Introduction: Several animal studies have been performed that demonstrates a relationship between the amount of magnesium ion in the plasma and the hearing thresholds following exposure to noise, Mg++ has been considered as an effective factor in  prevention of noise induced hearing loss in animals.The aim of this study was to discover whether Mg for a long period of time have a protective effect on occurrence of Noise Induce Hearing loss.
Method: The subjects were randomly chosen among individuals who were under training in army service for two months. The subjects were treated in a double-blind manner by placebo and magnesium ion. Threshold estimation and blood examination was performed for all subjects before and after treatment. All subjects were exposed to noise during 8 weeks training in the army.
Results: The statistical difference between two groups which was treated with placebo and magnesium ion was significant.
Discussion: This study is compatible with previous in vivo observations and animal studies demonstrating the protective effects of magnesium on noise-induced impairment of inner ear.

We expect some people benefit more from their hearing aids, but after a while they complain of inappropriate loudness growth.  Currently fitting hearing aids based on their loudness growth curves one of the best and most acceptable ways of fitting hearing aids we should study this curve based on the disturbed function of inner and outer hair cells. We should also know that based on which curves can make the growth curve of the damaged cells to normal ones.

Auditory integration training (AIT) is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depressin, and hyperacute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of The Sound of a Moracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

Objective: Comparing analog and digital hearing aids reducing disability caused by hearing deficiency among moderate to severe sensorineural hearing-impaired persons.
Method and Material: This descriptive-analytic study was carried out on two groups of subjects participated in this study in some audiology clinics of hearing aid since May 2002 to October 2003. Twenty subjects wore analog hearing aids and twenty one subjects wore digital hearing aids. In this study , no subject had previous middle ear or psychological problems. APHAB questionnaire was completed before using hearing aid and 2 months after to determine benefit of hearing aid use. Results: Total score mean of APHAB inventory before and after use of analoge hearing aids were 52.215+6.420 and 32.300+3.443 respectively. Also total score mean of APHAB inventory before and after use of digital hearing aids were 54.9252+9.028 and 26.321+10.916 respectively. There was no significant difference between total mean score of APHAB inventory before and after using analog and digital hearing aids (P=0.058).While there was significant difference between total mean score of APHAB questionnaire before and after use of analog hearing aids (P<0.001) and also before and after use of digital hearing aids (P<0.001). Moreover age, gender , litracy level , occupation , degree of hearing loss and manner of hearing aid usage did not have significant effect on APHAB results. Configuration of loss had siginficant effect on aversiveness subscale before and after use of analog hearing aids (P=0.008). Previous experience and duration of hearing aid usage had significant effect on aversiveness subscale before and after use of digital hearing aids (P=0.043) and (P=0.024), respectively , while all of these three items did not have significant effect on total mean score of APHAB inventory and also total mean scores of three subscales of ease of communication , reverberation and background noise.
Conclusion: Comparing to analog hearing aid , digital one is significantly benefitial for reverberation and background noise for hearing-impaired persons , but it has no benefit for ease of communication and aversiveness that may be arised from effects of the individual expectation , psychological and personal factors.

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: 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: One of the most common complaints, particularly among patients with normal or near normal low-frequency hearing, is that their voice sounds "hollow". This is associated with "Occlusion effect". The aim of this study was to comparison of occlusion effect in normal hearing subjects via Real Ear Measurement and Audiometric Bing test.
Materials and Method: Twenty volunteers with normal hearing (10 male, 10 female), with ages ranging from 18 - 24 years were enrolled in this study. First, audiometric Bing test was performed in frequencies of 250, 500, 750 and 1000 Hz. Then in real ear measurement, subjects were instructed to vocalize /â/ and /i/ for 5 seconds. Probe microphone was recorded the sound pressure in the ear canals. The degrees of occlusion effect unit were obtained for further analysis.
Results: The means of occlusion effect were present in all subjects. There was no correlation between the results of audiometric Bing test and real-ear measurement. No significant difference was obtained between genders and monaural or binaural occlusion in real-ear measurement. But in audiometric Bing test, the difference between monaural or binaural occlusion was significant(p<0.05).
Conclusion: The peak of occlusion effect varies significantly among hearing aid users, so the hearing aid must be tuned. Probe- microphone measures will assist in determination how much gain is enough, and where frequency- specific adjustments are needed.

