William J. Lutter

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OBJECTIVE To follow the development of MEG sleep patterns and auditory evoked responses (AERs) during the first six months of life. METHODS The subjects were 18 neonates, born at conceptional age (CA) 36-42 weeks, following uncomplicated pregnancies. During each session, several 10-min MEG recordings were acquired in the presence of auditory stimulation.(More)
OBJECTIVE To follow the development of the auditory evoked on- and off-responses in early infancy. METHODS The subjects were healthy infants, studied at conceptional age (CA) 39-66 weeks. Serial auditory evoked responses (AERs) were recorded in 17 subjects in response to tones of frequency 1.5 kHz and duration 1.0 s in order to follow the development of(More)
The inversion technique of Nowack and Lutter (1988a) and Lutter et al. (1990) has been applied to first arrival seismic refraction data collected along Line A of the 1986 Lake Superior GLIMPCE experiment, permitting comparison of the inversion image with an independently derived forward model (Trehu et al., 1991; Shay and Trehu, in press). For this study,(More)
Several recent studies have demonstrated the usefulness of fetal magnetocardiogram (fMCG) actography, a relatively new method of detecting fetal movement that can be performed in conjunction with fMCG assessment of fetal heart rate and rhythm. In this study, we formulate indices of fetal activity that incorporate information from all channels to achieve(More)
We have developed a two-step procedure for signal processing of fetal biomagnetic recordings that removes cardiac interference and noise. First, a modified matched filter (MF) is applied to remove maternal cardiac interference; then, a simple signal space projection (SSP) is applied to remove noise. The key difference between our MF and a conventional one(More)
We investigated the utility of ICA for evaluation of fetal rhythm in five uncomplicated twin pregnancies and in five twin pregnancies complicated by fetal arrhythmia. Using objective and subjective criteria, we sought to determine how the signal-to-noise ratio, signal fidelity and interference rejection are affected when synthesizing the fetal signal using(More)
In this paper, ray theoretical amplitudes and travel times are calculated in slightly perturbed velocity models using perturbation analysis. Also, test inversions using travel time and amplitude are computed. The perturbation method is tested using a 3-D velocity model for NORSAR having velocity variations up to 8.0 percent. The perturbed amplitudes are(More)
In 1999, the U.S. Geological Survey and the Southern California Earthquake Center (SCEC) collected refraction and low-fold reflection data along a 150km-long corridor extending from the Santa Monica Mountains northward to the Sierra Nevada. This profile was part of the second phase of the Los Angeles Region Seismic Experiment (LARSE II). Chief imaging(More)
BACKGROUND Atrial flutter (AFl) accounts for up to one third of all fetal tachyarrhythmias and can result in premature delivery, hydrops, and fetal death in 10% of cases; however, the electrophysiology of AFl in utero is virtually unstudied. METHODS AND RESULTS In this observational study, we reviewed 19 fetal magnetocardiography studies from 16 fetuses:(More)
Objective: Recent studies utilizing fetal magnetocardiography have demonstrated the efficacy of corrected QT interval (QTc) measurement for in utero diagnosis and prognosis of long QT syndrome, a leading cause of sudden death in early life. The objective of the study was to formulate and test a novel statistical estimation method to detect the end of the(More)