Age-Dependent Differences in Attentional Processes in ADHD and Disruptive Behavior Disorder

The aim of this study was to analyze age-dependent differences in attentional performance in subjects aged 8–16 years with attention deficit/hyperactivity disorder (ADHD) with or without disruptive behavior disorders (DBD). Age effects were investigated in three different groups (ADHD [N = 118], ADHD + DBD [N = 105], and controls [N = 105]) on a sustained attention and a Go-No-Go paradigm. Attentional competencies increased with age and children in the two clinical groups performed worse than control children on both tasks. However, these group differences between ADHD, ADHD + DBD, and controls decreased with increasing age. Thus, age-related differences must be considered in neuropsychological studies.     

抑郁症的ERPs电流源模型与特征分析

采用3-刺激视觉oddball实验范式,研究干扰子刺激和靶刺激条件下抑郁症患者的大脑电流源的异常电流响应过程.分别采集了抑郁症和健康受试者的64导联脑电,以该实验任务的功能磁共振激活簇空间坐标为约束条件,建立了干扰子刺激和靶刺激条件下事件相关电位的脑区域源模型,通过脑源重建法计算得到14个区域源的源电流波形,经非配对t检验和置换检验后发现:在靶刺激条件下,抑郁症患者的右侧脑岛、右侧中央前沟在P300晚期产生的源电流幅度与正常人有显著差异(P＜0.05),它引起右侧头皮前额区的异常负电位.在干扰子刺激条件下,患者的左侧中央前沟在P300晚期产生的源电流与正常人有明显差异,差异显著性具有趋势意义(P=0.087),它引起左侧前额区的异常近零电位.结果表明:通过源电流计算发现了抑郁症患者的中央前沟和脑岛的P300活动发生显著异常.     

Bipolar and ADHD Comorbidity: Both Artifact and Outgrowth of Shared Mechanisms

[Clin Psychol Sci Prac 17: 350–359, 2010] Published rates of comorbidity between pediatric bipolar disorder (PBD) and attention‐deficit/hyperactivity disorder (ADHD) have been higher than would be expected if they were independent conditions, but also dramatically different across different studies. This review examines processes that could artificially create the appearance of comorbidity or substantially bias estimates of the PBD‐ADHD comorbidity rate, including categorization of dimensional constructs, overlap among diagnostic criteria, over‐splitting, developmental sequencing, and referral or surveillance biases. Evidence also suggests some mechanisms for “true” PBD‐ADHD comorbidity, including shared risk factors, distinct subtypes, and weak causal relationships. Keys to differential diagnosis include focusing on episodic presentation and nonoverlapping symptoms unique to mania.     

Differentiating Between Comorbidity and Symptom Overlap in ADHD and Early Onset Bipolar Disorder

Reported rates of comorbidity between early onset bipolar disorder (BD) and attention deficit hyperactivity disorder (ADHD) have a wide range, perhaps due to developmental issues and differences in interpretation of overlapping symptoms. We compared questionnaire-based and neuropsychological measures of inattention and impulsivity/hyperactivity, in children/adolescents with ADHD combined subtype (ADHD-C; n26), concurrent ADHD-C and BD (n15), BD (n25) with Controls (n69). Sub-analyses were performed on BD with and without inattention symptoms. The two ADHD-C groups displayed neuropsychological impairments that were not found in the BD group in spite of subjective and questionnaire-rated inattention. The findings caution against over-diagnosis of ADHD in BD.     

Neurocognitive Functioning in Bipolar Disorder

Neuropsychological processes may have direct bearing on the emotional dysregulation and functional impairments characteristic of bipolar disorder. Neuropsychological deficits that have been identified in adults and children with bipolar disorder include impairments in executive functions, declarative memory, attentional processes, and possibly working memory. Structural and functional magnetic resonance imaging and magnetic resonance spectroscopy studies of adults and children with bipolar disorder also indicate abnormalities in regions thought to underlie these neuropsychological deficits, including the basal ganglia, amygdala, and dorsolateral, orbitofrontal, and anterior cingulate cortices. Study of this area is made challenging by the heterogeneity of bipolar disorder, the heterogeneity of neuropsychological deficits among groups of patients with different clinical characteristics, the lack of specificity of neurocognitive deficits for bipolar disorder, and difficulty ascertaining whether deficits are inherent in the disorder, predate the disorder, or are influenced by mood state, course, treatment, and comorbidity with other disorders. In this review, we integrate the literature on neuropsychological functioning and neuroimaging in both children and adults with bipolar disorder, propose a nascent integrative model of cognitive function in bipolar disorder, and make suggestions for future studies and model development.     

