RESUMO
Objective:To compare the time domain and the frequency domain of speech-evoked auditory brainstem response measured by stimulation of left and right ears, and to explore the difference and possible reasons of neural coding for speech from different ears in auditory brainstem.Method:Speech-ABRs to syllable /da/ of 31 healthy adults were recorded. Statistical analysis was performed on time-domain parameters, such as latencies and amplitudes of featured peaks, and frequency-domain ones, such as amplitudes of the fundamental frequency and the first formant of speech-ABRs ranging from 20-50 ms. A scoring criterion to grade the appearance of featured waves was proposed for waveform evaluation.Result:There were no significant difference for the latencies of binaural featured peaks and amplitudes of feature peaks(except peaks A and O). The waveform scores of right ear were greater than that of left ear. The amplitudes of fundamental frequency of binaural waves were both greater than that of the first formant. There was no significant difference of amplitudes of fundamental frequency and the first formant between two ears.Conclusion:The origins and distributions of speech-ABR are essentially symmetrical in brainstem in contrast with the hemisphere asymmetry of speech.
RESUMO
To investigate the high-risk factors for newborn heating loss and to provide information for preventing the development of hearing loss and delaying its progression, from May 2003 to June 2006, neonates who failed to pass the universal newborn hearing screening (UNHS) were referred to Jinan Newborn Hearing Screening and Rehabilitation Center from 7 newborn heating screening centers in seven cities of Shandong province. One-to-one pair-matched case-control method was employed for statistical analysis of the basic features of definitely identified cases. High-risk factors relating to the bilateral hearing loss were evaluated by univariate and multivariate Logistic regression analysis. Our results revealed that 721 transferred newborns who didn't pass the heating screening received audiological and medical evaluation and 367 were confirmed to have heating loss. Of them,177 neonates with heating loss who met the matching requirements were included in the study as subjects. Univariate analysis showed that high-risk factors related to hearing loss incuded age of father, education backgrounds of parents, parity, birth weight, gestational weeks, craniofacial deformity,history of receiving treatment in neonatal intensive care unit (NICU), neonatal disease, family history of otopathy and family history of congenital hearing loss. Multivariate Logistic regression analysis revealed that 4 independent risk factors were related to bilateral hearing loss, including parity (OR=16.285, 95% CI 3.379-78.481), neonatal disease (OR=34.968, 95% CI 2.720-449.534),family history of congenital hearing loss (OR=69.488, 95% CI 4.417-1093.300) and birth weight (OR=0.241, 95% CI 0.090-0.648). It is concluded that parity, neonatal disease and family history of hearing loss are the promoting factors of bilateral hearing loss in neonates and appropriate intervention measures should be taken to deal with the risk factors.