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

Objectives: The individual replicability of the mismatch negativity (MMN) event-related brain potential (ERP) was studied at two different inter-stimulus 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 intervals (ITIs) were 0.4 s and 4.0 s in different blocks. ERPs were averaged to standard (75 ms) and deviant (25 ms) tones started equiprobably the stimulus trains. Results: Significant Pearson product–moment correlations coefficients were found between sessions at all scalp locations for the short ITI, when the MMN was quantified as the mean amplitude in the 100–200 ms latency window around its peak. However, none of the correlations reached significance for the longer ITI. Conclusions: MMN appears to be a reliable measure for single-case assessment and follow-ups when obtained at short ISIs and quantified as an integrated window of neuroelectric activation over a temporal span.