The Clinical Research Of The Correlation Between Auditory Mismatch Negativity And Speech Recognition

Although hearing loss is commonly assessed using pure-tone thresholds, the most debilitating aspect of a hearing loss is difficulty in speech perception. However, speech audiometry needs cooperation of subjects, so the speech recognition of infant and children can't be assessed accurately. The mismatch negativity (MMN) is a component of auditory event-related potentials, generated by the brain's automatic response to change in auditory stimulation and correlates closely with speech recognition. The MMN can be measured in the absence of attention and without any task requirements, which makes it suitable for testing different clinical populations, especially infants.The purpose of this research is to investigate the percentage of MMN evoked by frequency deviation and intensity deviation reliably in subjects with normal hearing and the stability of latence and amplitude of MMN of subjects with normal hearing, observe the correlation between latence and amplitude of MMN and PBmax of different form hearing loss. Details were described as following:Part one: The mismatch negativity of young subjects with normal hearing and the correlation between mismatch negativity and PBmaxThe variation of latence and amplitude of MMN and the presence percentage of MMN evoked by different frequency deviation and intensity deviation were observed by recording MMN of 24 subjects (24 ears) with normal hearing. The Pearson correlation coefficient between latence and amplitude of MMN and PBmax was analyzed. MMN could be evoked reliably by large frequencydeviation and intensity deviation in subjects with normal hearing, latence of MMN was stable and reproducible relatively, but amplitude of MMN was quite unstable. The negative correlation coefficient between latence of MMN evoked by intensity deviation and PBmax was signifcant. Results indicated that latence of MMN is hopeful in assessing speech recognition.Part two: The characteristic of mismatch negativity and the correlation between mismatch negativity and speech perception in patients with auditory neuropathyThe MMN and PBmax of 30 auditory neuropathy (AN) patients (51 ears) were examined, the correlation between latence and amplitude of MMN and PBmax were analyzed. Compared with subjects with normal hearing, the latence of MMN evoked by the same frequency deviation and intensity deviation of AN patients was prolonged obviously, the negative correlation coefficient between latence of MMN and PBmax was significant;the amplitude of MMN evoked by both frequency deviation and intensity deviation of AN patients reduced obviously, but the correlation coefficient between amplitude of MMN and PBmax was insignificant. The results indicated that the latence of MMN may be used to assess speech recognition of AN patients objectively, and become the only objective index of assessing speech perception gain of hearing rehabilitation and treatment.Part three: The influence of different form hearing loss and different PBmax on mismatch negativityThe MMN of 29 patients (44 ears) with sensorineural hearing loss and 29 patients (43 ears ) with conductive hearing loss were recorded.The correlation between latence and amplitude of MMN and PBmax were analyzed, the latence and amplitude of MMN were compared among different form hearing loss groups with similar PBmax and different PBmax groups with same form hearing loss.The latence of MMN evoked by both frequency deviation and intensity deviation of patients with SNHL or CHL correlated with PBmax significantly, but the amplitude of MMN of patients with SNHL or CHL correlated with PBmax insignificantly. The difference of latence of MMN among different form hearing loss groups with similar PBmax was not significant, but the difference of latence of MMN was obviously among different PBmax groups with same form hearing loss.The amplitude of MMN had no regular tendency. The results indicated that the latence of MMN may be used to assess the speech recognition ability of patients with different form healing loss, provide information of speech recognition of patient hard-to-test. The exact prediction and assessment of the speech perception gain of hearing rehabilitation and treatment is the key of selecting rehabilitation strategy correctly.