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Biomedical subjects

J D Frost

Publications and source records attributed to J D Frost.

12 recordsLinked to original sources
PubMed1992

Sleep organization and energy expenditure of breast-fed and formula-fed infants.

Sleep organization of infants may be influenced by differences in nutrient intakes from human milk and formula. Because sleep/awake and sleep stage patterns affect energy expenditure, we hypothesized that differences in sleep organization between breast-fed and formula-fed infants might account in part for differences in energy expenditure between feeding groups. Sleep stages and cycling of 4-mo-old breast-fed (n = 10) formula-fed (n = 10) infants were studied with simultaneous measurements of energy expenditure. EEG, electrooculogram, body movement by triaxial accelerometry, heart rate, and oxygen saturation were monitored during an overnight sleep session. Sleep stages, nonrapid eye movement (NREM), and rapid eye movement (REM) were determined. Behavioral observations were recorded by video tape and by a technologist. Oxygen consumption and carbon dioxide production were measured with an indirect calorimeter. Total number and duration of sleep cycles, REM latency, number of NREM and REM epochs, and duration of NREM epochs did not differ between feeding groups. Sleep latency was shorter (p < 0.05) and duration of REM epochs longer (p < 0.01) in the formula-fed group. Formula-fed infants spent a higher percentage of sleep time in REM compared with the breast-fed infants (42 versus 34%) (p < 0.003). Conversely, breast-fed infants spent a higher percentage of sleep time in NREM sleep and their heart rates during sleep were lower (114 versus 126 bpm; p < 0.01). Energy expenditure during REM sleep was 13.0 +/- 4.4% higher than during NREM sleep (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗
PubMed1979

Precise characterization and quantification of infantile spasms.

With the use of a time-synchronized video and polygraphic recording system, 5,042 infantile spasms were monitored and analyzed in 24 infants aged 1 to 43 months. Of these, 33.9% were flexor, 22.5% extensor, and 42.0% mixed flexor-extensor. Sometimes the spasms were followed by a period of akinesia and diminished responsiveness lasting up to 90 seconds, and rarely (1.0%) this "arrest" effect constituted the entire seizures. More than one type of seizure occurred in 21 of the 24 infants. In the same number, 78.3% of the seizures occurred in clusters, and the intensity and frequency of the spasms in each cluster often increased to a peak, then progressively decreased until they stopped. Predominantly, the clusters occurred soon after arousal from sleep. The number of seizures occurring at night (55.2%) was similar to the diurnal number (44.8%). The electroencephalographic seizure pattern was variable, but a marked generalized attenuation of electrical activity was a feature of 71.7% of the attacks. Attenuation episodes of similar degree and duration occurred with no evidence of a seizure.

Electroencephalography↗
PubMed1979

Microprocessor-based EEG spike detection and quantification.

A microprocessor-based system for the detection and quantification of sharp EEG waveforms is described. The hierarchical approach utilises initial transient detection based on computation of a second-derivative measure of curvature, followed by pattern-recognition and artifact-rejection routines based on consideration of specific waveform parameters. Initials results demonstrate an ability to approximate human-analysis results, while providing precise measures of amplitude, duration, and sharpness. The decreasing cost of microprocessors makes multichannel configurations economically feasible.

Analog-Digital Conversion↗
PubMed1979

A controlled study of prednisone therapy in infantile spasms.

A controlled study of 12 patients with infantile spasms was performed to determine the effectiveness of prednisone treatment. Patients were monitored serially, using a time-synchronized polygraphic and video system. Three patients (25%) showed prompt reduction in seizure frequency and normalization of the EEG after institution of treatment. The remaining patients showed no improvement in seizure frequency or significant change in the EEG.

Cerebral Hemorrhage↗
PubMed1979

Insomnia in the elderly: treatment with flurazepam hydrochloride.

Under sleep-laboratory control, the efficacy of flurazepam hydrochloride (15 mg) was evaluated in 6 women (age range, 67-82 years) with objectively verified insomnia. A 15-night, single-blind, crossover procedure was followed. Sleep records obtained during 3 placebo-baseline nights, 7 consecutive flurazepam nights, and 3 placebo-withdrawal nights were evaluated by means of electroencephalographic, electro-oculographic, and electromyographic criteria. A statistically significant reduction in sleep latency and total awake time and a corresponding increase in total sleep time (P less than 0.05) were demonstrated during the active drug period. No evidence of diminishing effectiveness was observed during the 7 days of drug administration. For the rapid-eye-movement (REM) stage, a significant decrease (P less than 0.05) in mean REM percent was noted during the drug period despite an increase in mean absolute REM time. No REM rebound occurred upon drug withdrawal. There were no significant changes in mean percentages for stages 3 and 4 during the drug period and the withdrawal period. Adverse reactions were rare (chiefly some daytime drowsiness in 2 subjects).

