The individual replicability of mismatch negativity at short and long inter-stimulus intervals

Objectives: The individual replicability of the mismatch negativity (MMN) e vent-related brain potential (ERP) was studied at two different inter-stimu lus intervals (ISIs), to establish its potential value for routine clinical evaluation of sound discrimination and auditory sensory memory. Methods: Ten healthy young subjects were presented sequences of 3 stimulus trains, in two recording sessions approximately 1 month apart. The stimuli in the trains were delivered at an ISI of 300 ms, whereas the inter-train i ntervals (ITIs) were 0.4 s and 4.0 s in different blocks. ERPs were average d to standard (75 ms) and deviant (25 ms) tones started equiprobably the st imulus trains. Results: Significant Pearson product-moment correlations coefficients were found between sessions at all scalp locations fur the short ITI, when the M MN was quantified as the mean amplitude in the 100-200 ms latency window ar ound its peak, However. none of the correlations reached significance for t he longer ITI. Conclusions: MMN appears ro be a reliable measure for single-case assessmen t and follow-ups when obtained at short ISIs and quantified as an integrate d window of neuroelectric activation over a temporal span. (C) 2000 Elsevie r Science Ireland Ltd. All rights reserved.