Background and Aim: Balance disturbance is one of the non-auditory effects of noisy industrial environments that is usually neglected. The aim of the current study was to investigate the effect of occupational noise on vestibular system among workers with noise-induced hearing loss (NIHL), based on both vestibular evoked myogenic potentials (VEMP) and caloric tests.

Methods: Thirty male workers with noise-induced hearing loss and thirty male matched controls were examined by VEMP and caloric tests. Study parameters included unilateral weakness, p13 and n23 latencies, and p13-n23 amplitude. Caloric test was performed only for 20 patients.

Results: No significant difference was observed in unilateral weakness between the two groups. On the other hand, the difference in mean latencies of p13 in the right ear (p=0.003) and left ear (p=0.01) was significant between the two groups. However, the difference in n23 latency was significant only in the right ear (p=0.03). There was no significant difference between groups in p13-n23 amplitude.

Conclusion: It seems that pars inferior of vestibule is the susceptible part in individuals with NIHL. In general, abnormal findings in both VEMP and caloric tests were more common compared to functional symptoms such as vertigo, which may be due to central compensation and the symmetry of the disorder.

Background and Aim: Hearing aid users complain about a phenomenon called "occlusion effect". The aim of this study was to compare the occlusion effect in normal hearing individuals and those with slight and mild sensory neural hearing loss via Real Ear Measurement.
Methods: Sixty volunteers (30 male, 30 female) aged 18-55 years were enrolled in this study. Subjects were instructed to vocalize /e/ and /i/ for 5 seconds. Sound pressure level was measured by a probe- microphone and recorded in the ear canal. Occlusion effect and the frequency in which maximum occlusion effect occurs were obtained for each individuals for further analysis.
Results: The peak of occlusion effect for /e/ was 10.25 dB and 9.77 dB respectively in 751.9 Hz and 542.98 Hz frequencies in female and male individuals. The maximum occlusion effect occurred with 19.03 dB and 19.10 dB for /i/ and in 518.88 Hz and 440.28 Hz in female and male individuals, in respect. In addition, no significant difference was seen among hearing levels and between genders.
Conclusion: The peak of occlusion effect varies significantly among hearing aid users so that the hearing aid must be tuned. Probe-microphone measures will assist in determination where frequency- specific adjustments are needed.

Background and Aim: Research conducted since the early 1900s has consistently identified differences between deaf and hearing children on performance of a wide variety of motor tasks, most notably balance. Our study was performed to test static and dynamic balance skills in congenital severe to profound hearing impaired children in comparison with normal age-matched children.
Methods: This cross-sectional study was conducted on 30 severe to profound hearing impaired and 40 normal children with age 6 to 10 years old. Bruininks-Oseretsky test of motor proficiency 2, balance subset with 9 parts was used for evaluation of balance skills.
Results: Hearing-impaired children showed 16.7 to 100% fail results in 7 parts of the balance subset. In normal children fail result was revealed just in 3 parts of the balance subset from 2.5 to 57.5%, and differences between two groups were significant (p<0.0001). There was a significant difference between two groups in two static balance skills of standing on one leg on a line and standing on one leg on a balance beam with eyes closed (p<0.0001).
Conclusion: It seems that development of static balance skills are longer than dynamic ones. Because severe to profound hearing-impaired children showed more weakness than normal children in both static and dynamic balance abilities, functional tests of balance proficiency can help to identify balance disorders in these children.

