Measurement of brainstem auditory evoked magnetic fields using a highly sensitive SQUID magnetometer with a variable baseline

Author

Iramina, Keiji ; Ueno, Shoogo

Author_Institution

Dept. of Comput. Sci. & Commun. Eng., Kyushu Univ., Fukuoka, Japan

Volume

31

Issue

6

fYear

1995

fDate

11/1/1995 12:00:00 AM

Firstpage

4271

Lastpage

4273

Abstract

This study focuses on the detection of ABR (auditory evoked brainstem response) magnetic fields using a SQUID magnetometer. The ABR magnetic field is a very weak signal with an intensity of less than 10-14 T which is near the limits of sensitivity of the SQUID magnetometer. The authors developed a highly sensitive DC-SQUID magnetometer, It has a first-order gradiometer with a variable baseline, i.e., the distance between two co-axial coils which are wound in opposite directions to reduce the environmental magnetic noise. In this system, one can choose the best pick-up coil to reduce the environmental magnetic noise. The authors tried to measure ABR magnetic fields using three gradiometers. It was possible to detect the ABR magnetic fields using a 50-mm baseline gradiometer. The authors also studied the optimum baseline to measure magnetic fields by computer simulation

Keywords

SQUID magnetometers; biomedical equipment; biomedical measurement; hearing; magnetic field measurement; magnetoencephalography; 10 to 14 T; 50 mm; brainstem auditory evoked magnetic fields measurement; coaxial coils; computer simulation; environmental magnetic noise reduction; first-order gradiometer; highly sensitive SQUID magnetometer; optimum baseline; pick-up coil; variable baseline magnetometer; Brain modeling; Coils; Computer simulation; Electroencephalography; Magnetic field measurement; Magnetic fields; Magnetic noise; Magnetic shielding; SQUID magnetometers; Wounds;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.489949

Filename

489949