Visuoperceptual Functioning Research Articles

Visual pathways functioning in healthy pre-term adolescents: Sex but not gestational age effect.

Visuo-spatial and visuo-perceptual functioning is widely studied in preterm child and is strongly sex-specific. However, little to no data is available regarding male-female differences in preterm children and adolescents and about the interaction effect between sex and preterm birth. We studied 30 adolescents born preterm with normal cognitive and clinical neurological outcomes and 34 age-matched controls to investigate the interaction between levels of prematurity and sex in predicting the outcome of visual pathways functioning and to explore the relation between psychophysiological perceptive processing and neuropsychological performance. In the presence of prematurity, a greater female vulnerability in central visuo-cognitive processing (Form Coherence Task), but not in neuropsychological accuracy (Street Completion Test and Visual Object and Space Perception battery), seems to be more evident. Moreover, the psychophysical threshold is correlated to neuropsychological accuracy only in preterm females and not in males. These results support the idea that the male vulnerability in cognitive functioning described in prematurity-related developmental conditions is negligible during school age in children-adolescents with normal cognitive and clinical neurological outcomes. Visuo-perceptual functioning is widely studied in prematurity. However, few data are available about the interaction effect between sex and preterm birth in predicting visuo-perceptual functioning. We evidenced that in females born preterm with preserved cognitive abilities, the efficiency of the psychophysical visuo-perceptual threshold is reduced, but not related to the neuropsychological performance. Females may implement compensation strategies to achieve good performance regardless of the perceptual threshold. The present study addresses an important gap in literature, suggesting possible sex-specific outcomes in visuo-perceptual ability among preterm children and adolescents with normal intelligence and neurological outcomes.

Regional white matter hyperintensities in posterior cortical atrophy and logopenic progressive aphasia

AbstractBackgroundWhite matter hyperintensities (WMH) are markers of cerebral small vessel disease and have been associated with higher risk of typical amnestic Alzheimer’s disease (AD), however, little is known about the role of WMHs in atypical variants of AD. This study aimed to determine the frequency and distribution of WMH in two atypical variants of AD: logopenic progressive aphasia (LPA) and posterior cortical atrophy (PCA), and determine whether WMH are associated with demographic and clinical outcomes in these cohorts.MethodSeventy‐five LPA and 39 PCA patients were recruited by the Neurodegenerative Research Group and underwent two‐ dimensional fluid‐attenuated inversion recovery (FLAIR) MRI and Pittsburgh Compound B (PiB) PET. All patients were PiB‐positive. All FLAIR images were segmented using an in‐house software, then were manually edited by a trained imaging analyst. WMH volume was scaled by total intracranial volume to correct for differences in head size. Adjusted WMH burdens were compared between LPA and PCA, and associations were assessed between WMH burden and age, global PiB standard uptake value ratios (SUVRs), and clinical metrics, including tests of general cognitive impairment, executive function, naming, repetition, visuospatial and visuoperceptual function, and parkinsonism. Associations between WMHs and clinical scores were adjusted for age and brain volume to correct for atrophy.ResultTotal WMH burden was similar in PCA and LPA, however, regional differences were identified with PCA having greater subcortical WMH burden in right occipital, parietal, and temporal lobes compared to LPA, and LPA having greater WMH burden in left deep grey and white matter and greater subcortical burden in left parietal lobe compared to PCA. Total WMH burden was greater with older age in both groups but was not related to global PiB SUVR either globally or locally. Greater total WMH was associated with visuoperceptual performance in both cohorts after correcting for atrophy. When assessed regionally, visuoperceptual performance was associated with right subcortical occipital WMH across the cohort.ConclusionRegional distribution of WMHs differ across clinical variants of atypical AD and WMHs may impact clinical outcomes, although further work is needed to determine whether they reflect cerebrovascular disease or regionally specific neurodegenerative changes.

Relationship between visuoperceptual functions and parietal structural abnormalities in temporal lobe epilepsy.

