Visual Continuous Performance Task Research Articles

Normative performance data on visual attention in neurotypical children: virtual reality assessment of cognitive and psychomotor development

Introduction: Virtual Reality (VR) is revolutionizing healthcare research and practice by offering innovative methodologies across various clinical conditions. Advances in VR technology enable the creation of controllable, multisensory 3D environments, making it an appealing tool for capturing and quantifying behavior in realistic scenarios. This paper details the application of VR as a tool for neurocognitive evaluation, specifically in attention process assessment, an area of relevance for informing the diagnosis of childhood health conditions such as Attention Deficit Hyperactivity Disorder (ADHD).Methods: The data presented focuses on attention performance results from a large sample (n = 837) of neurotypical male and female children (ages 6–13) tested on a visual continuous performance task, administered within an immersive VR classroom environment. This data was collected to create a normative baseline database for use to inform comparisons with the performances of children with ADHD to support diagnostic decision-making in this area.Results: Results indicate systematic improvements on most metrics across the age span, and sex differences are noted on key variables thought to reflect differential measures of hyperactivity and inattention in children with ADHD. Results support VR technology as a safe and viable option for testing attention processes in children, under stimulus conditions that closely mimic ecologically relevant challenges found in everyday life.Discussion: In response to these stimulus conditions, VR can support advanced methods for capturing and quantifying users’ behavioral responses. VR offers a more systematic and objective approach for clinical assessment and intervention and provides conceptual support for its use in a wide variety of healthcare contexts.

An ensemble-based Machine learning technique for dyslexia detection during a visual continuous performance task

BackgroundDyslexia is a neurological disorder which affects the learning of individuals suffering from it, especially children. It causes reading and writing difficulties, leading to anger, frustration, poor self-esteem, and other negative emotions. Early diagnosis of dyslexia can be extremely useful for dyslexic children since their learning requirements can be correctly handled. MethodThis study aimed to propose an efficient method for dyslexia detection via evoked-related potentials (ERPs) during a Visual Continuous Performance Task (VCPT). To this end, after extracting the latency and amplitude of the event-related potential components and a statistical analysis between the two groups, the number of data dimensions is reduced by the KS-test and principal component analysis (PCA). This method used the ensemble learning classification technique to classify the normal and dyslexic groups, including five classifiers, namely a Support Vector Machine (SVM), Decision Tree, Linear Discriminant Analysis (LDA), K-nearest Neighbors (KNN), and Naive Bayesian. Moreover, we have used an 8-fold cross-validation method to assess how generalized the process is and, more importantly, to have a well-performed control on overfitting. ResultsAccording to this approach, the overall average classification accuracy is 87.5%, and the sensitivity and specificity are 81.2% and 93.7%, respectively. ConclusionThe suggested technique can improve children's education before they start school and have any skills in writing and reading. The most discriminative electrodes were found in the left hemisphere, which can be related to the Wernicke and Broca areas that have an essential role in the brain's reading, writing, and language-related functions.

EEG Based Functional Brain Network Analysis and Classification of Dyslexic Children During Sustained Attention Task.

Reading is a complex cognitive skill that involves visual, attention, and linguistic skills. Because attention is one of the most important cognitive skills for reading and learning, the current study intends to examine the functional brain network connectivity implicated during sustained attention in dyslexic children. 15 dyslexic children (mean age 9.83±1.85 years) and 15 non-dyslexic children (mean age 9.91±1.97 years) were selected for this study. The children were asked to perform a visual continuous performance task (VCPT) while their electroencephalogram (EEG) signals were recorded. In dyslexic children, significant variations in task measurements revealed considerable omission and commission errors. During task performance, the dyslexic group with the absence of a small-world network had a lower clustering coefficient, a longer characteristic pathlength, and lower global and local efficiency than the non-dyslexic group (mainly in theta and alpha bands). When classifying data from the dyslexic and non-dyslexic groups, the current study achieved the maximum classification accuracy of 96.7% using a k-nearest neighbor (KNN) classifier. To summarize, our findings revealed indications of poor functional segregation and disturbed information transfer in dyslexic brain networks during a sustained attention task.

Development of visual sustained selective attention and response inhibition in deaf children.

