Background and Aim: Hearing has an important role in speech production and making phonological distinction, especially voicing distinction. Voice onset time (VOT) has been a reliable acoustic cue of voicing differences in plosive consonants. The purpose of this study was to measure VOT in initial Persian (Farsi) oral plosives produced by cochlear implanted children, comparing to normal hearing children.
Methods: In this cross-sectional study, 20 cases and 20 controls were assessed. Cases were prelingually deaf children who were cochlear implanted 4.5 years prior to test. Controls were normal hearing children at 4.5 years of age. VOT were measured while children uttered oral plosives. The effect of hearing status, voicing, and gender on VOT were assessed.
Results: The amount of VOT of plosives produced by girls was higher than boys, in both groups. This difference was significantly higher in voiceless plosives than in voiced ones. In both groups, voiceless plosives had long-positive VOT value while the amount of VOT was short-positive regarding voiced plosives.
Conclusion: It was demonstrated that VOT is significantly correlated with voicing. In voiceless plosives, VOT could not be considered as a phonetic correlate of hearing status whereas it made significant differences between cochlear implanted children and hearing controls. Furthermore, it was confirmed that concerning voiceless plosives, the amount of VOT of girls was significantly higher than boys. On the contrary, in voiced plosives, gender had no significant effect on the amount of VOT.

Background and Aim: listening, speaking, reading and writing are considered the lingual skills. These skills are in direct relation with each other. Listening is the first skill learnt by the individual through development. If damaged by hearing impairment, listening can cause serious defect to lingual skills. The goal of our research was to study the effect of hearing loss on reading literacy in hearing impairment students in comparison with normal hearing students.
Methods: Study was performed using the examination booklets of Progress in International Reading Literacy Study (PIRLS) 2001. 119 hearing impairment students of 4^th grade primary school, last year guidance school, and last year high school levels in schools providing exceptional student education were included. These individuals were compared to 46 normal hearing students of 4^th grade primary school of ordinary schools. Comparative statistical analysis was performed using t-test.
Results: Reading literacy and literal contents understanding was shown to have a significant difference between normal hearing and whole hearing impaired student (p<0.05), except the ones in high school level with moderate hearing loss. There was also seen a significant difference between normal hearing and hearing impairment students in understanding of information contents (p=0.03).
Conclusion: Hearing loss has a negative effect on reading literacy. Consequently, curriculum change and evolution of educational programs in exceptional centers is needed, in order to promote reading literacy and to enhance rest hearing

Background and Aim: Reflux laryngitis is extremely common among patients with voice disorder. Medical therapy approaches are not efficient enough. The main goal of this study is to assess the acoustic and laryngeal characteristics of patients with dysphonia before and after medical or voice therapy, and to evaluate the effectiveness of each.
Methods: In this retrospective study, 16 reflux laryngitis patients were assessed. Five received complete voice therapy, tow ceased voice therapy and nine received medication. Perceptual voice evaluation was performed by a speech-language pathologist, the severity of voice problem was calculated, based on the affected acoustic and laryngeal characteristics pre- and post-treatment.
Results: Post-treatment evaluation in patients who received complete voice therapy indicates 80 percent improvement in the severity of disorder and 100 percent improvement in the perceptual voice evaluation. After medical therapy, we observed that voice disorder and perceptual voice evaluation are improved 44 and 66 percent respectively. The improvement was statistically significant in both treatment approaches: complete voice therapy (P=0.039) and medical therapy (p=0.017).
Conclusion: In patients with reflux laryngitis, most acoustic and laryngeal characteristics were normal and satisfying after the treatment. It can be concluded that the proficiency of voice therapy in improving the acoustic and laryngeal characteristics is comparable to medical therapy.

Background and Aim: Laryngeal muscles contribute in sound production play a key role in specific language. Needle electromyography is the specific complementary method for muscle activity evaluation which is awfully painful and needs serenity of patient. The purpose of this study was to use Surface electromyography as a probable new approach for evaluation of laryngeal muscles activity.
Methods: 34 healthy women and 34 healthy men aged 20-30 years old were enrolled in this study. Each individual was seated in an armchair. Recording electrodes were placed bilaterally (right and left) in the low anterior neck at approximately one centimeter from midline on thyroarytenoid and cricothyroid muscles. Silent activity and fricative voice (/z/ , /ž/) and voiceless (/s/ , /š/) activities were recorded for ten seconds followed by 10 seconds of rest, for 5 repetition. All data were processed and frequency and non linear measurements were assessed. And were compared in time and frequency domain.
Results: Muscle activity in fricative voice in both groups was greater than rest condition (p<0.05). Moreover, muscle activity median frequency was significantly more in men than women (p<0.001).
Conclusion: Activity evaluation of thyroarytenoid and cricothyroid muscles using surface electromyography is difficult in women. That may be due to anatomical features such as length and width of neck in women.

