A modified parallel paradigm for clinical evaluation of auditory echoic memory.

We established a new parallel paradigm for mismatch negativity by presenting repetitive trains of three consonant-vowel syllables and those of three sinusoidal tones alternately. Magnetoencephalography was performed to test the new method, and mismatch negativities in six study participants with normal hearing were compared with the results of the conventional oddball paradigm. Peak amplitude and latencies of mismatch negativity showed no significant difference between the methods. The maximum amplitude in short memory probe interval of 1.0 s was significantly larger than in long memory probe interval of 3.0s, demonstrating decay in auditory echoic memory caused by a prolonged memory probe interval. The new method facilitated simultaneous evaluation of mismatch negativity with various stimuli in a shorter period.