Contrast sensitivity function of sine-wave gratings in children with acute malnutrition.

Santos, Natanael Antônio dos; Alencar, Caroline Costa Gomes; Dias, Yuri Henrique Nunes

doi:10.3922/j.psns.2009.1.03

Cited by 7 publications

(9 citation statements)

References 33 publications

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“…Dos Santos et al (2009) studied the effect of acute undernutrition on CS to Cartesian linear gratings and found a general diminishment of CS to all of the tested spatial frequencies in acute undernourished children. These results imply that acute undernutrition interferes with the visual pathways or areas that process Cartesian or linear gratings.…”

Section: Discussionmentioning

confidence: 99%

“…Early undernutrition occurs when the nutritional deficit lasts at least 6 months, until the age of 2 (i.e., during the critical period of development of the central nervous system, including the visual system). Dos Santos et al (2009) studied the effect of acute undernutrition on CS to Cartesian linear gratings and found a general diminishment of CS to all of the tested spatial frequencies in acute undernourished children. These results imply that acute undernutrition interferes with the visual pathways or areas that process Cartesian or linear gratings.…”

Section: Discussionmentioning

confidence: 99%

“…Low spatial frequencies represent global information about shape, such as general orientation and proportions. Dos Santos, Alencar, and Dias (2009) measured CS to stimuli in Cartesian coordinates in eight children, aged 7 to 9 years, with acute undernutrition. They found that acute undernourished children were 34%, 27%, 50%, and 36% less sensitive to the detection of .25, 1.0, 2.0, and 8.0 cycles per degree (cpd) spatial frequencies, respectively.…”

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confidence: 99%

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Acute undernutrition reduces polar visual contrast sensitivity in children.

Alencar¹,

Garcia²,

Gomes³

et al. 2015

Psychology & Neuroscience

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The objective of the present study was to examine the impact of acute undernutrition on polar visual contrast sensitivity (CS) in children. Undernutrition is a nutritional inadequacy that impairs many cognitive functions, including visual perception. Acute undernutrition refers to a current nutritional inadequacy that is related to low body weight according to height and age. We measured polar visual CS in 30 children of both sexes, aged 8 to 10 years. Fifteen eutrophic children constituted the control group (CG), and 15 acute undernourished children constituted the experimental group (EG). The children’s nutritional status was classified according to Waterloo’s anthropometric parameters and confirmed by records from the State Health Care System. Contrast sensitivity was measured using a 2-alternative forced-choice psychophysical method at a distance of 150 cm from the stimuli, binocularly, with a mean luminance of 40.1 cd/m2. One-way analysis of variance was applied, revealing significant differences between groups (F4,145 = 11.25, p < .05). Fisher’s least significant difference analysis revealed significant differences between groups at spatial frequencies of .25, 1.0, and 2.0 cycles per degree (cpd; p < .05). The CG was 33%, 53%, and 28% more sensitive than the EG in the detection of the .25, 1.0, and 2.0 cpd spatial frequencies, respectively. These results suggest that acute undernutrition reduces polar CS function in children. Therefore, acute undernutrition, which is known to affect primary visual cortical areas, may also affect higher visual cortical areas, such as V4 and the inferotemporal cortex.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Acute undernutrition reduces polar visual contrast sensitivity in children.

Alencar¹,

Garcia²,

Gomes³

et al. 2015

Psychology & Neuroscience

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“…The present study was based on the hypothesis that most diseases that change or affect the nervous system, including epilepsy, cause structural, functional, and behavioral changes in humans (Hilton et al, 2002). Consistent with this hypothesis, visual neuroscience research uses visual CS to evaluate and diagnose changes in optic and neural structures related to diseases that are not directly related to visual changes, such as depression (Wesner & Tan, 2006), schizophrenia (Slaghuis & Thompson, 2003), and malnutrition (Santos, Alencar, & Dias, 2009; Santos & Alencar, 2010), among others.…”

Section: Discussionmentioning

confidence: 99%

Visual contrast sensitivity in tonic-clonic epileptic patients.