Studies of deaf and hard-of-hearing (henceforth, deaf) children tend to make comparisons with typically hearing children for the purpose of either identifying deficits to be remediated or understanding the impact of auditory deprivation on visual or domain general processing. Here, we eschew these clinical and theoretical aims, seeking instead to understand factors that explain variability in cognitive function within deaf children. A total of 108 bilingual deaf children ages 7-13 years who use both English and American Sign Language (ASL) participated in a longitudinal study of executive function (EF) development. We report longitudinal data from a visual continuous performance task that measured sustained selective attention and response inhibition. Results show that the impact of deafness on these processes is negligible, but that language skills have a positive relationship with both: better English abilities were associated with better selective sustained attention, and better ASL abilities with better response inhibition. The relationship between sustained selective attention and English abilities may reflect the cognitive demands of spoken language acquisition for deaf children, whereas better ASL abilities may promote an "inner voice," associated with improved response inhibition. The current study cannot conclusively demonstrate causality or directionality of effects. However, these data highlight the importance of studies that focus on atypical individuals, for whom the relationships between language and cognition may be different from those observed in typically developing populations.

Prior Prognostic Expectations as a Potential Predictor in Neurofeedback Training

The present study evaluated whether subjects’ expectations and neurofeedback training performance predict neurofeedback efficacy in cognitive training by controlling both factors as statistical variables. Twenty-two psychology students underwent neurofeedback training, employing beta/theta protocol to enhance beta1 power (13–21 Hz) and suppress theta (4–7 Hz) power. Neurofeedback efficacy was evaluated by behavioral components measured on pre-tests and post-tests employing a visual continuous performance task. The results revealed a significant interaction term between change in reaction time from pre-test to post-test and expectancy effect, indicating that participants with high prognostic expectations showed better improvement in reaction time scores. The data did not reveal that actual neurofeedback performance influenced the post-test measurements of the visual continuous performance task. No significant differences were found for reaction time variability, omission, or commission errors. Possible factors contributing to the results are discussed, and directions for future research are suggested.

Comparison of Theta Beta Ratio in children with Attention deficit/hyperactive disorder and specific Learning Disorder during active EEG

Introduction: Theta-Beta Ratio (TBR) has been claimed as a biomarker to diagnose Attention Deficit and Hyperactivity Disorder (ADHD). However, the effectiveness of this index to differentiate between different groups of disorders is still under discussion. The primary purpose was to determine to what extent active TRB can differentiate between children with ADHD and specific Learning Disorder (sLD) as the most common comorbid disorder. Methods: Two groups of school-aged children with sLD (N=15) and ADHD (N=15) were diagnosed through a process of clinical interview and observation. Electroencephalography (EEG) was recorded in both groups during active condition. The implemented cognitive task was the visual continuous performance task (VCPT). TBR in sites of CZ and Fz, and cognitive measures of VCPT were calculated in the aforementioned groups. Results: There was no significant differences in cognitive measures (containing Commission, Omission, Reaction Time, and Variability of Reaction Times) shown in two matched groups of children with sLD and ADHD. According to TBR, two groups demonstrated no significant results in comparison. Conclusion: TBR cannot be considered as a reliable biomarker to differentiate between those groups of psychological disorders that contain primary cognitive deficits and require the allocation of attention and working memory loads.

Hemodynamic and behavioral peculiarities in response to emotional stimuli in children with attention deficit hyperactivity disorder: An fNIRS study

BackgroundChildren with attention deficit hyperactivity disorder (ADHD) exhibit behavioral inhibition deficits, which often lead to emotional dysregulation (ED) affecting individual ability to control emotions and behavioral responses. In ADHD, ED is associated with poor outcomes and comorbidities, with both externalizing and internalizing disorders. This work aims to evaluate sensitivity to emotional stimuli in children with ADHD using functional Near Infrared Spectroscopy (fNIRS). MethodsDuring frontal fNIRS recording, 20 children with ADHD and 25 typically developing (TD) peers performed a visual continuous performance task with stimuli of different emotional content (i.e., positive, negative, neutral, and control stimuli without emotional content). This is a cognitive task designed to evaluate the ability to recognize emotional stimuli and to deal with emotional interference. ResultsThe ADHD sample showed more variability in response time to stimuli and more false alarms compared to TD group. fNIRS data showed between-group differences in right prefrontal and frontal cortices, with wider hemoglobin concentration changes in the TD group, during positive, negative, and neutral conditions. LimitationsOwing to the limited possibility of near infrared light to penetrate tissue, fNIRS can only measure cortical activations, while it would be of interest to identify the subcortical areas linked to emotional processing, too. ConclusionsFindings suggest the presence of emotional processing deficits in children with ADHD, as suggested by poor performances on the e-CPT task, and of peculiar sensitivity to emotional stimuli, linked to atypical hemodynamics of right prefrontal and frontal areas.

