Neurophysiological responses to faces and gaze direction differentiate children with ASD,ADHD and ASD + ADHD

Children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) demonstrate face processing abnormalities that may underlie social impairment. Despite substantial overlap between ASD and ADHD, ERP markers of face and gaze processing have not been directly compared across pure and comorbid cases. Children with ASD (n = 19), ADHD (n = 18), comorbid ASD + ADHD (n = 29) and typically developing (TD) controls (n = 26) were presented with upright/inverted faces with direct/averted gaze, with concurrent recording of the P1 and N170 components. While the N170 was predominant in the right hemisphere in TD and ADHD, children with ASD (ASD/ASD + ADHD) showed a bilateral distribution. In addition, children with ASD demonstrated altered response to gaze direction on P1 latency and no sensitivity to gaze direction on midline-N170 amplitude compared to TD and ADHD. In contrast, children with ADHD (ADHD/ASD + ADHD) exhibited a reduced face inversion effect on P1 latency compared to TD and ASD. These findings suggest children with ASD have specific abnormalities in gaze processing and altered neural specialisation, whereas children with ADHD show abnormalities at early visual attention stages. Children with ASD + ADHD are an additive co-occurrence with deficits of both disorders. Elucidating the neural basis of the overlap between ASD and ADHD is likely to inform aetiological investigation and clinical assessment.     

The effect of gaze direction on the processing of facial expressions in children with autism spectrum disorder: An ERP study

This study investigated the neural basis of the effect of gaze direction on facial expression processing in children with and without ASD, using event-related potential (ERP). Children with ASD (10-17-year olds) and typically developing (TD) children (9-16-year olds) were asked to determine the emotional expressions (anger or fearful) of a facial stimulus with a direct or averted gaze, and the ERPs were recorded concurrently. In TD children, faces with a congruent expression and gaze direction in approach-avoidance motivation, such as an angry face with a direct gaze (i.e., approaching motivation) and a fearful face with an averted gaze (i.e., avoidant motivation), were recognized more accurately and elicited larger N170 amplitudes than motivationally incongruent facial stimuli (an angry face with an averted gaze and a fearful face with a direct gaze). These results demonstrated the neural basis and time course of integration of facial expression and gaze direction in TD children and its impairment in children with ASD.     

ERP evidence of semantic processing in children with ASD

25% of children with autism spectrum disorder (ASD) remain minimally verbal (MV), despite intervention. Electroencephalography can reveal neural mechanisms underlying language impairment in ASD, potentially improving our ability to predict language outcomes and target interventions. Verbal (V) and MV children with ASD, along with an age-matched typically developing (TD) group participated in a semantic congruence ERP paradigm, during which pictures were displayed followed by the expected or unexpected word.An N400 effect was evident in all groups, with a shorter latency in the TD group. A late negative component (LNC) also differentiated conditions, with a group by condition by region interaction. Post hoc analyses revealed that the LNC was present across multiple regions in the TD group, in the mid-frontal region in MVASD, and not present in the VASD group. Cluster analysis identified subgroups within the ASD participants. Two subgroups showed markedly atypical patterns of processing, one with reversed but robust differentiation of conditions, and the other with initially reversed followed by typical differentiation. Findings indicate that children with ASD, including those with minimal language, showed EEG evidence of semantic processing, but it was characterized by delayed speed of processing and limited integration with mental representations.     

Atypical Pupillary Light Reflex and Heart Rate Variability in Children with Autism Spectrum Disorder

We investigated pupillary light reflex (PLR) in 152 children with ASD, 116 typically developing (TD) children, and 36 children with non-ASD neurodevelopmental disorders (NDDs). Heart rate variability (HRV) was measured simultaneously to study potential impairments in the autonomic nervous system (ANS) associated with ASD. The results showed that the ASD group had significantly longer PLR latency, reduced relative constriction amplitude, and shorter constriction/redilation time than those of the TD group. Similar atypical PLR parameters were observed in the NDD group. A significant age effect on PLR latency was observed in children younger than 9 years in the TD group, but not in the ASD and NDD groups. Atypical HRV parameters were observed in the ASD and NDD groups. A significant negative correlation existed between the PLR constriction amplitude and average heart rate in children with an ASD, but not in children with typical development.     

