Using the Electronic Health Record to Implement Expedited Partner Therapy in the Pediatric Emergency Department.

OBJECTIVES: Expedited partner therapy (EPT) is a partner treatment strategy for sexually transmitted infections (STIs) including gonorrhea and chlamydia as well as trichomoniasis in some states. The process allows healthcare providers to write prescriptions for STI treatment among partners of infected patients without a previous medical evaluation. The Centers for Disease Control (CDC) has recommended EPT as a useful option to facilitate partner treatment, particularly male partners of women with chlamydia or gonorrhea infections. Our institution implemented EPT in 2016 after Ohio legislation was passed to authorize its use. We aim to describe the implementation process and descriptive outcomes of EPT adoption in a pediatric emergency department. METHODS: This study describes use of the electronic health record for implementation of EPT in our institution. We conducted a retrospective review of EPT utilization from implementation. Electronic records from the implementation date of January 1, 2017, through December 31, 2021, were reviewed. We describe basic demographics and overall uptake of the intervention. Fisher exact tests were used for categorical variables and two-sample t-tests for continuous variables. RESULTS: There was a total of 3275 positive test results and 739 EPT prescriptions written. Adolescent patients who received prescriptions for EPT were more likely to be female (78.7% of all EPT prescriptions, P = 0.007) and older than other patients (average age 17.7 vs 17.4 years, P = 0.004). There was no significant difference in race, insurance, or ethnicity among adolescent patients receiving and not receiving EPT. The percentage of positive STI tests associated with an EPT prescription ranged between 11.4% and 18.2%. Metronidazole was the most prescribed EPT medication. CONCLUSIONS: The use of the electronic health record provides a platform for implementation of EPT. Our study highlights a potential strategy for increasing treatments of STIs through EPT prescribing in the emergency department setting.

Test-retest Repeatability of the Ohio Contrast Cards.

SIGNIFICANCE: The Ohio Contrast Cards are a repeatable test of contrast sensitivity, and they reveal higher contrast sensitivity for low-vision patients than is shown by the Pelli-Robson chart. PURPOSE: This study aimed to compare the contrast sensitivity results and test/retest ±limits of agreement for the Ohio Contrast Cards and the Pelli-Robson letter contrast sensitivity chart on two challenging groups of participants, and to compare the Ohio Contrast Card results with grating acuity and the Pelli-Robson results with letter acuity. METHODS: The Ohio Contrast Card and Pelli-Robson tests were each performed twice by two different examiners within one visit on 40 elder patients in Primary Vision Care (>65 years old) and 23 to 27 low-vision school-aged students. Grating acuity was measured using the Teller Acuity Cards (all participants), and letter acuity was measured using ClearChart (elders) or the Bailey-Lovie chart (students). RESULTS: The ±95% limits of agreement were similar for the Ohio Contrast Cards and the Pelli-Robson chart. The elders' limits of agreement were ±0.27 (Ohio Contrast Cards) and ±0.28 (Pelli-Robson); the students' limits of agreement were ±0.42 (Ohio Contrast Cards) and ±0.51 (Pelli-Robson). However, Ohio Contrast Card results were 0.41 log10 Michelson units more sensitive than the Pelli-Robson chart (over one line on the Pelli-Robson chart) for the elders and 0.90 log10 Michelson units (three lines on the Pelli-Robson chart) more sensitive for the elders (0.11 and 0.6 log10 Weber units, respectively). The Pelli-Robson results were correlated with letter acuities and Ohio Contrast Card results for both groups, and the Ohio Contrast Card results were correlated with Teller Acuity Card acuities for the elders. CONCLUSIONS: The Ohio Contrast Cards and Pelli-Robson chart are similarly repeatable. Both contrast sensitivity tests can provide additional clinical information that is not available through visual acuity testing, and Ohio Contrast Card may provide additional information not available from the Pelli-Robson chart.

The Ohio Contrast Cards: Visual Performance in a Pediatric Low-vision Site.

