This case can be placed in a neurologic classification. The patient is a child with learning disability in school activities. He was first referred to an audiological clinic because of a central auditory processing disorder (CAPD). His mother has noticed several hearing problems and this led us to the evaluations for his central auditory processing disorder. He has problems in hearing speech in noise and speech processing and need his friends repeat words during communication. no vestibular disorder was noticed nor any localization problem. The child has a good progress in school and only suffered problems in reading tasks. Intelligence quotient(IQ) was also normal.

Auditory Hallucination or Paracusia is a form of hallucination that involves perceiving sounds without auditory stimulus. A common is hearing one or more talking voices which is associated with psychotic disorders such as schizophrenia or mania. Hallucination, itself, is the most common feature of perceiving the wrong stimulus or to the better word perception of the absence stimulus.Here we will discuss four definitions of hallucinations:1. Perceiving of a stimulus without the presence of any subject2. hallucination proper which are the wrong perceptions that are not the falsification of real perception, Although manifest as a new subject and happen along with and synchronously with a real perception3. hallucination is an out-of-body perception which has no accordance with a real subject In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. We are going to discuss it in details here.

Objective: OAE an audiologic study for diagnosis of exteracochlear auditory neuropathy.
Method & Material: Immitance audiometry, OAE and ABR and rehabilitation Intervention was performed for 3 children suffered from kernictrus.
Conclusion: 1) OAE in the from of screening, distorted product and transient evoked-otoacoustic emission has to be added to our audiology test battery. 2) OAE studies have their own merit when we are clinically involved with the diagnosis of especial clinical entities like neonatal hypoxia, kernicterus, multiple sclerosis, meningitides and meningoencephalitis. 3) Case selection for cochlear implantation needs a knowledge of patients' OAE results. 4) In the case of intracerebral auditory neuropathy the need for other rehabilitative measures will be better understood.

Objective: As the cerebrovascular diseases (CVD) are among the most common anomalies that are directly or indirectly affecting the auditory cortex, studying in this area is important. We tried to evaluate the function of CANS in a group of 50-70 years old cerebrovascular accident (CVA) patients with no hearing complaint by competing sentences test (CST) as a dichotic speech test.
Method and Material: This cross-sectional analytical study was conducted at Loghman-e-Hakim hospital between 22, august 1999 and 20, July 2000 in a group of 30 normal 50-70 years old persons and a group of 40 patients with CVA including 30 patients with abnormal CT scan and 10 patients with normal CT scan.
Results: The results point out the mean scores of CST in the normal group were at normal range (80-100%) in both ears. And mean scores of CST decreased in the patients groups. There were significant difference between mean scores of CST in the patients with CVA and control groups. Conclusion: CST seems to be a valuable test in the CANS test batteries for the cerebrovascular diseases.

Objective : To assess neonates and children suffering from meningitis , during the critical and recovery periods , using ABR , EOAE and Behavioral Audiometry.
Method and Material: 40 neonates to 12-year-old children were assessed. Using ABR test, the hearing of these cases was evaluated during the critical period-that is , 24-72 hours following the diagnosis. This test was repeated when patients recovered from meningitis-that is 24 hours before discharge (recovery period) Hearing function , again , was assessed 7-14 days following discharge through Immittance Audiometry, Behavioral Audiometry (PTA , SF and BOA). And EOAE (TEOAE and DPOAE) tests procedures.Findings: During the critical period , ABR test revealed normal hearing in 35 patients (87.5%) and severe to profound sensorineural hearing loss (unilateral and bilateral) in 5 patients (12.5%-girl=4, boy=1). The same result were obtained in re-evaluation in the recovery period. On the other hand , 7-14 days after of discharge , Immittance Audiometry and Behavioral Audiometry (including PTA , S.F and BOA tests), confirmed the mentioned results (cross - gcheck). EOAE test (DPOAE and TEOAE) in 35 normal hearing patients (according to ABR test) , showed normal cochlear function. 2 out of 5 cases suffering from severe to profound sensorineural hearing loss revealed normal cochlear function. According to EOAE results , abnormal cochlear function was evident in 3 patients.
Conclusion: ABR , EOAE tests , and Behavioral Audiometry in children meningitis during the critical period and recovery period can be used to diagnose any degree of hearing loss with a high level accuracy. The results of persent study is confirmed by previous investigations.

