Reduced P300 Amplitude Research Articles

T161. Effects of Ketamine Administration on the P300 Event-Related Potential: Implications for Schizophrenia

N-methyl-D-aspartate receptor (NMDAR) hypofunction has been implicated in the pathophysiology of schizophrenia and its associated cognitive impairments, including auditory processing deficits reflected by the P300 event-related potential (ERP) component. P300 amplitude reduction is one of the most widely replicated brain abnormalities observed in patients with schizophrenia. To test the hypothesized contribution of NMDAR hypofunction to P300 abnormalities, we examined the effects of the NMDAR antagonist ketamine on auditory P300 amplitudes in healthy individuals and compared these effects with those of schizophrenia.

Callousness and meanness traits are associated with increased N2 amplitude in a community sample of adolescents and adults

The lack of consistent findings in the research field of psychopathy unveils the heterogeneity of this personality structure and, therefore, a dissociation of its phenotypic components is a promising venue to conciliate paradoxical results. The current study aims to assess the dissociable effects of psychopathic traits on N2 and P3 modulation, while analyzing the stability of some endophenotypic processes across development. A sample of adolescents (n = 33) and adults (n = 31) completed, respectively, the Youth Psychopathy Inventory and the Triarchic Psychopathy Measure and performed the same Go/No-Go task during an EEG recording. For adolescents, the unemotionality and remorselessness subdimensions of the callous-unemotional (CU) factor predicted, respectively, reduced N2 and P3 amplitudes. This suggests impaired inhibitory control in both subdimensions of the broad CU factor. However, the callousness subdimension of the CU factor predicted increased N2 amplitude. This pattern of findings was also observed for meanness in adults, which leads to the hypothesis that callousness traits may be a specific precursor of meanness.

Female versus male migraine: an event-related potential study of visual neurocognitive processing

BackgroundSeveral studies have suggested cognitive deficits in migraineurs, and sex differences have also been observed in migraine, such as a higher prevalence in females. Nevertheless, little is known about gender-related differences in cognitive processing. In this study, we aimed to investigate the effect of gender on neurocognitive processing in migraineurs.MethodsAltogether, 46 migraine patients without aura (23 females; mean age 32.848 years) during the interictal period and 46 age-matched healthy controls (23 females; mean age 32.652 years) were recruited. The emotional characteristics of participants were evaluated, and attentive processing was analyzed via event-related potential examinations using a three-stimulus visual oddball paradigm.ResultsWe found that migraineurs suffered from emotional and visual cognitive processing abnormalities compared with healthy controls, including higher levels of anxiety and reduced P3 amplitude. These parameters were modulated by gender in migraine patients, but not in healthy participants. Our findings indicated that female patients seemed to be more anxious and have more severe impairment in attentive processing of visual stimuli than their male counterparts. The gender-related differences in migraineurs were further validated using event-related potential difference waveforms.ConclusionsThese results suggested that migraine might have an additional influence on females and lead to more dysfunction in their interictal neurocognitive processing. Our findings provide evidence that a gender effect exists in migraineurs, which should be considered when designing experiments and exploring treatment approaches. The gender-related differences and underlying mechanisms deserve further investigation for patients with migraine.

Target-related parietal P3 and medial frontal theta index the genetic risk for problematic substance use.

Theoretical and empirical work suggests that problematic substance use (PSU) is associated with individual differences in prefrontal cortex activity. While research has strongly linked parietal P3 amplitude reduction (P3AR) to genetic risk for problematic substance use, few studies have tested whether prefrontal EEG measures are sensitive to this genetic liability. In addition to P3, oddball target detection tasks elicit medial frontal theta power, reflecting attentional allocation, and parietal delta, indexing decision making or stimulus-response link updating. Midfrontal theta and parietal delta may index neurocognitive processes relevant to PSU beyond P3AR. The present investigation examined the etiological relationship between PSU and P3, frontal theta, and parietal delta in a large twin sample (N=754). EEG was recorded during a visual oddball task. Greater PSU was associated with reduced target P3 amplitude and midfrontal theta/parietal delta power, and increased mean reaction time and reaction time variability (RTV; indexing attentional fluctuations). P3, theta, and RTV, but not delta or mean RT, explained unique variance in PSU (R2 =0.04). Twin biometric modeling indicated a genetic relationship between PSU and P3, theta, and RTV. Theta accounted for distinct genetic variance in PSU beyond P3 and RTV. Together, 23% of the total additive genetic variance in PSU was explained by the three endophenotypes. Results replicate P3AR as an endophenotype and provide support for additional behavioral (RTV) and neurophysiological (midfrontal theta) endophenotypes of PSU. Reduced theta and greater RTV may reflect variations in a prefrontal attentional network that confers genetic risk for substance use problems.