Background and Aim: The dichotic auditory-verbal memory test (DAVMT) is useful in detecting auditory-verbal memory deficits and differences in memory function between the brain hemispheres. The purpose of this study was to prepare the Persian version of dichotic auditory-verbal memory test and to obtain its results in 18- to 25-year old normal individuals of both genders in Iran.
Methods: The Persian version of dichotic auditory-verbal memory test like the original one consisted of 18 lists of ten words. The lists were arranged such that 10 words were presented to one ear, with the reverse words simultaneously were presented to the other ear, constituting a dichotic test situation. After preparing the 18 lists, content validity was assessed by a panel of eight experts and then, the words of each list were recorded on CD in a dichotic mode. Thereafter, it was performed on one hundred and ten normal individuals with ages ranging from 18 to 25 years (mean age: 21.3 SD 1.9 years) and the scores were recorded on a specially designed scoring sheet.
Results: There was no significant difference between mean scores of 18 lists of the dichotic auditory-verbal memory test. The overall mean of CVI was 96% for the 18 lists and the mean score of dichotic auditory-verbal memory test was 6.5 SD 1.0 in the normal group.
Conclusion: Based on the obtained results, the Persian version of dichotic auditory-verbal memory test has a good content validity and can be used in detecting the auditory-verbal memory deficits.

Background and Aim: Temporal resolution refers to the ability of perceiving changes over time. This study was conducted to prepare Persian version of the temporal resolution test, which was first introduced by Phillips (1994) and Stuart (1996), and to obtain its results in 18 to 25 year old normal individuals of both genders.
Methods: To construct the Persian version of the temporal resolution test, like the original version, speech stimuli, continuous and interrupted noises were used. Speech stimuli comprised four lists of fifty words-monosyllabic lists, which were presented to the right ears first in quietness and then with continuous and interrupted noises on S/Ns of -20, -10, 0, +10 dB. The test was performed on thirty three right handed healthy individuals (14 male and 19 female with the mean age 21.02, SD=1.7 year old) in written response mode.
Results: Significant difference was shown between test scores in quiet with each of the continuous (p<0.0001) and interrupted (p≤0.0001) noises in four signal to noise ratios, and also between test scores of continuous and interrupted noise presentations (p<0.0001). No significant correlation was revealed between gender and test scores and age and test score and age in +10 dB S/N ratio.
Conclusion: Conducting this test on a group of healthy individuals showed its application for measuring temporal resolution with speech stimuli.

Background and Aim: Vestibular evoked myogenic potentials and acoustically evoked short latency negative response are two non-cochlear responses with probably saccular origin. The present study was conducted to determine the percentage of presence and the relation between these two responses in children with hearing loss.
Methods: Thirty children with profound congenital sensorineural hearing loss were studied.  Vestibular evoked myogenic potentials ellicitedby tone burst stimuli and acoustically evoked short latency negative response ellicited by click stimuli were recorded. Both responses were recorded at air conduction threshold level monaurally via an internal receiver.
Results: Vestibular evoked myogenic potentials in 53.3% of children and acoustically evoked short latency negative response in 40.0% of cases were recorded. There was a significant correlation between the percentage of recording these two responses (p=0.005). Gender and the stimulated ear had no effect on the results.
Conclusion: In almost half of these disabled children, both vestibular evoked myogenic potentials and acoustically evoked short latency negative response were recoreded. This finding may both indicate that hearing loss has no effect on the function of otolith organs in some children and vestibular deficits probably exist along with hearing impairment in others. This findng reiterates the importance of evaluation of vestibular system as part of standard auditory evaluations.

