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Biomedical subjects

N A Fox

Publications and source records attributed to N A Fox.

At least 37 records · Page 2Linked to original sources
PubMed1997

Behavioral and neuroendocrine responses in shy children.

Previous research has shown that infants who display a high frequency of motor activity and negative affect at 4 months of age are likely to be behaviorally inhibited toddlers. We examined social behaviors, maternal report of temperament, salivary cortisol, and baseline startle responses at age 4 in a sample of children, some of whom displayed a high frequency of motor activity and negative affect at 4 months of age. Infants who displayed this temperamental profile were reported by their mothers as more shy at age 4 compared with other children. We also found that 4-year-olds who displayed a high frequency of wary behavior during peer play exhibited relatively high morning salivary cortisol, were reported as contemporaneously shy by their mothers, and were behaviorally inhibited at 14 months of age. There were no significant relations found between baseline startle and morning salivary cortisol and measures of shyness at age 4. We speculate that high levels of cortisol in shy children may induce changes in the amygdala, exacerbating their fearfulness.

Affect↗
PubMed1997

EEG activation in 1-month-old infants of depressed mothers.

Previous research has documented differences in the pattern of EEG activation between 3-month-old infants of depressed mothers and infants of nondepressed mothers. In the present study, EEG was recorded in even younger 1-month-old infants of depressed and nondepressed mothers. The infants of depressed mothers exhibited greater relative right frontal EEG asymmetry (due to reduced left frontal activation), and this pattern at 1 month was significantly related to 3-month EEG asymmetry. Right frontal EEG asymmetry was also related to more frequent negative facial expressions (sad and pre-cry faces) during the Brazelton exam. Finally, the infants of depressed mothers showed more indeterminate sleep, were less active, and cried less than infants of nondepressed mothers.

Adolescent↗
PubMed1997

Factors affecting the outcome of orthodontic treatment within the general dental service.

Previous studies have suggested large differences in the outcome of orthodontic treatment as measured by the PAR index in two adjacent regions of England. The aim of this prospective study was to identify any factors contributing to the mean PAR score reduction in the North Western region and the Mersey region. Forty-one practitioners submitted 375 sets of start models and 250 end of treatment models. The study ran for 36 months. There were no significant differences detected in the type of malocclusion treated or in outcome of treatment between the two regions with respect to the PAR and IOTN indices. This study did, however, clearly demonstrate that qualified orthodontic practitioners were achieving significantly better results with fixed appliances that practitioners with no orthodontic qualification who used fixed appliances.

Adolescent↗
PubMed1997

Individual differences in object permanence performance at 8 months: locomotor experience and brain electrical activity.

This work was designed to investigate individual differences in hands-and-knees crawling and frontal brain electrical activity with respect to object permanence performance in 76 eight-month-old infants. Four groups of infants (one prelocomotor and 3 with varying lengths of hands-and-knees crawling experience) were tested on an object permanence scale in a research design similar to that used by Kermoian and Campos (1988). In addition, baseline EEG was recorded and used as an indicator of brain development, as in the Bell and Fox (1992) longitudinal study. Individual differences in frontal and occipital EEG power and in locomotor experience were associated with performance on the object permanence task. Infants successful at A-not-B exhibited greater frontal EEG power and greater occipital EEG power than unsuccessful infants. In contrast to Kermoian and Campos (1988), who noted that long-term crawling experience was associated with higher performance on an object permanence scale, infants in this study with any amount of hands and knees crawling experience performed at a higher level on the object permanence scale than prelocomotor infants. There was no interaction among brain electrical activity, locomotor experience, and object permanence performance. These data highlight the value of electrophysiological research and the need for a brain-behavior model of object permanence performance that incorporates both electrophysiological and behavioral factors.

Analysis of Variance↗
PubMed1996

Crawling experience is related to changes in cortical organization during infancy: evidence from EEG coherence.

Greenough's model of experience-expectant plasticity was used to examine EEG coherence among four groups of 8-month-old infants that varied in hands-and-knees crawling experience. Groups included prelocomotor infants, novice crawlers with 1-4 weeks experience, infants with 5-8 weeks, and long-term crawlers with 9+ weeks experience. Resting EEG was recorded from frontal, parietal, and occipital sites of both hemispheres. EEG coherence between intrahemispheric sites was computed. Novice crawlers (1-4 weeks) displayed greater coherence than either prelocomotor infants or experienced crawlers. These data suggest that the anticipation and onset of locomotion was related to an overproduction of cortico-cortical connections. Pruning of these overabundant connections may be a source of the decrease in coherence as crawling becomes more routine.

