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Biomedical subjects

R M Harper

Publications and source records attributed to R M Harper.

At least 181 records · Page 10Linked to original sources
PubMed1977

Effects of feeding on state and cardiac regulation in the infant.

The effects of feeding on polygraphic state patterns and associated cardiac rates were examined in 8 normal infants using data collected during 12-hr continuous monitoring sessions at 1 week and at 1, 2, 3, 4, and 6 months of age. The distribution of states and corresponding heart rate values were tabulated for each minute during 2-hr periods preceding and following wakenings with and without feedings. Rapid eye movement (REM) sleep was significantly more prevalent immediately following a waking accompanied by feeding than waking alone. Moreover, a distinct relationship was demonstrated between feeding periods and the ongoing sleep cycle. In younger infants (1 week to 1 month), heart rates in quiet sleep (QS) and REM were higher after feeding than before, suggesting a general arousal influence. This was not the case with nonfeeding wakenings. In older infants (2-3 months), heart rates were higher after nonfeeding periods than before, but similar before and after feeding periods.

Feeding Behavior↗
PubMed1977

Polygraphic studies of normal infants during the first six months of life: III. Incidence of apnea and periodic breathing.

The incidence of apnea and periodic breathing was studied in full-term infants between birth and 6 months of age. Apnea was defined as a pause equal to or exceeding six seconds, periodic breathing as two cessations of breathing within a 20-second period, each equal to or longer than three seconds but less than six seconds. Sleep and cardiopulmonary variables were monitored. Apnea was common in the normal full-term infant. The incidence of apnea was highest in the newborn period and apneas exceeding 15 seconds were limited to this age. A reduction in apnea incidence occurred between birth and 3 months of age; thereafter, the incidence remained unchanged. The majority of apneas occurred during active sleep (AS). Few minutes were classified as indeterminate; the number of apneas during these minutes was comparable to those during AS. The incidence of apneas during quiet sleep was low. Periodic breathing remained stable across the ages, occurring primarily in AS. Apnea exceeding 15 seconds in rare in infancy. The tabulation of shorter apnea may be of limited value in identifying infants at risk for abnormal apnea due to extreme variability among infants. The sleep-waking state of the infants must be considered in order to evaluate apnea counts.

Apnea↗
PubMed1976

A new technique for long-term recording of eye movements in infants.

A device for recording eye movements from infants over long time periods is described. The device consists of an infrared light-emitting diode and a phototransistor mounted in a small package which covers one eye. The eyepiece is insensitive to EEG, EKG, or EMG potentials, and avoids irritation of the infant's skin from application of electrode paste. Detection of eye movements compares favorably to conventional eye movement electrodes.

Electronics, Medical↗
PubMed1976

Polygraphic studies of normal infants during the first six months of life. I. Heart rate and variability as a function of state.

This study examined spontaneous heart rate (HR) and variability as a function of age and sleep state in eight normal full term infants from birth to 6 months of age. Heart rates recorded during sleep were lower and less regular at 1 week (quiet sleep (QS) mean rate= 128, interquartile range = 6.4 beats/min; rapid eye movement (REM) = 134.5, 11.6) than at 1 month (QS = 138.6, 3.4; REM 139.6, 4.2). Rate decreased sharply from 1 to 3 months (QS = 118; REM 123.8) and decreased only slightly therafter (6-month QS = 113.5; REM 118.9). Variability decreased rapidly in REM from 2 to 4 months (from 11.4 to 9.1) and less quickly from 4 to 6 months (from 9.1 to 8.2), while QS variability decreased at 1 month (from 6.4 to 5.7) and became stable from that point (6.0 at 6 months). Waking heart rate and variability were both relatively low at 1 week (163, 11.2 beats/min) and increased from that age to 1 month (167.4, 14.3). Rate decreased rapidly in waking at 3 months (152 beats/min) and more slowly therafter (152 beats/min at 4 months, 149 beats/min at 6 months), whereas variability remained elevated until after 3 months, becoming stable at a lower level during later infancy (3 months = 14.8,6 months 11.7). Lowest values of rate and variability were found in QS and the highest values were found in waking at all ages, except at 1 week. Heart rates during REM closely approximated those in QS, whereas variability values more closely resembled those of waking.

Age Factors↗