Color discrimination in fixed saturation level of patients with acute traumatic injury.

Introduction: Traumatic brain injury (TBI) is an important public health concern and that may lead to severe neural sequels, such as color vision deficits. Methods: We evaluated the color vision of 10 TBI patients with normal cognitive function using a color discrimination test in a fixed saturation level. We also analyzed computerized tomography scans to identify the local of the brain damages. Results: Four TBI patients that had lesions in brain areas of the ventral visual streams, five TBI patients had lesions inferred in brain areas of the dorsal visual stream, and one TBI patient had lesion in the occipital area. All the patients had cognitive and color vision screened and they had characterized the chromatic discrimination at high and low saturation. All participants had no significant cognitive impairment in the moment of the color vision test. Additionally, they had perfect performance for discrimination of chromatic stimulus at high saturation and similar to controls (n = 37 age-matched participants). Three of four TBI patients with lesions in the ventral brain and one patient with lesion in the occipital area had impairment of the chromatic discrimination at low saturation. All TBI patients with lesions in the dorsal brain had performance similar or slightly worse than the controls. Conclusion: Chromatic discrimination at low saturation was associated to visual damage in the ventral region of the brain and is a potential tool for functional evaluation of brain damage in TBI patients.

Visuospatial processing and fine motor function among 7-years old Guadeloupe children pre- and postnatally exposed to the organochlorine pesticide chlordecone.

BACKGROUND: Chlordecone is an organochlorine that was largely used as an insecticide to control a species of root borers, the Banana weevil (Cosmopolites sordidus), in the French West Indies, Guadeloupe and Martinique. Its molecules have been shown to be very persistent in the environment as pollution in soils leading to contamination of water sources and foodstuff will last for several decades. Our team previously reported associations between prenatal chlordecone exposure and poorer fine motor development at two points in time during infancy. OBJECTIVE: To document whether effects of prenatal exposure to chlordecone previously reported persists until middle-childhood, and whether deleterious effects are observed in domain of visual processing. Associations with postnatal exposure and sex-specific vulnerabilities were also investigated. METHODS: We examined 410 children from the TIMOUN mother-child cohort in Guadeloupe at 7 years of age. Concentrations of chlordecone and other environmental contaminants were measured in cord- and children's blood at age 7 years. Fine motor function was assessed using the Bruininks Oseretsky Test of Motor Proficiency Second Edition (BOT-2). The Computerized Adaptive Testing System (CATSYS) was used to evaluated postural hand tremor, while non-verbal visuospatial processing was measured using the Stanford Binet copying (S-B copying) test. We used adjusted multiple linear regressions to test the relationship between children's scores and both continuous and categorical blood chlordecone concentrations, adding child sex as a moderator in continuous models. RESULTS: Cord chlordecone concentrations are associated with a regular frequency pattern of subtle hand tremors in both hands, and not related to visual processing and fine motor precision. Chlordecone concentrations in blood sample collected at testing time are associated with poorer visual processing when copying geometric figures, but not significantly related to poorer fine movement precision in tasks requiring pencil, scissors and paper. No sex-specific vulnerability was reported in any of the outcomes. CONCLUSIONS: These results at school aged expand those previously reported in the same cohort during infancy at age 7- and 18 months, and corroborate the negative effects of chlordecone exposure on fine motor function in absence of intoxication. Our results support the need to continue public health efforts aimed at reducing exposure especially among women of child bearing age and young children.

Relation between smoking and visual processing in bipolar disorder.

Background: Although some studies have shown impairments in patients with bipolar disorder (BPD) and in smokers, it is unclear how these two factors work together. Our premise was that chronic smoking affects color discrimination and this is more pronounced in BPD. Objective: Our main purpose was to investigate the influence of smoking and BPD on color discrimination. Methods: Twenty-three smokers and 23 BPD smokers patients, aged 25-45 years old, participated in this study. Color vision testing was performed using the Trivector subtest of the Cambridge Colour Test. Participants' task was to indicate the pseudoisochromatic stimulus in four directions (up, down, right, and left). Results: It was shown that the smokers had better color vision than BPD smokers for the Protan (p < .001), Deutan (p < .001), and Tritan (p < .001) (red, green, and blue, respectively) axes. Thus, the BPD smokers' group had greater difficulty distinguishing the chromaticity variations (i.e., presented diffuse color vision impairments and not specific to any axis). Conclusions: The present study highlights a possible relationship between smoking and BPD in color discrimination. This highlights the importance of understanding the diffuse effects of this relationship.