Bezerra¹,

Alencar²,

Mousinho³

et al. 2011

Psychology & Neuroscience

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We measured the effects of epilepsy on visual contrast sensitivity to linear and vertical sine-wave gratings. Sixteen female adults, aged 21 to 50 years, comprised the sample in this study, including eight adults with generalized tonic-clonic seizure-type epilepsy and eight age-matched controls without epilepsy. Contrast threshold was measured using a temporal two-alternative forced-choice binocular psychophysical method at a distance of 150 cm from the stimuli, with a mean luminance of 40.1 cd/m 2 . A one-way analysis of variance (ANOVA) applied to the linear contrast threshold showed significant differences between groups (F[3,188] = 14.829; p < .05). Adults with epilepsy had higher contrast thresholds (1.45, 1.04, and 1.18 times for frequencies of 0.25, 2.0, and 8.0 cycles per degree of visual angle, respectively). The Tukey Honestly Significant Difference post hoc test showed significant differences (p < .05) for all of the tested spatial frequencies. The largest difference between groups was in the lowest spatial frequency. Therefore, epilepsy may cause more damage to the neural pathways that process low spatial frequencies. However, epilepsy probably alters both the magnocellular visual pathway, which processes low spatial frequencies, and the parvocellular visual pathway, which processes high spatial frequencies. The experimental group had lower visual contrast sensitivity to all tested spatial frequencies.

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“…Além de fazer uma completa descrição do processamento visual espacial, a FSC é sensível a mudanças no decorrer do desenvolvimento e envelhecimento do ser humano. Ou seja, ela é útil no estudo do desenvolvimento e envelhecimento do sistema visual (Mestre e Blin, 1990;França, Santos & Lacerda, 2008; (Kiss et al 2010), transtornos de humor (Colomb et al, 2009;Szabó et al, 2004), epilepsia (Bezerra et al, 2011), desnutrição (Santos, Alencar & Dias 2009, Santos & Alencar, 2010, dentre outras. Uma vez que essas patologias afetam sistemas de neurotransmissão envolvidos também no processamento visual, tais como GABA, dopamina e glutamato, pode-se utilizar a FSC para avaliar a fisiopatologia desses transtornos e sua possível recuperação.…”

Section: Visualunclassified

Processamento visual de contraste em pacientes com depressão maior

Lacerda¹

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The present study aimed to investigate potential changes in visual perception related to major depression. Then, we measure of contrast sensitivity (CS), one of the most used tools to study the humans visual system. The CS has established itself as one tool that allows to study and identify how certain diseases affect the vision and the central nervous system. The study included 33 volunteers aged between 19 and 37 years and they are normal or corrected visual acuity. 11 were diagnosed with major depressive disorder according to DSM-IV and were treated with antidepressants (Depression Group-DG). The other 22 were free of neuropsychiatric disease and were in good health (Control Group-CG). The CS was measured using the psychophysical method of forced choice between two temporal alternatives (2AF). Were tested linear spatial frequencies of 0.5, 2.5, 10 and 20 cycles per degree of visual angle (cpd) and the angular frequencies of 2, 4, 24, 48 and 96 cycles/360º. The stimuli were circular and were presented on a video monitor LG 19-inch RGB (screen resolution of 1024 x 768 pixels at 75 Hz) connected to a microcomputer and a BITS + + (Cambridge Research Systems). The average luminance of the display was 41.05 cd / m² measured by a photometer ColorCal (Cambridge Research Systems). The measurements were performed at a distance of 300 cm from the monitor screen. The stimuli were displayed in successive pairs, with a frequency tested (linear or angular) and the other was a gray circle with uniform luminance. Participants were instructed to press the left mouse's button when the test stimulus was presented first, and the right button when the stimulus was presented second. The results showed an interaction effect for the linear spatial frequency [F (3, 93) = 6.0814, p = 0.0008], the test post-hoc Newmann Kels showed significant difference in frequency of 0.5 cpd. The results for the angular frequencies showed a marginally significant effect of interaction. The analyzes with post-hoc showed a marginally significant difference for frequency of 2 cycles/360º. These results suggest changes in the CS of patients with major depression medicated.

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Contrast sensitivity function of sine-wave gratings in children with acute malnutrition.

Cited by 7 publications

References 33 publications

Acute undernutrition reduces polar visual contrast sensitivity in children.

Acute undernutrition reduces polar visual contrast sensitivity in children.

Visual contrast sensitivity in tonic-clonic epileptic patients.

Processamento visual de contraste em pacientes com depressão maior

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