We designed this study to measure the Percussion caused by pneumatic drill( 32gram) which is used commonly in different in city services. this study have been performed in the summer of 1375 in Hamedan. The results demonstrated that the average background noise level (including environment and compressor) was 92.4 with standard deviation of 5.4 dBC, the average background noise level of the drills while working was 109.6 dBC with the standard deviation of about 2.2dBC and the average peaking factor was 18.6 with a standard deviation of 3.7dBC. the average background noise level of the drills while working in a distance of 5m, 10m and 20m from the source respectively were 98.6 dBA(with a standard deviation of 2.8dBA), 91.5dBA(with a standard deviation of2.6dBA) and 86.8dBA with a standard deviation of 2.8dBA).Based on the obtained results and the potential effects of exposure to noise which mainly can be summarized to damage to auditory system, interference with the communication skills, neural excitation, Hypertension and tachycardia the side effects of noise should be taken in to account seriously.Based on the mounting evidences regarding the adverse impact of working in the noisy environment and the damaging consequences of living in such atmospheres and the findings of the current study which confirms that the noise exposure level is more than allowed limit, the health of the workers and citizens is threaded by the noise pollution factors mentioned in the current study and serious considerations should be taken in to account.

Background and Aim: Due to its ability in bonding with hard and soft tissue, healing and repairing of the bone, and proper replacing of the ossicles in middle ear, bioactive glass has come into consideration. The aim of this work was preparation, development and characterization of nanopowder bioactive glass obtained by the sol-gel technique.
Materials and Methods: Bioglass powder was made by sol-gel technique and the presence of desired elements is tested by X-ray fluorescence analysis. Trans Electronic Microscopic (TEM) technique was used to evaluate the powders shape and size. The prepared bioglass powder was immersed in the simulated body fluid solution for 30 days. Fourier transform infrared (FTIR) spectroscopy was utilized to recognize and to confirm the formation of apatite layer on prepared bioglass powder. (XRD) as a structural characterization technique was used to investigate the microstructure.
Results: The glass powder size was less than 100 nanometers. The formation of apatite layer confirmed the bioactivity of the bioglass powder and tests revealed that all the films had the signs of bioactivity. It was also found that at sintering temperatures above 900 ºC, crystalline phase Ca₂SiO₄ was formed.
Conclusion: The sol-gel nanopowder bioglass can be used as a replacement for small bones such as ossicles in middle ear, and it leads to bone osteointegration and growth of the surrounding tissue.

Background and Aim: Main feature of auditory processing abilities is temporal processing including temporal resolution, temporal ordering, temporal integration and temporal masking. Many studies have shown the superiority of musicians in temporal discrimination over non-musicians. In this study we compared temporal processing in musicians and non-musician controls via Gap in Noise (GIN) test.
Methods: This cohort study was conducted on 24 musicians with mean age of 25.3 years and 24 normal hearing non-musician controls with mean age of 24.5 years, in Faculty of Rehabilitation of Tehran University of Medical Sciences. GIN test results (approximate threshold and percent of corrected answers) obtained and analyzed by Mann-Whitney non-parametric statistical test.
Results: There was significant difference between approximate threshold and percent of corrected answers between musicians and non-musician group (p<0.001), while no sex difference was observed between both groups (p>0.05).
Conclusion: the lower approximate threshold and the more corrected answers in GIN test by musician group indicate rapid auditory temporal processing ability of this group rather than non-musicians group. This might be related to effects of musical training on central auditory processing.