Background and Aim: Early diagnosis of hearing loss lead to early intervention and improvement of developmental skills of children with hearing loss. The present study aimed to determine the mean age of hearing loss diagnosis and cochlear implantation (CI) in hearing impaired children and to compare the age of performing cochlear implantation in children who were identified by newborn hearing screening with those who were not.
Methods: This cross-sectional study was conducted on 96 children with severe to profound sensorineural hearing loss who received cochlear implantation in Amir-e-Alam cochlear implantation center between the years 2008 and 2010. For data gathering, we assessed subjects&apos medical archives, interviewed with their parents and took medical history including demographic information, birth history and hearing loss history.
Results: Mean age of hearing loss suspicion, diagnosis, hearing aids administration, Initiation of rehabilitation program, performing cochlear implantation and mean age when cochlear implantation was utilized were 6.73 (SD=5.79), 9.35 (SD=5.79), 13.41 (SD=6.10), 16 (SD=6.36), 41.25 (SD=11.12), and 42.15 (SD=11.00) months, respectively. There was statistically significant difference between them (p<0.05). 43.8% of hearing impaired children had been identified by newborn hearing screening. There was statistically significant difference between cochlear implantation operation age of children who were identified by newborn hearing screening with those who were not (p<0.0001).
Conclusion: In spite of notable reduction in the age of hearing loss diagnosis and intervention during recent years, compared to international indices it is still tardy. Conducting newborn hearing screening can significantly reduce these ages.

Background and Aim: Due to limitation of standardized tests for Persian-speakers with language disorders, spontaneous language sampling collection is an important part of assessment of language protocol. Therefore, selection of a language sampling method, which will provide information of linguistic competence in a short time, is important. Therefore, in this study, we compared the language samples elicited with picture description and storytelling methods in order to determine the effectiveness of the two methods.
Methods: In this study 30 first-grade elementary school girls were selected with simple sampling. To investigate picture description method, we used two illustrated stories with four pictures. Language samples were collected through storytelling by telling a famous children&aposs story. To determine the effectiveness of these two methods the two indices of duration of sampling and mean length of utterance (MLU) were compared.
Results: There was no significant difference between MLU in description and storytelling methods (p>0.05). However, duration of sampling was shorter in the picture description method than the story telling method (p<0.05).
Conclusion: Findings show that, the two methods of picture description and storytelling have the same potential in language sampling. Since, picture description method can provide language samples with the same complexity in a shorter time than storytelling, it can be used as a beneficial method for clinical purposes.

Background and Aim: Auditory memory plays an important role in developing language skills and learning. The aim of the present study was to assess auditory verbal memory and learning performance of 18-30 year old healthy adults using the Persian version of the Rey Auditory-Verbal Learning Test (RAVLT).
Methods: This descriptive, cross-sectional study was coducted on seventy 18-30 year old healthy females with the mean age of 23.2 years and a standard deviation (SD) of 2.4 years. Different aspects of memory, like immediate recall, delayed recall, recognition, forgetting rate, interference and learning, were assessed using the Persian version of RAVLT.
Results: Mean score increased from 8.94 (SD=1.91) on the first trial to 13.70 (SD=1.18) on the fifth trial. Total learning mean score was 12.19 (SD=1.08), and mean learning rate was 4.76. Mean scores of the participants on the delayed recall and recognition trials were 13.47 (SD=1.2), and 14.72 (SD=0.53), respectively. The proactive and retroactive interference scores were 0.86 and 0.96, respectively. The forgetting rate score was 1.01 and the retrieval score was 0.90.
Conclusion: The auditory-verbal memory and learning performance of healthy Persian-speaking females was similar to the performance of the same population in other countries. Therefore, the Persian version of RAVLT is valid for assessment of memory function in the Persian-speaking female population.

Background and Aim: Valid identification, prevention, and treatment of language disorders have a high priority for the clinicians. Story retelling is a method for studying language development which is faster than other procedures in implementing and analyzing, and has a reliable scoring system. The aim of this project is to construct story retelling test for assessing language structure in 6-7 year old, Persian children.
Methods: An appropriate story for 6-7 year old children was written by the help of a speech pathologist, a linguist, and a novelist. The validity of the constructed story was checked by 14 experts. Then related pictures were design and their validity was examined. The test was conducted on 72 children (36 girls, 36 boys) of 6-7 years. The reliability was administered with a test-retest design with a two week interval. The reliability of the scoring system was evaluated with inter-rater method.
Results: Content validity index for this test was 89%, interclass correlation was 83%, and standard error of measurement was 2.76. The interclass correlation for scoring system was 93% and Pearson&aposs correlation was 90%. Correlation of the test-retest scores was statistically significant (p<0.01).
Conclusion: This story retelling test has appropriate validity and reliability. It is suitable for quick assessment of language structure in 6-7 year old, Persian children.