Background and Aim: The auditory system changes by increasing age in both central and peripheral parts. The purpose of this study was to  investigate the effect of the increasing the stimulus rate on auditory brainstem response (ABR)  waves latency in old population with normal hearing.
Materials and Methods : In this cross-sectional study click ABR test performed on 20 young normal-hearing subject with mean age of 20.8 years old and 10 old normal-hearing subject with mean age of 66.4 years old. ABR results with different stimulus rates were compared between two group.
Results : ABR peak latencies and interpeak intervals were prolonged with increasing the click repetition rate. Peak latencies were slightly prolonged in older adults and the I-V interval did not differ with age but prolongation of  III-V interval were significantly differs in older population compared to young adults.
Conclusion : Using high click rates may sensitize the ABR to the identification. of lesions of auditory nerve or brainstem , but before that , we need to know the normal range of different age groups , so that we can decide about probability of a retrocochlear lesion.

Background and Aim: Hyperbilirubinemia is one of the most common abnormalities during the neonatal period. Approximately 60% full-term and 80% preterm neonates suffer from hyperbilirubinemia. Hearing loss is one of the most prevalent side-effects of hyperbilirubinemia. This happens when the serum concentration of indirect bilirubin increases dramatically. The main purpose of this study is to evaluate the hearing status and to diagnose the probable site of lesion in affected children.
Materiads and Methods: In this cross-sectional study, 33 newborn to two year old subjects uffering from hyperbilirubinemia were evaluated using auditory brainstem response (ABR) and transient evoked otoacoustic emissions (TEOAE) tests In the Audiology department of the Faculty of Rehabilitation Sciences Iran University of Medical Sciences sampling method was accessible.
Results: 21% of the subjects had severe to profound hearing loss and 9% of subjects had mild to moderate hearing loss. In 51% of the subjects there was no response to ABR and TEOAE tests indicating cochlear and/or retrocochlear lesion. The other 15% manifest only abnormal ABR test indicating the presence of the auditory neuropathy.
Conclusion: TEOAEs test has its own limitations in these subjects, that is the hearing status of such patients can not be completely evaluated by using just TEOAE test. Therefore, to detect hearing loss both ABR and TEOAE tests must be performed in these subjects.

Background and Aim: Auditory neuropathy (AN) can be diagnosed by abnormal auditory brainstem response (ABR), in the presence of normal cochlear  microphonic (CM) and otoacoustic emissions (OAEs).The aim of this study was to investigate the ABR and other electrodiagnostic test results of six patients suspicious to AN with problems in speech recognition.
Materials and Methods: this cross sectional study was conducted on 6 AN patients with different ages evaluated by pure tone audiometry, speech discrimition score (SDS) , immittance audiometry , electrocochleography , ABR, middle latancy response (MLR), late latency response (LLR), and OAEs.
Results: Behavioral pure tone audiometric tests showed moderate to profouned hearing loss. SDS was so poor which is not in accordance with pure tone thresholds. All patients had normal tympanogram but absent acoustic reflexes. CMs and OAEs were within normal limits. There was no contralateral suppression of OAEs. None of cases had normal ABR or MLR although LLR was recorded in 4.
Conclusion: All patients in this study are typical cases of auditory neuropathy. Despite having abnormal input, LLR remains normal that indicates differences in auditory evoked potentials related to required neural synchrony. These findings shows that auditory cortex may play a role in regulating presentation of deficient signals along auditory pathways in primary steps.

Background and Aim: The staggered spondaic word (SSW) test is potent to evaluate the function of the central auditory nervous system. As the Farsi version is not available, the purpose of this study was to prepare a Farsi language version of SSW (FLV-SSW), and to conduct a primary evaluation.
Materials and Methods: The Farsi-language version of SSW was first prepared and recorded on a tape. Fifty-eight normal hearing individuals with mean age 29.72 years were avaluated in Rehabilitation School of Iran University of Medical Sciences in 3 months.
Results: The mean scores of Raw SSW was 98.364 in the normal group. The minimum and maximum percentage of errors of Corrected SSW were -6 and 8 for each of the conditions, -4.75 and 5 for each ear and -3.88 and 3.75 for the entire test (total). The maximum number of reversals was one. There is no difference between males and females scores.
Conclusion: Based on the obtained results, the FLV-SSW test appears to have potential as a useful measure of central auditory processing but the generalization of this results needs further studies.

