Recent research suggests that by 4 months of age infants are able to individuate objects using form features, such as shape and size, but surface features, such as pattern and color, are not used until later in the first year (Wilcox, 1999). The current study sought to investigate two possible explanations for this developmental hierarchy. The visual maturation hypothesis suggests that the order in which infants use features to individuate objects corresponds to the order in which they are most readily processed by the developing visual system. A second hypothesis, the information processing biases hypothesis, suggests that infants are biased to attend to form features because form features provide information that is relevant to reasoning about object interactions. One way to test these hypotheses is to investigate infants' ability to individuate objects based on luminance. Luminance is detected at birth, so, according to the visual maturation hypothesis, luminance, like shape and size, will be used to individuate objects early in the first year. However, luminance is a surface property, so according to the information processing biases hypothesis, luminance, like pattern and color, will be used to individuate objects late in the first year. In the current study, 7-month-old (Experiment 1) and 11-month-old (Experiment 2) infants' use of luminance information in an object individuation task was investigated. The narrow-screen event-monitoring paradigm developed by Wilcox and Baillargeon (1998a) was used. Infants saw an event in which a ball moved behind a screen and a second ball emerged from behind the opposite edge of the screen. In one condition, the balls were identical, suggesting the presence of one object (same-luminance condition), and in another condition, the balls differed in luminance, suggesting the presence of two objects (different-luminance condition). The screen was either too narrow (narrow-screen event) or sufficiently wide (wide-screen event) to occlude two objects simultaneously. Seven-month-olds looked equally at each event, whereas 11.5-month-old's looked longer at the narrow-screen event in the different-luminance condition. These results suggest that 11.5-month-olds, but not 7.5-month-olds used luminance information to conclude that two distinct objects were involved in the event, thus supporting the information processing biases hypothesis.

Docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) are deposited in large amounts in membrane phospholipids of the developing central nervous system (CNS). High levels of 22:6n-3 are found in synaptic terminals and retina, and are important for normal visual development and function. 20:4n-6 and22:6n-3 are supplied in human milk. In contrast, infants fed formula rely completely on endogenous synthesis of 20:4n-6 and 22:6n-3 from linoleic (18:2n-6) and a-linolenic (18:3n-3) acid, respectively. Levels of 22:6n-3 in the blood lipids of infants fed formula are lower than in infants fed human milk. Concern over the supply of 22:6n-3 led to clinical trials in which premature infants were fed formulas containing fish oils as a source of 22:6n-3. Piglets, which have a similar lipid metabolism and perinatal timing of the brain growth spurt to humans, have a lower percentage of 22:6n-3 in blood, liver and CNS tissues when fed formula with 30% of fatty acids as18:2n-6 and 0.8% 18:3n-3, compared to sow milk. It was hypothesized that the low blood and tissue 22:6n-3 in formula-fed piglets was due to inappropriate quantities and/or ratios of dietary 18:2n-6 and 18:3n-3 limiting the synthesis of 22:6n-3. Thus, the main objectives of this thesis were to determine. (1) if 22:6n-3 is an essential dietary nutrient for the term gestation piglet, (2) if appropriate quantities and ratios of 18:2n-6 and 18:3n-3 in formula will support CNS membrane accretion of 20:4n-6 and 22:6n-3, comparable to piglets fed varying amounts of 22:6n-3 in natural milk, and (3) if lower blood phospholipid 22:6n-3 consistently reflects reduced 22:6n-3 in the CNS. Initial studies (Experiment I) showed that formula with 4% 18:3n-3 supported a similar percentage of22:6n-3 in piglet liver and CNS membrane lipids to sow milk, but was associated with lower brain weight. Deposition of 22:6n-3 in brain was influenced by the formula 18:3n-3 content. The 18:2n-6:18:3n-3 ratio (22:1and 37:1) seemed to be important, however, when formulas contained 1% 18:3n-3. Low levels of fish oil in formula, similar to those used in clinical trials, were effective in supplying 22:6n-3 to the developing piglet brain (Experiment II). The efficacy of 18:3n-3 in supporting the deposition of 22:6n-3 in the brain was estimated to be at least 20% that of dietary 20:5n-3 plus 22:6n-3. With increasing dietary fish oil, however, levels of eicosapentaenoic acid (20:5n-3) increased and 20:4n-6decreased in plasma, liver and retina, but not brain (Experiment III). This suggests regulatory mechanisms may exist to maintain relatively constant levels of 20:4n-6 and 20:5n-3 in brain. Milk 22:6n-3 varies with maternal intake of 22:6n-3. The effect of milk 22:6n-3 content was studied in piglets fed milk with 0.1% or 1.5% 22:6n-3 obtained from sows fed usual pig diets containing vegetable fats without or with fish oil, respectively (Experiment IV). Consumption of 1.5 vs 0.1% 22:6n-3 from sow milk resulted in 300% higher 22:6n-3 in liver and blood phospholipids and 11% higher 22:6n-3 in cerebrum of nursing piglets. Despite similar milk 20:4n-6, the % 20:4n-6 in tissues other than the brain was lower in piglets fed high22:6n-3 sow milk. Thus, high intakes of n-3 fatty acids decrease 20:4n-6 in piglet liver and blood lipids. The blood phospholipid % 22:6n-3 in piglets fed formulas containing 18:2n-6 and 18:3n-3 but not their long-chain derivatives, was lower than in piglets fed 22:6n-3 in natural milk, consistent with published findings in formula-fed infants. However, in contrast to circulating lipids, formulas with 4% 18:3n-3 maintained similar levels of 22:6n-3in the piglet CNS compared to milk. These studies show that blood phospholipid 22:6n-3 and 20:4n-6 are not specific indices of effects in CNS lipids. This thesis has shown (1) 22:6n-3 is not essential in the diet of the term piglet, if adequate 18:3n-3 is given, (2) fish oils are an effective source of 22:6n-3 for deposition in the developing brain, (3) high dietary n-3fatty acids interfere with 20:4n-6 metabolism, and (4) blood lipid 20:4n-6 and 22:6n-3 do not accurately reflect CNS fatty acids.

