Auditory Neuropathy Spectrum Disorders (ANSD) are new classification which was proposed in 2008 by Colorado Children’s Hospital Group and defined as normal otoacoustic emissions and absent ABRs in newborn. In our long term follow up study, hearing of ANSD are changed into three types. Type I is normal OAE and normal ABR (normal hearing), Type II is absent OAE and absent ABR (profound sensoryneural hearing loss), Type III is normal OAE and absent ABR (true Auditory neuropathy). However, still complications of Al-Meqbel1 vestibular problems in ANSD are not known so far.

Objectives: The aim of the present study was to assess the Auditory lateralization ability in children with (central) Auditory processing disorder.Methods: Participants were divided in two groups: 15 children with Central Auditory Processing Disorder (8-10 years) and 80 normal children (8-11 years) from both genders with pure-tone air-conduction thresholds better than 20 dB HL bilaterally and interaural pure tone threshold difference better than 5 dB.All subjects had normal IQ and normal otoscopy: In the present study 9 imaginary positions were simulated in horizontal plane by Interaural Time Difference (ITD) and Interaural Intensity Difference (IID) to evaluate the Auditory lateralization performance in normal and children with (central) Auditory Processing Disorder (C) APD. Lateralization performance were determined by ITD ranging from -880 to+880 microsecond and IID ranging from -10 to+10 dB for high pass and low pass noise (2 kHz cut off point). Boltzmann function was used to describe the Auditory lateralization performance and Independent Samples T-test was used to compare the two groups.Results: according to Boltzmann function two major types of abnormalities were revealed in the lateralization performances: 1- completely disoriented, 2- side-oriented.86.6% of (C) APD children showed significant increase in mean of test errors compared with normal ones (p<0.001).Discussion: The study supports the hypothesis that most children with (C) APD have poor Auditory lateralization and abnormal processing of binaural cues.

Background and Aim: Spatial hearing is one of the most important functions of binaural hearing processing that is based on detection of fine interaural time and interaural intensity difference. Spatial hearing is beyond Auditory localization and lateralization. It helps Auditory scene analysis and target stream segregation from other simultaneous sound sources. This function is important in speech perception in presence of competing messages. The aim of the present paper was reviewing spatial hearing, plasticity of binaural hearing in Auditory system and spatial hearing disorder in children with central Auditory processing disorder ((C) APD).Recent Findings: Recent studies show that spatial hearing disorder is one of the important problems in relatively high proportion of children with (C) APD. It is proposed that spatial processing disorder can cause speech perception difficulty in noise which is the main complaint of children with (C) APD. Spatial hearing rehabilitation through sound localization and lateralization training can be effective in improvement of speech perception in noise.Conclusion: In children suspected to (C) APD, spatial hearing evaluation is vital. Spatial hearing can be evaluated by using sound localization and lateralization tests. If spatial hearing disorder is detected, special rehabilitation is necessary to address this central processing problem. This rehabilitation has a potential to improve speech perception in noise.

Objectives: Auditory processing disorder (APD) is due to the deficits in perceptual processing of acoustic information in the Auditory system, characterized by poor speech perception of noise, regardless of normal hearing. The variability in speech function of APD children can be partly explained by changes in the encoding of spectro-temporal modulations (STMs) which have been overlooked, despite their significance. Given that enhancing STM sensitivity and its processing can be an appropriate way to improve the listener’, s ability to retrieve and integrate speech segments covered by noise, we decided to evaluate the effects of STM-based Auditory training on speech perception in noise and the reliability of this training in children with APD. Methods: Thirty-five children with APD (8-12 years old) were randomly divided into the training (n=17) and control groups (n=18) to evaluate the effectiveness and reliability of STM training on speech in noise perception. The intervention group was trained to detect STM by 120 trials every day for ten days. The STM detection thresholds and speech perception in noise were evaluated before and immediately after the finalization of formal training sessions in both groups. To address the training reliability, the tests were repeated one month after practice in the training group. Results: Following the completion of STM Auditory training, the trained APD children improved notably in STM detection tasks and speech in noise tests (P<0. 05). The post-training progress of STM detection thresholds and consonant-vowel in the noise test was preserved for one month after training (P>0. 05), but the word in the noise test, especially in the right ear, was not retained (P<0. 05). Discussion: Auditory spectro-temporal modulation training can lead to better processing of STM modulation. Its effects can be generalized to higher-order processing, such as speech perception in noise. Auditory training based on STM processing enhancement can play an essential role in improving speech comprehension in the noise abilities of children with APD.