Progressive gray matter volume reductions beyond the epileptogenic area has been described in temporal lobe epilepsy. There is less evidence regarding correlations between gray and white matter volume changepres and multi-domain cognitive performance in this setting. We aimed to investigate correlations between volume changes in parietal structures and visuospatial performance in temporal lobe epilepsy patients. we performed a cross-sectional study comparing global and regional brain volume data from 34 temporal lobe epilepsy patients and 30 healthy controls. 3D T1-weighted sequences were obtained on a 3.0 T magnet, and data were analyzed using age and sex-adjusted linear regression models. Global and regional brain volumes and cortical thickness in patients were correlated with standardized visual memory, visuoperceptual, visuospatial, and visuoconstructive parameters obtained in a per-protocol neuropsychological assessment. temporal lobe epilepsy patients had smaller volume fractions of the deep gray matter structures, putamen and nucleus accumbens, and larger cerebrospinal fluid volume fraction than controls. Correlations were found between: 1) visual memory and precuneus and inferior parietal cortical thickness; 2) visuoperceptual performance and precuneus and supramarginal white matter volumes; 3) visuospatial skills and precuneus, postcentral, and inferior and superior parietal white matter volumes; 4) visuoconstructive performance and inferior parietal white matter volume. Brain volume loss is widespread in temporal lobe epilepsy. Volumetric reductions in parietal lobe structures were associated with visuoperceptual cognitive performance.

Regional white matter hyperintensities in posterior cortical atrophy and logopenic progressive aphasia

White matter hyperintensities (WMH) are markers of cerebral small vessel disease and are associated with higher risk of typical amnestic Alzheimer's disease (tAD). Little is known about the frequency and distribution of WMH in atypical variants of AD, including logopenic progressive aphasia (LPA) and posterior cortical atrophy (PCA). We investigated WMHs in 75 LPA, 39 PCA, and 50 tAD patients and associations with age, beta-amyloid PET burden, and cognition. PCA had greater subcortical WMHs in right occipital, parietal, and temporal lobes compared to LPA, and greater parieto-occipital subcortical and occipital periventricular WMHs than tAD. LPA had greater subcortical WMHs in left parietal lobe and deep white matter WMHs than PCA, and greater fronto-occipital subcortical and occipital periventricular WMHs than tAD. Total WMH increased with increasing age but was not related to beta-amyloid burden. Greater WMH was associated with visuoperceptual performance in LPA and PCA after correcting for atrophy. WMH topography differs across AD variants. Further work is needed to determine whether they reflect cerebrovascular disease or regionally specific neurodegenerative changes.

The relation between visual orienting functions, daily visual behaviour and visuoperceptual performance in children with (suspected) cerebral visual impairment

BackgroundChildren with cerebral visual impairment (CVI) present heterogeneous visual orienting functions (VOF) and higher-order perception. Multiple assessment methods evaluate CVI, but the relations between them remain unclear. AimTo investigate the relations between VOF and (1) daily life behaviour and (2) visuoperceptual tests in children with (suspected) CVI. Methods and proceduresVOF were tested with a validated eye tracking-based paradigm. Visual perception was assessed using the children’s visual impairment test for 3- to 6-year olds (CVIT 3-6) and (retrospective) visuoperceptual dimension results. Caregivers completed the Flemish cerebral visual impairment questionnaire (FCVIQ) and an expert panel scored relations between VOF and the other methods. We compared experts’ survey responses with data-based results (linear mixed models and correlations). Outcomes and resultsFourty-four children (23 boys, 21 girls; median age = 7y11mo, SD = 2y7mo) participated. Twenty-one experts completed the survey. Slower VOF was significantly associated with (1) object and face processing impairments, (2) visual (dis)interest, (3) worse visual spatial perception (to local motion and form stimuli), and (4) worse CVIT 3-6 object and scene recognition (to cartoon stimuli). Conclusions and implicationsIntegration of VOF with existing visual assessments provides a better clinical picture of CVI and can prevent misdiagnosing children as inattentive, incapable, or unmotivated.

Sex influences on the neurocognitive outcome of preterm children.