Default mode and visual network activity in an attention task: Direct measurement with intracranial EEG

Dynamic attention states are necessary to navigate the ever changing task demands of daily life. Previous investigations commonly utilize a block paradigm to study sustained and transient changes in attention networks. fMRI investigations have shown that sustained attention in visual block design attention tasks corresponds to decreased signal in the default mode and visual processing networks. While task negative networks are anticipated to decrease during active task engagement, it is unexpected that visual networks would also be suppressed during a visual task where event-related fMRI studies have found transient increases to visual stimuli. To resolve these competing results, the current investigations utilized intracranial EEG to directly interrogate visual and default mode network dynamics during a visual continuous performance task. We used the electrophysiological data to model expected fMRI signals and to maximize interpretation of current results with previous investigations. Results show broadband gamma power decreases in the default mode network, corresponding to previous EEG and fMRI findings. Meanwhile, visual processing regions including the primary visual cortex and fusiform gyrus demonstrate both sustained decreases during task engagement and stimuli-driven transient increases in gamma power. Modeled fMRI based on gamma power reproduces signal decreases reported in the fMRI literature, and emphasizes the insensitivity of fMRI to transient, regularly spaced signal changes embedded within sustained network dynamics. The signal processing functions of the dynamic visual and default mode network changes explored in this study are unknown but may be elucidated through further investigation.

Evaluation of Neurofeedback for Posttraumatic Stress Disorder Related to Refugee Experiences Using Self-Report and Cognitive ERP Measures.

Background. Neurofeedback holds promise as an intervention for the psychophysiological dysfunction found in posttraumatic stress disorder (PTSD). Few empirical studies have assessed the efficacy of neurofeedback for PTSD, and none in individuals with refugee trauma. A proposed mechanism for neurofeedback efficacy in PTSD is through remediating deficits in cognitive control. We assessed pre- and postchanges in symptoms and neurocognitive functioning of refugee clients participating in a neurofeedback intervention for PTSD. Methods. Clinical data for 13 adult refugees with chronic PTSD who participated in neurofeedback combined with trauma counseling (NFT) was compared with 13 adult refugees placed on a waitlist to receive neurofeedback. Waitlist clients continued to receive trauma counseling alone (TC). NFT was additionally assessed pre- and posttherapy for changes in event-related potentials (ERPs) and behavioral indices of cognitive control using a visual continuous performance task (VCPT). Comparison VCPT data from healthy controls (HC) was available from the Human Brain Index database. Results. Posttherapy, NFT had significantly lower symptoms of trauma, anxiety, and depression compared with TC. NFT demonstrated an increased P3 amplitude and improved behavioral performance suggesting a normalization of cognitive control. Conclusions. These preliminary observations are consistent with a possible benefit of neurofeedback for remediating PTSD. This may be achieved at least partially by an improvement in cognitive control. Further confirmation of the effectiveness of the treatment now requires a randomized controlled trial that considers issues such as placebo response, nonspecific therapist effects, and duration of treatment.

Event-Related Potential Analysis of ADHD and Control Adults During a Sustained Attention Task.

Background. Event-related potentials (ERPs) of attention deficit hyperactivity disorder (ADHD) population have been extensively studied using the time-domain representation of signals but time-frequency domain techniques are less explored. Although, adult ADHD is a proven disorder, most of the electrophysiological studies have focused only on children with ADHD. Methods. ERP data of 35 university students with ADHD and 35 control adults were recorded during visual continuous performance task (CPT). Gray level co-occurrence matrix-based texture features were extracted from time-frequency (t-f) images of event-related EEG epochs. Different ERP components measures, that is, amplitudes and latencies corresponding to N1, N2, and P3 components were also computed relative to standard and target stimuli. Results. Texture analysis has shown that the mean value of contrast, dissimilarity, and difference entropy is significantly reduced in adults with ADHD than in control adults. The mean correlation and homogeneity in adults with ADHD were significantly increased as compared with control adults. ERP components analysis has reported that adults with ADHD have reduced N1 amplitude to target stimuli, reduced N2 and P3 amplitude to both standard and target stimuli than controls. Conclusions. The differences in texture features obtained from t-f images of ERPs point toward altered information processing in adults with ADHD during a cognitive task. Findings of reduction in N1, N2, and P3 components highlight deficits of early sensory processing, stimulus categorization, and attentional resources, respectively, in adults with ADHD.

