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It has always been attempted that systems connected to the ear through hearing aids efficiently meet the patient expectations. It is recommended to avoid using occluded earmolds when the hearing is normal or there is mild hearing loss. In order that natural sound  reaches to the ear, the ear canal should stay open as much as possible.To achieve the above goal and the suitable acoustic modifications, non-occluding ear molds are beneficial.

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Hearing aid selection as the first step in modifying the hearing loss is a critical point . people with severe to profound hearing loss need special consideration. In order to determine the amount of gain and output of hearing aids, some formulae are presented. Although most of these formulae are planned for mild to moderate hearing loss, they are used for severe to profound hearing losses. POGO method is one of these formulae.This method, based on halving the hearing threshold, is not suitable for profound hearing loss. There are some considerations in revising this method for severe to profound hearing loss and it’s name has changed to POGO II, too.

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Hearing aid selection as the first step in modifying the hearing loss is a critical point . people with severe to profound hearing loss need special consideration. In order to determine the amount of gain and output of hearing aids, some formula are presented. Although most of these formula are planned for mild to moderate hearing loss, they are used for severe to profound hearing losses. POGO method is one of these formula. This method, based on halving the hearing threshold, is not suitable for profound hearing loss. There are some considerations in revising this method for severe to profound hearing loss and its name has changed to POGO II, too.

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Many people around the world are in need for using hearing aid, a prothesis which is prescribed for compensating the hearing loss in hard of hearing patients.Although Hearing aid has crucial role in improving hearing skills in such patients, it has many psychological effects and Social premonitions for the users.we will discuss some of these distresses and the common approaches for resolving economical, cosmetic and the emotional and social problems relted to hearing aid will be discussed.

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Background: The current article is aimed at evaluating speech recognition scores in hearing aid wearers to determine whether nonsense syllables are suitable speech materials to evaluate the effectiveness of their hearing aids.
Method: Subjects were 60 children (15 males and 15 females) with bilateral moderate and moderately severe sensorineural hearing impairment who were aged between 7.7-14 years old. Gain prescription was fitted by NAL method. Then speech evaluation was performed in a quiet place with and without hearing aid by using a list of 25 monosyllable words recorded on a tape. A list was prepared for the subjects to check in the correct response. The same method was used to obtain results for normal subjects.
Results: The results revealed that the subjects using hearing aids achieved significantly higher SRS in comparison of not wearing it. Although the speech recognition ability was not compensated completely (the maximum score obtained was 60%) it was also revealed that the syllable recognition ability in the less amplified frequencies were decreased. the SRS was very higher in normal subjects (with an average of 88%).
Conclusion: It seems that Speech recognition score can prepare Audiologist with a more comprehensive method to evaluate the hearing aid benefits.

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Prescription of hearing aid is an extensive special category of knowledge in the field of audiology. This article is aimed at discussing the function of hearing aid and also management of patients in the noisy environments and presenting solutions to overcome problems regarding to this issue along with taking a look to the equipments prepared nowadays to cope with noisy situations.

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Rehabilitation of deaf individual is one of the important subjects that has attracted attention of many researchers during past centuries. Different opinions have been established in this direction. Electrophysiologic tests were established and developed parallel to developments in rehabilitation. Therefore, opinion of using electrophysiologic test for evaluation and fitting of hearing aid became gradually popular. Ultimately, the electrophysiologic tests are used in evaluation and fitting of hearing aid in two ways:1-Direct way2- Indirect wayIn direct way aided ABR is obtained and special attention is paid to wave V. This technique has many difficulties. Inindirect way, electrophysiologic tests such, ECochG, OAE and ABR, AMLR, ALR and P300 and other objective tests are used, especially in infants and neonates for evaluating the state of hearing. Researches are continuing in this field. It is probable to have aided electrophysiologic responses with speech stimuli in near future.

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Binaural hearing is an important phenomenon in hearing for human being. Nowadays, the role of binaural hearing in the process of amplification has been focused. Since hearing aids act separately in the process of amplification and hearing, the attentions has been devoted to designing a system for binaural amplification by means of Beam forming which will be explained in more details in the current article.

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Recent studies have been ocused on designing an intelligent system containing binaural fitting. Researchers are mostly aimed at seperating signals from background noise and other disturbing signals. most of such techniques include Digital Signal Processing(DSP). Here we will have a look in this technique.