This article presents a revision of the literature regarding the influence of sex differences on the recovery and long-term behavioral and cognitive outcomes of preterm children. After initial discussion of some methodological concerns, the literature regarding the concept of "male disadvantage," which is often used when talking about early neurological and psychomotor outcomes in preterm children, is presented. Subsequently, the literature data on sex-related differences in preterm children are discussed, focusing on their influence on the developmental pathways of cognition, language, executive function, behavior and affect, and response to rehabilitation therapies. Finally, evidence about brain structural and connectivity correlates of sex differences in the brain of preterm survivors is taken into account. Although visuo-spatial and visuo-perceptual functioning is widely studied in the preterm child and is strongly sex specific, little to no data are available regarding male-female differences in preterm children and the interaction effect between sex and preterm birth. For this reason, original data analyses of male-female differences in visuo-spatial performance from a small sample of preterm children are also presented.

Emerging Technological Trends and Human Cognition: A Review

Emerging technology, around which our world now revolves, has changed the way we live, work, communicate and entertain. Online transactions, seeking information, learning new skills and even finding love are just a click away. However, the pertinent question remains: Has technology changed the world for the better? Our generation has witnessed the most drastic jumps in technological advances which have not only changed the way we perceive the world, but also how our brains receive and process information. It has led to much attention on the longer term implications of the use of technology, and therefore its impacts on human brains and their socio-emotional, cognitive and physical development. Various emerging technological trends like Artificial Intelligence (AI), Internet of Things (IoT), quantum computing, upgraded wireless technologies, automation, assistance tools etc. are also serving as tools for the promotion of cognitive abilities such as memory, learning, perception, problem solving, concept formation, and information processing. Cognitive development of children growing up in this era of digital technology has been influenced by exposure of Internet-based devices such as computers, tablets and smart phones in educational settings. It has been proved that the use of technology increases the multitasking ability, enhances learning and cognitive processing, develops intellect, and improves verbal or visuo-perceptual performance, wellness and quick decision making skills. But on the other hand, it also increases narcissism, diminishes cognitive capacity and intelligence, impairs memory and concentration, results in delay in the development of effective strategies for organizing and remembering information. This review articles summarizes the possible impact of various technological exposures on socio-emotional development, physical development and human cognition such as memory, learning, problem solving, thinking, reasoning, retaining and recalling. Keywords : Human Cognition, Digital Technology, Information, Learning, Multitasking

Perceptual Function and Category-Selective Neural Organization in Children with Resections of Visual Cortex.

The consequences of cortical resection, a treatment for humans with pharmaco-resistant epilepsy, provide a unique opportunity to advance our understanding of the nature and extent of cortical (re)organization. Despite the importance of visual processing in daily life, the neural and perceptual sequellae of occipitotemporal resections remain largely unexplored. Using psychophysical and fMRI investigations, we compared the neural and visuoperceptual profiles of 10 children or adolescents following unilateral cortical resections and their age- and gender-matched controls. Dramatically, with the exception of two individuals, both of whom had relatively greater cortical alterations, all patients showed normal perceptual performance on tasks of intermediate- and high-level vision, including face and object recognition. Consistently, again with the exception of the same two individuals, both univariate and multivariate fMRI analyses revealed normal selectivity and representational structure of category-selective regions. Furthermore, the spatial organization of category-selective regions obeyed the typical medial-to-lateral topographic organization albeit unilaterally in the structurally preserved hemisphere rather than bilaterally. These findings offer novel insights into the malleability of cortex in the pediatric population and suggest that, although experience may be necessary for the emergence of neural category-selectivity, this emergence is not necessarily contingent on the integrity of particular cortical structures.SIGNIFICANCE STATEMENT One approach to reduce seizure activity in patients with pharmaco-resistant epilepsy involves the resection of the epileptogenic focus. The impact of these resections on the perceptual behaviors and organization of visual cortex remain largely unexplored. Here, we characterized the visuoperceptual and neural profiles of ventral visual cortex in a relatively large sample of post-resection pediatric patients. Two major findings emerged. First, most patients exhibited preserved visuoperceptual performance across a wide-range of visual behaviors. Second, normal topography, magnitude, and representational structure of category-selective organization were uncovered in the spared hemisphere. These comprehensive imaging and behavioral investigations uncovered novel evidence concerning the neural representations and visual functions in children who have undergone cortical resection, and have implications for cortical plasticity more generally.