Cervical Dystonia and Executive Function: A Pilot Magnetoencephalography Study.

Background: Cervical dystonia (CD) patients have impaired working memory, processing speed and visual-motor integration ability. We used magnetoencephalography (MEG) to investigate changes in cerebral oscillations in CD patients during an executive function test, before and after administration of botulinum toxin. Methods: MEG data were collected from five CD patients while they performed a visual continuous performance task (CPT), before and after they received a botulinum toxin injection. MEG data was also collected on five controls matched for age and gender. Coherence source imaging was performed to quantify network connectivity of subjects. Results: Controls demonstrated two errors with visual CPT; CD patients demonstrated six and three errors pre- and post-botulinum toxin respectively. After botulinum toxin, mean time from cue to correct response was 0.337 s in controls, 0.390 s in patients before botulinum toxin injection, and 0.366 s after the injection. Differences in coherence between controls and patients were found in the following brain regions: Fronto-frontal, fronto-parietal, fronto-striatal, fronto-occipital, parieto-parietal and temporo-parietal. Intrahemispheric and interhemispheric networks were affected. Post injection, there was minimal change in coherence in the above-mentioned networks. Discussion: Neuropsychological testing suggests difference in coherence in frontal circuits between CD cases and controls during the visual CPT, which may reflect subjects’ increased difficulty with the task. Botulinum toxin is associated with minimal improvement with executive function in CD.

Picture naming in typically developing and language-impaired children: the role of sustained attention.

Children with specific language impairment (SLI) have problems not only with language performance but also with sustained attention, which is the ability to maintain alertness over an extended period of time. Although there is consensus that this ability is impaired with respect to processing stimuli in the auditory perceptual modality, conflicting evidence exists concerning the visual modality. To address the outstanding issue whether the impairment in sustained attention is limited to the auditory domain, or if it is domain-general. Furthermore, to test whether children's sustained attention ability relates to their word-production skills. Groups of 7-9 year olds with SLI (N = 28) and typically developing (TD) children (N = 22) performed a picture-naming task and two sustained attention tasks, namely auditory and visual continuous performance tasks (CPTs). Children with SLI performed worse than TD children on picture naming and on both the auditory and visual CPTs. Moreover, performance on both the CPTs correlated with picture-naming latencies across developmental groups. These results provide evidence for a deficit in both auditory and visual sustained attention in children with SLI. Moreover, the study indicates there is a relationship between domain-general sustained attention and picture-naming performance in both TD and language-impaired children. Future studies should establish whether this relationship is causal. If attention influences language, training of sustained attention may improve language production in children from both developmental groups.

Sustained attention in language production: an individual differences investigation.

Whereas it has long been assumed that most linguistic processes underlying language production happen automatically, accumulating evidence suggests that these processes do require some form of attention. Here we investigated the contribution of sustained attention: the ability to maintain alertness over time. In Experiment 1, participants' sustained attention ability was measured using auditory and visual continuous performance tasks. Subsequently, employing a dual-task procedure, participants described pictures using simple noun phrases and performed an arrow-discrimination task while their vocal and manual response times (RTs) and the durations of their gazes to the pictures were measured. Earlier research has demonstrated that gaze duration reflects language planning processes up to and including phonological encoding. The speakers' sustained attention ability correlated with the magnitude of the tail of the vocal RT distribution, reflecting the proportion of very slow responses, but not with individual differences in gaze duration. This suggests that sustained attention was most important after phonological encoding. Experiment 2 showed that the involvement of sustained attention was significantly stronger in a dual-task situation (picture naming and arrow discrimination) than in simple naming. Thus, individual differences in maintaining attention on the production processes become especially apparent when a simultaneous second task also requires attentional resources.

The Importance of Sleep: Attentional Problems in School-Aged Children With Down Syndrome and Williams Syndrome

In typically developing (TD) children, sleep problems have been associated with day-time attentional difficulties. Children with developmental disabilities often suffer with sleep and attention problems, yet their relationship is poorly understood. The present study investigated this association in school-aged children with Down syndrome (DS) and Williams syndrome (WS). Actigraphy and pulse oximetry assessed sleep and sleep-disordered breathing respectively, and attention was tested using a novel visual Continuous Performance Task (CPT).Attentional deficits were evident in both disorder groups. In the TD group, higher scores on the CPT were related to better sleep quality, higher oxyhemoglobin saturation (SpO2), and fewer desaturation events. Sleep quality, duration, and SpO2 variables were not related to CPT performance for children with DS and WS.

