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GRZELLA, I., MÜLLER,
B.W., OADES, R. D., BENDER, S., SCHALL, U., ZERBIN, D., WOLSTEIN,
J. & SARTORY, G. (2001). Novelty-elicited
mismatch negativity (MMN) in patients with schizophrenia on
admission and discharge.
Journal
of Psychiatry and Neuroscience,
26, 235-246 . - - request
a copy .-- View
Article from PubMed
Introduction:
MMN, an electrophysiological measure of auditory working memory, is
usually recorded as the difference in the event-related potential
(ERP)
elicited by a rare deviant and a common standard
sound. The amplitude is usually reduced in patients with schizophrenia
(references below). Here we looked at the response in the extreme
and most simple
case of the deviant being always a novel, different tone on every
presentation. We compared the novelty-MMN with clinical symptoms
expressed - both measures being made soon after admission and again
2-3 months later just before discharge.
Methods:
We compared 20 patients (mean age 26y) with a first, second or third
episode of schizophrenia on admission with 21 healthy controls (mean
age 26y) and were able to repeat the measures with 12 patients at discharge
and with 15 controls. An early MMN component (80-140 ms), a later component
(140-300 ms) and the P3a were recorded and topography examined after
min-max norming from 19 sites. Symptoms were assessed with the positive
and negative syndrome scale (PANSS).
Results:
a) Novelty-elicited MMN was not
significantly reduced on admission (Fig.
1).
b) The early component remained unaltered,
but the amplitude of the later component
decreased significantly during
inpatient treatment. While the decrease appeared significant over
the left hemisphere in the raw data, the lateral difference was lost
after normalizing the data (Fig. 2).
c) Improved positive symptom ratings were
associated with increases of the early component latency, but decreases
of the late component latency.
d) P3a at Fz showed an increased latency
between sessions in the patients but there were no group differences
in amplitude.
Figure 1.
Figure 2. ![](Nov-MMN-2.gif)
Conclusions:
Our results are partially consistent with two other studies using
a conventional MMN that showed a lack of MMN normalization when symptoms
improved (Schall et al., 1998; Umbricht et al., 1998) - in the present
study MMN deteriorated. While trait features have been attributed
to conventional MMN reductions in schizophrenia, our results suggest
that if novelty responses are impaired in patients with schizophrenia
then the differences may be sensitive to state.
[Initial studies of MMN in schizophrenia
in 1991, 1993,
and 1995a, on the role of attention 1995b,
and topographical comparisons with other waveforms 1996:
attention, topography and schizophrenia-subgroup analysis 1997a,
and
the expression of MMN is comparison to other 'difference waveforms'
in normal adults (1995c) and the normal
development of MMN in children and adolescents (1997b)
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