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.