Early malnutrition decreases contrast sensitivity to circular concentric gratings.

Abstract

Early malnutrition refers to inadequate nutrition during the critical period of nervous system development followed by nutritional recovery, resulting in a short stature according to age but normal weight according to short stature. We measured the effects of early malnutrition on contrast sensitivity (CS) to concentric circular gratings in 18 children of both sexes, aged 8 to 11 years (mean = 9.2 years, standard deviation = .99 years). Nine of the children were eutrophic (E group), and nine experienced early malnutrition (EM group) based on state healthcare records and Waterlow's anthropometric parameters. Contrast sensitivity to four spatial frequencies (.25, 1.0, 2.0, and 8.0 cycles per degree [cpd]) was measured using a temporal two-alternative forced-choice psychophysical method with mean luminance of 40.1 cd/m 2 . Statistical analyses showed significant differences between groups and a group × frequency interaction. EM group was significantly less sensitive than the E group to the 8.0 cpd frequency and needed 1.49-times more contrast to detect the gratings. These results suggest that early malnutrition impairs CS to high-spatialfrequency concentric circular gratings in children. Therefore, early malnutrition, which is known to affect primary visual cortical areas, may also affect higher visual cortical areas such as V4 and the inferotemporal cortex.

Acute undernutrition reduces polar visual contrast sensitivity in children.

“…The effects of malnutrition on CS to non-Cartesian polar stimuli have already been reported, although the study tested children with a different type of nutritional deficiency. Alencar and dos Santos (2012) found impairments at all of the tested spatial frequencies (.25, 1.0, 2.0, and 8.0 cpd) in early undernourished children. 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).…”

“…To our knowledge, only one study has established a relationship between undernutrition and CS to polar stimuli, but it focused on early undernutrition rather than the acute form. Alencar and dos Santos (Alencar & dos Santos, 2012) reported impairment in CS to non-Cartesian concentric gratings in early undernourished children.…”

Efeitos da desnutrição proteica na percepção de contraste e acuidade visual em humanos e em ratos

“…Poucos estudos examinaram o desenvolvimento da SC para grades não-cartesianas (Alencar & Santos, 2012;Santos, França, & Cruz, 2007;Santos et al, 2008). Nesse contexto, o presente estudo avaliou os efeitos da desnutrição atual e pregressa na SC visual para estímulos em coordenadas polares em crianças de 8 a 11…”

Desenvolvimento da acuidade visual e sensibilidade ao contraste em recém-nascidos pequenos para a idade gestacional por potenciais visuais evocados de varredura

“…Dentre os estudos que envolvem a mensuração da AV e SC destacam-se os que visam avaliar o desenvolvimento da visão espacial (Hamer, Norcia, Tyler & Hsu-Winges, 1989;Norcia & Tyler, 1985;Norcia, Tyler & Hamer, 1990;Norcia, Tyler, Hamer & Wesemann, 1989;Salomão, Ejzenbaum, Berezovsky, Sacai & Pereira, 2008;Skoczenski & Norcia, 1999); os efeitos dos ácidos graxos no desenvolvimento visual Hoffman et al, 2000;Hoffman et al, 2004;Makrides, Neuman, Simmer, Pater & Gibson, 1995); os efeitos de substâncias neurotóxicas, tais como o mercúrio Ventura et al, 2005;Rodrigues et al, 2007;) e solventes orgânicos (Lacerda et al, 2012) e os efeitos de patologias oculares, fisiológicas e neuropsiquiátricas sobre a percepção visual, como por exemplo, a ambliopia (Dobson, Miller, Harvey & Mohan, 2003); a catarata congênita (Maurer, Lewis, Brent & Levin, 1999), a retinopatia da prematuridade (VanderVeen et. al, 2006), a prematuridade (Oliveira et al, 2004), o baixo peso ao nascimento (Mirabella, Kjaer, Norcia, Good & Madan, 2006;O'Connor et al, 2004;SanGiovanni et al, 2000a;Tornqvist & Källén, 2004), a desnutrição (Alencar & Santos, 2012;Santos & Alencar, 2010); a Síndrome de Down (John, Bromham, Woodhouse & Candy, 2004); paralisia cerebral (Costa, Salomão, Berezovsky, Haro & Ventura, 2004;Costa & Ventura, 2012); a hidrocefalia (Costa, Haro, Salomão & Ventura, 2008;Pereira & Costa, 2012), a distrofia muscular de Duchenne (Costa, Barboni & Ventura, 2011), dentre outras.…”