Objective: The objective of this study was to assess the prevalence of hearing impairment by automated Auditory brain stem response (AABR) in newborns admitted to an intensive and intermediate care unit and to analyze the associated risk factors.Methods: An observational cross-sectional study was conducted between January 2005 and January 2006. 834 newborns (62% boys and 38% girls) were assessed. Newborns had a mean (SD) gestational age of 36 (2.1) weeks with a mean (SD) birth weight of 2950 (1250) grams. The presence of the following neonatal pathologies was investigated: craniofacial malformations, hyperbilirubinemia (total bilirubin ³ 20 mg/dl for all newborns), neonatal asphyxia, congenital infections, septicemia, birth weight (£1500 g), meningitis, consanguinity, family history of congenital hearing loss and history of convulsion. Newborns who died before the age of 3 months and whose stay in the hospital lasted less than 48 hours were excluded. Chi-square test was used to identify the risk factors for hearing loss. Findings: Out of 834 neonates, 34 (4.07 %) had sensory-neural hearing loss. The most common risk factors of hearing loss included hyperbilirubinemia (11%), asphyxia (8%), birth weight less than 1500 g (6%), septicemia (6%), convulsion (2%), and meningitis (1%). There was a statistically significant association between hyperbilirubinemia (P=0.001), weight less than 1500 g (P=0.002), cesarean section (P=0.005) and impaired ABR results. There was no relation between family history of congenital hearing loss and craniofacial malformation as risk factors for hearing loss.Conclusion: This study showed statistically a relation between hyperbilirubinemia, weight less than 1500 g, cesarean section and impaired AABR results. The most common risk factors of hearing loss were hyperbilirubinemia, asphyxia, birth weight less than 1500 g, septicemia, convulsion, and meningitis.

Objective: It is easier for a listener to detect a brief tonal signal presented in a longer masking noise by increasing the delay between the signal and the masker. This phenomenon (overshoot) is influenced by a reduction in cochlear amplification and to date, there is no objective tool to investigate it. Therefore, a different paradigm of the Auditory brainstem response (ABR) was utilized to measure Auditory overshoot. It was assumed that increasing the delay onset time (DOT) between a signal and a masker reduces the latencies of waves I and III. Materials & Methods: Sixteen normal young male guinea pigs were tested. A tone burst stimulus (signal: 16 kHz, 5ms in duration) and wide-band noise (masker: 0. 1-8. 0 kHz, 100ms in duration) at three DOTs were used. To diminish the effect of the noise on waves, waveforms were subtracted from those derived from the noise burst alone. The absolute latency of the waves I and III, inter-peak latency of the waves I-III, and amplitude ratio of the waves III/I were compared for the 0, 30, and 100ms DOTs and five signal-to-noise ratios. Results: The latencies of increased from the 0 to 30ms DOT and then decreased from the 30 to 100ms DOT (p < 0. 001). No significant changes were observed in the latency waves at the 100ms DOT compared to the 0ms DOT (p > 0. 005). Moreover, there were no significant differences between the three DOTs regarding the inter-peak latency and amplitude ratio of the waves (p <0. 005). Conclusion: The study results showed an overshoot-like electrophysiological effect using ABR. Therefore, an objective test was used to investigate Auditory cochlear gain.