The purpose of the study is to assess the influence of correctional treatment on psychomotoric development in infants with muscle hypertonia. The following objectives were put forward: the assessment of specific features of the psychomotoric development of the infants with muscle hypertonia; to evaluate variations of psychomotoric function development; to compare infant psychomotoric development of the infants between in the experimental and control groups. Psychomotoric development of the infants' and the effectiveness of the correctional program were evaluated according to the Munich functional development diagnostic scale. Seven psychometric functions of the infants were being evaluated. Fifty - four infants with muscle hypertonia were included in the study, for which early correction of the disorders was recommended. The experimental group consisted of infants (n=30, at the average age of 6.45 ± 0.38 months) who underwent an early correctional development program applied by rehabilitation professionals at the correction service. The duration of correctional treatment lasted 1.85 ± 0.13 months. The control group (n=24, at the average age of 6.12 ± 0.40 months) consisted of the infants whom was correctional treatment recommended, but their parents refused it for various reasons or failed to complete. The following factors were analyzed: physical and intellectual development of the infants with muscle hypertonia, the age of infants, and their retardation from the... [to full text]

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.

For young infants, knowledge of physical objects and animate agents seems highly rigid, with no information combined across domains. Adult cognition, however, is more flexible. In this thesis, I use a special category of object—a tool—that can only be reasoned about appropriately if information is combined across domains. Using this special case, I examine whether older infants are capable of integrating functional information about the tool while making inferences about the intent of the tool-user. Experiment 1 shows that infants can reason about complex means-end sequences involving tools; and Experiments 2 and 3 both show that under some circumstances, infants can take into account functional information about the tool when making these sorts of inferences. Together, these studies extend previous findings about how infants understand complex means-end sequences, and demonstrate that by 13 months, infants are already combining knowledge across domains. / Thesis (Master, Psychology) -- Queen's University, 2007-08-28 11:26:07.974

No description available.

Premature birth occurs before parents have had time to prepare for the birth of the infant. This survey was conducted to describe the responses of fathers of preterm low birth weight babies (PTLBW) and their involvement in the care of those babies in a neonatal intensive care unit. A quantitative descriptive non-experimental study design using purposive sampling (a non -probability method of sampling) was adopted. Fifty fathers of PTLBW babies of less than 2500grams, who visited and were involved in the care of their babies in NICU, voluntarily participated in the study by completing a self-administered questionnaire. The questionnaire was designed to collect the demographic information of the participants and to address their responses and their involvement in the care of the baby. Analysis of the findings revealed that fathers reacted positively on the birth of their babies as the majority of the fathers indicated that they were happy despite the fact that their babies were born before time. Fathers in this study experienced varying reactions to the equipment that they saw being used on their babies, 76% mentioned that they were frightened. Moreover, the research findings revealed that a high percentage of fathers, 88%, in the study mentioned that talking to their wives, partners or spouses as well as talking to nurses and doctors in NICU was the main strategies that they had used to cope with their feelings. Teaching is part of the support available to fathers as a tool to enhance their psychological well being and increase their interdependence relationship. Fathers in this study indicated they received information about their babies during visits. Thirty four (68%) of the fathers in the study acknowledged that nurses gave the most teaching about the baby, baby's care, baby's progress and about their overall role while the baby is in NICU. The fathers also in the same manner demonstrated that the information that they received on the NICU environment has helped them to participate in the care of the baby. / Thesis (M.A.)-University of KwaZulu-Natal, 2007.