SIGNIFICANCE: This report describes the first clinical use of the Ohio Contrast Cards, a new test that measures the maximum spatial contrast sensitivity of low-vision patients who cannot recognize and identify optotypes and for whom the spatial frequency of maximum contrast sensitivity is unknown. PURPOSE: To compare measurements of the Ohio Contrast Cards to measurements of three other vision tests and a vision-related quality-of-life questionnaire obtained on partially sighted students at Ohio State School for the Blind. METHODS: The Ohio Contrast Cards show printed square-wave gratings at very low spatial frequency (0.15 cycle/degree). The patient looks to the left/right side of the card containing the grating. Twenty-five students (13 to 20 years old) provided four measures of visual performance: two grating card tests (the Ohio Contrast Cards and the Teller Acuity Cards) and two letter charts (the Pelli-Robson contrast chart and the Bailey-Lovie acuity chart). Spatial contrast sensitivity functions were modeled using constraints from the grating data. The Impact of Vision Impairment on Children questionnaire measured vision-related quality of life. RESULTS: Ohio Contrast Card contrast sensitivity was always less than 0.19 log10 units below the maximum possible contrast sensitivity predicted by the model; average Pelli-Robson letter contrast sensitivity was near the model prediction, but 0.516 log10 units below the maximum. Letter acuity was 0.336 logMAR below the grating acuity results. The model estimated the best testing distance in meters for optimum Pelli-Robson contrast sensitivity from the Bailey-Lovie acuity as distance = 1.5 - logMAR for low-vision patients. Of the four vision tests, only Ohio Contrast Card contrast sensitivity was independently and statistically significantly correlated with students' quality of life. CONCLUSIONS: The Ohio Contrast Cards combine a grating stimulus, a looking indicator behavior, and contrast sensitivity measurement. They show promise for the clinical objective of advising the patient and his/her caregivers about the success the patient is likely to enjoy in tasks of everyday life.

The modern Japanese color lexicon.

Despite numerous prior studies, important questions about the Japanese color lexicon persist, particularly about the number of Japanese basic color terms and their deployment across color space. Here, 57 native Japanese speakers provided monolexemic terms for 320 chromatic and 10 achromatic Munsell color samples. Through k-means cluster analysis we revealed 16 statistically distinct Japanese chromatic categories. These included eight chromatic basic color terms (aka/red, ki/yellow, midori/green, ao/blue, pink, orange, cha/brown, and murasaki/purple) plus eight additional terms: mizu ("water")/light blue, hada ("skin tone")/peach, kon ("indigo")/dark blue, matcha ("green tea")/yellow-green, enji/maroon, oudo ("sand or mud")/mustard, yamabuki ("globeflower")/gold, and cream. Of these additional terms, mizu was used by 98% of informants, and emerged as a strong candidate for a 12th Japanese basic color term. Japanese and American English color-naming systems were broadly similar, except for color categories in one language (mizu, kon, teal, lavender, magenta, lime) that had no equivalent in the other. Our analysis revealed two statistically distinct Japanese motifs (or color-naming systems), which differed mainly in the extension of mizu across our color palette. Comparison of the present data with an earlier study by Uchikawa & Boynton (1987) suggests that some changes in the Japanese color lexicon have occurred over the last 30 years.

The color lexicon of the Somali language.

This empirical study had three goals: (a) to describe Somali color naming and its motifs, (b) to relate color naming by Somali informants to their color vision, and (c) to search for historical and demographic clues about the diversity of Somali color naming. Somali-speaking informants from Columbus, Ohio provided monolexemic color terms for 83 or 145 World Color Survey (WCS) color samples. Proximity analysis reduced the 103 color terms to the eight chromatic color meanings from the WCS plus black, white, and gray. Informants' data sets were grouped by spectral clustering analysis into four WCS color naming motifs named after the terms for the cool colors: (a) Green-Blue, (b) Grue (a single term meaning "green or blue"), (c) Gray, and (d) Dark. The results show that, first, the Somali language has about four motifs among its speakers. Second, individuals' color vision test results and their motifs were not correlated, suggesting that multiple motifs do not arise from individual variation in color vision. Last, the Somali color lexicon has changed over the past century. New color terms often came from the names of familiar colored objects, and informants' motifs were closely related to their ages and genders, suggesting that the diversity of color naming across speakers of Somali probably results from ongoing language change.

The color lexicon of American English.