Attentional bias and response inhibition in severe obesity with food disinhibition: a study of P300 and N200 event-related potential.

In obesity there is growing evidence for common mechanism between food intake regulation and substance use disorders, especially more attentional bias and less cognitive control. In the present study we investigated whether severely obese subjects with or without disordered eating exhibit electroencephalographic (EEG) event-related potential (ERP) modifications as observed in substance abusers. A total of 90 women were included; 30 in the normal-weight (NW) group (18.5 < BMI < 24.5 kg/m2; no food disinhibition or restriction on the Three-Factor Eating Questionnaire) and 60 participants with BMI ≥ 35 kg/m2 were separated into two groups (n = 30): without food disinhibition (disinhibition score ≤8; ObFD- group) and with food disinhibition (score >8; ObFD+). Clinical and metabolic parameters as well as compartmental aspects (Eating Disorders Inventory-2, EDI-2) were assessed. Participants underwent an ERP recording with an auditory oddball paradigm. The mean ± SD P300 amplitudes in Pz were significantly (p < 0.05) lower in ObFD- (12.4 ± 4.6) and ObFD+ (12.5 ± 4.4) groups than in the NW group (15.8 ± 5.9). The mean ± SD N200 amplitude in Cz was significantly lower in the ObFD- group (-2.0 ± 5.4) than in the NW group (-5.2 ± 4.2 vs; p = 0.035). N200 Cz amplitude was correlated with EDI-2 Binge eating risk score (ρ = 0.331; p = 0.01), EDI-2 Body Dissatisfaction score (ρ = 0.351; p = 0.007), and Drive for Thinness score (ρ = 0.26; p = 0.05). The present study provides evidence for reduction of P300 and N200 amplitude in obese women and that N200 amplitude may be related to more disordered eating and eating disorder risk. This leads to consider attentional bias and response inhibition as core mechanisms in obesity and as possible targets for new therapeutic strategy.

N2 amplitude modulation across the antisocial spectrum: a meta-analysis.

Despite the accumulated knowledge on antisocial behavior and the positive event-related potential peaking around 300 ms (P3), less is known about the preceding negative electrophysiological response around 200 ms (N2). A systematic search of the literature was conducted to analyze the N2 modulation across the antisocial spectrum. Thirty-seven studies (n = 1199) were retrieved to the quantitative analysis. Reduced N2 amplitudes were found in the more severe antisocial manifestations (violent behavior and antisocial personality disorder), which is consistent with previous findings on P3 alterations and N2 reduced amplitudes in externalizing disorders. Findings on psychopathy were mixed, also in accordance with previous P3 results. From a dimensional lens, this supports the heterogeneity of the psychopathic personality structure: impulsivity features are a closer attribute of antisocial behavior and thus may be associated with N2 reduction, while adaptive psychopathic traits may be associated with intact (or even increased) N2 amplitude. The increased N2 amplitudes observed in impulsive behavior challenge, however, the previous meta-analytic findings. As most of the studies on impulsivity include subclinical samples, it leads to the hypothesis that some compensatory mechanisms can still occur at a subclinical level, reflecting the need for heightened allocation of brain resources to yield similar performances. Importantly, inhibition was the core deficit to explain N2 blunted amplitudes, alongside with deficits in the frontal brain region. From our findings, the reduction in P3 amplitude across the antisocial spectrum may be detected in the previous N2 time window.

Effect of acoustic features on discrimination ability in individuals with auditory neuropathy spectrum disorder: an electrophysiological and behavioral study.