Background and Aim: Central auditory processing disorders (CAPD) may have a variety of etiologies therefore, performing CAPD tests seem inevitable. Behavioral tests such as synthetic sentence identification (SSI) has gained considerable popularity because of high sensitivity to brainstem and cortical lesions, high diagnostic ability,  cost-benefiting, and also limitations of electrophysiologic tests. The purpose of this study was to prepare a Farsi-language version of SSI and to perform a primary evaluation. 
Materials and Method: Farsi SSI test was made and recorded on CD. Then sixty 20-to 35- year old normal-hearing participants were evaluated in audiology clinic, Faculty of Rehabilitation Sciences Iran University of Medical Sciences in three months.
Results: There is no significant difference between scores of Farsi and original versions of SSI. Gender has no significant effect on the scores.
Conclusion: According to this results, Farsi SSI is comparable to the original one. It can, therefore, be used in CAPD test battery.

Background and Aim: Lack of early detection of and intervention for infants hearing loss results in a significant delay in speech and language development. So auditory rehabilitation plays an important role in improving the diminished communication ability. One of the most successful auditory training approaches is the SKI-HI parent-infant program. The purpose of this study was preparation and evaluation of Farsi-Language SKI-HI program for under 3-year-old hearing impaired  children.
Materials and Methods: After translation and modification of the text of the program, fifteen under 3-year-old children with bilateral severe sensory hearing loss who were fitted with appropriate behind the ear hearing aids received intervention for 6 months. The levels of the auditory skills were measured pre and post intervention. Intervention Efficiency Index (IEI), Pretest Developmental Rate (PDR) and Proportional Change Index (PCI) were computed.
Results: The data indicated that there was a significant difference between means of IEI and PDR which were 0.87 and 0.31, respectively. PCI was 3.38 indicated that the children&aposs auditory skills developed at about 2.38 times higher rate after SKI-HI intervention than they did before.  PCI confidence interval showed that development in  the population is 1.46 to 3.30 times higher after SKI-HI intervention (with 95% probability) the rate of auditory skills.
Conclusion: The auditory training with Farsi-language SKI-HI Parent-Infant program may efficiently affect development of auditory skills of hearing impaired children.

Background and Aim: Auditory neuropathy is an hearing disorder in which peripheral hearing is normal, but the eighth nerve and brainstem are abnormal. By clinical definition, patient with this disorder have normal OAE, but exhibit an absent or severely abnormal ABR. Auditory neuropathy was first reported in the late 1970s as different methods could identify discrepancy between absent ABR and present hearing threshold. Speech understanding difficulties are worse than can be predicted from other tests of hearing function. Auditory neuropathy may also affect vestibular function.

Case Report: This article presents electrophysiological and behavioral data from a case of auditory neuropathy in a child with normal hearing after bilirubinemia in a 5 years follow-up. Audiological findings demonstrate remarkable changes after multidisciplinary rehabilitation.

Conclusion: auditory neuropathy may involve damage to the inner hair cells-specialized sensory cells in the inner ear that transmit information about sound through the nervous system to the brain. Other causes may include faulty connections between the inner hair cells and the nerve leading from the inner ear to the brain or damage to the nerve itself. People with auditory neuropathy have OAEs response but absent ABR and hearing loss threshold that can be permanent, get worse or get better.

Background and Aim: Learning disability(LD) is one of the most prevalent problems among elementary school children. Approximately 10 percent of all elementary school children suffer from this problem. It has been determined that learning disability is predominantly accompanied with subtle impairment in central auditory nervous system. The main idea of this study was to evaluate middle latency auditory evoked potential (MLAEPs) in learning disabled children.

Materials and Method: This cross-sectional study investigated middle latency auditory evoked potential in children with learning disability (n = 31) compared to normal children (n = 31). Latencies and amplitudes of MLAEPs results with different stimulus intensity and binaural stimulation were compared between two groups.

Results: Compared to control group, learning disabled children exhibited smaller amplitudes for all the components except the right ear Na and Pa. There is no significant difference between two groups for latencies of the components.

Conclusion: It seems that middle latency auditory evoked potential may be useful in diagnosis and evaluation of learning disabled children although more investigation is required.

