Conflict control processing in adults with developmental dyslexia: An event related potentials study

ObjectiveThe present study investigated the time course for processing conflict in dyslexic adults using a flanker task.MethodsSixteen dyslexic and 15 control adults performed a flanker task comprising congruent and incongruent trials in which participants had to indicate the direction of targets surrounded by flankers. Early negative potentials associated with orienting of attention (i.e., N1) and conflict monitoring (i.e., N2) and two positive potentials associated with conflict resolution (i.e., P3b and Nogo P3) were recorded.ResultsThe behavioral data showed differences between incongruent and congruent trials for reaction times in both groups but for error rate only in dyslexics. As in previous studies, controls displayed greater N1, N2 and NoGo P3 as well as a smaller P3b in incongruent trials. Dyslexics lacked N1, N2 and P3b modulation whereas NoGo P3 effect was preserved.ConclusionDyslexics showed impairments in conflict monitoring and in some aspects of conflict resolution (i.e., the allocation of attentional resources) whereas other aspects of conflict resolution (i.e., the inhibition) were preserved.SignificanceThis is the first study to investigate conflict control processing in dyslexic adults using ERPs. Results provide evidence for deficits in orienting of attention, conflict monitoring and allocation of attentional resources in dyslexics.     

Auditory event related potentials in children with peripheral hearing loss

ObjectiveThe aim of the study was to investigate the neurophysiological responses in children with hearing loss.MethodsCortical auditory evoked potentials and Mismatch Negativity (MMN) Responses were recorded in 40 children, 9–12 years old: 12 with hearing loss, 12 with central auditory processing disorder (CAPD) and 16 with normal hearing. Passive oddball paradigms were used with nonverbal and verbal stimuli.ResultsFor P1, no significant group differences were observed. A significant reduction in N2 amplitude with all stimuli was observed in the group of children with hearing loss compared to the results of those with normal hearing. N2 results did not reveal any significant differences between the group of children with hearing loss and the children with CAPD. MMN amplitude indicated a trend toward larger MMN amplitude among the group of children with hearing loss compared to the value of those of children with CAPD.ConclusionsAbnormal N2 characteristics could be a manifestation of a specific signature in children with hearing loss. This cortical response could be considered as a neurophysiologic marker of central auditory processing deficits in these children.SignificanceResults suggest maturational delays and/or deficits in central auditory processing in children with hearing loss.     

Event-related potentials of self-face recognition in children with pervasive developmental disorders

Patients with pervasive developmental disorders (PDD) often have difficulty reading facial expressions and deciphering their implied meaning. We focused on semantic encoding related to face cognition to investigate event-related potentials (ERPs) to the subject's own face and familiar faces in children with and without PDD. Eight children with PDD (seven boys and one girl; aged 10.8+/-2.9 years; one left-handed) and nine age-matched typically developing children (four boys and five girls; aged 11.3+/-2.3 years; one left-handed) participated in this study. The stimuli consisted of three face images (self, familiar, and unfamiliar faces), one scrambled face image, and one object image (e.g., cup) with gray scale. We confirmed three major components: N170 and early posterior negativity (EPN) in the occipito-temporal regions (T5 and T6) and P300 in the parietal region (Pz). An enhanced N170 was observed as a face-specific response in all subjects. However, semantic encoding of each face might be unrelated to N170 because the amplitude and latency were not significantly different among the face conditions. On the other hand, an additional component after N170, EPN which was calculated in each subtracted waveform (self vs. familiar and familiar vs. unfamiliar), indicated self-awareness and familiarity with respect to face cognition in the control adults and children. Furthermore, the P300 amplitude in the control adults was significantly greater in the self-face condition than in the familiar-face condition. However, no significant differences in the EPN and P300 components were observed among the self-, familiar-, and unfamiliar-face conditions in the PDD children. The results suggest a deficit of semantic encoding of faces in children with PDD, which may be implicated in their delay in social communication.     

事件相关电位在儿童注意力缺陷多动综合征中的应用研究

目的为了揭示注意力缺陷多动综合征（ＡＤＨＤ）患儿的认知能力，量化注意力缺陷的程度及探讨它们之间的关系。方法本文对４０例ＡＤＨＤ和２０例正常对照儿童进行了事件相关电位（ＥＲＰ）Ｐ３波的检测，同时用注意力缺陷测试仪进行评分。结果ＡＤＨＤ患儿Ｐ３波波幅显著下降、潜伏期明显延长（Ｐ＜００１）。注意力缺陷评分重度组较轻度组Ｐ３波波幅低，潜伏期长（Ｐ＜００５）。结论提示ＡＤＨＤ患儿存在一定程度认知功能障碍，并随注意力缺陷程度的增大而加重。     

Changes in human event related potentials with prolonged delta-9-tetrahydrocannabinol (THC) use.