Cortical thinning correlates of changes in visuospatial and visuoperceptual performance in Parkinson's disease: A 4-year follow-up

BackgroundGrowing evidence highlights the relevance of posterior cortically-based cognitive deficits in Parkinson's disease (PD) as possible biomarkers of the evolution to dementia. Cross-sectional correlational studies have established a relationship between the degree of atrophy in posterior brain regions and visuospatial and visuoperceptual (VS/VP) impairment. The aim of this study is to address the progressive cortical thinning correlates of VS/VP performance in PD. MethodsForty-four PD patients and 20 matched healthy subjects were included in this study and followed for 4 years. Tests used to assess VS/VP functions included were: Benton's Judgement of Line Orientation (JLOT), Facial Recognition (FRT), and Visual Form Discrimination (VFDT) Tests; Symbol Digit Modalities Test (SDMT); and the Pentagon Copying Test (PCT). Structural magnetic resonance imaging data and FreeSurfer were used to evaluate cortical thinning evolution. ResultsPD patients with normal cognition (PD-NC) and PD patients with mild cognitive impairment (PD-MCI) differed significantly in the progression of cortical thinning in posterior regions. In PD-MCI patients, the change in VS/VP functions assessed by PCT, JLOT, FRT, and SMDT correlated with the symmetrized percent change of cortical thinning of occipital, parietal, and temporal regions. In PD-NC patients, we also observed a correlation between changes in FRT and thinning in parieto-occipital regions. ConclusionIn this study, we establish the neuroanatomical substrate of progressive changes in VS/VP performance in PD patients with and without MCI. In agreement with cross-sectional data, VS/VP changes over time are related to cortical thinning in posterior regions.

Visuoperceptual processing in children with neurofibromatosis type 1: True deficit or artefact?

Impairments in visuoperceptual processing have long been considered a hallmark deficit of individuals with Neurofibromatosis type 1 (NF1). However, it is unclear which specific visuoperceptual subprocesses are impaired and whether impairments on these tasks really result from visuoperceptual impairments or rather from confounding factors like Executive Functioning (EF) impairments, lower intelligence (IQ) and/or co-occurring symptoms of Autism Spectrum Disorder (ASD). To answer these questions, we administered four visuoperceptual tasks and two control tasks in 39 children with NF1, 52 typically developing children and 52 children with ASD (8-18 years), all matched for age and gender. Furthermore, EF, IQ, and symptoms of ASD were assessed. Children with NF1 displayed intact visual form discrimination and intact information integration along the dorsal visual pathway. Moreover, their reduced performance on a task requiring integration of information along the ventral visual stream and their more detail-oriented processing style appeared to result from confounding EF impairments and not from visuoperceptual impairments per se. The co-occurring ASD symptoms and lower IQ of the children with NF1 did not impact substantially upon their visuoperceptual performance. These findings point to the large impact of EF impairments on the performance of visuoperceptual task and suggest that individuals with NF1 show intact visual form discrimination, intact visual integration, and typical visual processing style when potential confounding factors are controlled for. This may have large repercussions for the interpretation of other findings on visuoperceptual processing in individuals with NF1. © 2017 Wiley Periodicals, Inc.

A Racial/Ethnic Performance Disparity on the Facial Recognition Test

AbstractThe Facial Recognition Test is a widely used psychometric instrument for assessing visuoperceptual functioning. Only two prior studies have examined the effects of race/ethnicity on this test. Given that the United States has become more culturally diverse since the creation of the test, it is important to re-visit the effects of this demographic variable on performance. Participants were 75 males and 75 females between the ages of 18 and 43 years (M = 21.91, SD = 5.33). Racial/ethnic categories utilized by the U.S. Census Bureau were equally represented. No gender differences were observed. The race/ethnicity main effect was significant. The gender x race/ethnicity interaction was not significant. The data revealed a clear racial/ethnic performance disparity on the Facial Recognition Test.

Neuropsychological Outcomes in Extremely Preterm Preschoolers Exposed to Tiered Low Oxygen Targets: An Observational Study.

