Hemispheric asymmetries of early cortical somatosensory evoked potentials revealed by topographic analysis
Buchner, H.; Ludwig, I.; Waberski, T.; Wilmes, K.; Ferbert, A.
Electromyography and Clinical Neurophysiology 35(4): 207-215
1995
ISSN/ISBN: 0301-150X PMID: 7555925 Document Number: 445193
Scalp topography of the early cortical SEPs was analysed in 50 normal right handed subjects. The following hemispheric asymmetries of the potentials were found: 1) The maximal amplitude of N20 was located predominantly at the P electrode after right sided stimulation, but varied between the CP, P and O electrode after left sided stimulation. 2) The N20 amplitudes were higher after right sided stimulation in approximately 70% of the subjects and the P25 and N30 amplitudes were higher after left sided stimulation in again approximately 70% of the subjects. No side difference of amplitudes was found for the subcortical N14. The N20 amplitude and location asymmetries were attributed to an anatomical asymmetry of the somatosensory cortex.