Auditory event related potentials and contingent negative variation (CNV) were recorded in a series of behavioral tasks from 27 hospitalized human volunteers before, early during (1--3 days), late during (10--14 days) and after chronic THC intoxication at two dose levels (70--90 mg/day or 180--210 mg/day in divided doses). Twelve additional hospitalized volunteers served as a control group. The N1 component of the auditory event related potential in all tasks was depressed when tested early during 180--210 mg/day THC administration. No N1 changes were seen for the subjects receiving 70--90 mg/day or the control subjects. Ten to 14 days during the chronic THC perioe CNV was depressed in all tasks except the control task for both doses at the early THC testing. Only at the most difficult task at the higher of the doses was the CNV depressed at the test late in the THC period. The changes seen in the N1 and the CNV may be indicative of different aspects of a common attentional alteration during stimulus processing. The results on our more difficult tasks suggest the alteration may continue in complex stimulus processing tasks in heavy marijuana users.     

注意缺陷多动障碍儿童患者的事件相关电位研究

目的　研究注意缺陷多动障碍 (ADHD)儿童患者的事件相关电位 (ERP)主要成分 (P2 、N2 、P3 潜伏期与波幅 )。方法　用DSM Ⅳ诊断标准确定ADHD病例组 ,以年龄、性别 1:1匹配正常儿童为对照组。对所有儿童应用听觉Oddball模式诱发ERP ,记录主要成分进行分析比较。结果　ADHD组靶刺激计数正确率显著低于对照组 (P <0 .0 1) ;ADHD组P2 、N2 潜伏期显著延长 (P <0 .0 5 ) ;P3 潜伏期显著延长 (P <0 .0 1) ;N1～P2峰峰值显著低于对照组 (P <0 .0 5 ) ;两次记录P3 波重复性显著低于对照组 (P <0 .0 5 )。结论　ADHD患儿主动注意功能减弱 ,被动注意亢进 ,抗干扰能力减弱。其额前区功能可能受损     

Single trial analysis of event related potentials: non-linear de-noising with wavelets.

We present and apply a method for single trial analysis of event related potentials (ERPs) that combines techniques from non-linear time series analysis with the wavelet transform. For this method, convincing results have already been achieved for simulated data as well as for intracranially recorded ERPs (Physica D 140 (2000) 257). However, ERPs are affected by a variety of external and internal experimental parameters, which makes the appropriate configuration of single trial analysis difficult. Thus, several pitfalls may occur in realistic applications. In this paper, we applied the method of non-linear de-noising with wavelets to both intra- and extracranially recorded ERPs, and show examples of how and where this single trial analysis can be used to obtain additional information on dynamic neural processes.     

躯体形式障碍患者认知功能与事件相关电位P300的研究

目的:探讨躯体形式障碍患者的认知功能状况及其与P300的关系. 方法:对120例躯体形式障碍患者及60例正常对照组分别进行P300检测和瑞文标准推理测验、数字广度与数字符号测验,并对结果进行比较. 结果:躯体形式障碍组的瑞文推理、数字广度、数字符号分数均低于对照组,差异有统计学意义(P＜0.01);N1、P2、P3潜伏期较对照组延长,N1N2、N2P2、P2P3波幅低于对照组,差异有统计学意义(P＜0.01或P＜0.05);瑞文推理分数与N1潜伏期正相关;数字广度分数与P2潜伏期、N2潜伏期正相关,与N1N2波幅负相关;数字符号分数与N1N2波幅、P2P3波幅正相关,与N2P3波幅负相关. 结论:躯体形式障碍患者的认知功能缺陷范围较广,不同的P300成分可能反映躯体形式障碍不同类型的认知功能损害.     

注意缺陷多动障碍患儿事件相关电位N400研究

目的:探讨注意缺陷多动障碍(ADHD)患儿汉语句子结尾词匹配和非匹配语言时相关电位(ERP)N400的变化。方法:应用ERP仪,采用汉语正常句子结尾词匹配与非匹配的范式,对35例ADHD患儿(ADHD组)和41名正常儿童(正常对照组)进行视觉诱发电位N400检测。结果:在Cz脑区匹配及非匹配条件下,ADHD组N400潜伏期[(384±45)ms,(436±35)ms]比正常对照组[(348±32)ms,(399±29)ms]显著延迟(P均0.01);波幅ADHD组[(4.2±4.5)μV,(7.5±5.1)μV]显著低于正常对照组[(7.6±5.0)μV,(12.4±6.5)μV](P均0.01)。结论:ADHD患儿N400异常,N400检测可能成为判断注意缺陷多动障碍的客观指标。     