Nicotine gum enhances visual processing in healthy nonsmokers.

OBJECTIVE: The main purpose of this study was to investigate the isolated effects of nicotine on visual processing, namely contrast processing. METHODS: Thirteen participants, aged 18-40 years, were enrolled in this double blind, randomized and pilot controlled trial involving nicotine gum administration (placebo, 2-mg and 4-mg doses). The participants' instruction was to detect the location of vertical gratings (0.2; 1.0; 3.3; 5.7; 8.8; 13.2 and 15.9 cycles per degree) when it was presented either left or right on the monitor screen. A repeated multivariate analysis of variance was conducted to analyse the results for the visual processing tasks. Bayesian analyses were also carried out considering maximum robustness to avoid bias. RESULTS: The findings that nicotine gum administration resulted in better contrast discrimination when compared to placebo gum (p < .001). More specifically, the 4-mg resulted in better visual sensitivity when compared to the 2-mg (p < .01) and the placebo (p < .001) gum. Demographic data were not related to the outcomes. CONCLUSIONS: These data bring the need for support the findings. If proved, it is possible that nicotine, in small doses, can have a potential therapeutic use for those populations with low vision. TRIAL REGISTRATION NUMBER: RBR-46tjy3.

Effects of Nicotine Gum Administration on Vision (ENIGMA-Vis): Study Protocol of a Double-Blind, Randomized, and Controlled Clinical Trial.

Studies reported that tobacco addiction was related to visual impairments, but one unresolved issue is whether the impairments are related to the many compounds existing in the cigarettes or to the effects of nicotine. On the other hand, nicotine gum can be used as replacement therapy or as a neuroprotective agent for some diseases. The main purpose of this controlled trial is to investigate the effects of nicotine gum on vision. The ENIGMA-Vis trial aims to compare two dosages of nicotine gum (2 and 4 mg) and a placebo gum in a randomized, double-blind, placebo-controlled trial of 100 participants to be allocated into a single group assignment of repeated measures (two studies; N = 50 for each one). Eligibility criteria are healthy non-smokers not diagnosed with substance abuse and without an acute or chronic medical condition. Intervention will last three sessions for each participant with a window frame of 1 week per session. Study outcomes are (1) short-term effects of nicotine gum on contrast sensitivity; (2) short-term effects of nicotine gum on chromatic contrast discrimination; and (3) whether demographics, body mass index, or serum cotinine predicts response of visual processing. This study addresses an important gap in the effects of nicotine on vision. One of the main takeaways of this study is to understand the effects of nicotine on contrast sensitivity and chromatic contrast discrimination. This information will provide a further understanding of how nicotine interacts with early visual processes and help determine how the different components present during smoking can affect vision. Clinical Trial Registration Number: RBR-46tjy3.

Schizophrenia patients using atypical medication perform better in visual tasks than patients using typical medication.

Schizophrenia (SCZ) patients show deficits in many domains, including cognition and perception. However, results are often mixed. One reason for mixed results may be differences in medication. Very little is known about the role of medication in visual processing. Here, we investigated the effects of typical vs. atypical medication on contrast sensitivity (spatial frequencies ranging from 0.2 to 20 cycles per degree), vernier acuity, and visual backward masking. From a large pool of patients, we selected 50 patients (Study 1, conducted in Brazil) and 97 patients (Study 2, conducted in Georgia) taking either only typical or atypical medication. Patients with atypical medication performed significantly better than patients with typical medication for contrast sensitivity, vernier duration, and backward masking. As a secondary result, we found similar, but not significant, trends for the cognitive tasks (Stroop, Flanker, Trail-Making Test-B, Wisconsin Card Sorting Test and Continuous Performance Test) in the same patients. No correlations were found between demographics, psychopathology, chlorpromazine equivalents and visual processing. A conclusion of our study is that one needs to be careful comparing studies when medication is not comparable.

