Relationships among the mismatch negativity (MMN) response, auditory comprehension, and site of lesion in aphasic adults

We evaluated the mismatch negativity (MMN) response to speech stimuli in ap hasic adults to determine the relationships among aphasic patients' auditor y comprehension, site of lesion, and the presence or absence of the MMN. Pr esence of a MMN response was significantly related to auditory comprehensio n performance. MMNs were present in 89% of the aphasic patients with good a uditory comprehension and in 25% of the aphasic patients with poor auditory comprehension. Poor comprehension and the absence of a MMN were related to lesions in the temporal lobe. Good comprehension and the presence of a MMN response were related to lesions that spared the temporal lobe. However, t he magnitude of these relationships was not perfect. Thus, the MMN as an in dex of auditory comprehension and its relationship to site of lesion may de pend on where the lesion resides--primary auditory cortex and/or Wernicke's area--in the temporal lobe.