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Method and Materials: This cross- sectional analytical survey is carried out in department of audiology, rehabilitation faculty, IUMS, 1997-1998 on 10 normal and 28 sensory damaged ears out of 27,8 to 40 years old male individuals were evaluated according to following critria:Hearing threshold up to 7OdBHL.Normal middle ear status.
Results: There is good correlation between kiessling&aposs procedure and R-N.A.L, P.O.G.O 11 and Lyharger procedures in determining gain of hearing aid in individuals with flat and raising audiogram. There is poor correlation between them in individuals with high frequency sensory hearing loss.
Conclusion: Kiessling&aposs procedure can he used instead of Lyharger, R-N.A.L, P.0.0.0 11 procedures in children, difficult to test and multihandicapped persons who are not able to cooperate in behavioral audiometry.

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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.

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In order to develop oral communication, hearing impaired infants and young children must be able to hear speech comfortably and consistently. To day children with all degrees of hearing loss may be condidates for some kinds of amlification.As children differ from adults, many Factors should be consider in hearing aid selection, evaluation and fitting. For example the child age when he or she is candidate for custom instruments? Do we consider programmable Hearing aid? Are multi memory instruments appropriate for them? What about directional microphones? What style of hearing aid do we select? In this paper such questions are responded.

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Objective: Determining the frequency of hearing disorders and hearing aid using in the clients referring to the Avesina education and health center, audiometry clinic, 1377.
Method and Material: This is an assesive-descriptive survey that conducted on more than 2053 (1234 males and 819 females) who referred for audiometry after examination by a physician. Case history, otoscopy, PTA, speech and immittance audiometry were conducted for all the clients. The findings were expressed in tables and diagrams of frequency. The age and sex relationship. All types of hearing losses and the number of the hearing-impaired clients need a hearing aid were assessed.Findings: 56% of this population were hearing-impaired and 44% had normal hearing were hearing. 60% were males and 40% females. Of the hearing-impaired, 44% had SNHL, 35.6% CHL and 8.2% mixed hearing loss. The hearing aid was prescribed for 204 (83 females and121 males) if they need that only 20 females and 32 males wear it.
Conclusion: It this sample, SNHL is of higher frequency. According to this survey, the more the age, the more the hearing aid is accepted (85% of wearer are more than 49) the prevalence of the hearing impaired males are more than females (60% versus 40%). Only 25% of the hearing-impaired wear hearing aids.

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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.

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Background and Aims: As the hearing aid technology progressively promotes toward replacing analog hearing aids with digital and programmable ones, comparison of the patient satisfaction of those kinds of hearing aids by means of a valuable tool seems so necessary. So, the aim of this study was to compare self-reported benefit of analog, digitally controlled programmable and digital hearing aids for reducing disability caused by hearing impairment in mild to severe sensorineural hearing impaired persons.
Materials and Methods: This cross-sectional study was performed on 90 persons with mild to severe sensorineural hearing loss dividing into three groups: 43 subjects were fitted with digital, 15 with programmable, 23 with analog hearing aids. After pure tone audiometry, Abbreviated profile of hearing aid benefit (APHAB) was completed before and one month after using hearing aids to determine the benefit of them.
Results: Global APHAB mean scores for digital, programmable and analog hearing aids were 49.05, 33.19 and 39.53, respectively. Ease of Communication subscale mean scores were 53.46 for digitals, 37.66 for programmables and 39.09 for analogs. Background noise subscale mean scores for digital programmable and analog hearing aids were 46.36, 25.53 and 35.31, respectively. Global and also both subscale mean scores showed significant difference between digital hearing aids and programmable and analog ones. There was no significant difference between reverberation subscale mean scores of three groups.
Conclusion: It seems digital hearing aids may be more beneficial to reduce disability caused by hearing loss than analog and programmable hearing aids are.

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Background and Aim: Although for a child to maximize his or her mastery of language, hearing aids (HAs) must consistently be worn, and they must be functioning correctly many studies indicates some hearing- impaired children`s hearing aid do not work perfectly.The purpose of this study was to determine types of defects in students&apos hearing aid (HA) in Tehran Exceptional Schools.

Materials and method: In this cross-sectional analytic study defects in sixty –two HAs of 41 children were determined. All were the students of Exceptional Schools referred to Audiology Clinic, Faculty of Rehabilitation Medical Sciences University of Tehran. Functions of the HAs were first checked by a sthetoclips. Then the electroacoustic measurements performed to determine the values of maximum gain and maximum power output. The data were separately recorded in a questionnaire for each kind of the HAs.

