Relationship of the magnetoencephalogram to abnormal activity in the electroencephalogram

Autor: C. I. Mayman, John R. Hughes, M. L. Scholl, D. E. Hendrix, Jerome B. Cohen
Rok vydání: 1977
Předmět:
Zdroj: Journal of Neurology. 217:79-93
ISSN: 1432-1459
0340-5354
DOI: 10.1007/bf00312921
Popis: The EEG and also the MEG were recorded simultaneously from 10 patients with various types of EEG abnormalities; the characteristics of the MEG and its relationship to the EEG were investigated with the use of a digital computer. Examples are shown in which the EEG activity is poorly represented in the MEG and include one configuration of a slow wave with a slow descending limb (intermixed with a more sinusoidal waveform), posterior slow waves and the wave of the 3/sec spike and wave complex. Magnetic theory would suggest that these patterns are associated with dipolar sources oriented radially or perpendicularly to the outer surface of the cortex and each pattern is discussed in relation to this possibility. Examples are shown in which a given pattern is well represented in both MEG and EEG recordings. These include eye-blink artifact, slow waves from a tumor, diffuse theta activity, sinusoidal anterior delta rhythms and the spike of the 3/sec spike and wave complex. Magnetic theory would suggest that these patterns are likely associated with a dipolar source oriented tangentially or parallel to the cortex's surface and each pattern was appropriately discussed. An example is shown of a horizontally oriented delta EEG focus and its corresponding longitudinally oriented magnetic field. The few examples of activity recorded better in the MEG than EEG include some rare instances of slow waves associated with a known tumor, alpha activity in a patient with diffuse delta rhythms and the harmonic components of the 3/sec spike and wave complex. The MEG, as recorded with this particular magnetometer, tending to show diffuse, non-localizable changes associated with localized EEG abnormalities may have its maximum value in helping to determine the dipolar orientation of various EEG waveforms by simultaneously recording the MEG and EEG and also occasionally in its ability to record activity that is not found in the EEG.
Databáze: OpenAIRE
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