Purpose Early detection of abnormal visual acuity (VA) is crucial in the identification and management of ocular and visual abnormalities in infants. Currently, the Teller Acuity Cards (TACs) are considered the gold standard for clinical testing and are effective in obtaining a quick estimate of an infant’s VA, but they have certain drawbacks. They rely on a subjective assessment of the baby’s looking behavior. Despite this, TACs have been found to have good validity and repeatability. The current study investigates a new method to objectively assess visual acuity in infants, which is uses a video gaze tracker (GT) and computer-generated stimuli, developed in the lab of M. Eizenman at the University of Toronto. The purpose was to validate this method in adults and infants against current clinical VA tests. Visual scanning patterns were measured by the GT system that requires minimal subject cooperation in adult and infant populations. The targets were judged as seen when the relative fixation time on the grating exceeded a pre-determined threshold, as compared to the fixation time on the luminance-matched background. Methods Experiment 1: In 15 uncorrected myopic adults, binocular grating VA was measured. The targets were square-wave gratings of spatial frequency ranging from 2.3 to 37 cpd presented randomly in one of four positions on the screen. There were 6 objective protocols (in which VA was judged by fixations). The subjects were naïve, as the only instruction given to the participants was to look towards the screen. The experimenter, who presented the gratings also acted as an observer by making judgments of seen/not seen responses using the objective information provided by the software. Objective GT VA was compared with VA measured with subjective responses using the same stimuli and with Teller Acuity Cards (TACs). Experiment 2: Binocular grating VA for horizontal gratings was measured in 20 typically-developing infants aged 3 to 12 months. Spatial frequency ranged from 0.32 to 42 cpd and VA was measured on two visits with both the GT and TACs. A staircase protocol was used to obtain the VA threshold in the GT. The experimenter controlled the staircase method and an observer used the objective information of visual fixations using the software to judge if the grating was seen or not. Video cartoons were shown between stimulus presentations to keep the infant’s attention towards the screen. VA was also measured with the TACs held in the vertical orientation, so that the gratings were horizontal, similar to the GT method. A TAC stage was specially designed with a vertical slot in which the cards could be presented. The observer was masked regarding the participant’s age and the starting spatial frequency. The study co-ordinator determined the choice of the start card which was randomized between participants so as to give an equal number of participants with each start card. The same start card was used for the second session of each infant. The threshold was defined as the highest spatial frequency for which the infant gave a clear, correct look and an unclear/inconsistent look for the next higher level. The observer, who was masked regarding the absolute spatial frequency, increased or decreased the spatial frequency until this threshold was determined. Results Experiment 1: The mean age of participants in the adult study was 28.47±7.93 yrs and their mean uncorrected logMAR acuity was 0.9±0.2. There was no obvious difference among the mean acuities obtained by 6 objective GT protocols, the subjective GT protocol and the TACs. The GT showed agreement of 93% and 100 % within half an octave compared with the subjective protocol and TACs (horizontal gratings) respectively. There was 100% agreement within 1 octave of the objective GT with both the subjective protocol and the TACs (horizontal gratings). The objective gaze tracker VA showed significant correlation with uncorrected refractive error (r =0.87, p < 0.001). Experiment 2: The mean age of participants was 7.9±2.5 months. In both visits, the testability of the TACs was 100% across all infants. GT had 100% testability on the first visit and 95% testability on the second visit. The mean TAC acuity over two visits for all the infants was 0.7±0.23 log cycles per degree, while the mean log GT acuity over two visits was 0.86±0.30. Infant GT VA acuity estimates were within 1 octave of the TACs 90% and 79% of the time for the first and second visit respectively, while GT VA estimates were within half octave of the TACs 63.2% and 47% of the time for the first and second visit respectively. Eighty-seven percent of the GT VAs and 72.5% of TACs were within one octave of the mean age norms, although on average the GT gave better acuities than the TACs. There was an increase in GT VA with increasing age (r=0.80, p<0.005 for the first visit and r=0.77, p<0.005 for the second visit). Both the TACs and the GT had repeatability of 89.5% within 1 octave between visits and 84.2% and 79% within half octave between visits respectively. Conclusions In adults, the gaze tracker gave VA thresholds which were equivalent to the TACs and were not significantly different from subjectively determined grating VA. The agreement of the GT with TACs in infants and with norms in the infant literature established good validity for the GT. Finally, the significant correlation with age confirmed the validity of the measurements of the gaze tracker. The repeatability of the gaze tracker was similar to that of the TACs, demonstrating the quality usefulness of the test. These results demonstrate the potential for an automated test of infant visual acuity, which could be a powerful and useful tool for visual acuity assessment in infants and other population groups who cannot respond verbally. The staircase protocol established in the study could be fully automated in an objective version of the test. The raw data of eye movements obtained in this study such as the pattern of first fixations, time taken for first fixations, time spent fixing the stimulus, typical stimulus duration and time between presentations could be used to develop algorithms for fully automated testing of VA in infants.

