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Auditory cortex in each hemisphere mostly receives the sounds from the opposite ear. The present study aimed at the contralateral dominance of auditory brainstem response (ABR) among the ears in preterm neonates by comparing sex and gestational age. Transient Evoked Otoacoustic Emission (TEOAE) and Auditory Brainstem Response (ABR) were recorded at 3 months postconceptional age (PCA). The performance of two ears in ABR was compared. In addition, performance of each ear was analysed in females and males. A comparison of moderate gestational age also was performed. Twenty preterm neonates from 32 to 36 weeks gestational age admitted to the neonatal intensive care unit at Shafizadeh Children's Hospital were participated. No significant asymmetry in ABR absolute latency and inter-peak intervals of right and left ears in preterm infants was noticed. Females and males did not demonstrate statistically significant values in ABR latencies. Moreover, the results of four gestational ages were not statistically different from each other. The maturation of the auditory brainstem pathways most likely take places in both hemispheres simultaneously, independent of sex in preterm infants. Changes of gestational age in each month do not impact on the maturation of the auditory brain pathways. [ABSTRACT FROM AUTHOR]

Background and Aim: Recreational and occupational noise can cause permanent damage to the inner ear. Cochlear synaptopathy can be “hidden” because this synaptic reduction can occur without permanent hearing threshold changes. Our study aimed to assess synaptopathy in people with and without a history of occupational noise exposure by use of latency shift of wave V with masking. Methods:In this study, 38 males were involved. All participants had normal hearing thresholds. Of 38 males, 20-male identified with exposure to occupational noise and 18 identified without occupational noise exposure. Auditory brainstem response and masked were performed. Results: The main effect of the between-group factor was not significant in the right and left ears. But the main effect of the within-group factor in the right and left ears were significant (p<0.001 and p<0.001). Auditory brainstem response latencies at different levels in each group were significant. These results showed that there were no significant differences between latency changes in both groups. Conclusion: In order to diagnose cochlear synaptopathy in humans it is important to use audiological test batteries in the future. There is currently no effective way to diagnose noise-induced cochlear synaptopathy in human subjects. [ABSTRACT FROM AUTHOR]

Objectives Many studies have suggested that cochlear implant (CI) users vary in terms of speech recognition in noise. Studies in this field attribute this variety partly to subcortical auditory processing. Studying speech-Auditory Brainstem Response (speech-ABR) provides good information about speech processing; thus, this work was designed to compare speech-ABR components between two groups of CI users with good and poor speech recognition in noise scores. Materials & Methods The present study was conducted on two groups of CI users aged 8-10 years old. The first group (CI-good) consisted of 15 children with prelingual CI who had good speech recognition in noise performance. The second group (CI-poor) was matched with the first group, but they had poor speech recognition in noise performance. The speech-ABR test in a sound-field presentation was performed for all the participants. Results The speech-ABR response showed more delay in C, D, E, F, O latencies in CI-poor than CI-good users (P <0.05), meanwhile no significant difference was observed in initial wave (V(t= -0.293, p= 0.771 and A (t= -1.051, p= 0.307). Analysis in spectral-domain showed a weaker representation of fundamental frequency as well as the first formant and high-frequency component of speech stimuli in the CI users with poor auditory performance. Results revealed that CI users who showed poor auditory performance in noise performance had deficits in encoding the periodic portion of speech signals at the brainstem level. Also, this study could be as physiological evidence for poorer pitch processing in CI users with poor speech recognition in noise performance. [ABSTRACT FROM AUTHOR]

Background and Aim: Tinnitus is defined a phantom sound percept. Few studies have examined the occurrence of synaptopathy in tinnitus patients utilizing a battery of tests that indicate synaptopathy. This study aimed to investigate the role of synaptopathy in tinnitus production and compare the various characteristics of the auditory brainstem response (ABR) test and electrocochleography (ECochG) in normal-hearing people with and without tinnitus. Methods: This cross-sectional study was conducted on 34 normal-hearing individuals, 20 without tinnitus as controls (11 females and 9 males) and 14 with tinnitus (8 females and 6 men). The test components (amplitude, growth and slope of wave I, V/I ratio, action potential (AP) amplitude, and summating potential (SP)/AP) ratio were recorded during the ABR and ECochG tests for each subject. Results: The control group had higher mean values of amplitude, growth and slope of wave I, and AP amplitude compared to the tinnitus group, and this difference was statistically significant (p<0.05). The mean V/I ratio and SP/AP ratio were lower in the control group than in the tinnitus group, and this difference was statistically significant (p<0.05). Conclusion: The significant difference in the parameters of ABR and ECochG tests between normal-hearing people with and without tinnitus indicates that these parameters can be used to evaluate the presence of synaptopathy in tinnitus patients. These findings suggest the need for proper interpretation of the results of ABR and ECochG tests in tinnitus patients with a focus on the parameters indicating synaptopathy. [ABSTRACT FROM AUTHOR]