Cognitive impairment in major depressive disorder revealed by event-related potential N270.

Major depressive disorder (MDD) is a mood disorder that is often accompanied by the impairment of cognitive functions. The aim of this study was to investigate the feasibility of N270 as an index for evaluating the cognitive impairment in MDD patients. Twenty-five patients with MDD diagnosed according to DSM-IV and 25 age matched normal controls performed a matching task while event-related potentials (ERPs) were recorded from their scalp. There were two kinds of stimulus pairs in this study: match condition, the second stimulus (S2) in a pair was identical to the first one (S1); mismatch condition, S2 conflicted with S1 in the color attribute. Subjects were required to press a button in the match condition and to press another button in the mismatch condition. A negative ERP component, N270, which was considered to reflect conflict processing activity in human brain, was evoked by S2 of the mismatch condition. The patient group showed a delayed and smaller N270 than the control group. The prolongation of its peak latency was significant at P3 and P4 electrodes, and the reduction of its peak amplitude was significant at F3, F4, P3 and P4 electrodes. The amplitude of P300 elicited in the match condition was decreased in the patient group at P3 and P4 electrodes, but its latency did not differ from the control group. The results indicate that MDD patients as a group showed cognitive decline. N270 is a sensitive index in revealing cognitive impairment.     

Neurophysiological efficiency in male and female alcoholics

Chronic alcoholics often exhibit impairment in behavioral indicators of cognitive efficiency. However, potential neurophysiological correlates of this deficit are understudied. To examine this function, semantic expectancy was measured by recording the N400 component of the event-related potential (ERP), which is elicited by incongruent semantic information. Abstinent alcoholics, 21-45 days sober (n = 26; 12 males, 14 females), as well as age and education equated community controls (n = 26; 12 males, 14 females), were instructed to read silently 218 sentences ending with either congruent, related/incongruent, or unrelated/incongruent terminal words. Difference waveforms to the terminal word were derived, and amplitude and latency measures of the most negative peak between 300 and 600 ms were obtained. Electrode sites included the midline sites, Fz, Cz, and Pz; the temporal sites T3 and T4; and parietal sites P3 and P4. Significant group effects in amplitude were observed for the difference waveform under the unrelated/incongruent condition at T3, T4, and P4 (P < or = .05). Measures at P3, Pz, Fz, and Cz approached significance (P < or = .15). Although the overall pattern did not change when regression techniques were used to control for age, only the T4 site retained significance (P < or = .05). Across all electrode sites, alcoholics produced reduced N400 amplitudes relative to community controls. Latency was unaffected. There were no group effects for amplitude or latency measures in the related/incongruent condition. These data are consistent with the hypothesis that alcoholics suffer from a subtle deficiency in neurophysiologically based cognitive efficiency which renders them less likely to respond appropriately to irrelevant information.     

Cognitive impairment in Parkinson's disease revealed by event-related potential N270.

Disturbed cognitive function is a well-recognized feature of idiopathic Parkinson's disease (PD). The aim of this study was to find a susceptive index to reveal the minor cognitive impairment in PD patients. Thirty PD patients without clinical dementia and thirty-four age-matched normal controls performed a matching task while event-related potentials (ERPs) were recorded from their scalp. There were two kinds of stimulus pairs in this study: match condition, the second stimulus (S2) in a pair was identical to the first one (S1); conflict condition, S2 conflicted with S1 in the color attribute. Subjects were required to press a button in the match condition and another button in the conflict condition. A negative ERP component, N270, which was considered to reflect the conflict processing activity in human brain, was evoked by the S2 of the conflict condition. The patient group showed a delayed and smaller N270 than the control group. The prolongation of its peak latency was significant at P3 and P4 electrodes and the reduction of its mean amplitude was significant at P3 electrode. The amplitude of P300 elicited in the match condition was decreased in the patient group at P4 electrode but its latency did not differ from the control group. These results indicate that PD patients as a group showed cognitive decline even in the absence of clinical dementia. N270 is a sensitive index in revealing this minor cognitive impairment.     