Brain development and ADHD

Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by excessive inattention, hyperactivity, and impulsivity, either alone or in combination. Neuropsychological findings suggest that these behaviors result from underlying deficits in response inhibition, delay aversion, and executive functioning which, in turn, are presumed to be linked to dysfunction of frontal-striatal-cerebellar circuits. Over the past decade, magnetic resonance imaging (MRI) has been used to examine anatomic differences in these regions between ADHD and control children. In addition to quantifying differences in total cerebral volume, specific areas of interest have been prefrontal regions, basal ganglia, the corpus callosum, and cerebellum. Differences in gray and white matter have also been examined. The ultimate goal of this research is to determine the underlying neurophysiology of ADHD and how specific phenotypes may be related to alterations in brain structure.     

Assessment of Childhood Bipolar Disorder

Barriers to the comprehensive clinical assessment of child-onset bipolar disorder (BPD) are numerous and include factors common to many pediatric diagnoses (e.g., disentangling comorbid conditions and overlapping symptoms; cross-situational variability in behavior; limited reliability of child report), as well as issues more specific to child-onset BPD (e.g., lack of empirically validated screening instruments; disagreement over age-specific symptom presentation and temporal discontinuity of symptoms). Thorough assessment includes careful consideration of differential diagnosis, investigation of familial history of affective illness, a focus on longitudinal data collection, and the use of multiple informants. Though a number of standardized measures may assist clinicians in gathering diagnostic information, clinical judgment based on familiarity with the unique presentation of child-onset BPD remains essential.     

Commonalities in EEG Spectral Power Abnormalities Between Women With ADHD and Women With Bipolar Disorder During Rest and Cognitive Performance

While attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) denote distinct psychiatric conditions, diagnostic delineation is impeded by considerable symptomatic overlap. Direct comparisons across ADHD and BD on neurophysiological measures are limited. They could inform us on impairments that are specific to or shared between the disorders and, therefore, potential biomarkers that may aid in the identification of the diagnostic boundaries. Our aim was to test whether quantitative EEG (QEEG) identifies differences or similarities between women with ADHD and women with BD during resting-state and task conditions. QEEG activity was directly compared between 20 ADHD, 20 BD and 20 control women during an eyes-open resting-state condition (EO) and a cued continuous performance task (CPT-OX). Both ADHD (t₃₈ = 2.50, p = 0.017) and BD (t₃₈ = 2.54, p = 0.018) participants showed higher absolute theta power during EO than controls. No significant differences emerged between the two clinical groups. While control participants showed a task-related increase in absolute theta power from EO to CPT-OX (t₁₉ = ?3.77, p = 0.001), no such change in absolute theta power was observed in the ADHD (t₁₉ = ?0.605, p = 0.553) or BD (t₁₉ = 1.82, p = 0.084) groups. Our results provide evidence for commonalities in brain dysfunction between ADHD and BD. Absolute theta power may play a role as a marker of neurobiological processes in both disorders.     