This article describes color naming by 51 American English-speaking informants. A free-naming task produced 122 monolexemic color terms, with which informants named the 330 Munsell samples from the World Color Survey. Cluster analysis consolidated those terms into a glossary of 20 named color categories: the 11 Basic Color Term (BCT) categories of Berlin and Kay (1969, p. 2) plus nine nonbasic chromatic categories. The glossed data revealed two color-naming motifs: the green-blue motif of the World Color Survey and a novel green-teal-blue motif, which featured peach, teal, lavender, and maroon as high-consensus terms. Women used more terms than men, and more women expressed the novel motif. Under a constrained-naming protocol, informants supplied BCTs for the color samples previously given nonbasic terms. Most of the glossed nonbasic terms from the free-naming task named low-consensus colors located at the BCT boundaries revealed by the constrained-naming task. This study provides evidence for continuing evolution of the color lexicon of American English, and provides insight into the processes governing this evolution.

Color sorting and color term evolution.

When participants sort color samples into piles, Boster showed that their color groupings can resemble the "stages" of Kay & McDaniel's model of color term evolution. Boster concluded that both the unfolding of color piles in a sequential color sorting task and the unfolding of color terms according to Kay & McDaniel's model reveal how human beings understand color. If this is correct, then: (1) pile sorts should be reasonably robust across variations in the palette of colors to be sorted, as long as the palette contains good examples of Berlin & Kay's universal color categories, and (2) pile-sorting should be more related to lexical effects and less related to perceptual processes governed by similarity judgments alone. We report three studies on English speakers and Somali speakers (Study 1 only), where participants sorted colors into 2…6 piles. The three studies used varying numbers of palette colors (25, 30, or 145 colors) and varying chromaticity schemes (mainly hue, widely-separated in hue and lightness, or densely distributed at high chroma). We compared human sorting behavior to Kay & McDaniel's model and to the "optimal" patterns of color sorting predicted by Regier's well-formedness statistic, which quantifies the perceived similarity between colors. Neither hypothesis is confirmed by the results of our studies. Thus, we propose that color sorts are determined by pragmatic influences based on heuristics that are inspired by the palette of colors that are available and the task that the viewer is asked to perform.

Infant color vision and color preferences: a tribute to Davida Teller.

Almost 40 years ago, Davida Teller developed the forced-choice preferential looking method for studying infant visual capabilities and used it to study infant color vision. About 10 years ago, she used infant looking preferences to study infant color perception. Here, we examine four data sets in which the infant looking preference was measured using a wide range of saturated colors. Three of those data sets, from papers by Marc Bornstein and by Davida Teller and Anna Franklin and their respective collaborators, were fit successfully using MacLeod and Boynton's model of the equiluminant plane in color space, in spite of the varied luminances used in those studies. A fourth data set, from a paper by Zemach, Chang, and Teller, was less well fit by that model. Apparently, infants are able to ignore luminance, and pay attention just to the color of stimuli. These results are discussed in the context of Davida Teller's work on the philosophy of vision science.

The color communication game.

There is clear diversity among speakers of a typical language in how colors are named. What is the impact of this diversity on the people's ability to communicate about color? Is there a gap between a person's general understanding of the color terms in their native language and how they understand a particular term that denotes a particular color sample? Seventy English-speaking dyads and 63 Somali-speaking dyads played the Color Communication Game, where the "sender" in each dyad named 30 color samples as they would in any color-naming study, then the "receiver" chose the sample they thought the sender intended to communicate. English speakers played again, under instructions to intentionally communicate color sample identity. Direct comparison of senders' samples and receivers' choices revealed categorical understanding of colors without considering color naming data. Although Somali-speaking senders provided fewer color terms, interpersonal Mutual Information (MI) calculated from color naming data was similarly below optimal for both groups, and English-speaking dyads' MI did not improve with experience. Both groups revealed superior understanding of color terms because receivers showed better exactly-correct selection performance than was predicted by simulation from their senders' color-naming data. This study highlights limitations on information-theoretic analyses of color naming data.

World Color Survey color naming reveals universal motifs and their within-language diversity.

We analyzed the color terms in the World Color Survey (WCS) (www.icsi.berkeley.edu/wcs/), a large color-naming database obtained from informants of mostly unwritten languages spoken in preindustrialized cultures that have had limited contact with modern, industrialized society. The color naming idiolects of 2,367 WCS informants fall into three to six "motifs," where each motif is a different color-naming system based on a subset of a universal glossary of 11 color terms. These motifs are universal in that they occur worldwide, with some individual variation, in completely unrelated languages. Strikingly, these few motifs are distributed across the WCS informants in such a way that multiple motifs occur in most languages. Thus, the culture a speaker comes from does not completely determine how he or she will use color terms. An analysis of the modern patterns of motif usage in the WCS languages, based on the assumption that they reflect historical patterns of color term evolution, suggests that color lexicons have changed over time in a complex but orderly way. The worldwide distribution of the motifs and the cooccurrence of multiple motifs within languages suggest that universal processes control the naming of colors.