The present study aimed to investigate the discrimination ability for acoustic cues in individuals with auditory neuropathy spectrum disorder (ANSD) using both behavioral and neural measures and to compare the result with normal hearing individuals. Four naturally produced syllables /ba/, /da/, /ma/ and /pa/ were used to study discrimination skills. They were combined in pairs such that the two syllables differ in acoustic features, that is place (/ba/-/da/), manner (/ba/-/ma/) and voicing (/ba/-/pa/) cues. Thirty individuals with ANSD and 30 individuals with normal hearing sensitivity were the participants. Syllable discrimination skill was assessed using behavioral (reaction time, sensitivity and D-prime) and neural (P300) measures. There was prolongation in latency and reduction in amplitude of P300 in individuals with ANSD compared to individuals with normal hearing sensitivity. Individuals with ANSD showed better discrimination skill for stimulus pairs differing in the manner followed by place and the least perceived was voicing information. Discrimination ability of individuals with ANSD is found to be affected as evident on behavioral and neural measures. The discrimination ability varies with acoustic features of speech.

Orienting and memory to unexpected and/or unfamiliar visual events in children and adults

For children, new experiences occur very often, and learning to differentiate between old and new events is a fundamental process necessary for appropriate reactions to stimuli. Thus the present study is concerned with maturation of brain responses to repeated novel events. We examined the effect of repetition of familiar (meaningful) and unfamiliar (meaningless) symbols on the event-related-potentials (ERPs) recorded during novelty oddball and recognition memory tasks from children, adolescents and young adults. During the novelty oddball task, repetition of the familiar symbols elicited a reduction in the novelty P3 in the ERPs of all age groups, while repetition of the unfamiliar symbols elicited a reduction in novelty P3 amplitude only in children. As expected, recognition memory performance improved with age and was better for familiar than unfamiliar symbols. For all age groups, ERPs to correctly recognized familiar old symbols elicited a larger positivity than ERPs to correctly identified new symbols, indicating a reliable memory effect. However, ERPs to unfamiliar old and new symbols did not differ in adults and adolescents but did differ in children. The data suggest that children process familiar visual symbols in a similar fashion to that of adults, and that children process unfamiliar symbols differently from adults.

Diabetes Mellitus and Cognition-A Non Invasive Study

Background Diabetes mellitus is increasing worldwide due to improved lifestyle modifications. Particularly more common in developing countries. Peripheral, central and autonomic neuropathy are the most common complications of diabetes mellitus, which if not detected early can lead to early disability. Event related potential P300 is a non invasive test to detect one of the higher functions of brain namely cognition. The present study was conducted to evaluate impact of diabetes mellitus and its duration on cognition. Aims & Objectives To investigate neurophysiological alterations of higher brain functions in patients with diabetes mellitus. Materials & Method Auditory P300 event related potentials were recorded in 60 diabetic patients (NIDDM & IDDM) attending medical out patient department of Bapuji & Chigateri hospital, Davangere, who had no evidence of stroke, dementia, or any other neurological illness. The P300 wave latencies in diabetic patients were compared with those in neurologically healthy control subjects, with consideration of duration of diabetes and analyzed by using unpaired student T test for comparison between cases and controls and one way ANOVA for multiple group comparisons within diabetics based on duration of diabetes. Results Diabetics had significantly longer P300 latencies and reduced P300 amplitudes than control subjects. There was a positive correlation between prolongation of latencies and duration of diabetes mellitus. Conclusion The present study suggests that diabetes does relate significantly to cognitive decline. ERP P300 can be a useful neurophysiological test to detect cognitive decline early in diabetics and also beneficial to the clinician for further management of the patient.