Background and Aim: Vestibular evoked myogenic potential in response to click or short tone burst stimuli have been used as a clinical test for distinguish saccule and inferior vestibular nerve diseases. Different studies show that cochlear implant could have inverse effects on vestibular structures. We aimed to investigate vestibular evoked myogenic potential in unilateral cochlear implanted individuals in compare to normal individuals.
Methods: Thirty-three unilateral cochlear implanted patients (mean age 19.96 years) and 30 normal hearing individuals (mean age 24-27 years) as control group were enrolled in this cross- sectional study. Absolute latencies and amplitudes of myogenic potential responses were measured and compared in both groups.
Results: Myogenic potential recorded in both ears of all controls were normal. No response could be recorded in 16 patients (48.48%) from both ears. In three patients, responses were recorded in both ears though the amplitude of waves was reduced in implanted ear. Unilateral response could be recorded in 14 patients only in their non-implanted ear.
Conclusion: Vestibular evoked myogenic potential test is a useful tool for assessing saccular function in cochlear implant patients. Damages of osseous spiral lamina and basilar membrane after cochlear implantation could result in dysfunctions of vestibular organs specially saccule. It seems that saccule could be easily damaged after cochlear implantation. This would cause absence or reduced amplitudes in myogenic potential.

Background and Aim: N-acetylcysteine, a glutathione precursor and reactive oxygen species scavenger, is reported to be effective in reducing noise-induced hearing loss. Many workers in industry are exposed simultaneously to noise and chemical pollutants such as carbon monoxide. We investigated effectiveness of N-acetylcysteine in protecting the cochlea from simultaneous noise and carbon monoxide damages.
Methods: Twelve rabbits were exposed simeltaneously to 100 dB sound pressure level of broad band noise and carbon monoxide 8 hours a day for 5 days. One hour before exposure, experimental group received 325 mg/kg of N-acetylcysteine while normal saline was administered for the control group. The protective effect of N-acetylcysteine was evaluated 3 weeks after exposure by histological assessment of the hair cells.
Results: Simultaneous exposure to noise and carbon monoxide resulted in a considerable damage to the outer hair cells however, the inner hair cells and the pillar cells remained intact. Use of N-acetylcysteine in the experimental group significantly reduced the extent of outer hair cell loss.
Conclusion: N-acetylcysteine attenuates simultaneous noise and carbon monoxide induced hair cell damage in rabbits.
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Background and Aim: One of the chemical pollutions which is frequently common in industry-other than noise is carbon monoxide. The present study aimed to assess the putative protective effect of N-acetylcysteine on the function of outer hair cells of rabbits exposed simultaneously to noise and carbon monoxide.
Methods: 24 male rabbits are entered in this interventional study. After obtaining baseline distortion product otoacoustic emissions, rabits were randomely devided into four groups. The groups Included: exposed with noise and received saline, exposed with noise and carbon monoxide and received saline, exposed with noise and received N-acetylcysteine, and exposed with noise and carbon monoxide and received N-acetylcysteine. Subsequently, they were evaluated again with distortion product otoacoustic emissions in two stages (two hours and one week after the exposure). Data were recorded and analyzed using paired and independent sample t-tests.
Results: Exposure to noise, and also simultaneous exposure to noise and carbon monoxide, and moreover using N-acetylcysteine in both groups, produced significant changes in distortion product otoacoustic emissions amplitudes (p<0.005).
Conclusion: The findings of the present research reveal that simultaneous exposure to noise and carbon monoxide may potentiate noise induced hearing loss. In addition, utilizing N-acetylcysteine can be used as a preventive agent for noise induced hearing loss and to avoid its potentiation with carbon monoxide.