Application of a Child Sex Trafficking Screening Tool in Patients with Abuse: A Retrospective Chart Review in the Pediatric Emergency Department.

INTRODUCTION: Human trafficking (HT) is a global problem that may affect children's health. In the United States, victims and children are at risk in most communities. History of abuse is a risk factor for HT. This study explored associations between pediatric patients with positive universal abuse screens and indicators from the commercial sexual exploitation of children/child sex trafficking (CSEC/CST) screening tool. METHOD: A retrospective chart review was conducted on random patients, aged 11-17 years, with positive universal abuse screens at emergency/urgent care departments in a large Midwest pediatric medical center in 2018. Documentation identifying at least two CSEC/CST screening tool indicators was abstracted from these records. Data analysis included descriptive statistics, univariate analyses, and correlations. RESULTS: Two or more indicators from the CSEC/CST screening tool were identified in 43% (n = 121). Age and history of running away were significant predictors for a patient having two or more CSEC/CST positive indicators. DISCUSSION: Targeted screening and interventions are needed to identify and help these vulnerable youth.

Color names, color categories, and color-cued visual search: sometimes, color perception is not categorical.

The relation between colors and their names is a classic case study for investigating the Sapir-Whorf hypothesis that categorical perception is imposed on perception by language. Here, we investigate the Sapir-Whorf prediction that visual search for a green target presented among blue distractors (or vice versa) should be faster than search for a green target presented among distractors of a different color of green (or for a blue target among different blue distractors). A. L. Gilbert, T. Regier, P. Kay, and R. B. Ivry (2006) reported that this Sapir-Whorf effect is restricted to the right visual field (RVF), because the major brain language centers are in the left cerebral hemisphere. We found no categorical effect at the Green-Blue color boundary and no categorical effect restricted to the RVF. Scaling of perceived color differences by Maximum Likelihood Difference Scaling (MLDS) also showed no categorical effect, including no effect specific to the RVF. Two models fit the data: a color difference model based on MLDS and a standard opponent-colors model of color discrimination based on the spectral sensitivities of the cones. Neither of these models nor any of our data suggested categorical perception of colors at the Green-Blue boundary, in either visual field.

The Effect of Test Distance on Visual Contrast Sensitivity Measured Using the Pelli-Robson Chart.

Purpose: The Pelli-Robson (PR) chart is widely used to measure clinical contrast sensitivity (CS). It is generally believed that PR testing distance is not critical. Here, we examine whether a closer test distance than the usual 1 meter might be better for patients with low vision. Methods: PR CS was measured on two groups: low-vision students (<20 years old) and elder patients (>65 years old). Student PR was measured at 1 meter and at a closer distance d = visual acuity in log10cy/deg (d = 1.5-logMAR). Elder PR was measured at 1 and 3 meters. Grating CS was also measured using the Ohio Contrast Cards (OCCs). Results: Average CS was 0.398 log10 units (over one line on the PR chart) higher at the closer distance than at 1 meter for the students, but there was no effect of 1 vs. 3 meters test distance for the elders. The equivalent spatial frequencies of the PR letters at 1 meter were near the acuity limits of students with low vision, but were near the peak of the elders' CS functions. Especially for students with low vision, PR CS was below OCC CS, even when PR was tested at a closer distance. Conclusions: PR CS should be measured at a distance in meters that is equal to the patient's letter acuity in cy/deg, or 1.5-logMAR. Translational Relevance: Contrast sensitivity is highly associated with quality of life, and it is important to measure it accurately. Using a closer distance, or measuring grating CS, can reveal visual abilities missed when patients with low vision are tested using PR at 1 meter.

Lexical Color Categories.