Machine-learning-based classification between post-traumatic stress disorder and major depressive disorder using P300 features

BackgroundThe development of optimal classification criteria for specific mental disorders which share similar symptoms is an important issue for precise diagnosis. We investigated whether P300 features in both sensor-level and source-level could be effectively used to classify post-traumatic stress disorder (PTSD) and major depressive disorder (MDD).MethodEEG signals were recorded from fifty-one PTSD patients, 67 MDD patients, and 39 healthy controls (HCs) while performing an auditory oddball task. Amplitude and latency of P300 were evaluated, and the current source analysis of P300 components was conducted using sLORETA. Finally, we classified two groups using machine-learning methods with both sensor- and source-level features. Moreover, we checked the comorbidity effects using the same approaches (PTSD-mono diagnosis (PTSDm, n = 28) and PTSD-comorbid diagnosis (PTSDc, n = 23)).ResultsPTSD showed significantly reduced P300 amplitudes and prolonged latency compared to HCs and MDD. Moreover, PTSD showed significantly reduced source activities, and the source activities were significantly correlated with symptoms of depression and anxiety. Also, the best classification accuracy at each pair was as follows: 80.00% (PTSD-HCs), 67.92% (MDD-HCs), 70.34% (PTSD-MDD), 82.09% (PTSDm-HCs), 71.58% (PTSDm-MDD), 82.56% (PTSDc-HCs), and 76.67% (PTSDc- MDD).ConclusionSince abnormal P300 reflects pathophysiological characteristics of PTSD, PTSD patients were well-discriminated from MDD and HCs when using P300 features. Thus, altered P300 characteristics in both sensor- and source-level may be useful biomarkers to diagnosis PTSD.

M98 - EVENT-RELATED P300 AMPLITUDE AS AN ENDOPHENOTYPE OF SCHIZOPHRENIA: ASSOCIATION WITH GENOME WIDE SIGNIFICANT INDEX SINGLE NUCLEOTIDE POLYMORPHISMS

Background Reduced amplitude of the event related P300 potential is a prominent finding in schizophrenia patients and a promising endophenotype for genetic research. As yet, little is known on common genetic risk factors for P300 amplitude reduction and the clinical manifestation of schizophrenia. Recently, the Psychiatric Genomics Consortium (PGC2) identified 128 independent associations spanning 108 conservatively defined loci that meet genome-wide significance. We used data from 269 normal subjects with both electrophysiological and genotype data to explore the possible relevance of these schizophrenia index SNPs on the P300 amplitude. Methods The sample comprised 269 unrelated healthy volunteers of German descent from the general population of Munich, Germany. Subjects with neuropsychiatric disorders were excluded. Evoked potentials were recorded using an auditory oddball paradigm with 80% non-target stimuli (540 tones, 500 Hz) and 20% target stimuli (135 tones, 1000 Hz) presented binaurally through headphones in a pseudo randomized order. The P300 amplitude was detected semiautomatically as the most positive value in the timeframe 250–500ms post-stimulus with a visual control afterwards at the electrode position Fz. The sample was genotyped on different platforms following established quality control and imputation protocols. After excluding two SNPs with insufficient quality of imputation, 126 genome-wide significant schizophrenia index SNPs from PGC2 could be evaluated for association with P300 amplitude by linear regression. Results There were 12 associations significant on the p=0.05 level (chr5_140143664_I, rs6002655, rs12887734, rs11191419, rs75059851, rs7907645, rs7432375, rs12421382, rs36068923, rs6065094, chr10_104957618_I, rs6670165). None of the associations survived Bonferroni correction for 126 comparisons. When employing the exact binomial test the number of significant associations observed exceeded chance expectation (p=0,024). Only one half of the associations showed effects in the expected direction (lower P300 amplitude associated with schizophrenia risk allele or amplitude associated with protective allele). Discussion Although we found an overrepresentation of significant associations of schizophrenia index SNPs with event related P300 amplitudes we were unable to establish the connection for any specific locus with sufficient statistical power. The pattern of observed effects was not supportive of a specific role of PGC2 schizophrenia risk alleles in P300 amplitude in normal subjects.

Changes in event-related potentials during dual task walking in aging and Parkinson's disease

