Evaluation and analysis of auditory function and its clinical characteristics in low birth weight premature infants / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate and analyze dynamic changes of auditory function in premature babies with fetal age of less than 37 weeks who were categorized into different birth weight groups and to detect abnormalities of auditory function in these babies and to describe the early development patterns of auditory function in infancy.</p><p><b>METHODS</b>Total of 252 subjects (504 ears) from neonatal ward, neonatal intensive care unit and auditory clinic in Guangzhou Children Hospital, whose fetal age were less than 37 weeks, were included in our study and received auditory function evaluation from January 2004 to February 2008. To investigate the correlation between birth weight and development and abnormality of auditory function in premature babies, all subjects were divided into four groups according to birth weight: </= 1.50 kg, 1.51 - 2.00 kg, 2.01 - 2.50 kg and > 2.5 kg. Each group was further categorized by subject's age on first auditory function evaluation in 0 - 3 months (include 3 months), 3 - 6 months (include 6 months) and above 6 months, respectively. Subjects who were evaluated more than once in different age frame would be grouped into multiple evaluation subgroups. All subjects underwent one or more objective auditory examinations including auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), tympanometry and acoustic stapedius reflex.</p><p><b>RESULTS</b>A tendency of decreased wave V threshold of ABR was seen as birth weight increased, while the percentage of subjects with ABR wave V threshold </= 40 dB nHL increased as well. A tendency of decreased wave V threshold of ABR was also seen as age increased after birth, likewise the percentage of subjects with ABR wave V threshold </= 40 dB nHL increased with age after birth. For multiple evaluation subgroups, improvement rate ranged from 56.67% to 82.76% depending on subjects' birth weight. In all low birth weight (LBW) premature babies, 4 subjects and 6 ears with no wave or just wave V at maximum stimulation 103 dB nHL in ABR were diagnosed with auditory neuropathy, giving an incidence of 3.75%(by ears).</p><p><b>CONCLUSIONS</b>Auditory function (including middle ear and auditory nerve system) of premature LBW improved gradually within examined age frame, as birth weight and age after birth increased. For LBW preterm who showed abnormality in auditory evaluation, a 6-month follow-up should be scheduled, babies weighted less than 1.50 kg at birth that showed abnormality in the first auditory evaluation should be re-evaluated within 2 months. Babies weighted more than 1.50 kg who showed abnormality in the first auditory evaluation should be re-evaluated within 3 months.</p>

Correlation between chirp auditory brainstem response and behavioral hearing threshold in children / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the correlation between thresholds in the chirp-ABR and behavior audiogram in order to find out if it is possible to be used as an clinical application of the chirp-ABR in estimating hearing sensitivity.</p><p><b>METHODS</b>Twenty-two cases with hearing loss or normal hearing were enrolled in the study. The behavior audiogram and the response thresholds of chirp ABR (including chirp ABR, L-chirp ABR and U-chirp ABR) were obtained from 35 ears.</p><p><b>RESULTS</b>Twenty-two cases were of both genders. The age was between 3.3- 6.5-years-old with the average age of 4.8-years-old. Divided by the degree of hearing loss, in the 35 ears, there were 6 with normal hearing, 2 with slightly hearing loss, 4 with moderate hearing loss, 10 with severe hearing loss and 13 with profound hearing loss. The Pearson correlation coefficients were 0.939, 0.900 and 0.930, respectively, which got from the data between the average of 0.5 - 4 kHz and chirp ABR respond threshold, 0.5 kHz and L-chirp ABR, and the average of 1 - 4 kHz and U-chirp ABR.</p><p><b>CONCLUSION</b>As an objective test, the response threshold of chirp-ABR and the behavior audiogram were a highly correlated with each other, but more application in more subjects is needed.</p>

