Circadian Rhythms and Nursing Research: Methodological Considerations

Elmore, Shawn K.; Burr, Robert L.

doi:10.1891/1061-3749.1.1.81

Cited by 7 publications

(6 citation statements)

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“…These segments of data were excluded from computation of the diurnal rhythm summaries. A natural log transform was uniformly applied to the actigraphy epoch count data sequences, which were then processed to compute sets of established diurnal rhythm summary measures: (1) the three parameter fixed period single harmonic 24-h cosinor model family (mesor, magnitude, acrophase) and an associated descriptor of within-subject goodness of fit ( R 2 ) of the model (Elmore & Burr, 1993), (2) the Nonparametric Circadian Rhythm Analysis (NPCRA) family (L5 level and midpoint), M10 level and midpoint, midlevel, amplitude, relative amplitude (RA), interdaily stability (IS), intradaily variability (IV) (Van Someren et al, 1999), and (3) the 24-h lag serial autocorrelation measure (ACF at 1440 min) (Calogiuri, Weydahl, & Carandente, 2013; Nishihara, Horiuchi, Eto, & Uchida, 2001; Nishihara et al, 2002, 2012). …”

Section: Methodsmentioning

confidence: 99%

Maternal and infant activity: Analytic approaches for the study of circadian rhythm

Thomas

Burr

Spieker

2015

Infant Behavior and Development

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The study of infant and mother circadian rhythm entails choice of instruments appropriate for use in the home environment as well as selection of analytic approach that characterizes circadian rhythm. While actigraphy monitoring suits the needs of home study, limited studies have examined mother and infant rhythm derived from actigraphy. Among this existing research a variety of analyses have been employed to characterize 24-h rhythm, reducing ability to evaluate and synthesize findings. Few studies have examined the correspondence of mother and infant circadian parameters for the most frequently cited approaches: cosinor, non-parametric circadian rhythm analysis (NPCRA), and autocorrelation function (ACF). The purpose of this research was to examine analytic approaches in the study of mother and infant circadian activity rhythm. Forty-three healthy mother and infant pairs were studied in the home environment over a 72 h period at infant age 4, 8, and 12 weeks. Activity was recorded continuously using actigraphy monitors and mothers completed a diary. Parameters of circadian rhythm were generated from cosinor analysis, NPCRA, and ACF. The correlation among measures of rhythm center (cosinor mesor, NPCRA mid level), strength or fit of 24-h period (cosinor magnitude and R2, NPCRA amplitude and relative amplitude (RA)), phase (cosinor acrophase, NPCRA M10 and L5 midpoint), and rhythm stability and variability (NPCRA interdaily stability (IS) and intradaily variability (IV), ACF) was assessed, and additionally the effect size (eta2) for change over time evaluated. Results suggest that cosinor analysis, NPCRA, and autocorrelation provide several comparable parameters of infant and maternal circadian rhythm center, fit, and phase. IS and IV were strongly correlated with the 24-h cycle fit. The circadian parameters analyzed offer separate insight into rhythm and differing effect size for the detection of change over time. Findings inform selection of analysis and circadian parameters in the study of maternal and infant activity rhythm.

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Section: Methodsmentioning

confidence: 99%

Maternal and infant activity: Analytic approaches for the study of circadian rhythm

Thomas

Burr

Spieker

2015

Infant Behavior and Development

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“…[21][22][23] Mesor (mean of fitted curve) and median (midpoint) are measures of cycle central tendency. MAD (a nonparametric equivalent of standard deviation) and amplitude (mesor-to-peak difference) are measures of variance.…”

Section: Resultsmentioning

confidence: 99%

Preterm Infant Thermal Care: Differing Thermal Environments Produced by Air Versus Skin Servo-Control Incubators