Background and Aim: Hearing-impaired children make a lot of stress for the parents. Providing the parents of these children with suitable consultation and rehabilitation services results in increased satisfaction and reduced anxiety level. In this study we investigated the relationship between audiology service satisfaction and level of anxiety in parents of hearing-impaired children.
Methods: Seventy-five parents of hearing-impaired children, whose problem was diagnosed during the last year, participated in the study. The mothers were interviewed using satisfaction and anxiety questionnaires.
Results: There was no association between level of service satisfaction and parental state and trait anxiety level however, the group with a higher level of satisfaction (score 64-90) recorded a lower anxiety score (0-20). There was also a significant association between parental state and trait anxiety level (p<0.001). Considering the demographic data, only the living place (Tehran compared with other provinces) showed a significant association with satisfaction and anxiety levels people living in small provinces had a significantly less satisfaction level (p=0.002) and a more anxiety score (p=0.017).
Conclusion: Lack of durability of services was the concern of people living in small provinces which resulted in being more anxious and less satisfied.

Background and Aim: Patients with migraine commonly show vestibular symptoms. However, abnormal neurotological test findings during the inter-attack intervals, even in the absence of vestibular symptoms, are suggestive of subclinical vestibular dysfunction in migraine. This study aimed to compare the vestibular evoked myogenic potentials between migraine patients and normal individuals.
Methods: Subjects included 25 patients with migraine and 26 healthy volunteers with an age range of 20-53 years old. The vestibular evoked myogenic potentials were recorded with 500 Hz tone bursts at 95 dB nHL.
Results: Mean of absolute amplitude and p13 latency values in the migraine group were significantly less and more than the normal group, respectively (p=0.001 for absolute amplitude in right and left ears p=0.004 for p13 latency in right ears and p=0.02 in left ears). There was no statistically significant difference between the two groups in mean of the n23 latency and also the amplitude ratio (p>0.05).
Conclusion: According to the prolonged latency of vestibular evoked myogenic potentials response, vestibulospinal tract in brainstem is probably involved in migraine patients. However, due to small sample size, for generalizing this result to all patients with migraine, further researches are needed.

Background: Treacher-Collins syndrome is a congenital craniofacial disorder with multiple anomalies. This syndrome affects the maxilla, mandible, eyes, middle and outer ears, and soft palate. Conductive hearing loss due to the deformities of the middle and external ears is prevalent. The characteristics of this syndrome include multiple and serious threats to normal communication development in children. In this study, speech and language features of a Persian speaking child with this syndrome are presented.
Case: The case was an 8-year old girl with Treacher-Collins syndrome and bilateral moderate conductive hearing loss due to atretic canal. In language and speech assessments, moderate hypernasality, numerous compensatory errors and morphosyntactic deficits were observed. There were 13 phonemes that were incorrectly produced at least in one position. Besides, she used 22 types of phonological processes that were abnormal and disappear before the age of three in normal Persian speaking children.
Conclusion: Moderate hearing loss, velopharyngeal incompetency, malocclusion and dental anomalies, attention deficit/hyperactivity disorder (ADHD) and environmental factors resulted in severe speech and language disorders in this case. These disorders affected her academic performance as well. Moderate hypernasality, numerous compensatory errors, and excessive and abnormal use of phonological processes were not presented as prevalent characteristics of Treacher-Collins syndrome in other resources.

Background and Aim: Noise-induced hearing loss is the most common problem in industrial areas. This study aimed to determine effects of excessive noise exposure on measurable characteristics of distortion product otoacoustic emissions (DPOAEs) in rabbits.
Methods: The study was carried out on 12 adult male New Zealand White rabbits including case group - exposed to 500-8000 Hz broadband white noise with 100 dBA SPL for 8 hours per day in 5 consecutive days - and control group. After three days period of acclimatization to the experimental condition, rabbits&apos hearing status in each group were measured by distortion product otoacoustic emissions on days zero means before the study was initiated as a baseline, eight, one hour after the latest exposure to noise, and ten. The recorded results were analyzed using SPSS software.
Results: Highest mean distortion product otoacoustic emissions amplitudes in case group were allocated to frequencies of 5888.50 Hz, 8166.50 Hz, 9855.00 Hz, 3956.00 Hz, and 3098.50 Hz, respectively. However, the lowest mean distortion product otoacoustic emissions amplitude was related to frequency of 588.00 Hz (p=0.001).
Conclusion: This study revealed that distortion product otoacoustic emissions amplitude shifts due to noise occur first in high and then in middle frequencies. Additionally, exposure to noise can decrease distortion product otoacoustic emissions amplitudes. We conclude that distortion product otoacoustic emissions can be a reliable test for estimating personal susceptibility to noise-induced hearing loss.