The subtleties of cognitive decline in multiple sclerosis: an exploratory study using hierarchichal cluster analysis of CANTAB results.

BACKGROUND: It is essential to investigate cognitive deficits in multiple sclerosis (MS) to develop evidence-based cognitive rehabilitation strategies. Here we refined cognitive decline assessment using the automated tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) and hierarchical cluster analysis. METHODS: We searched for groups of distinct cognitive profiles in 35 relapsing-remitting MS outpatients and 32 healthy controls. All individuals participated in an automated assessment (CANTAB) and in a pencil and paper general neuropsychological evaluation. RESULTS: Hierarchical cluster analysis of the CANTAB results revealed two distinct groups of patients based mainly on the Simple Reaction Time (RTI) and on the Mean Latency of Rapid Visual Processing (RVP). The general neuropsychological assessment did not show any statistically significant differences between the cluster groups. Compared to the healthy control group, all MS outpatients had lower scores for RTI, RVP, paired associate learning, and delayed matching to sample. We also analyzed the associations between CANTAB results and age, education, sex, pharmacological treatment, physical activity, employment status, and the Expanded Disability Status Scale (EDSS). Although limited by the small number of observations, our findings suggest a weak correlation between performance on the CANTAB and age, education, and EDSS scores. CONCLUSIONS: We suggest that the use of selected large-scale automated visuospatial tests from the CANTAB in combination with multivariate statistical analyses may reveal subtle and earlier changes in information processing speed and cognition. This may expand our ability to define the limits between normal and impaired cognition in patients with Multiple Sclerosis.

Visual Processing during Short-Term Memory Binding in Mild Alzheimer's Disease.

Patients with Alzheimer's disease (AD) typically present with attentional and oculomotor abnormalities that can have an impact on visual processing and associated cognitive functions. Over the last few years, we have witnessed a shift toward the analyses of eye movement behaviors as a means to further our understanding of the pathophysiology of common disorders such as AD. However, little work has been done to unveil the link between eye moment abnormalities and poor performance on cognitive tasks known to be markers for AD patients, such as the short-term memory-binding task. We analyzed eye movement fixation behaviors of thirteen healthy older adults (Controls) and thirteen patients with probable mild AD while they performed the visual short-term memory binding task. The short-term memory binding task asks participants to detect changes across two consecutive arrays of two bicolored object whose features (i.e., colors) have to be remembered separately (i.e., Unbound Colors), or combined within integrated objects (i.e., Bound Colors). Patients with mild AD showed the well-known pattern of selective memory binding impairments. This was accompanied by significant impairments in their eye movements only when they processed Bound Colors. Patients with mild AD remarkably decreased their mean gaze duration during the encoding of color-color bindings. These findings open new windows of research into the pathophysiological mechanisms of memory deficits in AD patients and the link between its phenotypic expressions (i.e., oculomotor and cognitive disorders). We discuss these findings considering current trends regarding clinical assessment, neural correlates, and potential avenues for robust biomarkers.

Tareas de búsqueda visual: modelos, bases neurológicas, utilidad y prospectiva / Visual Search Tasks: Models, Neurological Bases, Usefulness and Prospective

Resumen Las tareas de búsqueda visual, fundamentadas en el reconocimiento de una forma, característica o estímulo visual en particular, han contribuido al desarrollo de la investigación en psicología. A partir de una revisión narrativa sobre las maneras de implementar dichas tareas, y haciendo un cotejo de su uso como elemento de instrumentalización de la investigación, se encuentra que diferentes modelos paradigmáticos convergen para el entendimiento de diversos procesos psicológicos. Se hace manifiesto que las tareas de búsqueda visual, no solo pueden implicar registros de actividad oculo-motora, sino que además operacionalizan sistemas de modulación de procesos atencionales y perceptuales, los cuales esencialmente están alineados con recompensas de tipo exógeno. Dichas recompensas, sumadas a procesos de adaptación al entorno, se integran para reivindicar la noción percepción para la acción.