The Association Between P3 Amplitude at Age 11 and Criminal Offending at Age 23

Reduced P3 amplitude to targets is an information-processing deficit associated with adult antisocial behavior and may reflect dysfunction of the temporal-parietal junction. This study aims to examine whether this deficit precedes criminal offending. From a birth cohort of 1,795 children, 73 individuals who become criminal offenders at age 23 and 123 noncriminal individuals were assessed on P3 amplitude. The two groups did not differ on gender, ethnicity, and social adversity. P3 amplitude was measured over the temporal-parietal junction during a visual continuous performance task at age 11, together with antisocial behavior. Criminal convictions were assessed at age 23. Reduced P3 amplitude at age 11 was associated with increased antisocial behavior at age 11. Criminal offenders showed significantly reduced P3 amplitudes to target stimuli compared to controls. Findings remained significant after controlling for antisocial behavior and hyperactivity at age 11 and alcoholism at age 23. P3 deficits at age 11 are associated with adult crime at age 23, suggesting that reduced P3 may be an early neurobiological marker for cognitive and affective processes subserved by the temporal-parietal junction that place a child at risk for adult crime.

Electrophysiological correlates of CU traits show abnormal regressive maturation in adolescents with conduct problems

Callous/unemotional (CU) temperament traits may denote a more severe form of conduct disorder (CD) and have been associated with abnormal cortical thinning. The present study investigated the maturational decline in N200 amplitude, and the association between N200 amplitude and callous/unemotional traits, in adolescents with CD. Twenty adolescent males (aged 10–18years old) with CD were age-matched to 27 clinical controls with Attention Deficit Hyperactivity Disorder (ADHD) and 30 non-clinical, typically developing controls. Participants completed a visual continuous performance task. As expected, N200 amplitude in response to background stimuli was inversely associated with age in controls (at frontal and temporal brain regions). Similar associations were seen in clinical controls. In contrast, the CD group showed a significant positive correlation between age and the right temporal N200 amplitude. Further, CU traits were positively correlated with N200 amplitude at midline frontal and temporal electrodes, even after covarying for age. These results highlight links between CU traits and abnormal neurodevelopment as indexed by N200 amplitude. This is in line with an impairment or delay in regressive maturational changes such as cortical thinning, as suggested by neuroimaging studies, which may underlie the persistence of certain psychopathic tendencies.

The Effect of Methylphenidate on Prefrontal Cognitive Functioning, Inattention, and Hyperactivity in Velocardiofacial Syndrome

Methylphenidate (MPH) is commonly used to treat attention-deficit/hyperactivity disorder (ADHD) in all children, including those with velocardiofacial syndrome (VCFS). Yet concerns have been raised regarding its safety and efficacy in VCFS. The goal of this study was to examine the safety and efficacy of MPH in children with VCFS. Thirty-four children and adolescents with VCFS and ADHD participated in a randomized, controlled trial with a 2:1 ratio of MPH versus placebo. All subjects underwent a cardiological evaluation before and after MPH administration. The primary outcome measure was prefrontal cognitive performance following a single dose of MPH or placebo. A follow-up assessment was conducted after a 6-month treatment with MPH. Compared with placebo, single MPH administration was associated with a more robust improvement in prefrontal cognitive performance, including achievements in the Hearts and Flowers executive function task and the visual continuous performance task. After 6 months of treatment, a 40% reduction in severity of ADHD symptoms was reported by parents on the Revised Conners Rating Scale. All subjects treated with MPH reported at least one side effect, but it did not necessitate discontinuation of treatment. MPH induced an increase in heart rate and blood pressure that was usually minor, but was clinically significant in two cases. No differences in response to MPH were observed between catechol-O-methyltransferase Met versus Val carriers. The use of MPH in children with VCFS appears to be effective and relatively safe. A comprehensive cardiovascular evaluation for children with VCFS before and during stimulant treatment is recommended.