Purpose: National prevalence of childhood overweight and obesity has plateaued in recent years, but rates remain high, with approximately 10% among children“high weight.” The relationship between adiposity and serum 25-hydroxyvitamin D [25(OH)D] status has been well-explored in older individuals, with inconsistent results. Furthermore, previous studies have suggested a relationship between adequate consumption of calcium and vitamin D and healthy weight status in older children and adults. However, in the infant population, there are few studies detailing the interaction between body composition and serum 25(OH)D or intake of calcium and vitamin D. Our study aims were to assess the association between serum 25(OH)D and body composition and to examine the association between adiposity and dietary intake of calcium and vitamin D in a sample of infants and toddlers. Methods: Our population included healthy male and female infants and toddlers from Pittsburgh, PA who participated in the “Practices Affecting Vitamin D Status in Pittsburgh Infants and Toddlers” study. Parents completed a Vitamin D and Sunlight Exposure Questionnaire, which assessed dietary intake of foods high in calcium and vitamin D as well as daily sunlight exposure (≥2 hours vs. >2 hours). Anthropometric measures and bloodwork for serum 25(OH)D were obtained during at the time of the study visit. Weight-for-length (WFL) percentile status was determined using WHO growth standards (low weight97.7 %ile) and WFL z-scores were calculated. ANOVA was used to compare mean serum 25(OH)D and calcium and vitamin D intake by WFL status. Chi square analysis was used to evaluate the relationship between serum 25(OH) D status (deficient =/mL, insufficient = 12-20 ng/mL, sufficient >20 ng/mL), calcium intake status (sufficient = >700 mg), vitamin D intake status (sufficient = >400 IU) and WFL percentile status. Pearson’s correlation coefficient was used to assess the strength and significance of associations between serum 25(OH)D, calcium and vitamin D intake and WFL z-score. The analysis was repeated after subdivision by race and sun exposure. Results: 125 infants and toddlers (9 to 24 months of age, 68% African American) participated in the study. Approximately 11% of the population had a high weight. Mean vitamin D intake (~600 IU/d) and median calcium intake (~1550 mg/d) exceeded recommendations. Prevalence of high weight was higher among children with adequate intake compared to those who consumed less than the recommendations (calcium: 41% vs. 36%, respectively; vitamin D: 45% vs. 29%, respectively). However, this difference was not statistically significant. Mean serum 25(OH)D level (37 ng/mL) was sufficient. When compared across WFL status, neither mean serum 25(OH)D nor mean intake of calcium and vitamin D varied significantly. No significant correlation was found between WFL and serum 25(OH)D for the cohort or any of the subgroups examined. Conclusions: Rates of infant overweight and obesity in our sample are similar in comparison with the national average. Our results do not support a relationship between calcium and vitamin D intake on weight status or an association between serum vitamin D and body composition in children of this age. Future studies are needed to re-examine these relationships in a larger group of children of more evenly distributed weight status.