An observational study of neuropsychological outcomes at preschool age of tiered lowered oxygen (O2) saturation targets in extremely preterm neonates. We studied 111 three-year-olds born <28 weeks' gestational age. Fifty-nine participants born in 2009-2010 during a time-limited quality improvement initiative each received three-tiered stratification of oxygen rates (83-93% until age 32 weeks, 85-95% until age 35 weeks, and 95% after age 35 weeks), the TieredO2 group. Comparisons were made with 52 participants born in 2007-2008 when pre-initiative saturation targets were non-tiered at 89-100%, the Non-tieredO2 group. Neuropsychological domains included general intellectual, executive, attention, language, visuoperceptual, visual-motor, and fine and gross motor functioning. Descriptive and inferential analyses were conducted. Group comparisons were not statistically significant. Descriptively, the TieredO2 group had better general intellectual, executive function, visual-motor, and motor performance and the Non-tieredO2 group had better language performance. Cohen's d and confidence intervals around d were in similar direction and magnitude across measures. A large effect size was found for recall of digits-forward in participants born at 23 and 24 weeks' gestation, d=0.99 and 1.46, respectively. Better TieredO2 outcomes in all domains except language suggests that the tiered oxygen saturation target method is not harmful and merits further investigation through further studies. Benefit in auditory attention appeared greatest in those born at 23 and 24 weeks. Participants in the tiered oxygen saturation group also had fewer ventilation days and a lower incidence of bronchopulmonary dysplasia, perhaps explanatory for these neuropsychological outcomes at age 3.

Effects of transcranial direct current stimulation upon attention and visuoperceptual function in Lewy body dementia: a preliminary study.

Individuals with Lewy body dementia (LBD) typically exhibit impairments in attentional and executive function. Current pharmacological treatments have limited efficacy, with associated side effects. Transcranial direct current stimulation (tDCS) may represent an alternative treatment, as cognitive improvements have been demonstrated in healthy individuals. However, no studies to date have assessed the feasibility of tDCS in an LBD population. The aim of this preliminary study, therefore, was to assess the tolerability of tDCS, as well as its effects upon attentional and visuoperceptual performance, in LBD patients. Thirteen participants completed attentional (simple reaction time, choice reaction time, and digit vigilance) and forced-choice visuoperceptual (angle and motion perception) tasks before and after one 20-min session of active tDCS (0.08 mA/cm2). The anodal electrode was applied to the left dorsolateral prefrontal cortex and the cathodal electrode was applied to the right deltoid. Attentional (task accuracy and reaction time to correct answers) and visuoperceptual (task accuracy and difficulty) outcome measures were compared using paired t-tests. All participants tolerated stimulation and did not report any side effects during or immediately after stimulation. Post-stimulation improvements were observed in the choice reaction time (increased percentage of correct answers; p = 0.01) and digit vigilance (reduced mean reaction time to correct answers; p = 0.02) attention tasks. Visuoperceptual task performance did not improve (all p-values > 0.05). Attentional, but not visuoperceptual, improvements were observed following stimulation in LBD patients. Larger-scale, placebo-controlled trials are needed to confirm whether tDCS is a useful treatment option for attentional deficits in LBD.

Cognition in children with neurofibromatosis type 1: data from a population-based study.

This study aimed to investigate the core cognitive deficits in children with neurofibromatosis type 1 (NF1). The study recruited 49 children with NF1 (25 males, 24 females; mean age 11y 9mo [SD 3y 2mo]), 19 healthy siblings of children with NF1 (sibling comparisons; mean age 12y 7mo [SD 2y 7mo], 9 males, 10 females) and 29 healthy children from the community (community comparisons; mean age 11y [SD 2y 7mo], 12 males, 17 females). Participants completed a battery of cognitive tests including tests of intelligence, academic achievement, attention, visuoperceptual functioning, visual learning, executive functioning, and non-verbal working memory tests. Our study, using a population-based sample, confirmed previous findings from studies using variable sampling methods. Children with NF1 had significantly lower Full-scale IQs (p=0.04) and lower academic achievement (p=0.026-0.005) than their siblings. Compared with their siblings, they also had significantly poorer visuospatial processing (p=0.007), visual associate learning (p=0.014), non-verbal working memory (p=0.023), and executive function (p<0.001). Data from the community comparisons were not included because they were subject to significant selection bias. Population-based frequencies for cognitive deficits in children with NF1 are similar to the frequencies in non-population based samples. This study highlights the heterogeneous nature of cognitive problems in children with NF1 and the need for monitoring and support at school.