Abstract Visual search tasks, that are based on the recognition of either a characteristic or an specific visual stimulus, have contributed to the development of psychological research. By doing a narrative review of the ways to carry out these tasks, and considering their usages as factors that instrumentalise research, several paradigms emerge so as to understand multiple psychological processes. It has been manifested that visual search tasks can imply eye-movement recordings as well as operationalizing systems connected to the modulation of both attentional and perceptual processes, which are essentially aligned with exogenous rewards. These rewards, added to some processes related to the adaptation to the environment, are incorporated in such a way that the notion of perception to action is enforced.

Chronic Organic Solvent Exposure Changes Visual Tracking in Men and Women.

Organic solvents can change CNS sensory and motor function. Eye-movement analyses can be important tools when investigating the neurotoxic changes that result from chronic organic solvent exposure. The current research measured the eye-movement patterns of men and women with and without histories of chronic organic solvent exposure. A total of 44 volunteers between 18 and 41 years old participated in this study; 22 were men (11 exposed and 11 controls), and 22 were women (11 exposed and 11 controls). Eye movement was evaluated using a 250-Hz High-Speed Video Eye Tracker Toolbox (Cambridge Research Systems) via an image of a maze. Specific body indices of exposed and non-exposed men and women were measured with an Inbody 720 to determine whether the differences in eye-movement patterns were associated with body composition. The data were analyzed using IBM SPSS Statistics version 20.0.0. The results indicated that exposed adults showed significantly more fixations (t = 3.82; p = 0.001; r = 0.51) and longer fixations (t = 4.27; p = 0.001, r = 0.54) than their non-exposed counterparts. Comparisons within men (e.g., exposed and non-exposed) showed significant differences in the number of fixations (t = 2.21; p = 0.04; r = 0.20) and duration of fixations (t = 3.29; p = 0.001; r = 0.35). The same was true for exposed vs. non-exposed women, who showed significant differences in the number of fixations (t = 3.10; p = 0.001; r = 0.32) and fixation durations (t = 2.76; p = 0.01; r = 0.28). However, the results did not show significant differences between exposed women and men in the number and duration of fixations. No correlations were found between eye-movement pattern and body composition measures (p > 0.05). These results suggest that chronic organic solvent exposure affects eye movements, regardless of sex and body composition, and that eye tracking contributes to the investigation of the visual information processing disorders acquired by workers exposed to organic solvents.

Long-range correlations and patterns of recurrence in children and adults' attention to hierarchical displays.

In order to make sense of a scene, a person must pay attention to several levels of nested order, ranging from the most differentiated details of the display to the integrated whole. In adults, research shows that the processes of integration and differentiation have the signature of self-organization. Does the same hold for children? The current study addresses this question with children between 6 and 9 years of age, using two tasks that require attention to hierarchical displays. A group of adults were tested as well, for control purposes. To get at the question of self-organization, reaction times were submitted to a detrended fluctuation analysis and a recurrence quantification analysis. H exponents show a long-range correlations (1/f noise), and recurrence measures (percent determinism, maximum line, entropy, and trend), show a deterministic structure of variability being characteristic of self-organizing systems. Findings are discussed in terms of organism-environment coupling that gives rise to fluid attention to hierarchical displays.

Três hipóteses sobre a natureza das tarefas de nomeação seriada rápida / Three hypotheses on the nature of rapid automatized naming tasks

O presente estudo investigou a natureza das tarefas de nomeação seriada rápida, considerando três hipóteses sobre o que elas representariam: (1) medidas da recuperação de códigos fonológicos da memória de longo prazo; (2) medidas da velocidade de processamento geral; e (3) medidas de processos relacionados ao reconhecimento de padrões visuais. Participaram da pesquisa 174 crianças brasileiras cursando o 5º ano do Ensino Fundamental em escolas particulares. Análises fatoriais confirmatórias indicaram que nenhuma das três hipóteses se mostrou consistente com os dados. Porém, em um modelo de regressão estrutural construído para avaliar a contribuição desses fatores para a nomeação seriada rápida, o único que contribuiu significativamente foi o fator 'velocidade de processamento geral'.(AU)