Altered automatic face processing in individuals with high-functioning autism spectrum disorders: Evidence from visual evoked potentials

Individuals with autism spectrum disorders (ASDs) have different automatic responses to faces than typically developing (TD) individuals. We recorded visual evoked potentials (VEPs) in 10 individuals with high-functioning ASD (HFASD) and 10 TD individuals. Visual stimuli consisted of upright and inverted faces (fearful and neutral) and objects presented subliminally in a backward-masking paradigm. In all participants, the occipital N1 (about 100 ms) and P1 (about 120 ms) peaks were major components of the evoked response. We calculated “subliminal face effect (SFE)” scores by subtracting the N1/P1 amplitudes and latencies of the object stimuli from those of the face stimuli. In the TD group, the SFE score for the N1 amplitude was significantly higher for upright fearful faces but not neutral faces, and this score was insignificant when the stimuli were inverted. In contrast, the N1 amplitude of the HFASD subjects did not show this SFE in the upright orientation. There were no significant group differences in SFE scores for P1 amplitude, latency, or N1 latency. Our findings suggest that individuals with HFASD have altered automatic visual processing for emotional faces within the lower level of the visual cortex. This impairment could be a neural component of the disrupted social cognition observed in individuals with HFASD.     

Visual event-related potential changes in two subtypes of multiple system atrophy,MSA-C and MSA-P

We investigated the visual event-related potentials (ERPs) in two subtypes of multisystem atrophy (MSA) in 15 MSA-C patients, 12 MSA-P patients, and 21 normal control (NC) subjects. We used a visual oddball task to elicit ERPs. No significant changes were seen in N1 or N2 latency, in either MSA-C or MSA-P, compared with the NC group. An early stage of visual information process related to N1 and a visual discrimination process related to N2 might be preserved in both MSA-C and MSA-P. The P3a peak was more frequently undetectable in MSA than in the NC group. Significant P3a amplitude reduction in both MSA-C and MSA-P suggests impairment of the automatic cognitive processing in both MSA-C and MSA-P. Significant difference was found in P3b latency and P3b amplitude only in MSA-C, compared with the NC group. The result suggests the impairment of the controlled cognitive processing after the visual discrimination process in the MSA-C group. We further investigated the correlation between visual ERP changes and magnetic resonance imaging (MRI) data. Quantitative MRI measurements showed reduced size of the pons, cerebellum, perisylvian cerebral area, and deep cerebral gray matter in both MSA-C and MSA-P, and of the corpus callosum only in MSA-P, as compared to NC group. In both MSA-C and MSA-P, P3b latency was significantly correlated with the size on MRI of the pons and the cerebellum. P3b latency in the whole MSA group was also significantly correlated with the size of the pons and the cerebellum. These results indicate that P3b latency changes in parallel with the volume of the pons and the cerebellum in both MSA-C and MSA-P. Received: 28 August 2001 Received in revised form: 22 January 2002 Accepted: 25 January 2002     

Deficits of visuospatial attention with reflexive orienting induced by eye-gazed cues in children with developmental coordination disorder in the lower extremities: An event-related potential study

The present study aims to investigate and compare the behavioral performance and event-related potentials (ERPs) measures in children with developmental coordination disorder (DCD) and typically developing (TD) children when performing the visuospatial attention task with reflexive orienting. Thirty children with DCD and 30 TD children were recruited and presented with central eye-gazed cues. The children needed to detect and respond to laterally presented reaction signals preceded by centrally presented non-predictive directional and non-directional eye-gazed cues, which directed them to attend covertly to the right or left field location, or straight ahead, via stepping on pedals with their bilateral lower limbs, while brain ERPs were concurrently recorded. The behavioral data showed that children with DCD responded slowly and exhibited a deficit in inhibitory control capacity as compared to TD children. In terms of electrophysiological characteristics, children with DCD showed distinct modulatory effects upon longer N2 and P3 latencies, smaller P3 amplitude, an elongated interval between N2 and the motor response (N2 latency-RT), and small areas on Contingent Negative Variation (CNV). The behavioral and ERP data suggest that children with DCD could have deficits in the ventral attention network and the mechanisms on the inhibitory control difficulty, when performing such a task, could be a slower response inhibitory process and stimulus classification speed, less ability in interhemispheric and cognitive-to-motor transfer speed, and less mature abilities with regard to anticipatorily executive and motor preparatory processes.     