Cortisol Effects on Attentional Processes in Man as Indicated by Event-Related Potentials

Glacocorticoids which are secreted from the adrenal cortex, particularly in response to stressful stimuli, are assumed to influence brain functions related to stimulus perception and processing. To determine underlying mechanisms of this action the present study investigated the effects of physiologically enhanced plasma glucocurticoid levels on auditory event-related potentials (AERPs) reflecting different aspects of stimulus processing. Sixteen male adult subjects were tested in a dichotic listening paradigm containing four types of tone pips: standard and deviant target pips, which the subject either had to attend to, or to ignore. AERPs to the tone pips provided measures of different perceptual and attentional processes. Subjects were tested in a double-blind fashion according to a within-subject cross-over design under either 16 mg hydrocortisone, infused over the experimental period of 1 hrs, or placebo. Compared to placebo sessions, under cortisol treatment a slightly decreased amplitude of the N1 component was obtained independently of the type of tone pip presented. In addition, mismatch negativity, measured as the difference amplitude between AERP waveforms to standard and deviant target pips in the unattended ear, was substantially reduced by hydrocortisone. Results support an inhibitory action of enhanced plasma cortisol levels on stimulus processing mediated by the nonspecific sensory system.     

Event-Related Potential Evidence for Age-Related Differences in Attentional Allocation During a Source Monitoring Task

Event-related potentials (ERPs) were recorded while older and younger adults were engaged in a source monitoring task. After studying a list of words, participants were presented with a recognition test during which some of the new words were repeated, rendering them as familiar as the study words. Instructions at test indicated whether the goal was to select the previously studied words or the repeated test items. Behaviorally, the younger adults were less likely to make source monitoring errors. ERPs, averaged only for correct trials, indicated that younger adults produced late positivities of greatest amplitude in response to whichever word type was designated as target irrespective of its familiarity. The ERPs of the older adults were generally less differentiated and their late positivities greater for recently repeated words irrespective of target designation. These results suggest that source monitoring in young adults is facilitated by their ability to allocate and withdraw attention from stimuli on the basis of task relevance rather than familiarity alone, and that this attentional flexibility declines with age.     

Eveningness and Its Associated Impairments in Remitted Bipolar Disorder

Sleep-wake and circadian rhythm disturbances are common in remitted bipolar disorder. These disturbances include difficulty initiating and maintaining sleep, daytime sleepiness, sleep irregularity, and a circadian tendency toward eveningness. To date, few studies have examined the impact of eveningness on impairments in remitted bipolar disorder. Ninety-eight adults diagnosed with bipolar disorder I, II, or not otherwise specified were evaluated. Hierarchical linear regression analyses showed that eveningness was associated with greater sleep-wake disturbances, more unhealthy dietary habits, worse quality of life, more impaired interpersonal relationships, and more dysfunctional sleep-related cognitions and behaviors, controlling for age, gender, and years of education. Targeted intervention on dysfunctional sleep-related cognitions and behaviors may reverse eveningness and improve functioning in bipolar disorder.     

Cognitive Event-Related Brain Potentials in Children with Attention and Reading Deficits

ERPs were recorded from four groups of children: reading disabled, attentional deficit disorder with and without hyperactivity, and normal controls. Subjects pressed a button to a low probability nonsense syllable (target, p= .168) and ignored all other events, which included a high probability nonsense syllable (nontarget, p= .664) and either low probability (category, p= .168) symbols (Block 1) or 3-letter words (Block 2). The amplitudes of several late ERP components and the latency of the P3 component were examined. The overall amplitude of P3 was significantly smaller in all clinical groups than in controls, but the difference in P3 amplitude between targets and nontargets was smaller only in the two attentional deficit groups. Reading disabled children had smaller P3 and Pc components to words than to symbols, while controls had equivalent values. The N2 component had a different scalp distribution for words and symbols, but did not differentiate reading disabled children from controls. P3 latency was significantly longer in the three clinical groups than in controls, but only the attentional deficit groups showed an increase in P3 latency across blocks of the task. The results are discussed within the framework of recent cognitive models dealing with attentional processes.     

Event-Related Brain Potentials in Selective Listening to Frequent and Rare Stimuli

Our previous event-related brain potential (ERP) results suggest that during selective listening, relevant stimuli are selected for further processing by comparing each stimulus to an “attentional trace,” a neuronal representation of the physical features of the relevant stimuli that distinguish them from the irrelevant stimuli. This comparison process is reflected by the early component of the processing negativity (PN), which is largest and longest to the relevant stimuli (perfectly matching with the trace). In the present study, the subjects selectively listened to designated tone stimuli which randomly appeared among irrelevant tones of a different pitch. The probability of relevant stimuli in a block was varied. The processing negativity elicited by relevant stimuli was smaller the less frequent they were. The results support the attentional-trace theory of selective attention, which proposes that, in addition to active maintenance, the trace also depends on the rate of sensory reinforcement provided by the relevant stimuli.     

