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Biomedical subjects

A F Korner

Publications and source records attributed to A F Korner.

At least 19 recordsLinked to original sources
PubMed1991

Establishing the reliability and developmental validity of a neurobehavioral assessment for preterm infants: a methodological process.

The Neurobehavioral Assessment of the Preterm Infant was developed in 3 phases: a pilot study, an exploratory study, and a validation study. In the exploratory study, clusters characterized by conceptual cohesion and face validity were systematically subjected to statistical analyses to determine whether they also had high test-retest reliability and developmental validity. In the validation study, a shortened version of the test was used with an independent cohort of 290 preterm infants. A step-by-step methodological process was used to test whether the results from the exploratory study would generalize over cohorts, different versions of the test, different hospitals, and changes in examiners. This process yielded 7 highly stable, developmentally valid, and representative preterm neurobehavioral functions that generalized over the exploratory and the validation studies. These were: motor development and vigor, scarf sign, popliteal angle, alertness and orientation, percent asleep ratings, irritability, and vigor of crying.

Apgar Score↗
PubMed1990

Infant stimulation. Issues of theory and research.

This article addresses the topic of infant stimulation from two directions. The first is the developmental relevance of stimulation for infants in general; the second is the issue of differences in responsiveness to stimulation on the part of individual infants. The author will elucidate the conceptual differences between these two issues by giving examples, mostly from intervention studies with preterm infants.

Humans↗
PubMed1990

Sleep enhanced and irritability reduced in preterm infants: differential efficacy of three types of waterbeds.

The purpose of this study was to determine whether waterbeds enhance preterm infants' sleep and reduce irritability, and whether plain, continuously, or intermittently oscillating waterbeds are differentially effective in producing these effects. The baseline states and motility of 52 stable preterm infants were assessed on two consecutive days for 100 minutes each. The infants then were randomly assigned to four groups: a control group who remained on the incubator mattress, or to one of the three experimental groups, each using a different waterbed. On days 3 and 4 in the assigned test condition, the infants' states and motility were again assessed for 100 minutes each day. The results indicate that, compared with infants in the control group, infants assigned to any of the waterbed groups slept significantly more and better, had significantly fewer unsmooth movements, state changes, and transitional states, and were significantly less irritable. Differential treatment effects were found, with infants on continuously oscillating waterbeds showing the most marked reductions in irritability, restlessness, state changes, and unsmooth movements. Thus, to enhance restful sleep and to reduce irritability and/or restlessness, it would be clinically advantageous to use waterbeds in the care of preterm infants. Since even the simple, nonoscillating waterbed improved sleep and reduced restlessness, the use of these beds would be the least costly to achieve these effects.

Arousal↗
PubMed1989

Stable individual differences in developmentally changing preterm infants: a replicated study.

In a longitudinal study with the Neurobehavioral Maturity Assessment (NB-MAP), developmental changes and stability of individual differences were assessed in 2 independent samples of preterm infants ranging from 32 weeks conceptional age to term. Individual stability of response was assessed using regression analysis with repeated measures on subjects. The large majority of the functions tested showed highly significant developmental gains with age and highly significant individual stability of performance across age. These findings replicated well across the 2 cohorts. The results are discussed in the light of the neurobiological stage of development of preterm infants during the last 8 weeks prior to term.

Humans↗
PubMed1987

Does a vigorous feeding style influence early development of adiposity?

A prospective study of a cohort of healthy infants observed from birth to 2 years of age was carried out to investigate factors influencing the development of early adiposity. Infant suckling was measured in the laboratory twice during the first month of life. Multiple regression analyses revealed that parental educational level and a measure of feeding behavior, the interval between bursts of suckling, accounted for 18% of the variance in triceps skinfold measures at 1 year of age. A lower level of education and shorter interburst interval were associated with increased adiposity. Two feeding variables, pressure of suckling and the number of reported feeds per day, accounted for 21% of the variance in skinfold thickness at 2 years of age. Fewer, but larger, feeds and a higher sucking pressure were associated with a greater degree of adiposity. It seems that a vigorous infant feeding style, consisting of sucking more rapidly, at higher pressure, with a longer suck and burst duration, and a shorter interval between bursts of sucking, is associated with higher caloric intake and greater adiposity. The early development of this feeding style suggests that it may be a genetically endowed behavior. Breast-feeding protected against early adiposity only to the age of 6 months in this cohort of infants.