Thomas

Burr

1999

J Perinatol

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OBJECTIVE:Incubator thermal environments produced by skin versus air servo-control were compared. STUDY DESIGN:Infant abdominal skin and incubator air temperatures were recorded from 18 infants in skin servo-control and 14 infants in air servo-control (26-to 29-week gestational age, 14 Ϯ 2 days postnatal age) for 24 hours. Differences in incubator and infant temperature, neutral thermal environment (NTE) maintenance, and infant and incubator circadian rhythm were examined using analysis of variance and scatterplots. RESULTS:Skin servo-control resulted in more variable air temperature, yet more stable infant temperature, and more time within the NTE. Circadian rhythm of both infant and incubator temperature differed by control mode and the relationship between incubator and infant temperature rhythms was a function of control mode. CONCLUSION:The differences between incubator control modes extend beyond temperature stability and maintenance of NTE. Circadian rhythm of incubator and infant temperatures is influenced by incubator control.Maintenance of body temperature is a primary challenge facing the preterm infant. Preterm infants are vulnerable to both overand under-heating resulting from limited heat production capacity, propensity for heat loss related to body configuration, skin maturation, and immature sudomotor responses. Incubators, the mainstay in providing thermal care for these fragile infants, operate in two modes: air and skin servo-control. 1,2 The choice of air versus skin servo-control is typically based on infant clinical parameters such as birth weight, gestational age, and health status, and unit protocol, individual care provider preference and experience, equipment availability, marketing, purchasing decisions, and trends in neonatal care.The research examining incubator control mode has focused essentially on the description of environmental temperature stability, efficacy in maintaining a neutral thermal environment (NTE), and minimizing oxygen consumption. In general, skin servo-control incubators produce incubator air temperatures that are extremely variable, often exhibiting a lag effect in response to infant temperature change and overshoot and undershoot. Excursions in incubator temperature greater than 2°C have been reported during skin servocontrol operation. 3,4 Variability in air temperature is also related, in part, to the discrepancy between air temperature, measured at the site of the thermostat, and the incubator temperature as a whole; specifically, air temperature recorded mid-incubator differs from temperature measured at the thermostat. 4 The variable air temperatures observed in skin servo-control incubators result in part from probe artifacts. 4 -7 The two types of artifact in skin temperature measurement are: (1) probe insulation, resulting in probe temperature falsely greater than skin surface temperature and consequently lower incubator (or radiant warmer) temperature, and (2) convective and radiant heating or cooling of the skin probe by the surrounding environment. ...

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“…Finally, cosinor analysis assumes the presence of a deterministic cycle that is sinusoidal with a known period length, amplitude, and phase (Lentz 1990). Yet, rhythmic phenomena that do not meet these assumptions exist for 24-h periods, as well as other time intervals (Elmore and Burr 1993). Thus, if a rhythm is not detected by cosinor analysis, one cannot conclude that a rhythm does not exist.…”

Section: Discussionmentioning

confidence: 98%

How Enteral Feeding Options Influence Corticosterone Patterns in Rats

Westfall

2000

Biological Research For Nursing

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Even with all the nutritional research conducted to date, it is not clear which enteral nutrition delivery and composition options are most physiologically sound. Glucocorticoid temporal patterns are reported to be shifted or disrupted with restricted feeding schedules, but because of intermittent sampling, temporal patterns have not been completely depicted. The purpose of this study was to characterize corticosterone temporal patterns while systematically varying selected enteral feeding options in a well-established nutritional animal model. A 2 x 2 x 2 x 2 randomized block experimental design was used in which enteral feeding schedules, delivery methods, kilocalorie levels (kcal), and fiber contents were systematically varied in rats (n = 80), and plasma corticosterone was measured by 125I radioimmunoassay. Blood samples were drawn hourly over 24 h. With cosinor analysis, 24-h and 12-h corticosterone rhythmic components were tested in each feeding group. Five of 16 feeding groups had a significant (p < or = 0.05) 24-h rhythmic component, and 3 more showed a trend (p > 0.05 < 0.10); 7 of these groups were on 24-h feeding schedules. When rhythmic components were detectable, groups receiving high-fiber formula displayed more uniform rhythm characteristics than did no-fiber groups. Only 1 group had a significant 12-h rhythmic component, and 1 showed a trend. Both were on 12-h, high-fiber restricted kcal feedings. In this small animal sample, no one enteral feeding option guaranteed a 24-h corticosterone pattern. The option coming closest was formula delivered on a 24-h schedule. This temporal pattern is one aspect to consider in enteral nutrition. The underlying mechanisms have yet to be elucidated.

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Circadian Rhythms and Nursing Research: Methodological Considerations

Cited by 7 publications

References 0 publications

Maternal and infant activity: Analytic approaches for the study of circadian rhythm

Maternal and infant activity: Analytic approaches for the study of circadian rhythm

Preterm Infant Thermal Care: Differing Thermal Environments Produced by Air Versus Skin Servo-Control Incubators

How Enteral Feeding Options Influence Corticosterone Patterns in Rats

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