Background and Aim: Formant structure and vowel space are the most important acoustic characteristics of speech sounds. The purpose of this study was to determine formant frequency and vowel space in six Persian vowels.
Methods: This cross-sectional descriptive-analytic study was performed on 60 Persian students of Tehran University of Medical Sciences (30 males, 30 females) with their age ranging from 18 to 24 years. The subject articulated six Persian vowels in isolation and data was recorded by real-analyzer software. Then, the first three formant frequency of each vowel was determined for each subject. Vowel formant frequency averages were measured separately for each vowel and each gender. Vowel space was plotted. The difference between F0 in two groups was compared by Leven and independent sample t tests.
Results: Maximum and minimum values of F0 in both group was related to /æ/ and /a/ (135 Hz in males and 239 Hz in females) and /i/ (146 Hz in males and 239 Hz in females). Besides, F0 in females was significantly higher than males (p<0.001). Maximum and minimum values of F1 were related to /æ/ and /i/. Furthermore, maximum and minimum values of F2 were related to /i/ and /u/. Maximum and minimum values of F3 were related to /i/ and /u/.
Conclusion: The lowest vowels were /æ/ and /a/ and the highest was /i/. The frontest was /i/ and the backest was /u/. the spreadest vowel was /i/ and the roundest was /u/.

Background and Aim: Deafness is a heterogeneous disorder induced by genetic and environmental factors. It is the most common hereditary sensory-neural disorder that affects 1/1000 to 1/2000 of the newborns. More than 70% of hearing loss cases are caused by genetic disorders, 85% of which result from nonsyndromic autosomal recessive sensory-neural hearing loss. Up to now, more than 100 genes contributing in hearing loss have been determined. Alteration of these genes may result in hearing loss.
This study was performed to identify the inheritance patterns of deafness and its relation with ethnicity, gender and consanguineous marriages.
Methods: In this survey, data from 356 families affected by hearing loss and referred to welfare organization of Ahvaz during the time were collected based on sex, ethnic groups and relativeness.
Results: The results state a high frequency of autosomal recessive deafness caused by consanguineous marriages within Arab and non-Arab ethnic groups (p<0.05). But no significant difference in gender.
Conclusion: In conclusion, the high frequency of autosomal recessive deafness among the population with a high frequency of consanguineous marriages is considerable. The dominant pattern of deafness observed in this population was autosomal recessive.

Background and Aim: About 1.5 percent of exceptional children suffer from impaired hearing and this factor affects the teaching and learning process. The aim of this study was to investigate the effect of frequency of knowledge of results (KR) on the learning of children with hearing impairment.

Methods: Twenty-four individuals with hearing impairment with the mean age of 10.56 with SD 2.53 years (range: 7-14 years) were divided into three homogenous groups according to their records after pre-test. They practiced for eight sessions according to mentioned ways (feedback of 0%, 50% and 100%). The acquisition, learning and translation tests were run. MANOVA with repeated measures and ANOVA were used to analyze the data from the acquisition, retention and transition tests.

Results: All groups progressed during training and at various stages (acquisition, retention and transition). However, the results of the comparison between means of the three training groups showed significant differences in the acquisition process (p=0.008), learning (p=0.001) and transition (p=0.035). This means that feedback training groups (100%) had better performance in acquisition process, and also in retention and transition (50%).

Conclusion: According to the results of this study, too much feedback interferes with learning of tasks in individuals with hearing impairment and feedback (50%) had better learning. This finding shows that rules regarding feedback also affect the people with hearing impairment.

Background and Aim: Dyslexia is the most common learning disability. One of the main factors have role in this disability is auditory perception imperfection that cause a lot of problems in education. We aimed to study the effect of auditory perception training on reading performance of female students with dyslexia at the third grade of elementary school.

Methods: Thirty-eight female students at the third grade of elementary schools of Khomeinishahr City, Iran, were selected by multistage cluster random sampling of them, 20 students which were diagnosed dyslexic by Reading test and Wechsler test, devided randomly to two equal groups of experimental and control. For experimental group, during ten 45-minute sessions, auditory perception training were conducted, but no intervention was done for control group. An participants were re-assessed by Reading test after the intervention (pre- and post- test method). Data were analyed by covariance test.

Results: The effect of auditory perception training on reading performance (81%) was significant (p<0.0001) for all subtests execpt the separate compound word test.

Conclusion: Findings of our study confirm the hypothesis that auditory perception training effects on students' functional reading. So, auditory perception training seems to be necessary for the students with dyslexia.

Background and Aim: Universal newborn hearing screening program (UNHS) using otoacoustic emission (OAE) has been expanded dramatically. The aim of this study was to compare the characteristics of OAE in different time periods.