Color is a continuous variable, and humans can distinguish more than a million colors, yet world color lexicons contain no more than a dozen basic color terms. It has been understood for 160 years that the number of color terms in a lexicon varies greatly across languages, yet the lexical color categories defined by these terms are similar worldwide. Starting with the seminal study by Berlin and Kay, this review considers how and why this is so. Evidence from psychological, linguistic, and computational studies has advanced our understanding of how color categories came into being, how they contribute to our shared understanding of color, and how the resultant categories influence color perception and cognition. A key insight from the last 50 years of research is how human perception and the need for communication within a society worked together to create color lexicons that are somewhat diverse, yet show striking regularities worldwide.

Appearance of special colors in deuteranomalous trichromacy.

Deuteranomalous color matching behavior is different from normal because the middle-wavelength sensitive cones contain an abnormal L' pigment instead of the M pigment of the normal observer. However, there is growing evidence that deuteranomalous color experience is not very different from that of normal trichromats. Here, normal and deuteranomalous observers chose monochromatic unique yellow lights. They also chose broadband lights, displayed on a computer monitor, that corresponded to eight special colors: the Hering unique hues (red, yellow, green, blue), and binary colors perceptually midway between them (orange, lime, cyan, purple). Deuteranomalous monochromatic unique yellow was shifted towards red, but all the broadband special color selections were physically similar for normal and deuteranomalous observers. Deuteranomalous special colors, including monochromatic unique yellow, were similar to those of normal observers when expressed in a color-opponent chromaticity diagram based on their own visual pigments, but only if (1) color-opponent responses were normalized to white, and (2) the deuteranomalous diagram was expanded along the r - g dimension to compensate for the reduced difference between deuteranomalous L- and L'-cone photopigments. Particularly, deuteranomalous observers did not choose binary colors with extra r - g impact to overcome their insensitivity along the r - g dimension. This result can only be compatible with the known abnormality of the deuteranomalous L' photopigment if deuteranomalous observers adjust their perceptual representation of colors to compensate for their color vision deficiency.

Color channels, not color appearance or color categories, guide visual search for desaturated color targets.

In this article, we report that in visual search, desaturated reddish targets are much easier to find than other desaturated targets, even when perceptual differences between targets and distractors are carefully equated. Observers searched for desaturated targets among mixtures of white and saturated distractors. Reaction times were hundreds of milliseconds faster for the most effective (reddish) targets than for the least effective (purplish) targets. The advantage for desaturated reds did not reflect an advantage for the lexical category "pink," because reaction times did not follow named color categories. Many pink stimuli were not found quickly, and many quickly found stimuli were not labeled "pink." Other possible explanations (e.g., linear-separability effects) also failed. Instead, we propose that guidance of visual search for desaturated colors is based on a combination of low-level color-opponent signals that is different from the combinations that produce perceived color. We speculate that this guidance might reflect a specialization for human skin.

Testing the Cross-Cultural Generality of Hering's Theory of Color Appearance.

This study examines the cross-cultural generality of Hering's (1878/1964) color-opponent theory of color appearance. English-speaking and Somali-speaking observers performed variants of two paradigms classically used to study color-opponency. First, both groups identified similar red, green, blue, and yellow unique hues. Second, 25 English-speaking and 34 Somali-speaking observers decomposed the colors present in 135 Munsell color samples into their component Hering elemental sensations-red,green,blue, yellow, white, and black-or else responded "no term." Both groups responded no term for many samples, notably purples. Somali terms for yellow were often used to name colors all around the color circle, including colors that are bluish according to Hering's theory. Four Somali Grue speakers named both green and blue elicitation samples by their term for green. However, that term did not name the union of all samples called blue or green by English speakers. A similar pattern was found among three Somali Achromatic speakers, who called the blue elicitation sample black or white. Thus, color decomposition by these Somali-speaking observers suggests a lexically influenced re-dimensionalization of color appearance space, rather than a simple reduction of the one proposed by Hering. Even some Somali Green-Blue speakers, whose data were otherwise similar to English, showed similar trends in yellow and blue usage. World Color Survey data mirror these results. These within- and cross-cultural violations of Hering's theory do not challenge the long-standing view that universal sensory processes mediate color appearance. However, they do demonstrate an important contribution of language in the human understanding of color.

Contrast insensitivity: the critical immaturity in infant visual performance.