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: To date, the function of auditory efferent system remains unclear. There is evidence that medial olivocochlear bundle receives descending input from the cortex. In this study, the effect of auditory selective attention on stimulus-frequency otoacoustic emissions (SFOAE) was analyzed to investigate the modification of peripheral auditory system by auditory cortex activity in frequency specific mode.
Methods: Thirty-six normal hearing adult subjects with their age ranging from 18 to 30 years (mean age: 21.9 years) participated in this cross-sectional study. Contralateral suppression of stimulus-frequency otoacoustic emissions was recorded in the right ear at 2 KHz. In order to eliminate the auditory attention, subjects were instructed to read a text. Besides, in order to evaluate the effect of auditory attention on contralateral suppression, subjects were instructed to detect target tones in background noise at 1000, 2000, and 4000 KHz.
Results: A significant increase at contralateral suppression of stimulus-frequency otoacoustic emissions was observed in auditory selective attention conditions (p≤0.001). The largest magnitude of stimulus-frequency otoacoustic emissions suppression was seen at 2 KHz.
Conclusion: The results of this study indicated that the activities of medial olivocochlear bundle enhanced by contralateral auditory selective attention increase the magnitude of stimulus-frequency otoacoustic emissions suppression. In fact, these results provided evidence for influence of auditory cortex on the peripheral auditory system via corticofugal pathways in a frequency specific way.

Background: Phonemic awareness is one of the most important predictors of reading skills that has been taught by different procedures. One of the procedures is implementation of direct instruction in instruction of phonemic awareness. Current study is one of the unique studies in Iran that investigate impact of direct instruction in phonemic awareness on reading achievement of students with reading disorder.
Case: Three male second grade elementary students with reading disorder in a regular school in district six of the office of education in Tehran were selected. Multiple-baseline across subjects was selected as a research design. The following tests were used as diagnostic criteria: reading and dyslexia test and Wechsler intelligence scale for children-revised. Moreover, a reading inventory consisting of 100 words was developed by researchers to assess the reading ability of the subjects. Data were collected in three phases: baseline, intervention, and follow-up. During the intervention phase, the intervention strategies were used while during baseline and follow-up, data were collected without any intervention. Comparing three phases of the study, we may conclude that intervention package consisting of direct instruction of phonological awareness was an effective strategy in reading achievement of all three students. In addition, follow-up data indicated that the effects of the intervention procedures were stable across time.
Conclusion: Direct instruction of phonological awareness was effective in reading achievement of students with reading disorder in elementary school and increasing their abilities in reading.

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: In different language approaches, reading is considered as a major skill. Language skills comprising listening, speaking, reading and writing are completely interlinked with each other. Thus, providing active application of listening and speaking skills, children will learn reading and writing skills easily. The aim of this research was to compare reading skills of hearing-loss students studying at exceptional schools with normal students of different degrees.
Methods: The research was conducted post-traumatically using standardized 2006 PIRLS test. 80 students in fifth grade of exceptional primary schools, and first and fourth grade of exceptional high schools in Tehran City who had severe and or profound hearing loss were randomly selected along with 80 normal students in ordinary schools who were selected using available sampling method.
Results: There were significant differences between reading comprehension of hearing-loss and normal students of all three grades (p<0.001). Reading comprehension in female students was significantly higher than the male ones (p<0.001). There were not any significant differences in mean reading comprehension scores of hearing-loss students in different grades which demonstrate that their reading skills had not developed in tandem with their age and school educations.
Conclusion: This study shows that one of the significant concerns regarding hearing-loss students is their reading comprehension ability. Considering reading ability as one of the most important acquisitive abilities which students learn at school, evaluation of reading skills of hearing loss students as well as recognition of their strengths and weaknesses in this field is indispensable.

