A method for the assessment of facial hedonic reactions in newborns / Método para a avaliação de reações faciais hedônicas em recém-nascidos

Abstract Objective: This study describes a quantitative and qualitative methodology to assess hedonic responses to sweet stimulus in healthy newborns. Methods: A descriptive, cross-sectional, observational study, with healthy newborns (up to 24 h of life), between 37 and 42 gestational weeks, vaginally born and breastfed previously to all tests. The evaluation of the newborns reactions was performed by hedonic facial expression analysis, characterized by facial expressions with rhythmic serial tongue protrusion after neutral or sweet solution intake. Initially, 1 mL of water solution was provided to the newborn, followed by a 1-minute recording. Afterwards, the same amount of 25% sucrose solution was provided, performing a second recording. The concordance between researchers was analyzed by the Bland-Altman statistical method. Results: A total of 100 newborns (n = 49 males, n = 51 females; mean lifetime = 15 h 12 min ± 6 h 29 min) were recorded for neutral and sucrose solution intake, totaling 197 videos (n = 3 missing in the water treatment). These videos were double-blind analyzed and the test revealed a 90% concordance between the two trained researchers, in relation to both solutions. The intraclass correlation coefficient was 0.99 for both solutions, with a significant increase in frequency of hedonic expressions evoked by sucrose solution intake. Conclusions: These results confirm that the proposed method has an efficient power to detect significant differences between neutral and sucrose stimuli. In conclusion, this evaluation method of hedonic facial reactions in newborns reflects the response to a specific taste.

Resumo Objetivo: Descrever quantitativamente e qualitativamente uma metodologia para avaliar as respostas faciais hedônicas, em recém-nascidos saudáveis, ao estímulo doce. Métodos: Trata-se de um estudo descritivo, transversal e observacional, com recém-nascidos saudáveis (com até 24 horas de vida), entre 37-42 semanas gestacionais, nascidos por parto vaginal e alimentados previamente aos testes. A avaliação das reações hedônicas dos recémnascidos foi considerada pelas expressões faciais com séries rítmicas de protrusões de língua após a ingestão de solução neutra ou doce. Inicialmente, 1 mL de solução neutra (água) foi fornecida para o recém-nascido, seguido de uma filmagem de 1 minuto. Sequencialmente, a mesma quantidade de solução de sacarose 25% foi fornecida, realizando-se uma segunda gravação. A concordância entre os pesquisadores foi analisada pelo método estatístico de Bland-Altman. Resultados: Um total de 100 recém-nascidos (n = 49 do sexo masculino, n = 51 do sexo feminino, tempo de vida média = 15 h 12 min ± 6 h 29 min) foram registrados para a ingestão de solução neutra e de sacarose, totalizando 197 vídeos (n = 3 perdas para o tratamento água). Estes vídeos foram analisados em duplo-cego e o teste revelou uma concordância de 90%, para ambas as soluções, entre os pesquisadores treinados. O coeficiente de correlação intraclasse foi de 0,99 para as duas substâncias, com um aumento significativo nas frequências das expressões faciais hedônicas evocadas pela ingestão de sacarose. Conclusões: Estes resultados confirmam que o método proposto possui poder estatístico eficiente para detectar diferenças entre estímulos neutros e sacarose. Em conclusão, este método de avaliação de reações faciais hedônicas em recém-nascidos reflete a resposta para um gosto específico.

A method for the assessment of facial hedonic reactions in newborns.

OBJECTIVE: This study describes a quantitative and qualitative methodology to assess hedonic responses to sweet stimulus in healthy newborns. METHODS: A descriptive, cross-sectional, observational study, with healthy newborns (up to 24h of life), between 37 and 42 gestational weeks, vaginally born and breastfed previously to all tests. The evaluation of the newborns reactions was performed by hedonic facial expression analysis, characterized by facial expressions with rhythmic serial tongue protrusion after neutral or sweet solution intake. Initially, 1mL of water solution was provided to the newborn, followed by a 1-minute recording. Afterwards, the same amount of 25% sucrose solution was provided, performing a second recording. The concordance between researchers was analyzed by the Bland-Altman statistical method. RESULTS: A total of 100 newborns (n=49 males, n=51 females; mean lifetime=15h 12min±6h 29min) were recorded for neutral and sucrose solution intake, totaling 197 videos (n=3 missing in the water treatment). These videos were double-blind analyzed and the test revealed a 90% concordance between the two trained researchers, in relation to both solutions. The intraclass correlation coefficient was 0.99 for both solutions, with a significant increase in frequency of hedonic expressions evoked by sucrose solution intake. CONCLUSIONS: These results confirm that the proposed method has an efficient power to detect significant differences between neutral and sucrose stimuli. In conclusion, this evaluation method of hedonic facial reactions in newborns reflects the response to a specific taste.

Intrauterine growth restriction and the fetal programming of the hedonic response to sweet taste in newborn infants.

Intrauterine growth restriction is associated with increased risk for adult metabolic syndrome and cardiovascular disease, which seems to be related to altered food preferences in these individuals later in life. In this study, we sought to understand whether intrauterine growth leads to fetal programming of the hedonic responses to sweet. Sixteen 1-day-old preterm infants received 24% sucrose solution or water and the taste reactivity was filmed and analyzed. Spearman correlation demonstrated a positive correlation between fetal growth and the hedonic response to the sweet solution in the first 15 seconds after the offer (r = 0.864, P = 0.001), without correlation when the solution given is water (r = 0.314, P = 0.455). In fact, the more intense the intrauterine growth restriction, the lower the frequency of the hedonic response observed. IUGR is strongly correlated with the hedonic response to a sweet solution in the first day of life in preterm infants. This is the first evidence in humans to demonstrate that the hedonic response to sweet taste is programmed very early during the fetal life by the degree of intrauterine growth. The altered hedonic response at birth and subsequent differential food preference may contribute to the increased risk of obesity and related disorders in adulthood in intrauterine growth-restricted individuals.

Satiety assessment in neonatally handled rats.

We have previously demonstrated that neonatal handling increases sweet food ingestion. In the present study, we examined whether food intake, using different kinds of food, is altered in neonatally handled animals, with or without inducing satiety using a sucrose solution. Abdominal fat, glycemia and hormones linked to appetite including leptin, ghrelin and insulin were also measured. We tested palatable food consumption in the homecage to verify whether environmental cues could influence ingestion. Nests of Wistar rats were either (1) non-handled or (2) handled (10 min/day). Handling was performed on days 1-10 after birth. When adults, rats were habituated to sweet food (Froot Loops, Kellogg's) and to palatable fiber pellets (Fiber One), Nestlé). Sweet food consumption was increased in the neonatally handled group, when tested in the homecage, and also in the satiety experiment. These rats displayed a satiety curve when compared to the control group, which ate less but constantly. Handled rats exposed to a sucrose solution decreased sweet food ingestion, which did not occur in the control group. When exposed to a food with complex carbohydrates, these differences disappeared. There were no differences in body weight, abdominal fat or in glycemia, as well as no differences in plasma levels of insulin or leptin. However, ghrelin was decreased in neonatally handled rats. Neonatally handled rats demonstrated an increased consumption of sweet food, satiety responses to sucrose, as well as decreased levels of plasma ghrelin. It is possible that signaling mechanisms related to satiety, both peripherally and/or centrally may contribute to these behavioral findings.