Electroencephalography↗
PubMed1996

Behavioral and physiological antecedents of inhibited and uninhibited behavior.

4-month-old infants were specifically selected for patterns of affective and motoric reactivity that were hypothesized to be associated with later inhibited and uninhibited behavior. Infants were classified as high on motor activity and negative affect, high on motor activity and positive affect, or low on motor activity and affect. Brain electrical activity was assessed in these infants at 9 months of age, and behavior toward novelty was observed at 14 months of age. Infants who were high on motor activity and negative affect exhibited greater right frontal EEG activation at 9 months of age and inhibited behavior at 14 months of age. Infants classified as high motor/high positive at 4 months of age exhibited uninhibited behavior at 14 months of age. No relations were found between frontal asymmetry at 9 months of age and inhibited behavior at 14 months of age. However, greater activation in both the left and right frontal hemispheres was associated with higher inhibition scores at 14 months of age. These findings are discussed in terms of the role that affective and physiological reactivity may play in the development of social behavior during toddlerhood.

Affect↗
PubMed1996

Perceptions of the risks and benefits of orthodontic treatment.

Recent National Health Service changes have brought about a greater involvement of the consumers of medical and dental care in decision making regarding their treatment. The aim of this study was to investigate the level of awareness of the risks and benefits of orthodontic treatment among potential consumers and their referring dentists. Parents of patients referred for orthodontic treatment were issued with a questionnaire about the risks and benefits of treatment and the reason the child had been referred. Study models were also made of the child's teeth. The patients' dentists were issued with a similar questionnaire. The results revealed that most of the parents were aware of the benefits of treatment in general and the reason that their own child required it. This awareness was greater where the orthodontic need on aesthetic grounds was greater. There was less awareness of the risks of treatment though again this was greater among those with a greater need for treatment. When the perceptions of the dentists were evaluated, they were more aware of the risks but were not communicating this to the parents. Since for some patients the risks of treatment may outweigh the benefits, it would be helpful if dentists could provide this information for patients before referral.

Adolescent↗
PubMed1996

Individual differences in emotion regulation and behavior problems in preschool children.

Emotion regulation (ER) was assessed during a negative mood induction in 79 preschoolers who varied in degree of behavior problems. Facial expressivity during the induction was used to identify 3 ER groups: inexpressive, modulated expressive, and highly expressive. Group differences in ER were significantly related to heart rate and skin conductance. Inexpressive preschoolers had the highest heart rate, lowest vagal tone, and smallest autonomic nervous system (ANS) change during the induction. Highly expressive preschoolers had the slowest heart rate, highest vagal tone, and largest ANS change. The inexpressive and highly expressive groups had more externalizing symptoms than the modulated group at preschool age and at follow-up at the end of 1st grade. Inexpressive preschoolers appeared to have more depressed and anxious symptoms at follow-up.

Adaptation, Psychological↗
PubMed1995

Of the way we were: adult memories about attachment experiences and their role in determining infant-parent relationships: a commentary on van IJzendoorn (1995).

In his meta-analysis of studies demonstrating the predictive validity of the Adult Attachment Interview (AAI), van IJzendoorn (1995) relies on current thinking in attachment theory. Although the data he presents are forceful, there are alternate explanations for the relations he finds that are ignored. Narrative about personal memories may be a function of personal theories about developmental processes as well as current psychological state (e.g., personal self-esteem). There is currently no evidence that the coherency of discourse about early childhood experiences is a function of either actual early experience or reworkings of that experience. In the absence of such evidence, the data indicating that maternal personality influences infant behavior are not theoretically surprising.

Humans↗
PubMed1995

Frontal activation asymmetry and social competence at four years of age.

The pattern of frontal activation as measured by the ongoing electroencephalogram (EEG) may be a marker for individual differences in infant and adult disposition to respond with either positive or negative affect. We studied 48 4-year-old children who were first observed in same-sex quartets during free-play sessions, while making speeches, and during a ticket-sorting task. Social and interactive behaviors were coded from these sessions. Each child was subsequently seen 2 weeks later when EEG was recorded while the child attended to a visual stimulus. The pattern of EEG activation computed from the session was significantly related to the child's behavior in the quartet session. Children who displayed social competence (high degree of social initiations and positive affect) exhibited greater relative left frontal activation, while children who displayed social withdrawal (isolated, onlooking, and unoccupied behavior) during the play session exhibited greater relative right frontal activation. Differences among children in frontal asymmetry were a function of power in the left frontal region. These EEG/behavior findings suggest that resting frontal asymmetry may be a marker for certain temperamental dispositions.