ObjectiveTo investigate EEG changes during an auditory odd-ball task while walking (dual-task) in young adults, older adults, and patients with Parkinson's disease. Methods11 young adults, 10 older adults, and 10 patients with Parkinson’s disease (PD) performed an auditory oddball task during standing and walking on a treadmill, while wearing a wireless EEG cap. The amplitude and latency of P300 were compared between groups and within conditions using linear mix model analysis. Gait was evaluated using wearable sensors and cognition was assessed using the Color Trail Test. ResultsP300 latency became longer during walking in all groups (p = 0.005). During walking, older adults (p = 0.005) and patients with PD (p = 0.001) showed prolonged P300 latency compared to young adults. Significant task by group interaction was found in P300 amplitude (p = 0.008). Patients with PD demonstrated reduced P300 amplitude during walking compared to standing (p = 0.023). Among all subjects, better motor and cognitive performance correlated with shorter P300 latency (r = 0.457, p = 0.014 and r = 0.431, p = 0.040, respectively). ConclusionsThese findings provide direct evidence of the physiological recruitment of attentional networks during walking and their impact by ageing and disease. SignificanceThis study is the first to report on changes in P300 latency and amplitude during dual-task oddball walking in older adults and patients with PD.

Effects of methylphenidate treatment in children with ADHD: a multimodal EEG/fNIRS approach

OBJECTIVEIn this study we investigated the stimulant methylphenidate (MPH) effects in Attention deficit hyperactivity disorder (ADHD) from neuroimaging and neurophysiological perspective by simultaneous recording functional near infrared spectroscopy (fNIRS) and electroencephalography (EEG) during attention task.METHODSUsing fNIRS we obtained frontal cortex hemodynamic responses and using event related potentials (ERP) we obtained amplitude values of P3 component of 18 children with ADHD and gender matched 18 healthy controls performing an oddball task. Same recordings were repeated 3 months after extended-release MPH (OROS-MPH) administration for ADHD group. Prefrontal cortex oxygenation and P3 amplitude were compared between control and pre-MPH ADHD groups and between Pre-MPH and post-MPH ADHD groups.RESULTSfNIRS indicated that the healthy controls exhibited higher right prefrontal activation than pre-MPH children with ADHD. Reduced P3 amplitude values were found in children with ADHD compared the control group. Reduced right prefrontal activation and P3 amplitude was normalized in ADHD group after MPH therapy.CONCLUSIONRecently multimodal neuroimaging which combine signals from different brain modalities have started to be considered as a potential to improve the accuracy of diagnosis. The current study provides MPH effect assessment in children with ADHD using multimodal EEG/fNIRS system for the first time. This study suggests combination of neuroimaging and electrophysiological parameters is a promising approach to investigate MPH effect assessment in children with ADHD.

Performance monitoring and post-error adjustments in adults with attention-deficit/hyperactivity disorder: an EEG analysis

Recently, research into attention-deficit/hyperactivity disorder (ADHD) has focused increasingly on its neurobiological underpinnings, revealing (among other things) frontal lobe alterations. Specifically, action-monitoring deficits have been described, including impaired behavioural adjustments following errors. Our aim was to examine the neurophysiological background of post-error behavioural alterations in an adult ADHD sample for the first time, hypothesizing that people with ADHD would differ from controls in neurophysiological markers of cognitive preparation and stimulus processing, specifically following errors. In total, 34 people with ADHD and 34 controls participated in an electroencephalography measurement while performing a flanker task. The final number of electroencephalography samples included in the analyses ranged from 23 to 28. We recorded event-related potentials for the erroneous response itself (error-related negativity) and for events following errors (intertrial interval: contingent negative variation; next flanker stimulus: P300). Over frontal electrode sites, error-related negativity amplitudes were significantly reduced in people with ADHD across response conditions. Both groups showed reduced P300 amplitudes on flanker stimuli following errors. Moreover, during the intertrial interval, patients exhibited significantly reduced contingent negative variation, specifically following errors. At the behavioural level, we observed no significant group differences in post-error data. Only adults were examined (no longitudinal data). Based on previous reports of post-error behavioural alterations in childhood samples, we conclude that people with ADHD develop compensatory strategies across the lifespan that lead to inconspicuous post-error behaviour in adulthood. Neurophysiologically, however, subtle alterations remain, indicating a perseverance of at least some frontal lobe deficits in people with ADHD who are partially medicated, particularly with respect to action-monitoring and post-error adaptation.