This is a targeted review of the critical immaturities limiting psychophysical luminance contrast detection in human infants. Three-month-old infants are 50 times less sensitive to contrast than adults are. Rod experiments suggest that early-stage immaturities, like the short length of infant rod outer segments, have only a modest direct effect on infant visual performance. Infant contrast sensitivity may resemble adult extrafoveal sensitivity, because the foveal cones of the neonate are immature and may not generate strong enough responses to mediate visual performance. This use of the extrafoveal retina reduces the high-spatial frequency end of the infant contrast sensitivity function (CSF), contributing to poor infant resolution acuity. The remaining difference between infant and adult CSFs may be a simple overall reduction in infant sensitivity. The maximum of the infant CSF increases proportionately with age, and may be numerically near the infant's age in weeks. Contrast discrimination experiments indicate that the critical immaturity that limits infant contrast sensitivity is a mid-level phenomenon, occurring before the site of the contrast gain control. For example, the infant ascending visual pathway might be limited by large amounts of intrinsic noise. These results suggest that there is little effect of inattentiveness to the psychophysical task by ostensibly alert infant patients or subjects. The clinician or researcher can interpret behavioral measurements of infant visual performance with confidence.

Neonatal Contrast Sensitivity and Visual Acuity: Basic Psychophysics.

PURPOSE: This research was prospectively designed to determine whether a 0.083 cycles per degree (cy/deg) (20/7200) square-wave stimulus is a good choice for clinical measurement of newborn infants' contrast sensitivity and whether the contrast sensitivity function (CSF) of the newborn infant is band-pass. The results were retrospectively analyzed to determine whether the method of constant stimuli (MCS) and the descending method of limits (dLIM) yielded similar results. METHODS: In across-subjects experimental designs, a pilot experiment used MCS (N = 47 visual acuity; N = 38 contrast sensitivity at 0.083 cy/deg), and a main experiment used dLIM (N = 22 visual acuity; N = 22 contrast sensitivity at 0.083 cy/deg; N = 21 at 0.301 cy/deg) to measure visual function in healthy newborn infants. Three candidate CSFs estimated maximum neonatal contrast sensitivity. MCS and dLIM psychometric functions were compared while taking the stimulus presentation protocols into account. RESULTS: The band-pass CSF fit the data best, with a peak sensitivity near 0.31 at 0.22 cy/deg. However, the 0.083 cy/deg square-wave stimulus underestimated the best performance of newborn infants by less than 0.15 log10 units. MCS and dLIM data agreed well when the stimulus presentation contingencies were taken into account. CONCLUSIONS: Newborn contrast sensitivity is well measured using a 0.083 cy/deg square-wave target, regardless of which CSF shape is correct. MCS and dLIM yield wholly comparable results, with no evidence to suggest effects of other factors such as infant inattention or examiner impatience. TRANSLATIONAL RELEVANCE: These measurements open the way for clinical behavioral measurement of infant visual acuity and contrast sensitivity in the neonatal period.

Critical immaturities limiting infant binocular stereopsis.

PURPOSE: To determine what critical immaturity is responsible for the poor binocular stereopsis of human infants. METHODS: Infant and adult psychometric functions were measured for detection of stereoscopic depth in a random-texture display. A test stimulus defined by horizontal binocular disparity and a distracter stimulus defined by vertical disparity were used. Adults were tested by direct psychophysical methods at several contrast values, and infants by forced-choice preferential looking at 100% contrast. RESULTS: Infant stereoacuity matured from unmeasurable at age 12 weeks to 7.9 arc min at 20 weeks, which was still far from the nominal adult value of 5 to 10 arc seconds. In contrast, infant d-max (maximum disparity) was 86.8 minutes at 20 weeks, which was near the adult d-max of 110.6 minutes. The average maximum level of infant performance at 20 weeks was 77% correct, still far below adult performance. When the adult stereogram was low contrast, adult extrafoveal performance was similar to infant performance. Infant and adult stereo performance was predicted quantitatively, using infant and adult monocular performance in detecting the stereogram texture. Infant and adult stereopsis performance approached, but did not reach, the predicted values. CONCLUSIONS: The infantlike performance of adults tested at low contrast and the similarity of infant maximum percentage of correct data relative to the predicted values suggested that the critical immaturity limiting infant stereopsis is the well-known insensitivity of the infant visual system to contrast. This conclusion supports the clinical use of stereopsis as a screening test for bilateral monocular function in infants.