Birth Weight↗
PubMed1987

A methodological approach to developing an assessment procedure for testing the neurobehavioral maturity of preterm infants.

Using data from 179 preterm infants, a neurobehavioral maturity assessment was developed by using a process in which clusters characterized by conceptual coherence and face validity were systematically subjected to statistical analyses designed to test whether they also had high test-retest reliability, statistical cohesion, and developmental validity. The psychometric soundness of the test items was made a precondition for their inclusion into the assessment procedure. Also tested were cluster redundancy, as well as the impact of gestational and conceptional age, and of postbirth influences on the functions tested. 8 dimensions of neurobehavioral functioning were found to be stable with a test-retest reliability of at least .6 or higher on 2 consecutive days, nonredundant and developmentally valid. They were: Active Tone/Motor Vigor, Alertness and Orientation, Excitation Proneness, Inhibition Proneness, Scarf Sign, Popliteal Angle, Maturity of Vestibular Response, and Vigor of Crying.

Arousal↗
PubMed1985

Physical activity and adiposity: a longitudinal study from birth to childhood.

Physical activity was reassessed in cohort of 52 children aged 4 to 8 years whose activity had been measured during the first 3 days of life. Neonatal adiposity was not significantly correlated with parental adiposity, neonatal physical activity, or gender, nor was neonatal activity significantly correlated with adiposity in childhood. Neonatal adiposity did not predict adiposity in childhood. However, in a stepwise multiple regression, parental adiposity and the children's daytime high activity levels were significantly associated with childhood adiposity. The age or gender of the child did not significantly correlate with childhood adiposity. As parental adiposity increased or daytime high activity of a child decreased, the adiposity in a 4- to 8-year-old child was likely to increase.

Adipose Tissue↗
PubMed1985

Activity level and behavioral style in young children.

A portable microcomputer activity recorder was used to measure a 24-hour sample of activity level in 4-to 8-year-old children. Recorded activity level was not related to parental perception of activity level and did not differentiate children with differing behavioral styles. Parental perception of activity level, on the other hand, significantly differentiated children's behavioral style. Parents may be responding to a composite image of the child's behavioral style when they rate activity level. We urge caution in the use of the term 'activity level', which may have different meanings according to how it is measured.

Child↗
PubMed1985

The relation between neonatal and later activity and temperament.

Evidence from several longitudinal studies suggests that individual activity characteristics tend to persist over time and to influence the development of temperamental style. The activity of 50 children whose motility had been monitored by an electronic activity monitor when they were neonates was again monitored by an ambulatory microcomputer when they were 4-8 years old. Additionally, the parents of these children filled out the Behavioral Style Questionnaire by McDevitt and Carey. The results showed that the level of the children's day and night activity was unrelated. The vigor of neonatal movements was later positively related to high daytime activity. Also, the least vigorous infants tended to become the most inactive children during the day. The results further showed that the most active neonates became children who, as perceived by their parents, tended to approach rather than withdraw from new experiences.

Affect↗
PubMed1983

Effects of vestibular-proprioceptive stimulation on the neurobehavioral development of preterm infants: a pilot study.

This paper reports the results of an intervention study which assessed the effects of compensatory vestibular-proprioceptive stimulation provided by waterbed flotation on the neurobehavioral development of preterm infants. The subjects, who were randomly assigned to experimental and control groups before they were four days old, consisted of infants who were on ventilators for severe RDS. Twenty infants were tested with a new neurobehavioral assessment procedure when they were between 34 and 35 weeks conceptional age. The examiner, a pediatric neurologist, was unaware of the group status of the subjects he examined. The results showed that infants in the experimental group performed significantly better in attending and pursuing animate and inanimate visual and auditory stimuli, demonstrated more mature spontaneous motor behavior, showed significantly fewer signs of irritability and/or hypertonicity and were more than twice as often in th visually alert, inactive state. The assessment procedure, which can be used for longitudinal evaluation of infants ranging between 24 and 36 weeks conceptional age, shows promise of becoming generally useful as a research instrument. Our preliminary results show that the procedure discriminated between an experimental and control group, that inter-observer reliability was readily established and that test-retest reliability is very high in a number of important areas of neurobehavioral functioning.

Beds↗
PubMed1978

Reduction of sleep apnea and bradycardia in preterm infants on oscillating water beds: a controlled polygraphic study.