40例颈动脉狭窄患者事件相关电位(P300)的探讨

目的:探讨与颈动脉狭窄(CAS)相关的认知功能障碍。方法:检测40例CAS患者听觉事件相关电位(P300),并与38例对照组对比。结果:CAS组的P300潜伏期异常率为57.5%。CAS组与对照组的P300相比,潜伏期显著延长,波幅降低,且与颈动脉狭窄程度相关。结论:CAS患者存在认知功能障碍,而且可用P300动态观察。     

The yield of the medical evaluation of children with pervasive developmental disorders

Little information is available regarding the yield of the medical evaluation of children diagnosed with pervasive developmental disorder–not otherwise specified (PDD-NOS) compared to children diagnosed with autistic disorder. Medical records were reviewed for 182 patients less than 18 years of age with either PDD-NOS or autistic disorder evaluated between 1994 and 1998 at Mayo Clinic. A condition likely to be etiologically relevant was identified in 6/117 (5.1%) patients diagnosed with PDD-NOS and 2/65 (3.1%) patients diagnosed with autistic disorder. Genetic disorders, both chromosomal and single-gene, were the most commonly identified conditions. Seizure disorders, electroencephalogram abnormalities, and anomalies on brain imaging were common in both groups. The likelihood of uncovering an etiologically relevant condition in children diagnosed with either PDD-NOS or autistic disorder may be equivalent. The scope of the etiological search in an individual patient with an autistic spectrum disorder should not be limited by the specific diagnostic category.     

Counselling and supporting parents of children with developmental delay: a research evaluation

ABSTRACT. This paper describes an evaluation study of a home-based, family focussed counselling scheme providing support for English-speaking and Bangladeshi families of children wilh intellectual or multiple disabilities. Mothers and children in the intervention groups showed significant and positive changes compared to randomly allocated controls. The greatest benefits were derived by the more deprived and initially less well-supportcd Bangladeshi families. Mothers changed positively in ratings of perceived support and family functioning, and in their constructions of their child, themselves, husbands and family relationships. Although systematic teaching was not included, their children also showed improvements in developmental progress and behaviour problems.     

Suicidal behavior in children and adolescents with developmental disorders.

Children and adolescents with developmental disorders exhibit a wide range of self-destructive behaviors. Interestingly, suicidal ideation and gestures have been underreported in this population. This study was designed to examine suicidality in a clinically referred sample. The medical records of all individuals assessed in a specialized program during a 1-year period were reviewed looking at the incidence, the type and the clinical characteristics of any suicidal behavior. Forty-seven patients (20%) experienced either suicidal ideation, threats, or attempts with hanging being the most frequent method considered. Suicidality was more often encountered in individuals diagnosed with oppositional defiant disorder, depressive disorders, and post traumatic stress disorder, and less often in the autistic and the severely/profoundly mentally retarded groups. Suicidal behaviors were frequently encountered in children and adolescents with developmental disabilities. Prospective studies should be conducted to examine rigorously the variables associated with suicidality in this population.     

Visual and auditory event related potentials in epileptic children: a comparison with normal and abnormal MRI findings

Visual and auditory event related potentials (VERPs and AERPs) in 32 epileptic children with magnetic resonance imaging (MRI) abnormalities and 18 with normal MRI were recorded and compared to the data of 21 healthy children. Of all 50 epileptic children (34 male, 16 female) aged 14.42+/-4.27 (7-20) years, 21 were medically intractable and receiving polytherapy. The mean latencies of N2 and P3 components of VERPs and AERPs in all epileptic children were significantly higher than those of the controls (P<0.05). Epileptic children with structural abnormalities had more prolonged latencies of N2 and P3 components of AERPs and VERPs than those of the healthy children (P<0.05). The epileptic children with normal MRI had significantly more prolonged latency of N2 and P3 of VERPs and P3 of AERPs than those of the controls (P<0.05). The difference of the mean latency of N2 and P3 components or the mean amplitude of P3 components of ERPs between the two epileptic groups was insignificant. The type of medication (mono- versus polytherapy) did not affect the wave components of ERPs. We suggest that epileptic activity, itself, leads to prolonged N2 and P3 components of AERPs and VERPs. The presence of structural abnormality indicated by imaging is not a predictor of ERPs abnormalities.     

Measurement of maximum variability within event related potentials in schizophrenia.

One limitation of averaging individual late component event related potential (ERP) responses is that a single average ERP cannot reflect the variability of responses from epoch to epoch. In this article, we describe a method to quantify this variability and determine if any part of the overall ERP reflects a maximum variance through the use of response variance curves. We then apply this method to one disorder, schizophrenia, in which variability of information processing is hypothesized to underlie aspects of the symptomatology. Response variance curves in a group of unmedicated schizophrenic patients reveal systematic differences, maximal between 190 and 250 ms, compared with those in a group of medicated schizophrenic patients and normal control subjects.