Background and Aim: Social interaction plays an essential role in acquisition of speech and language as one of the most important developmental factors. The recent studies indicated that language abilities have a close relationship to social skills. The aim of this study was to determine the relationship of development of expressive language and dimensions of social skills in 4-6-years-old Persian-speaking children.
Methods: In this study, 123 normal Persian-speaking 4-6-year-old children (76 boys and 47 girls) who had all the specific criteria for normality were randomly selected from several preschools in Shiraz, Iran. During the first stage of testing, test of language development (TOLD) was administered to investigate language development of participants later, the social skills rating system (SSRS) including the teachers&apos and parents&apos forms were completed by the parents and teachers of participants. The data were analyzed using Pearson&aposs correlation coefficients.
Results: The correlations between expressive language and dimensions of social skills were significant (p<0.001), but teachers&apos form had a greater correlation with language development (p=0.031). Besides, Pearson&aposs correlations between teachers&apos and parents&apos forms was not significant (p=0.27).
Conclusion: According to our results, expressive language develops along with social skills development. On the other hand, these results are based on the differences between home and educational environment in social skills achievements of children. These findings are to be considered to provide crucial training in both environments for the children to improve the development of their expressive language.

Background and Aim: Sustained attention refers to the ability to maintain attention in target stimuli over a sustained period of time. This study was conducted to develop a Persian version of the sustained auditory attention capacity test and to study its results in normal children.
Methods: To develop the Persian version of the sustained auditory attention capacity test, like the original version, speech stimuli were used. The speech stimuli consisted of one hundred monosyllabic words consisting of a 20 times random of and repetition of the words of a 21-word list of monosyllabic words, which were randomly grouped together. The test was carried out at comfortable hearing level using binaural, and diotic presentation modes on 46 normal children of 7 to 11 years of age of both gender.
Results: There was a significant difference between age, and an average of impulsiveness error score (p=0.004) and total score of sustained auditory attention capacity test (p=0.005). No significant difference was revealed between age, and an average of inattention error score and attention reduction span index. Gender did not have a significant impact on various indicators of the test.
Conclusion: The results of this test on a group of normal hearing children confirmed its ability to measure sustained auditory attention capacity through speech stimuli.

Background and Aim: Pragmatics refers to speech interactions and the social aspect of communication in language contexts. Due to the crucial role of hearing in language skill development, hearing-impaired children have problems with all aspects of language, including pragmatics. These skills are crucial in children's daily life. There is a lack of Persian studies on hearing-impaired children. Therefore, the purpose of the present study is to describe some pragmatic skills of hearing and hearing-impaired children.
Methods: This descriptive case study was conducted on five hearing-impaired and two normal-hearing 6 year old children. Their pragmatic language skills were studied by the Persian story retelling test. in a quiet room. The children's re-told story was recorded, analyzed, and scored.
Results: There was no difference between the scores of hearing and severe hearing-impaired children. However, children with severe hearing loss and cochlear implant, and hearing children were different in maintaining the subject and sequence of events. Children with profound hearing loss and hearing aid, and hearing children had a significant difference in all aspects except main information. All subjects used conjunctions correctly.
Conclusion: The pragmatic skills of hearing-impaired children are weaker than hearing children. There are also differences between hearing-impaired children's abilities. This difference in pragmatic skills shows the difference in amount of hearing loss, kind of assistive device, effective use of remaining hearing, onset and quality of aural rehabilitation program, and other factors. Therefore, a research with a greater sample size is necessary to explain these differences.