Neurophysiological Correlates of Attentional Fluctuation in Attention-Deficit/Hyperactivity Disorder

Cognitive performance in attention-deficit/hyperactivity disorder (ADHD) is characterised, in part, by frequent fluctuations in response speed, resulting in high reaction time variability (RTV). RTV captures a large proportion of the genetic risk in ADHD but, importantly, is malleable, improving significantly in a fast-paced, rewarded task condition. Using the temporal precision offered by event-related potentials (ERPs), we aimed to examine the neurophysiological measures of attention allocation (P3 amplitudes) and preparation (contingent negative variation, CNV), and their associations with the fluctuating RT performance and its improvement in ADHD. 93 participants with ADHD and 174 controls completed the baseline and fast-incentive conditions of a four-choice reaction time task, while EEG was simultaneously recorded. Compared to controls, individuals with ADHD showed both increased RTV and reduced P3 amplitudes during performance on the RT task. In the participants with ADHD, attenuated P3 amplitudes were significantly associated with high RTV, and the increase in P3 amplitudes from a slow baseline to a fast-paced, rewarded condition was significantly associated with the RTV decrease. Yet, the individuals with ADHD did not show the same increase in CNV from baseline to fast-incentive condition as observed in controls. ADHD is associated both with a neurophysiological impairment of attention allocation (P3 amplitudes) and an inability to adjust the preparatory state (CNV) in a changed context. Our findings suggest that both neurophysiological and cognitive performance measures of attention are malleable in ADHD, which are potential targets for non-pharmacological interventions.     

Attentional processing in adults with ADHD as reflected by event-related potentials

Attention deficit/hyperactivity disorder (ADHD) is a well known childhood disease and well researched via event-related potentials (ERPs), but unfortunately there is little information on this illness in adults in ERPs. In the present study, 12 adults diagnosed with ADHD and 12 healthy control adults were examined with respect to ERPs in a visual Go/NoGo-experiment to gain information about target evaluation processing in these patients. Two attention-related ERP-components, the N1 and N2 were significantly increased for the ADHD adults compared to the healthy control adults. These findings were illustrated using source analysis results: In the time frame corresponding to the N1, significant increases of activity were found in the medial frontal gyrus and during the N2 time frame significant increases were detected in the lingual gyrus. The P300 showed a tendency towards decreased activity in the patient group, however, only a subsequent slow wave activity indicated significant differences. Neuronal activity related to early attentional mechanisms (N1 and N2) appears to be enhanced in ADHD patients. Together with the finding of a reduction in the P300, the data suggest that ADHD adults have learned to gather their attention more strongly than healthy adults in order to achieve the same results and compensate for their impairment. This is supported by the source analysis results which show activity in additional brain areas.     

酒依赖与双相情感障碍共病

本文对酒依赖与双相情感障碍共病的概念、流行病学、临床特点、共病诊断的意义及治疗进展进行概述。     

广泛性发育障碍与感觉统合失调的关系

目的:探讨广泛性发育障碍(PDD)与感觉统合失调之间的关系.方法:对90例我院门诊的广泛性发育障碍患儿进行评估,以儿童感觉统合发展评定量表(SIS)评定感觉统合失调问题,以儿童期孤独症评定量表(CARS)评价病情的严重程度.结果:PDD中感觉统合轻-重度失调率为92.2%,儿童孤独症组与Asperger综合症组的感觉统合失调率比较差异无显著性(x2=1.87,P＞0.05).PDD的CARS总分与触觉过分防御(r=-0.34)、本体感失调(r=-0.21)呈负相关,差异均有显著性(P＜0.05).结论:感觉统合失调与PDD密切相关,这为PDD的治疗提供了新思路.