Error and feedback processing in children with ADHD and children with Autistic Spectrum Disorder: an EEG event-related potential study

OBJECTIVE: Performance monitoring was investigated in typically developing (TD) children, children with Autistic Spectrum Disorder (ASD), and Methylphenidate (Mph)-treated and medication-free children with Attention Deficit Hyperactivity Disorder (ADHD). METHODS: Subjects performed a feedback-based learning task. Event-related Potentials (ERPs) time locked to responses and feedback were derived from the EEG. RESULTS: Compared to the TD and ASD groups, the medication-free ADHD group showed a decreased response-locked Error Related Negativity (ERN) and error Positivity (Pe), particularly as learning progressed throughout the task. Compared to the medication-free ADHD group, the Methylphenidate-treated group showed a normalised Pe. All clinical groups showed or tended to show a decreased feedback-locked late positive potential to negative feedback. CONCLUSIONS: The ERPs suggest that medication-free children with ADHD, but not with ASD, have a diminished capacity to monitor their error responses when they are learning by performance feedback. This capacity partially 'normalises' in Mph-treated children with ADHD. Both children with ADHD and children with ASD are suggested being compromised in affective feedback processing. SIGNIFICANCE: This study shows that measuring ERPs of error and feedback processing is a useful method for (1) dissociating ADHD from ASD and (2) elucidating medication effects in ADHD on component processes of performance monitoring.     

Autistic traits modulate conscious and nonconscious face perception

Difficulty with emotion perception is a core feature of autism spectrum disorder (ASD) that is also associated with the broader autism phenotype. The current study explored the neural underpinnings of conscious and nonconscious perceptions of affect in typically developing individuals with varying levels of autistic-like traits, as measured by the Autism Quotient (AQ). We investigated the relationship between autistic traits and face processing efficiency using event-related potentials (ERPs). In 20 typically developing adults, we utilized ERPs (the P100, N170, and P300) to measure differences in face processing for emotional faces that were presented either (a) too quickly to reach conscious awareness (16 ms) or (b) slowly enough to be consciously observed (200 ms). All individuals evidenced increased P100 and P300 amplitude and shorter N170 latencies for nonconscious versus consciously presented faces. Individuals with high AQ scores evidenced delayed ERP components. Nonconsciously perceived emotional faces elicited enhanced neural responses regardless of AQ score. Higher levels of autistic traits were associated with inefficient face perception (i.e., longer latency of ERP components). This delay parallels processing delays observed in ASD. These data suggest that inefficient social perception is present in individuals with subclinical levels of social impairment.     

多发性硬化患者认知改变与事件相关电位研究

目的研究多发性硬化(MS)患者认知功能障碍的发生情况,及其与事件相关电位(ERPs)的相关关系。方法对70例MS患者进行韦氏智力量表测查及ERPs检查。结果韦氏智力量表测试发现MS组全量表智商(FIQ)不正常者(<90分)的比率为40%(28/70),与正常组比较差异显著(P<0.01)。MS组N2、P300潜伏期明显延长,与对照组比较差异具有显著性(P<0.05)。脑或脑脊髓型及进展型MS患者P300潜伏期明显延长,P300波幅降低。病程与P300潜伏期呈显著正相关。言语量表智商(VIQ)、FIQ与P300潜伏期呈负相关,与P300波幅呈正相关;操作量表智商(PIQ)与P300波幅呈正相关。结论MS患者存在有认知障碍。ERPs检查对MS认知障碍的判断有一定参考意义。     

Parameters of semantic multisensory integration depend on timing and modality order among people on the autism spectrum: evidence from event-related potentials