Aged↗
PubMed1978

Quantitative analysis and characterization of infantile spasms.

An effective, time-synchronized monitoring system for the study of patients with infantile spasms has been developed. This system utilizes concurrent graphically recorded data, including EEG, body movement via triaxial accelerometry, respiration, electrocardiogram, electromyogram, electro-oculogram, and galvanic skin response. These data, when evaluated in conjunction with a closed-circuit TV recording of the patient, greatly facilitate the differentiation of seizures from nonictal activity and permit the characterization and quantification of the behavioral, motor, and autonomic phenomena intrinsically associated with infantile spasms.

Electrocardiography↗
PubMed1977

Clinical research techniques in tardive dyskinesia.

The authors have developed standardized assessment and control techniques designed to provide objective measures of tardive dyskinesia in patients progressing through an experimental treatment program. Standardized videotaping is carried out and blind ratings on the Abnormal Involuntary Movement Scale are made by a team of psychiatrists and neurologists. Other assessments include several measurements of vocal function and a quantitative acceleration profile standardized on normal subjects. Such measures allow quantifiable determination of response to drug treatment and may provide clues to the etiology and definition of the dyskinetic syndrome.

Central Nervous System↗
PubMed1976

Sleep monitoring: the second manned Skylab mission.

The first objective measurements of man's ability to obtain adequate sleep during prolonged space flight were made during the three manned Skylab missions. EEG, EOG, and head-motion signals were acquired during sleep by use of an elastic recording cap containing sponge electrodes and an attached miniature preamplifier/accelerometer unit. A control-panel assembly, mounted in the sleep compartment, tested electrodes, preserved analog signals, and automatically analyzed data in real time (providing a telementered indication of sleep stage). One subject was studied during each manned mission and, while there was considerable variation among individuals, several characteristics were common to all three: stage 3 sleep increased during the flight and decreased in the postflight period; stage 4 was consistently decreased postflight, although this stage was variable during the flight; stage REM (rapid eye movement) was elevated, and REM latency decreased in the late postflight period (after day 3 postrecovery); and the number of awakenings during sleep either showed no change or decreased during the flight. In only the 28-d mission (Skylab 2) was there a significant decrease in total sleep time; in that case it was a result of voluntarily reduced rest time and was not due to difficulty in sleeping nor frequent awakening. The subject on the 84-d mission (Skylab 4) experienced more difficulty in the first half of the flight, showing a decreased total sleep time and increased sleep latency, but this resolved itself with time. Sleep latency presented no problem in the other flights. While many of the findings are statistically significant, in no case would they be expected to produce a noticeable decrement of performance capability. These findings suggest that men are able to obtain adequate sleep in regularly scheduled 8-h rest periods during extended space flights. It seems likely, based upon these results, that the problems encountered in earlier space flights did not arise from the zero-g environment per se but possibly were a result of more restricted living and working areas in the pre-Skylab spacecraft.

Adult↗
PubMedDate not supplied

Spike morphology in childhood focal epilepsy: relationship to syndromic classification.

The waveform morphology of interictal spike activity associated with uncontrolled childhood focal epilepsy was quantified in 40 patients by a computer-based technique. The findings were then analyzed with respect to epileptic syndromes. Samples of spike activity from each patient were characterized by determination of average amplitude (A), duration (D), and sharpness (S). A single morphologic index, the composite spike parameter (CSP), was also derived from the basic spike parameters (CSP = A x D/S). The spikes of patients in the benign focal epilepsy category differed from those of patients in other syndromic categories (symptomatic, cryptogenic, and Landau-Kleffner). Specifically, they were higher in amplitude, longer in duration, less sharp, and had a higher CSP value. The pretreatment spike parameters did not differ significantly in patients who responded favorably to initial antiepileptic drug (AED) therapy as compared with those whose seizures were harder to control. The findings suggest that quantitative assessment of interictal spike morphology may help develop a more objective basis for classifying patients according to epileptic syndrome.

Adolescent↗