Background and Aim: There are evidences that indicate a relationship between auditory processing disorders and stuttering, and any disorder in the central auditory function can be at least one of the underlying causes of stuttering. Even though, using the most state of the art radiographic technologies, i.e. MRI, no definitive answer has been given in relative to this question. In this research, using Mask-ing Level Difference (MLD) and Synthetic Sentence Identification (SSI) tests, the central auditory function of stutters and normal group was evaluated.
Materials and Methods: In this study was analytic cross-sectional, fifteen male patients with stutter-ing and 15 male normal cases with the age range from 16 to 40 years (average age 26.78 year) were evaluated. SSI-ICM, SSI-CCM and MLD tests were performed. The results were compared in both groups.
Results: Although stutterers mean MLD was less than that of normal group, the different was not significant between stutters and normal group in SSI test in right ear at negative MCRs. There was a significant difference in ICM state, but in CCM state, there was no significant difference between the average score of two groups in various MCRs.
Conclusion: The findings of this research is compatible with those of similar researches about the SSI test and the pattern of results, probably indicates a partial dysfunction of brainstem in some of the stutters.

Background and Aim: Physiologic measures of cochlear and auditory nerve function may be of assistance in distinguishing between hearing disorders due primarily to auditory nerve impairment from those due primarily to cochlear hair cells dysfunction. The goal of present study was to measure of cochlear responses (otoacoustic emissions and cochlear microphonics) and auditory brainstem response in some adults with auditory neuropathy/ dys-synchrony and subjects with normal hearing.
Materials and Methods: Patients were 16 adults (32 ears) in age range of 14-30 years with auditory neuropathy/ dys-synchrony and 16 individuals in age range of 16-30 years from both sexes. The results of transient otoacoustic emissions, cochlear microphonics and auditory brainstem response measures were compared in both groups and the effects of age, sex, ear and degree of hearing loss were studied.
Results: The pure-tone average was 48.1 dB HL in auditory neuropathy/dys-synchrony group and the frequency of low tone loss and flat audiograms were higher among other audiogram&aposs shapes. Transient otoacoustic emissions were shown in all auditory neuropathy/dys-synchrony people except two cases and its average was near in both studied groups. The latency and amplitude of the biggest reversed cochlear microphonics response were higher in auditory neuropathy/dys-synchrony patients than control people significantly. The correlation between cochlear microphonics amplitude and degree of hearing loss was not significant, and age had significant effect in some cochlear microphonics measures. Auditory brainstem response had no response in auditory neuropathy/dys-synchrony patients even with low stimuli rates.
Conclusion: In adults with speech understanding worsen than predicted from the degree of hearing loss that suspect to auditory neuropathy/ dys-synchrony, the frequency of low tone loss and flat audiograms are higher. Usually auditory brainstem response is absent in this patients and use of both otoacoustic emissions and cochlear microphonics responses to measure cochlear hair cells function are suggested in them.

Background and Aim: Hearing assessment in infants and children younger than two years is an important issue, because the golden time of the language learning and speaking is under the age of two. Steady state auditory evoked potentials (SSAEPs) is one of the best ways of the objective hearing assessment for infants and young children. The need for long time of stimulation and recording restricted the clinical uses of this method. Therefore, the reduction of the recording time is a common problem. SSAEP signals are contaminated with background EEG signals of the brain and nervous system. To discriminate these signals the approach is using averaging method.
Materials and Methods: In this work two adaptive methods were programmed and tried on (SSAEP) signals. The first method was the work of the Ziarani et al. and the second was the enhanced Kalman filter. To assess suggested methods and to compare them with traditional averaging one, two sets of clinical signals prepared with Rotmen research group in university of Toronto were applied.
Results: The speed of the extraction of the SSAEP signals with the Ziarani method is 1.6 times faster than the averaging method. The extraction time of the enhanced adaptive Kalman filter is 13.1 times faster than currently used averaging methods.
Conclusion: The Kalman filter method seems to be more reliable than the other two methods. In addition, this new application of the Kalman filter in hearing assessment could be more beneficial and faster than other methods as an objective method.

