Auditory and Vestibular Research
Volume:9 Issue: 1, 2000

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.

Methods and Materials: Investigation of electrically evoked auditory brain stem response (EABR) is a new issue, especially in implanted patients. Experiments were performed in C.I Center of Iranian Institute for Science and research expansion,1996 on 30 implanted patients with 22 spectra and MSP cochlear implant system and 30 normal subjects with the range of 3-33 years.I- EABR was obtained in the implanted patients.2- Absolute latency of EABR waves is 1-1.5 ms shorter than ABR waves ‘P<0.05).3-Absolute latency of wave V decreases as a function of electric stimulus magnitude (P<0.05).4- No significant difference was observed in IPL Ill-V between ABR and EABR.

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. There is good correlation between kiessling's 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. Kiessling's 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.

In recent years there has been increased interest in the use of Al for assessing hearing handicap and for measuring the potential effectiveness of amplification system.AI is an expression of proportion of average speech signal that is audible to a given patient, and it can vary between 0.0 to 1.0.Method and Materials: This cross-sectional analytical study was carried out in department of audiology, rehabilitation, faculty, IUMS form 31 Oct 98 to 7 March 1999, on 40 normal hearing persons (80 ears; 19 males and 21 females) and 40 hearing impaired persons (61 ears; 36 males and 25 females, 25-65 years old) with moderate to moderately severe SNI-IL The pavlovic procedure (1988) for calculating Al, open set taped standard mono syllabic word lists, and the real -ear probe- tube microphone system to measure insertion gain were used, through test-retest. 1/A significant correlation was shown between the Al scores and the speech recognition scores of normal hearing and hearing-impaired group with and without the hearing aid (P<0.05) 2/ There was no significant differences in age group & sex: also 3 In test-retest measures of the insertion gain in each test and 4/No significant in test-retest of speech recognition test score. According to these results the Al can predict the unaided and aided monosyllabic recognition test scores very well, and age and sex variables have no effect on its ability. Therefore with respect to high reliability of the Al results and its simplicity, easy -to- use, cost effective, and little time consuming for calculation, it's recommended the wide use of the Al, especially in clinical situation.

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.

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.

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.

Method and Materials; this cross sectional descriptive and analytic survey was done at Golestan navy hospital in Tehran, between June 1998 and March 1999 on total of 69 male subject (104 ears,) 50 acoustic trauma & 54 noise induced H.L) between 20 to 40 ears old.- The mean acoustic reflex threshold at 1 kHz showed there is no significant difference between two groups.2- The intensity elicited maximum reflex amplitude at 1 kHz didnt produce at a significant linear correlation with subject's age and ear canal volume in both groups.3- The intensity elicited maximum reflex amplitude in NIHL group wasnt shown a significant correlation with ear compliance and gradient.4- The mean Intensity (SPL) elicited maximum reflex amplitude in NIHL group was more than mean intensity (SPL) in acoustic trauma group.5- The mean intensity (SL) elicited maximum reflex amplitude in NIHL group was More than mean intensity (SL) in acoustic trauma group. Acoustic reflex amplitude is reduced for subjects with NIHL compared with acoustic trauma subjects.

Title: Comparing Intensity Elicited Maximum Reflex Amplitude Between Noise Induced Hearing Loss & Acoustic Trauma at 1kHZ, Contralaterally, and Investigate Relationship Between Amplitude and Hearing Impairment Method and Materials: This cross sectional descriptive and analytic survey was done at Golestan navy hospital in Tehran, between June 1998 and March 1999 on total of 69 male subject (104 ears, 50 acoustic trauma & 54 noise induced H.L)between 20 to 40 years old.

Method and Materials: This cross - sectional survey is carried out in pediatric clinic; department of audiology; faculty of rehabilitation, TMSU, on spring 1998. 102 top grade ranking children with normal hearing threshold (Results