Audiological characteristics and localization of lesions in children with retrocochlear auditory nerve impairment / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the clinic characteristics, audiological characteristics and location of lesions in children with retrocochlear auditory nerve impairment which, including auditory neuropathy characterized by severely abnormal results of ABR and normal results of DPOAE.</p><p><b>METHODS</b>Between 2002 and 2006, eighty-six cases (165 ears) with severely abnormal ABR but normal results of DPOAE were enrolled in the study group. The mean patient age was one year and one-month-old, with a range of 8 days to 7 years. The cases with abnormal conductive function were excluded. The cases with severely abnormal ABR and normal cochlear functions as measured by DPOAE and without abnormal conductive function were selected as the cochlear lesion group. Some same age healthy children without hearing loss were subjected as normal control group. The latency and amplitude of waves I, III and V, the inter peak latency I-III was compared among the three group.</p><p><b>RESULTS</b>(1) Fifty-one cases (59.3%) had a history of hypercholesterolemia during neonatal period, but 40 cases (46.51%) had a severe hypercholesterolemia and 11 cases (12.79%) had mild or moderate hypercholesterolemia. Clinical features common among the population included a history of dyskinesia [n = 40 (46.51%)], hearing and language disorder [n = 10 (11. 63%)]. Thirty-two cases (37.2%) were accompanied by cerebral palsy . (2) Among the 165 ears, absent ABRs to click stimuli presented at 103 dB was in 103 ears, only wave I was developed in 27 ears and only wave V was developed in 19 ears,wave I and III in 13 ears and differentiated wave I and V in 3 ears. (3) When compared to control group, the latency of wave I was prolonged and amplitude of wave I was lower in cases with only wave I developed (t = -6.75 and 2.58, P < 0.05). For for cases with only wave I and III differentiated, the latency and amplitude of wave I was the same but the latency of wave III was prolonged and amplitude of wave III was lower while interpeak latency I-III was prolonged.</p><p><b>CONCLUSIONS</b>Auditory neuropathy which was characterized by severely abnormal ABR was the most common type of retrocochlear auditory nerve impairment. It was mainly due to a disorder of VIII nerve. The pathologies that affect higher levels of the auditory pathway, from the brainstem to the auditory cortex, might be the main sites of lesion in cases with only wave I developed. Superior olivary nucleus where wave III was generated and higher levels of the auditory pathway might be the main sites of lesion in cases with wave I and III differentiated. The low-amplitude wave V was not characteristics of auditory neuropathy. Cerebral cortex, brain stem auditory nucleus and VIII nerve might be damaged successively in cases with retrocochlear auditory nerve impairment induced by hypercholesterolemia.</p>

Hearing evaluation of infants failed in hearing screening / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To analyze the confusing factors and clinical and audiological characteristics in infants failed in hearing screening.</p><p><b>METHODS</b>Between August 2004 and January 2006, 166 infants (315 ears) with detailed birth record and hearing screening record were reviewed in the study. The age of this series ranged from 2 to 6 months. They were born in maternal and child health hospitals (MCH) in Guangzhou city and surrounding areas, and had hearing screened by otoacoustic emissions (OAE). However, they failed in the first and second hearing screening. The birth history, high-risk factors of hearing-impaired during newborn period and pregnancy history of subjects were fully detailed. Subjects were classified according to the age: 2 to 3 months old infants were considered as group 1, while 4 to 6 months old infants were considered as group 2. Auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAE) and acoustic immittance measurement were examined. Subjects with abnormal hearing-evaluation were retested during the following one to three months (before 6-month-old). The ABR results, DPOAE results and tympanic cavity pressure and static compliance value were compared between the two tests and then diagnosis was made.</p><p><b>RESULTS</b>(1) Among the 166 cases, 34 (20.5%) cases were once suffered from hypercholesterolemia of newborn, and 10 cases (6.0%) had asphyxia and hypoxia history. (2) The proportion of presenting type B tympanogram in group 2 was higher than that of group 1 (chi2 = 26.22, P < 0.01). (3) The proportion of normal ABR in group 2 (37.2%) was significantly higher than that of in group 1 (23.4%, chi2 = 0.527, P < 0.05). Fifty-six percent of infants accepted twice ABR test had improving ABR results during the second test. (4) The proportion of normal DOPAE in group 2 (39.7%) was slightly lower than that of in group 1 (42.2%, chi2 = 0.14, P > 0.05). Among the infants who accepted twice DPOAE test, 32.0% had improving results in the second test. (5) Four cases (4 ears ) were diagnosed as auditory neuropathy.</p><p><b>CONCLUSIONS</b>Middle ear function and development of auditory system in infants may be confusing factors in hearing screening. The results of hearing screening should be interpreted appropriately.</p>