Conjunctive Continuous Performance Task (CCPT)—A pure measure of sustained attention

Among the large variety of attentional tasks that have been used to study sustained attention, the Continuous Performance Task (CPT) is perhaps the most widely used. Despite substantial differences in task characteristics and demands, all CPT paradigms have been referred to as measures of sustained attention. In the present study we introduce a new variant of CPT, which minimizes perceptual and memory components while maximizing the sustained attention components of the task. In addition, we tested the contention that the ability to sustain attention should not be overly dependent on the specific stimuli and task-modality. To this end, we used a new visual Conjunctive CPT (CCPT) developed by Tsal, Shalev, & Mevorach (2005) and its auditory analogue. Using a Multi-Trait-Multi-Method (MTMM) analysis investigating reliability coefficients, convergent validity coefficients and divergent (discriminant) validity coefficients, we established that the new CCPT is a valid measure of sustained attention. In particular, high correlations were obtained between mean RT and SD-RT within each sensory modality. High correlations were also found between performance across sensory modalities (mean convergent validity: .71). Finally, low correlations (mean correlation of .18) were found between performance in the CCPT tasks and performance in two additional visuospatial attention tasks, which do not rely on sustained attention. These findings suggest that independent of sensory modality, the two CCPT tasks used here tap the same stable construct, namely, sustained attention. We conclude that when a measure of sustained attention is required, researchers should be aware of the caveats of standard CPT's and should be careful in selecting a proper task. Moreover, clinicians should appreciate that some CPT measures may reflect a combination of different cognitive operations rather than pure sustained attention.

Quantitative EEG Spectrum-weighted Frequency (Brain Rate) Distribution in Adults with ADHD.

The aim of this study is to explore the applicability of brain rate (fb) for the diagnosis of attention-deficit/hyperactivity disorder (ADHD), analyzing the spatial distribution of fb through analysis of its values in sagittal and lateral electrodes' positions, recorded in four conditions (eyes closed, eyes opened, visual continuous performance task and emotional continuous performance task). Sixty-seven adults diagnosed with ADHD according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and 50 age-matched control subjects participated in the study. The brain activity of the subjects was recorded by 19 channel quantitative electroencephalography (QEEG) system and fb was calculated with the fb software. Maximum values of fb for sagittal topography are obtained in central region and the minimum in frontal region, while lateral topography maximum values are found in the left and right sides and the minimum in midline region. A positive correlation between the fb values and the QEEG spectra subtypes was obtained, with lower values for normals, first and second subtype, and higher values for the third and fourth subtype. On the other hand, there was no correlation between behavioral symptoms and fb values. The applicability of an fb indicator in the diagnosis of ADHD is especially pronounced for the higher subtypes (ADHD III and IV), corresponding to heterogeneous and multifactorial character of this disorder.

Early Sensory Contributions to Contextual Encoding Deficits in Schizophrenia

The AX version of the visual continuous performance task (AX-CPT) is widely used for investigating visual working memory dysfunction in schizophrenia. Event-related potentials (ERP) provide an objective index of brain function and can be used to evaluate brain substrates underlying impaired cognition in schizophrenia. To assess the mechanisms that underlie visual working memory dysfunction in schizophrenia relative to impairment of early visual processing. Case-control study. Inpatient and outpatient facilities associated with the Nathan Kline Institute for Psychiatric Research. A total of 30 individuals with schizophrenia and 17 healthy comparison subjects. Three versions of the AX-CPT, with parametric variations in the proportions of trial types, were used to test performance and underlying neural activity during differential challenge situations. Contrast sensitivity measures were obtained from most subjects. Behavioral performance was assessed using d' context scores. Integrity of stimulus- and task-related cortical activation to both cue and probe stimuli was assessed using sensory (C1, P1, N1) and cognitive (N2, contingent negative variation [CNV]) ERP components. Early magnocellular/parvocellular function was assessed using contrast sensitivity. Linear regression and path analyses were used to assess relations between physiological and behavioral parameters. Patients showed reduced amplitude of both early sensory (P1, N1) and later cognitive (N2, CNV) ERP components. Deficits in sensory (N1) and cognitive (N2) component activation to cue stimuli contributed independently to impaired behavioral performance. In addition, sensory deficits predicted impaired cognitive ERP generation. Finally, deficits in performance correlated with impairments in contrast sensitivity to low, but not high, spatial frequency stimuli. Working memory deficits in schizophrenia have increasingly been attributed to impairments in stimulus encoding rather than to failures in memory retention. This study provides objective physiological support for encoding hypotheses. Further, deficits in sensory processing contribute significantly to impaired working memory performance, consistent with generalized neurochemical models of schizophrenia.