Diagnostic ultrasound is a beneficial technique which can be used the audiologists based on essential instruction. Although there are a lot of barriers in relation to the size of the probe and the resolution of the pictures which are obtained,with this method some kind of information can be gained that is impossible to get by any other method. The ability of real- time A and B modes for direct visualization makes them useful tools to study the changes of the ear structures. Ultrasound system is a useful method to evaluate dizzy patients, which can be potentially used along with vestibular tests.

Diagnostic ultrasound is a beneficial technique which can be used the audiologists based on essential instruction. Although there are a lot of barriers in relation to the size of the probe and the resolution of the pictures which are obtained, with this method some kind of information can be gained that is impossible to get by any other method. The ability of real- time A and B modes for direct visualization makes them useful tools to study the changes of the ear structures. Ultrasound system is a useful method to evaluate dizzy patients, which can be potentially used along with vestibular tests.

In this article we aimed at studying the function of Melanin in the inner ear. To reach this goal TTS was studied in people with blue or brown eye color. Subjects were 68 male teenagers with normal hearing. Auditory thresholds were obtained by means of high frequency audiometry (.8-8KHz)before and after TTS.  We used narrowband noise with frequency width of 1665-2335Hz, central frequency of 2 KHz, intensity of 105dBSPL and duration of 10 minutes. A significant difference was discovered in the average TTS of this two group in the frequency range of 2-8 KHz. Brown-colored eye boys manifested the least TTS and the blue- colored eyes one the most discovered TTS.

Studying noise effect at the workplace has more various aspects than other factors. So it is not surprising that its adverse impact on the physical and mental state of the society has been detected to some extent. There is a significant correlation between the hearing loss and the noise pollution of the workplaces. The most important ways to lessen and control the impact of noise are: substituting the noisy equipments with ones that produce less noise, correcting noise sources and isolating the sound source.In the current study we tried to control the noise level by using various sound absorbents and measured sound level by using these different substances. The results of these measurements have reported in the current article in details.

We prepared 300 eggs from Isfahan Poultry farm industrial complex. All the eggs were fertilized and their average weight in the first turn was 61±2gr, in the second turn was 60±.5gr and in the third turn was 59.5±.5gr which was measured 6 hours after laying eggs. We were aimed at studying the effect of magnesium chlorate on the fetus chicken in preventing stress induced sound 6 weeks after birth.The eggs were divided into four groups and prepared magnesium chlorate with a concentration of 2.5 /100 ml. the first group contained of 25 eggs drilled in the air Sac with a small hole and 1cc of magnesium chlorate was injected and the hole was sealed with paraffin. The same procedure was performed for the second group in the 4^th embryonic age and in the two control groups. All groups were hatched in the days 21 and 22. The effect of sound was studied in all groups.our research demonstrated that the chickens who received magnesium chlorate during their embryonic stage had more resistance toward noise exposure.

Industrialization has had many complications for human beings and has been a threat to social mental and physical health. Vibration induced noises in the workplace is one of the main devastating factor in producing hearing loss in workers.Recently, several investigations on the issue of noise pollution and noise dosimetry and also Noise induced hearing loss have been developed. In the current article we will have a look and sometimes reconsideration on the results and of these studies and will discuss the findings in regard to noise control and management in details.

As the industry develops in the societies, human being is more likely to exposed to high level of noises and be at risk of hearing loss. Urbanism and working in the situation which are not in accordance with the personal nature make people even more susceptible to risk factors of hearing loss.   Exposure of workers to industrial noise has been the subject to several studies and it seems that reconsidering the situations in both society and nature can be a key to change environment for decreasing noise in the society.For example in Tehran, geographically, the slope of the earth from north to south is 5-10% which is a main factor contributing in noise pollution.Moreover, the source of most outdoor noise worldwide is mainly construction and transportation systems including motor vehicles, air craft noises and rail noises. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.In the current article we have examined both conditions in the hearing condition of workers with high levels of noise exposure.

This study was designed to measure the noise caused by a 63.20KV transformer in the residential area close to it that consisted of 36 points inside the post and the surrounding area around it (including 29 points+30 points). the results demonstrated that noise caused by the function of the transformer t1 was 59.1dBA with the standard deviation of 6.89dBA and for transformer t2 was 59.89dBA with a standard deviation of 6.86dBA .The measured noise in the west residential area around the post was 54.95dBA with a standard deviation of 1.76dBA, in the east was 54.1dBA with a standard deviation of 2.52dBA and in the south was 49.71dBA with a standard deviation of 1.07dBA.The statistical measurements showed no significant difference in the measured noise around in the mentioned direction.The results of this measurements manifested that the noise measured in all residential areas close to the post was more than noise permitted in night.

NIHL occurs when too much sound intensity is transmitted into and through the auditory system and can be occur following a shot gun or the exposure to a moderately intense sound for a long period of time. NIHL caused by acoustic trauma refers to permanent cochlear damage from a one-time exposure to excessive sound pressure. This form of NIHL commonly results from exposure to high-intensity sounds such as explosions, gunfire, a large drum hit loudly and firecrackers.Meanwhile the sound intensity, duration of exposure and personal hearing thresholds as the effective factors in the amount of noise induced hearing loss should not be overlooked.  Since numerous investigations have been performed about intense sudden sound we will discuss it in detail in the current article.

Sounds are the creatures of God which are found in nature in diverse forms. In addition to sounds naturally exist in the environment there are artificial sounds that is hand-maid and we experience them in our daily life. Industrialization has had detrimental effect on manufacturing such sounds in the environment which in turn can affect our mental and physical state.The current article is taking sound from a religious point of view into account. We want to discuss the role of sounds in perceiving the meanings of related concepts and also will have an overall look on the devastating effects of noise and irritating sounds on human life and the human mental and physical health.

