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Hari Eswaran

Publications and source records attributed to Hari Eswaran.

20 records · Page 2Linked to original sources

Magnetoencephalographic recordings of visual evoked brain activity in the human fetus.

We investigated the feasibility of recording visual evoked brain activity in the human fetus by use of non-invasive magnetoencephalography (MEG). Each recording lasted 6 min and consisted of a sequence of 180 flashes with 33 ms duration delivered 2 s apart over the maternal abdomen. Four of ten fetuses included showed a response; the ranges of amplitude and latency of peak response were 15-30 x 10(-15) Tesla and 180-390 ms, respectively. Six fetuses showed no discernible response. With improvement, this method could aid in the testing of fetal neurological status throughout pregnancy.

Brain↗

First magnetomyographic recordings of uterine activity with spatial-temporal information with a 151-channel sensor array.

OBJECTIVE: The purpose of this study was to examine the feasibility of recording the spatial-temporal magnetomyographic activity from the pregnant uterus with the use of the newly developed 151-channel noninvasive device, known as the superconducting quantum interference device array for reproductive assessment. STUDY DESIGN: Uterine magnetomyographic signals were recorded from 10 pregnant subjects with the 151-channel sensor array curved to fit the pregnant abdomen. The recording sessions were 16 minutes in length, with a sampling rate of 250 Hz. RESULTS: Uterine activity bursts were successfully recorded with the superconducting quantum interference device array for reproductive assessment system. By obtaining a contour plot of the magnetic field distribution, we were able to localize the areas of activation over the uterus during a contraction. Also, it was possible to calculate the time delay in the propagation of the activity across the uterus. CONCLUSION: Using superconducting quantum interference device array for reproductive assessment system, we have established the feasibility of recording uterine contractile activity with spatial-temporal resolution that is high enough to determine the regions of localized activation and propagation over the uterus.

Female↗