Facial emotion recognition in paranoid schizophrenia and autism spectrum disorder

Schizophrenia (SZ) and autism spectrum disorder (ASD) share deficits in emotion processing. In order to identify convergent and divergent mechanisms, we investigated facial emotion recognition in SZ, high-functioning ASD (HFASD), and typically developed controls (TD). Different degrees of task difficulty and emotion complexity (face, eyes; basic emotions, complex emotions) were used. Two Benton tests were implemented in order to elicit potentially confounding visuo-perceptual functioning and facial processing. Nineteen participants with paranoid SZ, 22 with HFASD and 20 TD were included, aged between 14 and 33years. Individuals with SZ were comparable to TD in all obtained emotion recognition measures, but showed reduced basic visuo-perceptual abilities. The HFASD group was impaired in the recognition of basic and complex emotions compared to both, SZ and TD. When facial identity recognition was adjusted for, group differences remained for the recognition of complex emotions only. Our results suggest that there is a SZ subgroup with predominantly paranoid symptoms that does not show problems in face processing and emotion recognition, but visuo-perceptual impairments. They also confirm the notion of a general facial and emotion recognition deficit in HFASD. No shared emotion recognition deficit was found for paranoid SZ and HFASD, emphasizing the differential cognitive underpinnings of both disorders.

Breaking the balance: Ocular BDNF‐injections induce visual asymmetry in pigeons

In pigeons, asymmetric photic stimulation around hatch induces functional visual asymmetries that are accompanied by left-right differences in tectal cell sizes. Different aspects of light-dependent neuronal differentiation are known to be mediated by the brain-derived neurotrophic factor (BDNF). Therefore, we investigated by means of single or triple BDNF- or saline-injections into the right eye of dark-incubated pigeon hatchlings if ocular BDNF enrichment mimics the effects of biased visual input. As adults, the birds were tested in a grit-grain discrimination task to estimate the degree and direction of visual lateralization followed by a morphometric analysis of retinal and tectal cells. The grit-grain discrimination task demonstrated that triple BDNF-injections enhanced visuoperceptual and visuomotor functioning of the left eye system. Morphometric analysis showed bilateral cell-type dependent effects within the optic tectum. While single-BDNF injections increased cell body sizes of calbindin-positive efferent neurons, triple-injections decreased cell sizes of parvalbumin-positive cells. Moreover, single BDNF-injections increased retinal cell sizes within the contralateral eye. Analysis of BDNF-induced intracellular signaling demonstrated enhanced downstream Ras activation for at least 24 h within both tectal halves whereas activity changes within the contralateral retina could not be detected. This points to primarily tectal effects of ocular BDNF. In sum, exogenous BDNF modulates the differentiation of retinotectal circuitries and dose-dependently shifts lateralized visuomotor processing towards the noninjected side. Since these effects are opposite to embryonic light stimulation, it is unlikely that the impact of light onto asymmetry formation is mediated by retinal BDNF.

Raven's Coloured Progressive Matrices as a measure of cognitive functioning in Cerebral Palsy

Cognitive dysfunction is frequent in Cerebral Palsy (CP). CP motor impairment and associated speech deficits often hinder cognitive assessment, with the result being that not all CP studies consider cognitive dysfunction. Raven's Coloured Progressive Matrices is a simple, rapid test which can be used in persons with severe motor impairment and speech limitations. We studied whether this test can offer a reliable measure of cognitive functioning in CP. Visuoperceptual, language, memory and frontal lobe functions were evaluated in 30 participants with severe motor impaired CP and a variety of speech difficulties. The relationship between Raven's Coloured Progressive Matrices and a variety of tests was analysed. Raven's Coloured Progressive Matrices performance was associated with visuoperceptual, language, visual and verbal memory but not with frontal functions. Receptive vocabulary and visuospatial measures were the best predictors of Raven's Coloured Progressive Matrices raw scores. Raven's Coloured Progressive Matrices is a fast, easy-to-administer test able to obtain a measure related with linguistic, visuoperceptual, and memory cognitive functioning in persons with CP despite their motor and speech disorders.