Method & Material: This descriptive analytical survey was performed in pars Hospital, Tehran on 45 children (22 girls, 23 boys aged 2-5 years, 1377-78 (solar).Finding: In 2-3 years old group, accurdacy of PTA test (87/7%) was more than FNS test (66%). In 3-5 years old group, Specificity & NPV showed no significant differences, between two test.
Conclusion: Since the PTA showes greater possibility of false positive response than FNST, the accuracy of the latter test is greater the PTA.

Background and aim: Noise pollution is one of the main cause of occupational hearing loss. According to WHO reports in many countries workers have been exposed to 85 - 90 dB noise level. The purpose of this study is to manufacture a sound absorber based on combined recycled polyethylene trephetalat (PET) and polystyrene (PS) with an economical method in order to control of noise pollution
Materials and methods: Sound absorber were made of PET and PS with equal weight percent, polyester fiber, and polyvinyl acetate resine, with five to ten centimeters thick. Sound mean absorption coefficient percents were determined by acoustic impedance tube and compared with those of rock wool.
Results: Mean absorption coefficient percent of  samples with one to five millimeter pore size and ten centimeters thickness was significantly better than those with six to twenty millimeters pore size in 50 to 630, 1250, and 1600 Hz, (p<0.05). In general, samples mean absorption coehicient was significally different from those rock wool (p=0.005).
Conclusion: Recycle polymere absorbers may play an important role in national economics as they are prophylactic to some occupational disease and also are economical.

Background and Aim: Although the ability of speech perception has been improved in implanted subjects with recent progress in technology, cochlear implantation alone is not enough and more aural rehabilitation is necessary. The aim of this study was to assess improvement of speech perception in children with cochlear implant.
Methods: Fourteen cochlear implanted children with a mean age of 5.5 years participated in this study. Auditory training was performed in 10 to 43 sessions. Speech recognition and perception were evaluated every 3 months. Third evaluation was done only for 4 patients.
Results: Mean total score of the first evaluation was 43.21%, of the second was 63.76%, and of the third evaluation was 78%. All children obtained complete score for sound awareness at the first evaluation. In environmental sounds discrimination, 71.3%, 84.36%, and 100% answered completely to the questions of three evaluations respectively. In speech sounds discrimination, 34.7% in the first, 57.04% in the second, and 85% in the third evaluation obtained the complete score, and in auditory memory, complete responses were 21% for the first, 57.12% for the second, and 83% for third evaluation. In story rephrasing and comprehension, no one answered to questions completely. However, 12.83% obtained the complete score in the second and third evaluations. There were statistically significant differences between the first and the second evaluation (p=0.002(.
Conclusion: Sound awareness ability seems to be achieved rapidly. Development of speech and environmental sound discrimination abilities, particularly speech comprehension which is the most important skill, need more impressive training.

Background and Aim: Sound conditioning is exposure to a non-traumatic, moderate level of sound which increases inner ear resistance against further severe noise. In this study, we aimed to survey the effect of sound conditioning on auditory brainstem response (ABR) threshold shifts using click stimulus, and the effect of the frequency of conditioning on hearing protection.
Methods: Fifteen guinea pigs were randomly divided into 3 groups. Two conditioned groups were exposed to 1 kHz, and 4 kHz octave band noise at 85 dB SPL, 6 hours per day for 5 days, respectively. On the sixth day, the animals were exposed to 4 kHz octave band noise at 105 dB SPL, for 4 hours. The control group was exposed to intense noise, 4 kHz at 105 Db SPL for 4 hours (without conditioning). After exposure, ABR thresholds using click were recorded an hour, and 7 days after noise exposure.
Results: The results of the ABR with click stimulus showed less thresold shifts in conditioned groups than control (p≤0.001). Comparison of the results of conditioned groups, showed less threshold shift by 4 kHz conditioning, however, this difference was not statistically significant (p>0.05).
Conclusion: Electrophysiological data of our study showed that sound conditioning has a protective effect against subsequent intensive noise exposure, and the frequency of conditioning does not have significant effect on ABR threshold shifts when using click stimulus.

Background and Aim: Some children with speech sound disorder (SSD) have difficulty with phonological awareness skills therefore, the purpose of this study was to survey the correlation between phonological processes and phonological awareness.

Methods: Twenty-one children with speech sound disorder, aged between 5 and 6, participated in this cross-sectional study. They were recruited from speech therapy clinics at the Tehran University of Medical Sciences. They were selected using the convenience sampling method . Language, speech sound, and phonological awareness skills were investigated by the test of language development-third edition (TOLD-3), the Persian diagnostic evaluation articulation and phonology test, and the phonological awareness test. Both Pearson’s and Spearman’s correlations were used to analyze the data.

Results: There was a significant correlation between the atypical phonological processes and alliteration awareness (p=0.005), rhyme awareness (p=0.009), blending phonemes (p=0.006), identification of words with the same initial phoneme (p=0.007), and identification of words with the same final phoneme (p=0.007). Analyzing the correlation on the basis of the phoneme and syllable structure separately showed there was a significant correlation between the atypical phoneme structure and alliteration awareness (p=0.001), rhyme awareness (p=0.008), blending phonemes (p=0.029), identification of words with the same initial phoneme (p=0.007), and identification of words with the same final phoneme (p=0.003).

Conclusion: Results revealed a relationship between phonological processes and phonological awareness in children with speech sound disorder. Poor phonological awareness was associated with atypical phonological processes especially at the phoneme level.