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Oades, R. D., Wild-Wall,
N., Juran, S., Weisbrod, M., Chen; E. Y. H., Röpcke, B., (2004)
Mismatch negativity (MMN) sources
in the frontal and temporal lobes of adolescent patients with schizophrenia:
an ERP- and MR-imaging study.
Proceedings of the 16th World Congress of the International Association
for Child and Adolescent Psychiatry and Allied Professions, 22-26
Aug 2004, Berlin, Germany (p.71 - 72).
Introduction: MMN is an electrophysiological
measure of automatic auditory change detection. A smaller MMN in patients
with schizophrenia may reflect altered frontal activity (Oades
et al. 1995). We sought dipole sources in newly ill adolescent and
older residual patients.
Methods: Following our report on
a) the coordinates for frontal and temporal lobe dipole-loci contributing
to normal MMN (Jemel et al
2002)
b) we replicated this result using
brain electrical source analysis (BESA) and MR-images of the brain
c) in healthy teenagers (mean age 17y) and adults (mean age 34y) and
compared it with adolescent patients with a first episode of schizophrenia,
and a group 15 years after the onset of schizophrenia in adolescence..
Results: For
MMN associated with a frequency deviant tone asymmetric loci in the
superior-temporal and left anterior-cingulate gyri were replicated,
while that in the right inferior-frontal gyrus moved to the mid-frontal
border (residual variance [RV] <1%).:
First: Healthy subjects showed maturational
changes between the second and fourth decades that included a changed
orientation of the left cingulate dipole and a more dorso-medial location
of the right frontal dipole in older subjects:
Second: Patients showed a modest MMN
reduction, a weaker left temporal lobe source but essentially similar
loci (RV~1%). :
Third: Discrete changes
in the locus of left temporal and cingulate sources were illustrated
by plotting volumes around the group solution for individual’s
data to 4% RV, with the radius illustrating the standard deviation of
the distance to the solutions for other subjects’ loci;
Fourth: The left
temporal lobe source was marginally more medial in patients (5 mm, p<0.01),
while the left cingulate was more rostral (10 mm, p<0.0001).
Conclusions:
The data show a degree of compensation of function
despite altered source locations in the left hemisphere, even at onset
in adolescence.
..... Support: NW-W
was supported by the Alfried Krupp von Bohlen u. Halbach Stiftung
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