There is a growing body of research on interventions to decrease infant distress during painful procedures, and distraction is a particularly practical option. However, the effectiveness data for distraction for infant pain relief are mixed. Inconsistencies in response to distraction might be explained by unique characteristics of the infant patient. Some researchers argue that temperament is the best predictor of differences observed between individuals and also the most sensitive to novel environmental factors such as exposure to pain. This study examined whether infants’ temperament is predictive of response to immunization injection pain and whether temperament moderates the relation between a distraction intervention and infant distress. Data for this study came from two prior studies of healthy infants receiving immunizations (Cohen, 2002; Cohen et al., 2006). Participants included 252 healthy infants and toddlers who ranged from 1 to 22 months of age. Infants were randomly assigned to “typical care” condition or “distraction” condition. The period of time before, during, and after the injection was videotaped and observational coding was used to assess infant distress. Prior to the immunization, parents completed six pre-injection visual analogue scales about their child’s temperament. An oblique rotation factor analysis was conducted with the temperament data and provided two temperament factors that map onto the ‘easy/difficult’ and ‘time-to-warm-up’ dimensions documented in the literature; these two factors were used for analyses. After controlling for site and gender, regression analyses revealed that neither easy/difficult temperament (p = .098, b = .109) nor time-to-warm-up temperament (p = .572, b = -.037) was predictive of distress. There was a significant treatment condition and time-to-warm-up temperament interaction, b = .0011, SE = .0005, p = .0254, such that distraction decreased distress in infants that were slower to warm up, or warmed up neither slowly nor quickly. No other significant distraction x temperament interactions were found. Temperament was not found to impact infant distress during immunizations in this study but results speaking to whether temperament serves as a moderator of the relation between distraction and distress were mixed. Results suggest that temperament is a factor that warrants closer attention when examining how infants respond to interventions around pain.

A landmark experiment by Kiley Hamlin, Karen Wynn, and Paul Bloom demonstrated that infants as young as 6 months old possess previously unrecognized abilities to form social evaluations. In the experiment, infants were shown a shape that was made to appear as if it was climbing a hill. In one event, another shape helped the climber up the hill, while in a separate event, a different shape prevented the climber from reaching the top. When offered a choice between the helping and hindering shapes, both 6- and 10-month-olds chose the helping shape over the hindering shape, showing that they had evaluated the actions and preferred the helper as a result. In an additional test, the climber was made to appear as if it was "choosing" the helping shape or the hindering shape. Infant looking times were measured in order to assess which "choice" was more surprising. Interestingly, the 6-month-olds looked equally for both events, while the 10-month-olds looked longer when the hinderer was approached. This demonstrated that the 10-month-olds were attributing preferences to the climber, and expected that the climber would prefer the helper just as they had. This ability was apparently beyond that of the 6-month-olds, but no assessment or explanation has been offered for why this would be. The current study attempted to remedy this problem by replicating this experiment with 7- and 8-month-olds. The 7-month-olds in this experiment performed as expected, preferring the helper over the hinderer. The 8-month-olds, however, showed no clear preference. This was unexpected and not easily explainable. Neither age showed a difference in looking time whether the climber approached the helper or the hinderer. These looking time data suggest that 7- and 8-month-olds are closer to 6-month-olds in their ability to attribute evaluations to other agents, indicating that these abilities do not develop until later infancy, around 9 or 10 months. However, lack of significant results on the looking time test need not indicate a lack of social knowledge, and may instead stem more directly from developing theory of mind abilities. Options for future studies pitting social knowledge against theory of mind are explored.

No description available.

No description available.

Neuroscientists have uncovered much about the dorsal and ventral visual object processing pathways. However, little is understood about the functional development of these pathways in human infants. Behavioral data has shown that as early as 2.5 months, infants are sensitive to spatiotemporal information for object individuation in occlusion events. This study used Near Infrared Spectroscopy to assess neural activation (as evidenced by an increase in HbO2) in four areas of the pathways: primary visual cortex (O1), posterior parietal cortex (P3), lateral occipital (T5), and inferior temporal (T3) in awake human infants aged 5.5 months while they view either a spatiotemporaldiscontinuity event or a control event. Three major predictions were made: 1) since the events contain visually distinct objects, there should be significant neural activation in O1 to both events, 2) if the dorsal route mediates the processing of spatiotemporal discontinuities, then there should also be a significant increase in P3 in response to the spatiotemporal-discontinuity event but not to the control event, and 3) activation present in T3 and T5 should not vary by condition if the ventral pathway is not responsible for the processing of spatiotemporal discontinuities. Results supported all three predictions.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 246-268). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 125-134). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 41-46).