Methods: In this cohort study, 54 well babies were tested using screening transient-evoked otoacoustic emission in 12, 24, 36, 48 hours and 1 week of their age in Tamin Ejtemaii hospital of Zahedan, Iran. Parameters of "pass" and "fail" level, duration of the test, repetition rate for getting definite result and cooperation level of the parents were analyzed.

Results: The failing rate decreased markedly with age. The major part of this decrement concerned to the age of 12 to 24 hours (left ear: p=0.012 and right ear: p=0.057). Only for the age of 12 hours, the test repetition reduced the failing rate significantly (left ear: p=0.001 and right ear: p<0.001). The test duration reduced significantly with age increment and decreased from the 75 second in age 12 hours to 21 second in age of 24 hours. The test time median for 36, 48 hours and one week of age was 13, 8.4 and 14.3 second, respectively. Among the 54 parents requested to come back for retest one week later, 5 (9.3%) cooperated.

Conclusion: Age effect on referral rate were confirmed in this study high referral rate and poor parent cooperation were the main problems in universal newborn hearing screening program in Zahedan city.

Background and Aim: Phonological awareness (consisting of phoneme, syllable and intra-syllable awareness) is an important part of receptive and expressive language it facilitates reading and writing skills through phonological re-coding. Multiple studies in several languages have studied the relationship between phonological awareness and dictation. This research is based on a study of the relationship between phonological skill and spelling score in first-grade Persian students.

Methods: Four hundred first-grade students participated in the study, including 209 girls and 191 boys. A phonological awareness test was individually administered for each student and then a spelling exam was administered in groups. The correlation between the two tests was studied using a simple regression model. The comparison of mean scores of girls and boys was evaluated employing an independent t-test.

Results: A correlation coefficient of 0.82 was obtained between phonological awareness and spelling proficiency (p<0.001). Phonological skill sub-tests also showed a significant correlation with spelling proficiency (highest for phoneme awareness r=0.34 and lowest for rhyme awareness r=0.12). The mean scores of girls and boys differed significantly (p<0.05).

Conclusion: There is a strong positive association between phonological awareness and spelling proficiency. Therefore, if phonological skill is improved, spelling score can be enhanced.

Background and Aim: Empathy is a basic human skill that is important in daily life. The purpose of this study was to evaluate the role of the theory of mind in predicting empathy.

Methods: This study adopted a causal-comparative design. 40 students with profound hearing impairment and 40 students with normal hearing, aged between 8 and 14, participated in the study. Instruments including false belief tasks and empathy questionnaires were distributed to the participants. For multivariate analysis of variance, a correlation analysis and multiple regression methods were used.

Results: Results indicated a significant difference between the total score of false belief tasks and empathy in students with hearing impairment and those with normal hearing (p<0.001 ). A significant relationship between the theory of mind and empathy was found in both groups (p<0.01). Also theory of mind could predict the empathy (p=0.001).

Conclusion: Based on the obtained results, significant reduction in the theory of mind and empathy was seen in students with hearing impairment. Therefore, training programs that focus on social skills are required for students with hearing impairment in order to address this problem. Moreover, training materials need to be tailored to their cognitive understanding.

Background and Aim: Students with hearing impairment show delayed development of theory of mind (ToM) compared with normal children. One factor impacting development of theory of mind is parent-child interaction. The present study investigated the relationship between maternal emotional intelligence and theory of mind in students with hearing impairment.

Methods: The present study employed correlational research. 40 students with profound hearing impairment (age range: 8-14 years) and their mothers were selected to participate. Measurement instruments included the false belief task and emotional intelligence questionnaire. The questionnaire was completed by mothers. Correlational analysis and multiple regression methods were used for data analysis.

Results: Results indicated no significant correlation between the total score on false belief task and the emotional intelligence score and its components (p>0.01). Multiple regression analysis showed that maternal emotional intelligence and its components cannot predict student's scores in false belief tasks (p>0.01).

Conclusion: The results show that there is no significant correlation between maternal emotional intelligence and theory of mind in students with hearing impairment. Therefore, maternal emotional intelligence cannot predict the development of theory of mind in students with hearing impairment.