Background and Aim: Contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) test evaluates the efferent auditory system. In this test, acoustic reflex is an important confounding variable. In recent years, application of this test is growing especially in children suspect to central auditory processing disorder. Therefore, the magnitude of influence of this confounding variable on the suppression of TEOAEs should be made clear. The aim of this study was to investigate the impact of acoustic reflex on contralateral suppression of TEOAEs.
Methods: This research was performed on 39 normal-hearing adults of both sexes and of 18-26 years of age. Tests were used for the determination of interaural attenuation (IA), acoustic reflex, TEOAEs and contralateral suppression of TEOAEs.
Results: TEOAEs amplitudes and their contralateral suppression were significantly higher in females and males respectively (p=0.01). The amount of TEOAEs suppression before reflex activity ranged between 2000 to 3000 Hz. Activation of acoustic reflex significantly increased the magnitude of suppression in all frequency bands (p≤0.01) and maximum suppression occurred in 500 to 1000 Hz.
Conclusion: For achieving accuracy of clinical findings, clinicians should always use suppressant levels lower than the acoustic reflex threshold. It is recommended that different norms for males and females be used in contralateral suppression of TEOAEs.

Background and Aim: Recently, researchers have increasingly turned to study the relation between stuttering and syntactic complexity. This study investigates the effect of syntactic complexity on the amount of speech dysfluency in stuttering Persian-speaking children and adults in conversational speech. The obtained results can pave the way to a better understanding of stuttering in children and adults, and finding more appropriate treatments.
Methods: In this cross-sectional study, the participants were 15 stuttering adult Persian-speakers, older than 15 years, and 15 stuttering child Persian-speakers of 4-6 years of age. In this study, first a 30 minute sample of the spontaneous speech of the participants was provided. Then the utterances of each person were studied in respect to the amount of dysfluency and syntactic complexity. The obtained information was analyzed using paired samples t-test.
Results: In both groups of stuttering children and adults, there was a significant difference between the amount of dysfluency of simple and complex sentences (p<0.05).
Conclusion: The results of this study showed that an increase in syntactic complexity in conversational speech, increased the amount of dysfluency in stuttering children and adults. Moreover, as a result of increase of syntactic complexity, dysfluency had a greater increase in stuttering children than stuttering adults.

Background and Aim: In many migraine patients prophylactic drugs are effective in reducing attacks and symptoms such as vestibular complaints. Therefore, related neural pathways are probably also affected. This study aimed to compare vestibular evoked myogenic potential in migraine patients under treatment with prophylactic drugs and those without any treatment.
Methods: Subjects included 46 patients with migraine. They were evaluated in two groups those under treatment with prophylactic drugs (21 subjects) and those without treatment (25 subjects). The age range of patients was 20-60 years. The vestibular evoked myogenic potential were recorded with 500 Hz tone bursts at 95 dB nHL.
Results: Mean of amplitude ratio (p=0.02), and interpeak latency values in the right ear (p=0.03) and left ear (p=0.001) were higher in patients with prophylactic therapy than the group without therapy this difference was statistically significant. There was no statistical difference between the two groups in terms of mean of latency of p13 and n23 peaks, and absolute amplitude (p>0.05).
Conclusion: Prophylactic drugs probably improve mean of main response parameters of vestibular evoked myogenic potential in migraine patients with prophylactic therapy.

Background and Aim: Reading skills, a complicated process, should be learnt and solely is not depend on sounds conforming with the written symbols on a page. Readers will be able to understand and perceive the deeper meaning of the text based on their experiences and knowledge obtained through reading. This research aimed to compare hearing-impaired students&apos reading literacy in exceptional and ordinary schools in Iran.
Methods: This cross-sectional study was done on 28 hearing-impaired students of the 4^th year of primary exceptional and ordinary schools of Shahr-e-Ray and Shahryar cities, Iran, using the Progress in International Reading Literacy Study (PIRLS 2006) booklets. Comparative statistical analysis was performed using Student&aposs t-test.
Results: The hearing-impaired students in ordinary schools had significantly (p<0.05) higher scores [mean (SD)] in reading literacy [3.67 (1.74)], comprehension of informational contents [4.21 (2.48)], and comprehension of literary contents [3.14(1.23)] than hearing-impaired students in exceptional schools [1.78 (1.06), 1.92 (1.49), and 1.64 (1.62), respectively].
Conclusion: Hearing-impaired students in ordinary schools meaningfully had higher performance of reading skills in comparison with hearing-impaired students in exceptional schools. It seems that an appropriate cultural bed should be provided in order to conduct these students and accept them in ordinary schools.