Mild traumatic brain injury induces prolonged visual processing deficits in children

Primary objective: To compare the sensitivity to simple and complex visual stimuli of children who have sustained a mild traumatic brain injury (mTBI) to that of matched non-injured children and to determine the evolution of visuo-perceptual performance over time.Research design: A prospective design was used to assess 18 children with mTBI and 18 matched healthy controls (8–16 years of age).Methods and procedures: Sensitivity to static and dynamic forms of simple (first-order) and complex (second-order) stimuli were assessed at 1, 4 and 12 weeks post-injury and at equivalent times for controls. Orientation and direction identification thresholds were measured for all participants for static and dynamic conditions, respectively. In addition, sensitivity to radial optic flow (inward vs outward), a complex motion stimulus, was assessed.Main outcomes and results: Thresholds measured from all complex stimuli were significantly affected for the mTBI children over time whereas no difference in threshold between groups across all testing conditions was found for simple, first-order information. Sensitivity to all complex stimuli was still affected 12 weeks after the injury.Conclusion: These findings suggest that injured children present selective processing deficits for higher-order information and that this deficit persists over relatively long periods. Such measures could be useful to assess children who have sustained mTBI and possibly contribute to identifying potential risks of returning these children to demanding physical activities.

Neuropsychological functioning of dementia patients with psychosis

The current research sought to test the hypothesis that psychotic symptoms in patients with dementia might be due to relatively greater executive control and visuoperceptual deficits. Twenty-four dementia patients with psychosis and 24 outpatients without psychosis diagnosed with either probable Alzheimer's disease (AD) or possible/probable Ischemic Vascular Dementia (IVD) were studied. Groups did not differ with respect to age, education, severity of dementia, or depression. Presence and severity of psychosis was measured with a modification of the Neuropsychiatric Inventory (NPI; Cummings, J. L., Mega, M., Gray, K., Rosenberg-Thompson, S., Carusi, D. A., & Gorbein, J. (1994). The neuropsychiatric inventory: Comprehensive assessment of psychopathology in dementia. Neurology, 44, 2308–2314). Between-group and regression analyses found a consistent relationship such that patients with psychosis obtained low scores on the Boston Revision Wechsler Memory Scale-Mental Control subtest (WMS-MC subtest), a test of executive control. On some analyses patients with psychosis also made more perceptual errors on tests of naming and obtained higher scores on tests of delayed recognition memory. However, the relationship between severity of psychosis and performance on visuoperceptual and memory measures was considerably less robust. These data suggest a strong relationship between severity of psychosis and poor performance on executive control. Less evidence was obtained to support our contention that psychotic symptoms in dementia may arise from an interaction of neuropsychological deficits involving greater impairment in executive and visuoperceptual functioning.

EEG spectral analysis of wakefulness and REM sleep in high functioning autistic spectrum disorders

Objective The aim of this study was to investigate the involvement of temporo-occipital regions in the pathophysiology of autistic spectrum disorders (ASD) by using REM sleep and waking EEG. Methods The EEG recordings of 9 persons with ASD and 8 control participants were recorded using a 12-electrode montage. Spectral analysis (0.75–19.75 Hz) was performed on EEG activity recorded upon two activated states: REM sleep and wakefulness. Results During REM sleep, persons with ASD showed a selective, significantly lower absolute beta (13.0–19.75 Hz) spectral amplitude over the primary (O 1, O 2) and associative (T 5, T 6) cortical visual areas compared to controls. Persons with ASD showed significantly higher absolute theta (4.0–7.75 Hz) spectral amplitude over the left frontal pole region (Fp1) compared to controls during evening wakefulness, but not during morning wakefulness. Significance The results of waking EEG are consistent with previously reported observations of neuropsychological signs of frontal atypicalities in ASD; results from REM sleep are the first EEG evidence to support the hypothesis of abnormal visuoperceptual functioning in ASD. Altogether, these results point toward atypical thalamo-cortical mechanisms subserving the neural processing of information in ASD.