Background and Aim: Studies have shown that several factors affect the hearing loss of infants hospitalized in the neonatal intensive care unit (NICU). These factors include hyperbilirubinemia, low birth weight, asphyxia, and prematurity. This study aimed to investigate the prevalence of hearing loss and its risk factors in NICU infants. Methods: This is a cross-sectional study. Samples were 159 infants admitted to the NICU in Fatemieh and Shahid Beheshti hospitals in Hamadan, Iran, who were selected using a convenience sampling method. Their hearing was screened using transient evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR) tests; in case of failure in these tests, auditory brainstem response (ABR) was performed. Results: Of 159 infants, 9 (5.66%) were identified with different types of hearing loss where 4 (2.51%) had sensory-neural hearing loss, one (0.62%) had auditory neuropathy and 4 (2.51%) had conductive hearing loss. There was a statistically significant relationship between hearing loss and birth weight < 1500 g, hyperbilirubinemia, antibiotic therapy, family history of hearing loss, asphyxia and Apgar score < 5. Conclusion: Prevalence of hearing loss in NICU infants is noticeable so hearing assessment after discharge is necessary. Due to the presence of auditory neuropathy, simultaneous use of TEOAE and AABR tests in these infants is recommended. [ABSTRACT FROM AUTHOR]

Objectives Hearing loss is one of the most important disabilities in neonates. Delay in the detection of hearing loss leads to impaired development and may prevent the acquisition of speech. We aimed to determine the risk factors associated with hearing loss in neonatal patients aged more than 6 months with a history of hospitalization in Neonatal Intensive Care Unit (NICU). Methods In this case-control study, screening for hearing loss was carried out on 325 neonates aged 6-12 months referred to Pediatric Neurology Office of Vali-e-Asr Hospital, Tehran, Iran up to 2011. Hearing loss was confirmed using Auditory Brainstem Response screening test (ABR). Results The prevalence of mildly and moderately hearing loss in neonates was determined as 3.6%. The most significant risk factors for hearing loss in neonates were neonatal icterus associated with phototherapy, respiratory distress syndrome (RDS) and lower Apgar score. Conclusion It seems to quantitative auditory system screening using ABR is necessary for all neonates; because rehabilitation support such as speech therapy and hearing training in this age period is more effective than older ages. [ABSTRACT FROM AUTHOR]

Objectives The implementation of Neonatal Hearing Screening (NHS) program is still at the preliminary stage particularly in developing countries despite the burden of permanent congenital and early-onset hearing impairment. The purpose of this study was to report results for universal newborn NHS in a cohort of children born in the southwestern region of Iran, as part of a national screening program set up by the Iranian National Health System. Methods During this cross-sectional study, which took place between March 2013 and April 2016, healthy newborns were screened using transient evoked otoacoustic emissions (TEOAEs) and automated auditory brainstem responses (AABRs) methods at several points in time as early as possible after birth. Screening followed a two-stage strategy and newborns referred after the second-stage screening were scheduled for diagnostic evaluation. Results A total of 92,521 newborns were screened in the urban (n = 67,780) and rural (n = 24,741) regions. Hearing impairment was confirmed in 223 (2.41 per 1000) newborns. One hundred forty-one (1.52 per 1000) of these newborns were affected bilaterally. More than 87% of these infants (195/223) showed a sensorineural hearing loss, while the defect was found to be conductive in 12 cases (P < 0.001). Of the 223 cases with hearing loss, 28 (12.5%) infants had auditory neuropathy. The majority of the infants, in both urban and rural regions, showed severe hearing impairment. We did not observe any significant difference among the incidences associated with gender (p = 0.29). Conclusion Our results demonstrated that universal newborn hearing screening program is an adequate program for southwestern of Iran with high coverage, low referral rate, and good follow-up rate. [ABSTRACT FROM AUTHOR]

Background: Previous studies have indicated that the majority of cases with "failed" results related to transient evoked otoacoustic emissions (OAE) test have the normal hearing. The present study aimed to assess the possible relationships between perinatal factors and the false-positive OAE results., Methods: A case-control study was carried out in an Iranian Hospital in 2020. Based on the OAE results on the first day of life, newborns were divided into 2 groups; Control group included subjects with "Pass" OAE results. Every neonate with "Fail" OAE result was referred for auditory brainstem response (ABR). Neonates with bilateral fail OAE but normal ABR results (false-positive OAE) were considered as the case group. All recorded data were analyzed to assess the possible correlations between maternal/neonatal factors and the false-positive OAE results., Results: One hundred and eighty-one neonates entered the study. Of all included neonates, 87 (48.1%) cases showed bilateral fail OAE and 94 (51.9%) subjects passed the OAE test. Normal ABR results (false-positive OAE) were observed in all cases with bilateral fail OAE. Comparisons of variables affecting the OAE results showed that of all perinatal factors, neonate's sex (p = 0.046) and cesarean section (p = 0.003) were the only influencing factors that increased the risk of false-positive OAE results., Conclusion: Based on the results, the cesarean section delivery and neonate's male sex increased the risk of false-positive results related to OAE test. Implementing other screening tests such as ABR or Automated ABR as the initial screening test could be suggested for such cases.