The present study aimed to investigate the nature of rapid automatized naming tasks, considering three hypotheses about what they represent: (1) measures of retrieval of phonological codes from a long-term store; (2) measures of general processing speed; and (3) measures of visual pattern recognition processes. The participants were 174 children from the 5th grade of Brazilian private schools. Confirmatory factor analyses indicated that none of the hypotheses were consistent with the data. However, in a structural regression model the factor 'general processing speed' was the only one that contributed significantly to rapid automatized naming.(AU)

Três hipóteses sobre a natureza das tarefas de nomeação seriada rápida / Three hypotheses on the nature of rapid automatized naming tasks

O presente estudo investigou a natureza das tarefas de nomeação seriada rápida, considerando três hipóteses sobre o que elas representariam: (1) medidas da recuperação de códigos fonológicos da memória de longo prazo; (2) medidas da velocidade de processamento geral; e (3) medidas de processos relacionados ao reconhecimento de padrões visuais. Participaram da pesquisa 174 crianças brasileiras cursando o 5º ano do Ensino Fundamental em escolas particulares. Análises fatoriais confirmatórias indicaram que nenhuma das três hipóteses se mostrou consistente com os dados. Porém, em um modelo de regressão estrutural construído para avaliar a contribuição desses fatores para a nomeação seriada rápida, o único que contribuiu significativamente foi o fator 'velocidade de processamento geral'...

The present study aimed to investigate the nature of rapid automatized naming tasks, considering three hypotheses about what they represent: (1) measures of retrieval of phonological codes from a long-term store; (2) measures of general processing speed; and (3) measures of visual pattern recognition processes. The participants were 174 children from the 5th grade of Brazilian private schools. Confirmatory factor analyses indicated that none of the hypotheses were consistent with the data. However, in a structural regression model the factor 'general processing speed' was the only one that contributed significantly to rapid automatized naming...

The phonological and visual basis of developmental dyslexia in Brazilian Portuguese reading children.

Evidence from opaque languages suggests that visual attention processing abilities in addition to phonological skills may act as cognitive underpinnings of developmental dyslexia. We explored the role of these two cognitive abilities on reading fluency in Brazilian Portuguese, a more transparent orthography than French or English. Sixty-six children with developmental dyslexia and normal Brazilian Portuguese children participated. They were administered three tasks of phonological skills (phoneme identification, phoneme, and syllable blending) and three visual tasks (a letter global report task and two non-verbal tasks of visual closure and visual constancy). Results show that Brazilian Portuguese children with developmental dyslexia are impaired not only in phonological processing but further in visual processing. The phonological and visual processing abilities significantly and independently contribute to reading fluency in the whole population. Last, different cognitively homogeneous subtypes can be identified in the Brazilian Portuguese population of children with developmental dyslexia. Two subsets of children with developmental dyslexia were identified as having a single cognitive disorder, phonological or visual; another group exhibited a double deficit and a few children showed no visual or phonological disorder. Thus the current findings extend previous data from more opaque orthographies as French and English, in showing the importance of investigating visual processing skills in addition to phonological skills in children with developmental dyslexia whatever their language orthography transparency.

Analysis of psychometric properties of the cube test to evaluate visuospatial reasoning / Análise das propriedades psicométricas do teste dos cubos: para a avaliação do raciocínio visuoespacial

The objective of the present research was to contribute with new information regarding the validity evidence of the Cube Test. More specifically, psychometric properties of the items were analyzed through the Item Response Theory (IRT) and the test structure was analyzed using Confirmatory Factor Analysis (CFA). The sample was composed of 684 subjects, with a mean age of 21.3 years (SD = 5.94) and 50.3% were female. Results showed that IRT analyses confirm the adjustment of the items to the model, whereas the CFA suggested that a two-factor model was the most adequate. The findings, besides offering favorable results about the instrument, supported the validity evidence present in the Cube Test manual. (AU)