The sleep and respiratory patterns of eight apneic preterm infants were polygraphically recorded for 24 hours. This polygraphic study was designed to test and extend our previous finding that gently oscillating water beds reduce apnea in premature infants. The infants who ranged in gestational age from 27 to 32 weeks and in birth weight from 1,077 to 1,650 gm served as their own controls, off and on the water bed. The 24-hour recordings were divided into four time blocks with the infant being placed on the water bed during alternate six-hour periods. Apnea was significantly reduced while the infants were on the oscillating water beds, with the longest apneic periods and those associated with severe bradycardia being reduced the most. Reduction of apnea was most consistent during indeterminate sleep and most pronounced during quiet sleep. Short respiratory pauses and periodic breathing were not significantly reduced. Reductions of central, obstructive, and mixed apneas were approximately equal.

Apnea↗
PubMed1976

Individual consistency in behavioral states in neonates.

In this study we identified consistent characteristics of the sleep-wake state of newborn infants. Forty-one normal, full-term infants were observed in a warmer-skin temperature maintained at 36.1 degree C--located in a sound-attenuated room for 1 hr during 2 successive mid-feeding periods. The infant's state was recorded on a check-list every 10 sec using the following categories for sleep and wakefulness: Quiet Sleep A, Quiet Sleep B, Active Sleep Without REM, Active Sleep With REM, Active Sleep With Dense REM, Drowsy, Alert Inactivity, WAKING Activity, Fussing, Crying, and Indefinite State. Immediately following the completion of each observation, the 2 observers made independent judgments of the degree of organization shown by the infant, using a 6-point scale. Over the two 1-hr observations, only Quiet Sleep A, Quiet Sleep B, and Crying showed any consistency. Active Sleep as typically defined showed no consistency whatsoever. However, 2 of the 3 components of Active Sleep were significantly reliability measures for the 2 observations; in sleeping infants all 3 components of active sleep showed high reliability. These results indicate that Active Sleep may be a composite of at least 3 meaningful categories. To look at overall state organization in the neonate, including both sleep and wake states, we considered Active Sleep as 3 separate states and then combined the resulting 11 behavioral states into derived clusters such that each combination of states showed a test-retest reliability above .52. With these 5 state clusters we viewed each infant's state behaviors in terms of a profile depicting the percent of time spent in each state cluster. We found a close association between these profiles and the subjective judgments of sleep-wake state organization made by the observers. The results clearly indicate that a 1-hr observation provides reliable information on individual sleep-wake states in the newborn.

Child Behavior↗
PubMed1976

The relative efficacy of vestibular-proprioceptive stimulation and the upright position in enhancing visual pursuit in neonates.

48 healthy neonates born to multiparae were randomly assigned to view a moving stimulus either in the horizontal or the upright position, with or without added vestibular stimulation and with or without pacifier sucking. The infant was shown a moving black line inside a strictly controlled visual environment provided by an apparatus which permitted horizontal and upright positioning and displacement of the infant. Visual tracking was recorded by a concealed TV camera positioned at a constant distance and angle from the infants' eyes in both positions. Quality of tracking during each of 4 trials was scored on a 7-point scale. Results indicate that vestibularproprioceptive stimulation provided to the infant either horizontally or semivertically significantly enhanced his visual tracking, whereas the upright position did not. Pacifier sucking also improved his performace.

Eye Movements↗
PubMed1975

Effects of waterbed flotation on premature infants: A pilot study.

Two types of waterbeds were developed to impart compensatory vestibular-proprioceptive stimulation to premature infants. Twenty-one infants ranging in gestational age from 27 to 34 weeks and birthweights from 1,050 to 1,920 gm were included in this pilot study. Assignment to experimental and control groups was made by random design. The experimental group consisted of ten infants who were placed on a gently oscillating waterbed before the sixth postnatal day, where they remained for seven days. Their clinical progress was compared with that of a control group of 11 similar babies. Waterbed flotation was found to be a safe procedure; there was no significant effects on the infants' vital signs, weight, or frequency of emesis. Highly significant differences were found in the incidence of apnea between the two groups, with infants on the oscillating waterbed having significantly fewer apneic spells. Infants placed on the waterbed during the first four postnatal days benefited more than those placed later. A non-oscillating waterbed was found clinically useful for very small prematures with severe skin problems, for infants recovering from abdominal surgery, and for infants receiving parenteral nutrition.

Apnea↗