Results: Fifty-six percent of HAs functioned perfectly and forty-four percent were not. The most Frequet defects were 24% and 20% pertained to the battery and manual controls respectively. External components had more difficulties than internal components. Seventy percent of ear molds were damaged. There were significant differences between peak of FOG and MPO curves in the catalogue and electroacoustic measurements in 2cc coupler.

Conclusion: Most damaged parts of HAs in Tehran Exceptional students is related to the battery and controls which are external components of HAs. Because of high rate of dysfunctioning HAs and ear molds in this population in this survey, it is necessary to promote orientation and counseling level after fitting and to develop the quality of HAs and ear molds for Exceptional School students.

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Background and Aim: Hearing loss is one of the most prevalent chronic conditions affecting the elderly. The impacts of hearing loss are depression, social isolation, and functional disability, particularly for those who have not yet been evaluated or treated for hearing loss. The aim of this study was audiologic screening and assessing candidacy  for hearing aid in the elderly people.
Materials and Methods: This analytic-cross sectional study was performed on 52 older adults aged from 51 to 97. Subjects were evaluated according to ASHA guidelines for audiologic screening in adults (1997). Using HHIE-S as hearing disability screening instrument, the need for hearing aid use was evaluated.
Results: About 86 percent of subjects had some degree of hearing loss. There were significant correlation between PTA(0.5, 1, 2) KHz>26 and HHIE-S>10. According to these two factors 21.2 percent of subjects needed to use hearing aid while 18 percent of this group had hearing aids.
Conclusion: There is high prevalence of hearing loss among older adults, thus it&aposs necessary to evaluate the need for hearing aid in this rapidly growing population. Among different factors affecting hearing aid candidacy the most correlated were PTA(0.5, 1, 2)KHz>26 and HHIE-S>10. Therefore according to this study by combination of these two evaluation of hearing aid candidacy would be more appropriate.

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Background and Aim: It is well established that adult sensory systems can reorganize following environmental changes hearing aid stimulates a deprived auditory system resulting in changes in received stimuli and may be capable of inducing changes within the auditory system abilities such as difference limen for intensity. Hearing aid fitting induces perceptual and physiological modifications. The present study was conducted to evaluate the effects of hearing aid use on the intensity discrimination performance.
Methods: The study group consisted of 30 monaural users of hearing aid with symmetrical moderate or moderately severe sensorineural hearing loss in both ears (15 males, 15 females), aged 45-65 years old with the mean of 57.73 and SD of 8.12 years. difference limen for intensity was measured at two frequencies, 500 Hz, 2000 Hz, and two intensity levels (10 dB SL, 40 dB SL). The results of fitted ears were compared with not-fitted ones.
Results: The results of the study showed better difference limen for intensity scores at high frequency and high intensity levels. A significant lower difference limen for intensity in fitted ears was observed compared with not-fitted ears (p<0.05), while there was no significant difference between the difference limen for intensity in the two groups at 500 Hz with 10 dB SL intensity (p=0.132).
Conclusion: Hearing aid use affects intensity discrimination performance. Besides, perceptual modification following use of hearing aid is confirmed by our study which suggests a possible functional plasticity due to hearing aid use. However, further

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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.

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Background and Aim: Behavioral audiometry is the best method of hearing evaluation. Hearing thresholds are estimated with auditory evoked responses in patients who are not able to cooperate in behavioral audiometry. Because rehabilitative decisions are based on behavioral thresholds, it is essential to determine the amount of difference between behavioral and evoked response thresholds. The purpose of this study was to evaluate the difference between functional and auditory steady-state response (ASSR) gains.

Methods: Twenty six moderate to severe hearing impaired adolescents and adults (age range: 14 to 55 years) participated in this interventional-comparative study. Audiometery and ASSR testing was performed (without hearing aid and then with hearing aid). Finally, functional gain with ASSR gain, and behavioral thresholds with ASSR thresholds were compared using paired t-test and correlation statistical methods. All tests were performed in the sound field.

Results: The mean difference was 6.19 dB between unaided behavioral and ASSR thresholds, 4.33 dB between aided thresholds, and 2.43 dB between functional and ASSR gains. There was no significant difference between functional and ASSR gains (p>0.05).

Conclusion: The difference between functional and ASSR gains is less than the difference between behavioral and ASSR thresholds and it has less variability between different frequencies. So, it may be better to use ASSR gain instead of ASSR thresholds in hearing aid fitting in difficult-to-test population.