Individuals with autism spectrum disorders (ASD) report difficulty integrating simultaneously presented visual and auditory stimuli (Iarocci & McDonald, 2006), albeit showing enhanced perceptual processing of unisensory stimuli, as well as an enhanced role of perception in higher-order cognitive tasks (Enhanced Perceptual Functioning (EPF) model; Mottron, Dawson, Soulières, Hubert, & Burack, 2006). Individuals with an ASD also integrate auditory-visual inputs over longer periods of time than matched typically developing (TD) peers (Kwakye, Foss-Feig, Cascio, Stone & Wallace, 2011). To tease apart the dichotomy of both extended multisensory processing and enhanced perceptual processing, we used behavioral and electrophysiological measurements of audio-visual integration among persons with ASD. 13 TD and 14 autistics matched on IQ completed a forced choice multisensory semantic congruence task requiring speeded responses regarding the congruence or incongruence of animal sounds and pictures. Stimuli were presented simultaneously or sequentially at various stimulus onset asynchronies in both auditory first and visual first presentations. No group differences were noted in reaction time (RT) or accuracy. The latency at which congruent and incongruent waveforms diverged was the component of interest. In simultaneous presentations, congruent and incongruent waveforms diverged earlier (circa 150 ms) among persons with ASD than among TD individuals (around 350 ms). In sequential presentations, asymmetries in the timing of neuronal processing were noted in ASD which depended on stimulus order, but these were consistent with the nature of specific perceptual strengths in this group. These findings extend the Enhanced Perceptual Functioning Model to the multisensory domain, and provide a more nuanced context for interpreting ERP findings of impaired semantic processing in ASD.     

P300 event-related potentials and cognitive function in social phobia

The aim of the study was to investigate abnormalities of event-related potentials (ERPs) in social phobia patients indicating deficits in speed and amount of perceptual and cognitive resources as well as relationships between ERPs and cognitive functioning. ERPs were recorded from 19 EEG leads in a two-tone oddball paradigm in medication-free patients with DSM-IV social phobia (n=25) and in age- and sex-matched healthy controls (HC). Neuropsychological test performance was administered. Compared with the HC group, patients with social phobia showed reductions in N1 at temporal leads, N2 and P300 amplitudes, predominantly centroparietally, and longer P300 latencies. The observed P300 latency prolongation was associated with reduced Non-Verbal Learning Test (NVLT) but not the Wisconsin Card Sorting Test (WCST) scores. The reduction in N1 amplitude indicates an impairment in perceptual processing. The reduced P300 amplitudes may reflect reduced cognitive resources for the evaluation of relevant information. The increased P300 latency, indicating longer stimulus evaluation time, was correlated to deficits in learning processes as measured by the Non-Verbal Learning Test but not to executive function as measured by the Wisconsin Card Sorting Test. It may therefore be concluded that social phobia patients show deficits in cognitive information processing as reflected by ERPs.     

Event-related potential dysfunction in posttraumatic stress disorder: the role of numbing

The purpose of this study was to examine the relationship between disturbance in event-related potentials (ERPs) and symptom clusters in posttraumatic stress disorder (PTSD). ERPs were recorded in 17 unmedicated civilian PTSD patients and 17 age- and sex-matched controls during a conventional auditory oddball task. PTSD symptom clusters (re-experiencing, active avoidance, numbing, hyperarousal) were correlated with ERP measures. The PTSD group showed ERP disturbances to target stimuli (reduced P200 and P300 and increased N200 amplitude, increased N200 and P300 latency) and reduced P200 amplitude to common stimuli compared to the control group. A significant negative correlation was found between the intensity of numbing symptoms and parietal P300 amplitude. This study replicates findings of disturbed N200 and P300 components in PTSD, reflecting impairments in stimulus discrimination and attention. The finding that numbing was associated with reduced attention processing (P300) is consistent with models positing a relationship between disordered arousal and attention in PTSD.     