Suppressing movements with a phantom limb: an ERP study

There are no reliable outcome predictors for severely impaired patients suffering from large infarctions or hemorrhages within the territory of the middle cerebral artery. This study investigated whether the amplitude of the event-related potential (ERP) component P300 predicts if a patient will be transferred to the next stage of rehabilitation (positive outcome) or to a nursing home (negative outcome). The second goal was to look for lesion locations determining the generation of the P300 amplitude.Forty-seven patients performed an auditory oddball task to elicit the P300 and were assessed with different scores for activities of daily living (ADL). Patients were divided in two groups according to their outcome. P300 amplitudes were compared between these groups controlling for age and gender. Post-hoc analyses were performed to analyse the relationship between P300 amplitude and neurological outcome scores. In addition, lesion overlaps were created to detect which lesion pattern affects P300 generation.Patients with a positive outcome showed higher P300 amplitudes at frontal electrode sites than those with a negative outcome. P300 amplitude correlated with ADL score difference. Lesions in the superior temporal gyrus, middle and inferior frontal and prefrontal regions led to visibly diminished P300 amplitudes.The findings suggest that an impairment of attention (P300 amplitude reduction) negatively influences successful neurological rehabilitation. Left superior temporal lobe and the left premotor/prefrontal areas are essential brain areas for the generation of the P300.P300 amplitude may be used as an outcome predictor for severely impaired patients suffering from middle cerebral artery strokes or hemorrhages.

Response Inhibition Deficits in Insomnia Disorder: An Event-Related Potential Study With the Stop-Signal Task.

Background: Response inhibition is a hallmark of executive function, which was detected impaired in various psychiatric disorders. However, whether insomnia disorder (ID) impairs response inhibition has caused great controversy.Methods: Using the auditory stop-signal paradigm coupled with event-related potentials (ERPs), we carried out this study to examine whether individuals with ID presented response inhibition deficits and further investigated the neural mechanism correlated to these deficits. Twelve individuals with ID and 13 matched good sleepers (GSs) had participated in this study, and then they performed an auditory stop-signal task (SST) in the laboratory setting with high density EEG recordings.Results: The behavioral results revealed that compared to GSs, patients with ID presented significantly longer stop-signal reaction time (SSRT), suggesting the impairment of motor inhibition among insomniacs. Their reaction time in go trials, however, showed no significant between-group difference. Considering the electrophysiological correlate underlying the longer SSRT, we found reduced P3 amplitude in patients with insomnia in the successful stop trials, which might reflect their poor efficiency of response inhibition. Finally, when we performed exploratory analyses in the failed stop and go trials, patients with ID presented reduced Pe and N1 amplitude in the failed sop trials and go trials respectively.Discussion: Taken together, these findings indicate that individuals with ID would present response inhibition deficits. Moreover, the electrophysiological correlate underlying these deficits mainly revolves around the successful stop P3 component. The present study is the first to investigate the electrophysiological correlate underlying the impaired response inhibition among insomniacs.

Visual function assessed by visually evoked potentials in optic pathway low-grade gliomas with and without neurofibromatosis type 1

To investigate the contribution of full-field transient pattern-reversal visually evoked potentials (PRVEP) on cross-sectional evaluations of visual function in patients with and without neurofibromatosis type 1 (NF1) affected by optic pathway low-grade gliomas (OPLGG). Participants were children and adolescents referred for visual function evaluation and receiving treatment for OPLGG, linked (NF1-OPLGG) or not to NF1 (Non-NF1-OPLGG). An age-adjusted control group was included for comparison. Monocular full-field PRVEPs were recorded from each eye in accordance with ISCEV standards. Parameters of peak-to-peak P100 amplitude (µV) and P100 peak time (ms) were measured. Cutoff normative values obtained from controls for 15' and 60' check sizes were ≥ 9.0µV for N75-P100 amplitude and ≤ 103.0ms for P100 peak time. The association of age, gender, tumor resection and NF1 with P100 amplitude reduction and P100 peak time delay was explored by Firth logistic regression modeling. Participants were 30 patients (15 males, 60% Non-NF1) with ages from 3.6 to 19.9years (mean ± SD = 9.2 ± 3.8years; median = 8.4years) and 19 controls (12 males) with ages from 3.7 to 19.9years (mean ± SD = 10.4 ± 4.9years; median = 9.5years). Overall, 68% of tested eyes presented reduced P100 amplitudes for both check sizes (46% in the NF-1 and 83% in the Non-NF1) and delayed P100 for both check sizes (38% in NF1 and 89% in Non-NF1). Absence of NF1 adjusted for age, gender and tumor resection was significantly associated with marginally reduced P100 amplitude for 15' checks [odds ratio (OR): 6.26; 95% confidence interval (CI) = 0.96-40.94; p = 0.055]. Full-field PRVEP on cross-sectional evaluations contributed to detect visual dysfunction in two-thirds of patients with OPLGG by highlighting subclinical evidence of visual loss. Abnormalities were more frequent and more severe in OPLGG not linked to NF1 than in NF1-OPLGG; however, there was a difference in surgical management between these groups. PRVEP parameters may provide reliable evidence of visual pathway involvement in OPLGG, helping to hasten treatment before optic atrophy is detected.