Background and Aim: Hyperbilirubinemia during the neonatal period is known to be an important risk factor for neonatal auditory impairment, and may reveal as a permanent brain damage, if no proper therapeutic intervention is considered. In the present study some electroacoustic and electrophysiologic tests were used to evaluate function of auditory system in a group of children with severe neonatal Jaundice.
Materials and Methods: Forty five children with mean age of 16.1 14.81 months and 17 mg/dl and higher bilirubin level were studied, and the transient evoked otoacoustic emission, acoustic reflex, auditory brainstem response and auditory steady-state response tests were performed for them.
Results: The mean score of bilirubin was 29.37± 8.95 mg/dl. It was lower than 20 mg/dl in 22.2%, between 20-30 mg/dl in 24.4% and more than 30 mg/dl in 48.0% of children. No therapeutic intervention in 26.7%, phototherapy in 44.4%, and blood exchange in 28.9% of children were reported. 48.9% hypoxia and 26.6% preterm birth history was shown too. TEOAEs was recordable in 71.1% of cases. The normal result in acoustic reflex, ABR and ASSR tests was shown just in 11.1% of cases. The clinical symptoms of auditory neuropathy were revealed in 57.7% of children.
Conclusion: Conducting auditory tests sensitive to hyperbilirubinemia place of injury is necessary to inform from functional effect and severity of disorder. Because the auditory neuropathy/ dys-synchrony is common in neonates with hyperbilirubinemic, the OAEs and ABR are the minimum essential tests to identify this disorder.

Background and Aim: Middle latency auditory evoked potentials (MLAEPs) development takes longer time than the auditory brainstem response (ABR) development does, which makes them difficult to record in some children. The purpose of this study was to investigate the age effect on characteristics and detection of MLAEPs in children and adults.
Materials and Methods: This cross sectional study was conducted on 15 children aged   7-12 yr and 31 adults aged 20-50 yr with normal peripheral hearing. To investigate precisely, children were divided in two subgroups of older and younger than 10 years old, as well. The MLAEPs amplitudes and latencies were recorded by conventional protocol and compared.
Results: Adult Na mean latency, 20.86 ms, was less than that of children, 22.86 ms, (p=0.0025).  In contrast, the adult Nb mean latency, 44.93 ms, was longer (p=0.0001). Children Nb mean latency was 42.02 ms. There was no significant difference in MLAEP amplitudes and latencies between two children subgroups, although variance was more in younger children.
Conclusion: MLAEPs are reliably recorded after 7 years old. Characteristics of MLAEPs are different in adults and children so that the primary MLAEPs generators have a course of development extending beyond the first decade of life. As those potentials were recorded in all children, it is suggested to be used in their test batteries for hearing evaluation.

Background and Aim: One of the most important problems of children who suffer from autism is abnormality in receiving and integrating sensory inputs, especially hearing input. It has been shown that brainstem has a key role in receiving, encoding and integrating hearing input. Auditory brainstem response (ABR) is a tool by which we can evaluate this function. The purpose of this study was to assess and to compare autistic and normal children brainstem hearing function.
Materials and Methods: This case-control study was conducted on thirty (58 ears) autistic and thirty (57 ears) normal 6-12 years old children. The children with autism were divided into slight and severe subgroups according to Autism Diagnostic Interview-Revised questionnaire. Click-evoked ABR was recorded and compared between groups.
Results: There was significant difference between two groups V and III wave latencies and I-III and I-V interpeak latencies (p<0.05). In fact, comparison of the results of autism subgroups with normal children indicated that the latencies of the severe subgroup significantly prolonged.
Conclusion: Increasing latencies of ABR waves in severe subgroup maybe due to abnormality in low level of brainstem. Brainstem abnormality may result in exacerbating the symptom of autism. It is therefore suggested that ABR is included in diagnostic test batteries for these patients.

Background and Aim: Assessment of central auditory processing skills needs various behavioral tests in format of a test battery. There is a few Persian speech tests for documenting central auditory processing disorders. The purpose of this study was developing a dichotic test formed of one-syllabic words suitable for evaluation of central auditory processing in Persian language children and reporting its preliminary results in a group of normal children.
Materials and Methods: Persian words in competing manner test was developed utilizing most frequent monosyllabic words in children storybooks reported in the previous researches. The test was performed at MCL on forty-five normal children (39 right-handed and 6 left-handed) aged 5-11 years. The children did not show any obvious problem in hearing, speech, language and learning. Free (n=28) and directed listening (n=17) tasks were investigated.
Results: The results show that in directed listening task, there is significant advantage for performance of pre-cued ear relative to opposite side. Right ear advantage is evident in free recall condition. Average performance of the children in directed recall is significantly better than free recall. Average row score of the test increases with the children age.
Conclusion: Persian words in competing manner test as a dichotic test, can show major characteristics of dichotic listening and effect of maturation of central auditory system on it in normal children.