Uniqueness of action monitoring in children with autism spectrum disorder: Response types and temporal aspects

Background: Action monitoring, the process for evaluating the appropriateness of one’s own actions, is reported to be atypical in individuals with autism spectrum disorder (ASD). Method: We examined the characteristics of action monitoring in 11 children with ASD and 12 children with typical development (TD), analyzing stimulus-locked and response-locked event-related potential components (i.e., N2; error-related negativity, ERN; and error positivity, Pe) related to execution of a flanker task. Results: We found a smaller N2 amplitude in children with ASD than in those with TD. Children with ASD also had a larger amplitude of ERN for partial error responses (electromyographic activity corresponding to the inappropriate hand side before response execution) than did children with TD. Additionally, the ERN amplitude for the partial error response was correlated with the Autistic Mannerisms of the Social Responsiveness Scale. There were no significant differences in Pe amplitudes between children with ASD and those with TD. Conclusion: The results suggest that action monitoring in children with ASD is significantly different both before and after response execution. We hypothesized that the detail-focused processing style of ASD reduces the demands of action monitoring before response execution; however, autistic mannerisms evoke excessive concern regarding trivial mistakes after response execution.     

The modulation of late component event related potentials by pre-stimulus EEG theta activity in ADHD

Electroencephalography (EEG) and Event Related Potentials (ERPs) studies in ADHD have generally been studied separately. This study examined these measures simultaneously in 54 adolescent unmedicated ADHD males and age and gender matched normal controls during an auditory oddball paradigm. Compared with controls, ADHD patients showed increased pre-stimulus EEG Theta activity and post-stimulus reduced N200 amplitude, increased P200 amplitude and delayed N200 and P300 latencies evoked to target stimuli. Moreover, Theta activity was negatively correlated with N200 amplitude and positively correlated with P200, N200 and P300 latency in ADHD. There were no correlations in the control group. Pre-stimulus preparatory state increases in Theta activity in ADHD may underlie some of the reported disturbances in information processing reflected in ADHD.     

Event-related potentials in children with specific visual cognitive disability

Event-related potentials (ERPs) elicited by novel and well memorized non-verbal visual patterns were recorded over the right and left hemispheres from ten children with Specific Visual Cognitive Disability (SVCD) and ten matched Control subjects (C). ERPs of SVCD children were generally longer in latency (particularly N2) and decreased in amplitude (particularly P3) relative to the ERPs of Cs. No hemisphere differences were observed in the SVCD group, while the latency of N2 in the C group tended to be slightly shorter and the amplitude of P3 was significantly larger over the right than over the left hemisphere. The results are discussed in terms of deficits in visual learning and visual pattern analysis. The different hemispheric pattern in SVCD children as compared to Cs is suggested to be a symptom secondary to basic visual cognitive deficits.     

Event-related potentials for response inhibition in Parkinson's disease

This study investigated inhibitory function in patients with Parkinson's disease (PD) by recording event-related brain potentials (ERPs) during a Go/NoGo task. Fourteen healthy volunteers and 13 patients with PD without dementia performed a cued continuous performance test that included Go and NoGo trials. The peak latency, amplitude, and topographic distributions of the ERPs to Go and NoGo stimuli were analyzed. Cognitive function was evaluated using the Wisconsin Card Sorting Test (WCST), Kana Pick-out Test, and Verbal Fluency Test (VFT). Performances in the WCST and VFT were significantly impaired in the PD group as compared with the control group. The PD group had significantly higher rates of omission and commission errors during the ERP task. The ERP study found no differences in the latency and amplitude of the Go-P3 between the two groups. By contrast, the NoGo-P3 latency was significantly longer in the PD group than in the control group. The amplitudes of the NoGo-P3 and NoGo-N2 were also significantly smaller in the PD group than in the control group. The NoGo-P3 latency was significantly correlated with the Kana Pick-out Test and VFT scores. The NoGo-P3 amplitude was significantly correlated with the WCST and VFT scores, as well as with the number of commission errors. There were no significant correlations between the cognitive function tests and either the Go-P3 or NoGo-N2 measures. The behavioral and ERP data suggest that there is selective impairment of inhibitory function in PD and that this deficit may be related to impaired inhibitory executive function in the frontal lobe.