Oades, R. D., Wild-Wall, N., Juran, S., & Röpcke, B. (2005).
Mismatch negativity (MMN) sources in the frontal and temporal lobes of adolescent patients with schizophrenia at onset and 14 years later.
Australian Journal of Psychology, in press. (Proceedings of the Australian Society for Psychophysiology,
Melbourne, 9-12th Dec. 2004)


Severer illness, poorer prognosis and impaired brain structure are reported for patients with an adolescent-onset of schizophrenia. Is this reflected in early stimulus processing? Mismatch negativity (MMN), an electrophysiological measure of automatic auditory change detection, is reduced in patients with schizophrenia (refs. 1,2). We calculate dipole sources in newly ill adolescent and older patients.


MMN associated with frequency and duration deviant tones was recorded from 29 patients (17.5y) at onset, 18 patients 14y after an early onset (32.1y) and age-matched healthy subjects


Brain electrical source analysis replicated 4 MMN dipoles bilaterally in the temporal and frontal lobes (ref. 3). Peak MMN dipole-latencies show a bottom-up sequence of activation from temporal and left cingulate to right inferior/mid-frontal loci. Superior temporal sources alter location modestly on the ventrolateral axis in the younger patients, with stasis on the left and progression on the right in the older patients. Cingulate and frontal sources change on the rostrocaudal axis. These changes progress or normalise in older patients depending on the tone-presentation.


There is a degree of dissociation between anatomical changes and functional recovery indexed by scalp-records from patients with an early-onset 14y before compared to those in their first episode. Improvement, stasis or deterioration depend on the psychopathology and heterogeneous course.
Support: N. W-W.: Alfried Krupp von Bohlen und Halbach Stiftung

1. Oades et al. 1995 EEG Clin Neurophysiol 44, 428-438
2. Catts et al. 1995 Am J Psychiat 152, 213-219
3. Jemel et al. 2002 Brain Topogr 15, 13-27