggered by the stimulus train onset was analyzed by 3 methods: (1) event-related potentials; (2) event-related power spectra for the investigation of spectral perturbation effects on theta activity; and (3) an approach to break down the stimulus-induced theta activity into phase-locked activity and effects on the spontaneous, ongoing theta activity using digital filtering. RESULTS: The main findings are a frontal midline activation in the theta band with the beginning of the stimulus train, which habituates during the subsequent stimulation cycles, as well as evidence that distinct effects of the first stimulus on the ongoing, non-phase-locked, theta activity exist.     

个案管理模式在广泛性焦虑障碍患者中的应用

目的探讨个案管理模式对广泛性焦虑障碍患者生活质量及临床结局的影响。方法选取来自四川省精神卫生中心心身疾病科且符合《中国精神障碍分类与诊断标准(第3版)》(CCMD-3)广泛性焦虑障碍(GAD)诊断标准的120例住院患者,随机分为个案管理组和对照组各60例,两组均采用原有抗焦虑药物和日常心理治疗,个案管理组还进行个案管理干预。于干预前、干预后1、2、4、8、12、24、48周采用汉密尔顿焦虑量表(HAMA)、汉密尔顿抑郁量表(HAMD)、临床疗效总评量表(CGI)和幸福指数量表(Index of Well-being)进行评定。结果两组服药依从性、复发率、满意度比较差异均有统计学意义(P均0.05);治疗后两组HAMA、HAMD、CGI评分均较基线期低,差异有统计学意义(P0.01);在治疗及随访期间,个案管理组HAMA、HAMD、CGI及总体幸福感评分均较对照组低,差异有统计学意义(P均0.05)。结论对GAD在药物治疗及一般心理支持治疗基础上实施个案管理服务48周后患者的焦虑、抑郁症状缓解更明显,服药依从性更好,复发率更低、生活质量更好,患者对治疗的满意度提高。     

广泛性焦虑障碍患者风险决策特点

目的 探讨广泛性焦虑障碍(General anxiety disorder, GAD)患者在风险明确情境下的决策功能。方法 采用骰子博弈测试(Game of dice test, GDT)评估首次诊断为GAD的21例患者及性别、年龄、受教育年限相匹配的20例健康对照者风险明确情境下的决策功能,同时进行神经心理学量表测评。结果 GAD组风险选项次数(4.14±2.61)与健康对照组(6.55±4.56)比较有明显差异(t=-2.087,P<0.05);GAD组非风险选项次数(13.86±2.61)与健康对照组(11.45±4.56)比较也存在明显差异(t=2.087,P<0.05);2组负反馈利用率无明显差异(P>0.05);GAD组数字符号编码测验(Symbol digit modalities, SDMT)测验成绩(49.29±17.85)明显较健康对照组(59.4±17.67)差(z=-1.971,P=0.049)。结论 GAD患者在风险明确情境下决策更倾向于风险规避,且对负面损失的敏感度与健康对照组比较无明显差异;GAD患者注意力和信息处理速度能力较健康个体差。     

Appearance of frontal mid-line theta rhythm during sleep and its relation to mental activity

Fm theta occurred not only during mental tests in the waking state but also during nocturnal sleep in which it was most frequent during REM and secondarily most frequent during stage 1 of NREM sleep. As for the inner experience of the subjects, they frequently reported dream and distinct mentations on awakening from REM sleep whether or not it was accompanied by Fm theta. They reported dream and distinct mentations more frequently when awakened from stage 1 of NREM sleep with Fm theta than when awakened from stage 1 of NREM sleep without Fm theta. Relationship of Fm theta to mental activity during sleep was briefly discussed.     

Cortical surface anatomy in pediatric patients with generalized anxiety disorder

BackgroundIt is established that pediatric patients with generalized anxiety disorder (GAD) exhibit functional abnormalities and altered gray matter volumes in neural structures that subserve emotional processing, yet there are no data regarding the surface anatomy of the cerebral cortex in youth with GAD.MethodsUsing an automated surface-based approach (FreeSurfer), cortical thickness was assessed node-by-node over the entire cerebral cortex in adolescents with GAD and no co-occurring major depressive disorder (n = 13) and healthy subjects (n = 19).ResultsCompared with healthy adolescents, youth with GAD exhibited increased cortical thickness in the right inferolateral and ventromedial prefrontal cortex (i.e., inferior frontal gyrus), the left inferior and middle temporal cortex as well as the right lateral occipital cortex. No relationships were observed between cortical thickness and the severity of anxiety symptoms in the significant regions that were identified in the vertex-wise analysis.ConclusionsThese findings suggest that, in adolescents with GAD, abnormalities in cortical thickness are present in an ensemble of regions responsible for fear learning, fear extinction, reflective functioning (e.g., mentalization), and regulation of the amygdala.     

Interictal rhythmical midline theta differentiates frontal from temporal lobe epilepsies

Purpose:   We evaluated the role of interictal rhythmical midline theta (RMT) in the identification of frontal lobe epilepsy (FLE) and its differentiation from temporal lobe epilepsy (TLE) and nonepileptic controls.
Methods:   We included 162 individuals in the study: 54 FLE patients, 54 TLE patients, and 54 nonepileptic controls. Continuous electroencephalographic (EEG)-video monitoring was performed in all individuals. Interictal RMT was included only if it occurred during definite awake states. RMT associated with drowsiness or mental activation and ictal RMT was excluded.
Results:   We identified RMT significantly more frequently in FLE patients (48.1%, 26 of 54) than in TLE patients (3.7%, 2 of 54) (p < 0.01), and not in the control group. The average frequency was 6 Hz (range 5–7 Hz), and the average RMT bursts lasted 8 s (3–12 s). Interestingly, all mesial FLE patients (n = 4) (as established by invasive EEG recordings) showed RMT, whereas this was less frequently the case in the other FLE patients (44%, 22 of 50) (p = 0.03). Thirteen of our 54 patients with FLE (24%) did not have any interictal epileptiform discharges (IEDs), but RMT was observed in the majority of these patients (62%, 8 of 13).
Conclusion:   Interictal RMT is common and has a localizing value in patients with FLE, provided that conditions such as drowsiness and mental activation as confounding factors for RMT are excluded. RMT should be included in the evaluation of patients considered for resective epilepsy surgery.     

Cognitive processes of generalized anxiety disorder in comorbid generalized anxiety disorder and major depressive disorder

This study examines how cognitive variables, which play a central role in the development and maintenance of generalized anxiety disorder (GAD), manifest themselves when GAD and major depressive disorder (MDD) are comorbid. Thirty-two participants were divided into two groups, a group of individuals with a principal diagnosis of comorbid GAD and MDD and a group of people with a principal diagnosis of GAD without MDD. Groups were compared using four cognitive variables: intolerance of uncertainty, poor problem orientation, cognitive avoidance, and beliefs about worry. Our results show that the group of individuals with a principal diagnosis of comorbid GAD and MDD were more intolerant of uncertainty, presented poorer problem orientation, and displayed more cognitive avoidance. The cognitive implications of these results are discussed, and diagnostic criteria are presented to facilitate the differential diagnosis between both groups.