The present study examined 8 -10 month-old and 11 -13 month-old infants’ capabilities to infer constraints imposed by an explicit visual pathway on object movement of object. In a preferential looking paradigm, infants observed a ball rolling down a U– or V–shaped path. In the U-shaped path, infants observed a ball rolling from beginning to the end of the path (possible), and a ball rolling down from the beginning and stopping midway of the path (impossible). In the V-shaped path, infants observed a ball rolling from beginning and stopping midway (possible), and a ball rolling down the beginning to end of the path (impossible). Analyses of looking times showed a marginal effect on path, with longer looking times towards the possible V-shaped path by both age groups. Overall, infants had weak representations for constraints induced by an explicitly presented path on movement of the object.

This thesis examines inter-relationships between the feeding, health, and growth of infants (aged 0-24 months) in low-income households in Addis Ababa, Ethiopia. Mixed-longitudinal data were collected from a sample of 113 infants and their mothers in Kebele 11, Keftegna 24 from November 1987 to April 1988. Breastfeeding is the culturally esteemed mode of infant feeding. The culture-specific concept of weaning places the emphasis on the termination of breastfeeding, with little consideration of the quality and quantity of weaning foods. As a result, weaning foods are basic and monotonous. Survival data analysis shows that weaning is commenced at the mean age of 9.2 months, and completed at the median age of 20 months. A probabilistic model is proposed that includes a set of inter-related 'infant-centred', 'mother-centred', and other factors such as the seasonal availability of weaning foods influencing the process of weaning. Culturally-prescribed norms appear to play little or no part in the timing of weaning, in particular, the infant's age is of secondary importance. Direct observations of suckling behaviour and infant care reveal that 'on demand' breastfeeding was practised, and the mean duration of suckling sessions was 10.96 minutes. The duration of breastfeeding was influenced significantly by maternal body-mass index. Seasonal patterns were detected in the prevalence of fever, coughing, and vomiting in the infants. Associations between morbidity and other data using log-linear models suggest that infant's diarrhoea is closely linked to the level of household hygiene, maternal education, and mother's morale. Infant's ilnesses caused appreciable deficits in weight, but not in stature. Processes of 'catch-up' and 'catch-down' growth are demonstrated by the seasonal effect of diarrhoeal illness on weight. Avenues for further research and policy reform suggested by the findings of this study are discussed.

This project was designed to investigate the ability of newborn infants to respond to surgical stress and to consider alternative methods of anaesthetic management in view of their hormonal and metabolic response. Concentrations of blood metabolites (glucose, lactate, pyruvate, alanine, acetoacetate, 3-hydroxybutyrate, glycerol, non-esterified fatty acids, triglycerides) and plasma hormones (insulin, glucagon, noradrenaline, adrenaline, aldosterone, corticosterone, cortisol, 11-deoxycorticosterone, 11-deoxycortisol, progesterone, 17-hydroxyprogesterone, cortisone) were measured in blood samples drawn before and after surgery, at 6, 12 and 24 hours postoperatively. Urinary total nitrogen and 3-methylhistidine/ creatinine ratios were measured for 3 days postoperatively. Peri-operative management was standardised and severity of surgical stress was assessed by a scoring method. In a preliminary study of 29 neonates, substantial hormonal and metabolic changes demonstrated the ability of neonates to mount a stress response to surgery. Compared to adult responses, the magnitude of these changes was greater but their duration was remarkably short-lived. Significant differences were found between preterm and term neonates, and between neonates given different anaesthetic management. Randomised controlled trials were designed for studying the effects of : (1) halothane anaesthesia in 36 neonates undergoing general surgical procedures, (2) fentanyl anaesthesia in 16 preterm neonates undergoing ligation of patent ductus arteriosus, (3) high-dose fentanyl anaesthesia in 13 neonates undergoing cardiac surgery. On comparing the responses of neonates within each trial, the stress response of neonates given halothane or fentanyl anaesthesia was diminished; their : (a) catecholamine responses were decreased or abolished, (b) glucocorticoid responses were suppressed, (c) changes in blood glucose and gluconeogenic precursors were decreased, (d) postoperative analgesic requirements were reduced, and (e) their clinical condition after surgery was more stable. The neonatal response was related to the severity of surgical stress, as assessed by the scoring method. Thus, hormonal and metabolic changes following surgery in preterm and term neonates are distinctly different from those of adult patients; the lack of adequate anaesthesia may cause an accentuation of the stress response.