Prospects and limitations of the application of the mismatch negativity a methodological study

Mismatch Negativity (MMN) is a component of the late auditory evoked potent ial. It arises as the outcome of an automatic comparison process. if a "dev iant" stimulus is presented in a sequence of identical ("standard") stimuli . A missing Mismatch Negativity might be a sign of central auditory process ing disorders. The aim of this study was to investigate the stability of th e MMN during an experimental session and between two sessions on two differ ent days. 22 young, healthy subjects were tested twice during a two weeks p eriod using pure tones of different frequency and two different consonant-v owel syllables to elicit the MMN. Determining the reliability of the measur ement of the MMN is necessary before using it in a clinical context. A visu al rating of the ERP-curves produced a stable result for most of the person s in both stimulus conditions, but quantitative measures showed sufficient reliability only when phonemes are used as stimuli. Stability of amplitudes was higher for phonemes than for pure tone-stimuli. With pure tones only p eak latencies showed moderate stability. Regarding clinical applications of the MMN we conclude that the reliability of quantitative measures is not s ufficient for individual diagnosis so far. But the MMN can be a useful tool to study specific processing deficits in certain disorders like developmen tal language disorder or aphasia.