Affect↗
PubMed1994

Cardiorespiratory functioning of preterm infants: stability and risk associations for measures of heart rate variability and oxygen saturation.

Cardiorespiratory measures are used with increasing frequency to assess individual differences in development in full-term and preterm infants, yet little information exists concerning the stability of these measures or their relations to each other. This study assessed three common cardiac measures (heart period, heart period variability, and vagal tone) and two measures of arterial oxygenation based on pulse oximetry (mean pulse oxygen saturation and variability) in a sample of 35 preterm infants. Data were collected on five occasions: on 3 consecutive days in the early neonatal period, at 34 weeks postconceptional age, and at discharge. Results indicate both short-term and longer term stability for all cardiac measures. Oxygen saturation demonstrated only short-term stability prior to 34 weeks. Mean heart period was positively associated with both measures of heart period variability at each assessment point, while mean oxygen saturation level was inversely related to oxygen saturation variability. In addition, significant associations between cardiorespiratory patterns and perinatal risk measures were found. It is concluded that these measures reflect stable characteristics of neuroregulatory function in preterm infants.

Age Factors↗
PubMed1994

Patterns of cortical electrophysiology and autonomic activity in adults' shyness and sociability.

We examined differences in brain electrical activity (EEG), heart rate (EKG), heart rate variability, and behavior among 40 young women who were selected for high (HI) and low (LO) self-ratings of shyness and sociability. EEG and EKG were continuously recorded for 6 min from each subject, just prior to an expected novel social encounter. Each subject was also observed unobtrusively for 5 min during the social encounter. Analyses indicated that the pattern of frontal EEG asymmetry was related to sociability, but not to shyness. LOSOCIABLE subjects displayed greater relative right mid-frontal activation while HISOCIABLE subjects displayed greater relative left mid-frontal activation. A significant shy x sociable interaction was found for parietal asymmetry and for measures of heart rate and heart rate variability. LOSHY/HISOCIABLE subjects displayed greater relative right parietal activation while LOSHY/LOSOCIABLE subjects displayed greater relative left parietal activation. And HISHY/HISOCIABLE subjects displayed a significantly higher and more stable (less variable) heart rate than HISHY/LOSOCIABLE and LOSHY/HISOCIABLE subjects. Analyses also indicated that LOSOCIABLE subjects displayed significantly more signs of nonverbal social avoidance as compared with HISOCIABLE subjects. The present findings suggest that shyness and sociability may be subserved by different neurophysiological systems.

Adolescent↗
PubMed1994

A critique of bond strength testing in orthodontics.

The literature contains a large number of publications on in vitro bond strength testing of materials used in orthodontics. The results are often quoted by manufacturers to support their products. Little attention has been paid to the detail of the test procedures used. However, a review of the literature revealed a large variation in the methods used for bond strength testing in orthodontics making comparison of papers difficult and often impossible. The case for a possible standard technique is suggested. It is hoped that this will lead to more meaningful testing of new products, which will produce more reliable guidance for the clinical orthodontist.

Animals↗
PubMed1994

Behavioral and physiologic effects of nonnutritive sucking during gavage feeding in preterm infants.

Behavioral and physiologic responsivity to nasogastric gavage feeding was assessed in 36 preterm infants on 2 consecutive d. On one of these days, a pacifier was provided during and after the gavage segment of the standardized protocol. The protocol was divided into segments that included baseline, preparatory handling, pregavage, gavage, and postgavage periods. Patterns of cardiac (heart period and vagal tone), oxygen saturation, behavioral state, and defensive behavioral responses to gavage were quantified. These stable preterm infants responded to handling and gavage feeding with reduction in heart period, vagal tone, and oxygen saturation. These responses were not altered by provision of a pacifier, although there was a tendency for fewer episodes of bradycardia and oxygen desaturation. Conversely, behavioral state was affected significantly by nonnutritive sucking: when provided with a pacifier, infants exhibited less behavioral distress, spent less time in fussy and active awake states during and after feeding, and returned to a sleep state significantly faster. There is converging evidence to suggest that nonnutritive sucking lessens behavioral distress to iatrogenic stressors but does not alter physiologic responsiveness.

Enteral Nutrition↗
PubMed1994

The first 100 cases of orthodontic treatment: one year out of retention.

The Index of Orthodontic Treatment Need (IOTN) and Peer Assessment Rating (PAR) Index have been developed to assess need and outcome of orthodontic treatment. In this paper the authors evaluate the occlusal change and orthodontic treatment need of 100 consecutively started courses of orthodontic treatment at least 1 year after all retention measures had ceased using these indices.

Esthetics, Dental↗