Abstract
The purpose of this study is to investigate the primary somatosensory function in
patients with unilateral polymicrogyria. Somatosensory evoked fields (SEFs) due to
median and posterior tibial nerve stimulation were compared in the normal and dysplastic
cortices of five patients with unilateral polymicrogyria. SEFs were observed in all
five normal hemispheres and three dysplastic hemispheres. Latencies of N20m and P38m,
the first cortical components of and SEFs for median nerve and tibial nerve stimulation,
were all within the normal range in both normal and dysplastic hemispheres. The amplitudes
of the N20m and P38m in the dysplastic hemispheres were smaller in one patient and
larger in two patients compared to the normal hemispheres. Equivalent current dipoles
of N20m and P38m were localized on the anatomical central sulcus of the normal hemispheres
and over the central area of the dysplastic hemispheres. P38m dipoles were localized
medial and upward to the N20m dipole in both normal and dysplastic hemispheres. N20m
dipole orientation was normal in all normal hemispheres and in one dysplastic hemisphere,
but abnormally inferior in two dysplastic hemispheres. P38m dipole had normal medial
orientation in all hemispheres except one dysplastic hemisphere. Abnormality of the
primary somatosensory function in the dysplastic cortex of patients with unilateral
polymicrogyria was clearly demonstrated by magnetoencephalography with high resolution
in time and space. The normal somatotopic arrangement was preserved.
Keywords
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Article info
Publication history
Accepted:
February 19,
2004
Received in revised form:
February 19,
2004
Received:
August 25,
2003
Identification
Copyright
© 2004 Elsevier B.V. Published by Elsevier Inc. All rights reserved.