O objetivo da pesquisa foi contribuir com novas informações acerca das evidências de validade do Teste dos Cubos. Mais especificamente, analisaram-se as propriedades psicométricas dos itens por meio da Teoria de Resposta ao Item, e a estrutura do teste utilizando a Análise Fatorial Confirmatória. A amostra foi composta por 684 sujeitos, com idade média de 21,3 anos (DP=5,94), sendo 50,3% feminino. Nos resultados, as análises realizadas pela Teoria de Resposta ao Item corroboraram o ajuste dos itens ao modelo, enquanto a Análise Fatorial Confirmatória apontou o modelo com dois fatores como sendo o mais adequado. Os dados encontrados, além de oferecerem resultados favoráveis sobre o instrumento, sustentam as evidências de validade contidas no manual do Teste dos Cubos. (AU)

Procesamiento cortical de la visión: interacción de subsistemas parietales / Cortical processing of vision: parietal subsystems interaction

El procesamiento visual en el contexto de la neuropsicología exige la articulación de distintos niveles de análisis. Esto hace que el estudio de la visión se encuentre permeado por el avance en distintas disciplinas lo cual plantea como reto a la neuropsicología la construcción de un marco conceptual y de organización cerebral que permita la articulación de los vastos y distintos conocimientos que en la actualidad se tienen sobre el tema. Por tal motivo el presente artículo tiene como objetivo revisar los aportes de los principales modelos dicotómicos del procesamiento visual empleados en neuropsicología para detenernos con mayor detalle en la participación del Lóbulo Parietal Posterior y los retos que plantea a dichos modelos.

Visual processing requires, from a neuropsychological view, the integration of different analysis levels. This makes visual studies dependent on the advances produced by different scientific disciplines, leading into an increasing and comprehensive conceptual demand as well as more consistent brain functioning models. Thus, the aim of this article is to review the most outstanding dichotomic visual processing models used in neuropsychology, so as to painstakingly analyze the role of the Posterior Parietal Lobe and the risks taken by those different models.

Produção e compreensão do texto escrito: Um estudo junto a surdos universitários / Production and comprehension of written texts: A study of deaf university students

Em Fávero e Pimenta (2006), apontou-se que a dificuldade dos surdos na compreensão de problemas escritos de matemática relaciona-se ao uso inadequado da LIBRAS pelos profissionais da instituição escolar, como instrumento para a organização de significados semióticos e aquisição deconhecimentos. Com o intuito de estudar o significado das irregularidades apontadas na literatura arespeito da produção escrita dos surdos, analisamos a produção de 6 surdos escolarizados,5 universitários e 1 secundarista, entre 17 e 29 anos, 4 do sexo masculino e 2 do feminino, em resposta a um protocolo sobre a sua compreensão de um texto jornalístico e sobre sua concepção arespeito de suas competências e dificuldades no que diz respeito à produção e compreensão textual.Evidenciou-se que: os participantes desvalorizam suas próprias competências de produção ecompreensão textual; apresentam uma adequada compreensão do texto; utilizam o processamento visual na escrita. Reitera-se a defesa da língua de sinais como língua materna dos surdos e anecessidade de se considerar o processamento visual e o desenvolvimento da consciência sintática emorfossintática, na aquisição da segunda língua. Para tanto, defende-se a importância da pesquisa,tendo por método de investigação, o próprio procedimento de intervenção psicopedagógica, o quesignifica considerar a atividade mediada.

Fávero and Pimenta (2006) demonstrated that the difficulties that deaf individuals experience incomprehending written mathematical problems is related to teaching professionals inadequate use of Brazilian Sign Language (LIBRAS) as an instrument for knowledge acquisition and for the organisation of symbolic meaning. In order to understand the irregularities observed in the literature regarding written production by deaf individuals, research was carried out involving six deaf subject saged between 17 and 29 (four male and two female), of which five were college students and one wasin secondary school. Subjects responded to a series of questions regarding comprehension of a newspaper article and evaluation of their own strengths and weaknesses in relation to textual production and comprehension. It was found that the subjects undervalued their textual production and comprehension skills, showed adequate textual comprehension and used visual processing in writing. Thus, the defence of sign language as the native language of deaf individuals is reiterated asis the need to take into account both visual processing and the development of syntactic and morphosyntactic awareness in the acquisition of a second language. We advocate further research which takes mediated activity into account, adopting the psycho-pedagogical intervention it self as the study method.