Fatigue Related to Speech Processing in Children With Hearing Loss: Behavioral, Subjective, and Electrophysiological Measures

The purpose of this study was to examine fatigue associated with sustained and effortful speech-processing in children with mild to moderately severe hearing loss. We used auditory P300 responses, subjective reports, and behavioral indices (response time, lapses of attention) to measure fatigue resulting from sustained speech-processing demands in 34 children with mild to moderately severe hearing loss (M = 10.03 years, SD = 1.93). Compared to baseline values, children with hearing loss showed increased lapses in attention, longer reaction times, reduced P300 amplitudes, and greater reports of fatigue following the completion of the demanding speech-processing tasks. Similar to children with normal hearing, children with hearing loss demonstrate reductions in attentional processing of speech in noise following sustained speech-processing tasks-a finding consistent with the development of fatigue.

The P1 visual-evoked potential, red light, and transdiagnostic psychiatric symptoms

A reduced P1 visual-evoked potential amplitude has been reported across several psychiatric disorders, including schizophrenia-spectrum, bipolar, and depressive disorders. In addition, a difference in P1 amplitude change to a red background compared to its opponent color, green, has been found in schizophrenia-spectrum samples. The current study examined whether specific psychiatric symptoms that related to these P1 abnormalities in earlier studies would be replicated when using a broad transdiagnostic sample. The final sample consisted of 135 participants: 26 with bipolar disorders, 25 with schizophrenia-spectrum disorders, 19 with unipolar depression, 62 with no current psychiatric disorder, and 3 with disorders in other categories. Low (8%) and high (64%) contrast check arrays were presented on gray, green, and red background conditions during electroencephalogram, while an eye tracker monitored visual fixation on the stimuli. Linear regressions across the entire sample (N = 135) found that greater severity of both clinician-rated and self-reported delusions/magical thinking correlated with a reduced P1 amplitude on the low contrast gray (neutral) background condition. In addition, across the entire sample, higher self-reported constricted affect was associated with a larger decrease in P1 amplitude (averaged across contrast conditions) to the red, compared to green, background. All relationships remained statistically significant after covarying for diagnostic class, suggesting that they are relatively transdiagnostic in nature. These findings indicate that early visual processing abnormalities may be more directly related to specific transdiagnostic symptoms such as delusions and constricted affect rather than specific psychiatric diagnoses or broad symptom factor scales.

Acute Psychological Stress Disrupts Attentional Bias to Threat-Related Stimuli

The present study investigated the effect of acute stress on attentional bias to threat using behavioral and ERP methods. Sixty-two male participants were randomly assigned to a stress condition (Trier Social Stress Test) or a control condition. To examine the impact of stress-induced cortisol on attentional bias to threat, participants in the stress group were split into Low- and High cortisol responders. All participants were then administered a modified dot probe task in which the cues were neutral and angry faces. Behavioral results showed a pattern of attentional bias toward threat in the Control group but not in the stress group. For the ERPs, the P100 peaked earlier for the angry-cued targets than the neutral-cued targets in the Control group, which suggests a rapid, adaptive response toward threat. However, this effect was not observed in the stress group, suggesting a suppressed attentional bias under stress. In addition, the stress group (including both Low and High cortisol responders) showed reduced P300 amplitude to target onset than the Control group. These results suggest that acute stress disrupts attentional bias to threat including a reduction in early bias to threat in addition to a subsequent change of attention allocation.