---

Background and Aim: Nowadays, auditory perception is not a complete method to assess vowels quality and we need to use more objective instruments.In this study we want to determine and compare the persian vowels formants in normal and hearing Impaired students in 7ـ9 year old children of Isfahan.
Materials and Methods: This cross sectional study was performed on 64 normal and hearing impaired students. Background information was by interview and then, vowel production test was performed. First three formants of each vowel were obtained and recorded by speech studio soft ware and Dr. Speech device Data were compared between groups.
Results: Mean F₁ and F₂, and F₂/F₁ and F₃/F₁ ratio of Persian vowels between these three studied groups were different significantly. Mean F₃ of /o/, /e/ and /a/ in all groups was different significantly. Although we could not find such a significant differences for /u/, /i/ and /æ/ between these groups(p<0.05).
Conclusion: The most important difference between normal and hearing impaired children is their vowel Space, and we found that, the more sever the hearing impairment is, the closer vowel space will be seen. The hearing impaired children rely mostly on their proprioceptive sense because of their hearing deficiency and it causes less movement of the tongue, so they usually substitute vowels which have similar F₁ and F₂.

---

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 impairment through the primary episode of development has an undeniable effect on communicative language and cognitive ability of children. The purpose of this study was to compare primary verbal, nonverbal and mathematical concept formation, between children with and without hearing impairment.
Methods: In this study 88 children with normal and impaired hearing were compared in four-, five- and six-year old age groups. Normal children were selected randomly and the other group consisted of the available children with impaired hearing. To evaluate verbal, nonverbal and mathematic concepts, a test was designed and developed based on language and cognitive developmental scale in normal children.
Results: Significant difference was seen in the average scores in each concept class between normal and impaired hearing group in all age groups (p<0.05). There was no statistical significance between girls and boys. Hearing groups had statistical significant difference in each group of concepts (p<0.001). Age had statistical significance only in mathematics&apos concepts (p=0.001).
Conclusions: This study supports the necessity of assessing the understanding of verbal, nonverbal and mathematic concepts, as well as cognitive and verbal skills in children with hearing impairment, prior to any formal education program planning. The curriculum should be arranged according to these abilities and skills. Otherwise it would be hardly practical and functional for these children to go through the curriculum which is planned without any notion to their basic abilities.

---

Background and Aim: Verb is one of the most important aspects of a sentence, and verb deficit is a noticeable part of developmental language disorders. In Iran, there is no standard test for evaluating this aspect of language in children. This study aimed to develop and evaluate a picture verb test for 36-54 month-old normal Persian-speaking children, and assess its ability to differentiate between children.
Methods: A list of verbs that could be depicted was collected and content validity was assessed by seven speech therapist. 55 verbs were selected. Then, three pictures were prepared for each verb and one of those pictures was chosen by the same seven specialists. 106 children aged 36-54 months participated in this study. They were divided into three groups (36-42, 42-48, and 48-54 months). Reliability of this test was assessed by Spearman&aposs correlation and internal consistency. Correlation between children&aposs scores and their age was calculated.
Results: Content validity index of all verbs were 1. Spearman&aposs correlation of 0.89 and internal consistency of 0.60 was obtained. By deletion of item method, the Kuder-Richardson score was enhanced to 0.71. There was a significant correlation between children&aposs ability to respond and their age (r=0.76, p < 0.001).
Conclusion: This test is a suitable tool for assessment of verbs in 36-54 month-old Persian-speaking children and can differentiate between three groups under study.

---

Background and Aim: The ability of conversational repair is a subset of pragmatic language. When the listener does not understand the speaker&aposs intention, and the speaker cannot find a way of repairing the conversation to make his/her massage clear, communication will fail. This study aims to examine and compare the conversational repair skill in two groups of three and five year old children, to determine different conversational repair strategies and compare these skills among these groups.
Methods: One hundred and twenty Persian speaking children of three and five years of Ahwaz, Iran, were selected. The study tools were two series of pictures. During the retelling of the pictures the examiner created a situation to elicit a conversational repair strategy. Percentages of the usage of different kinds of conversational repair in each group were calculated and compared using student&aposs t-test.
Results: The usage of repetition and inappropriate response is decreased in the group of five year olds compared to the three year olds, but cue-repair and repetition method is increased. The addition method has remained relatively constant. There was a significant difference between average percentage of using repetition (p=0.04) and cue-repair (p=0.001) of the two groups. The percentage of application of repetition method in three year olds and cue-term method in five year olds were significantly higher than other conversational repair strategies.
Conclusion: With the increase in age and development of language skills the probability of using more complex and difficult strategies, like the cue-repair method, increases.

---

Background and Aim: Sustained attention refers to the ability to maintain attention in target stimuli over a sustained period of time. This study was conducted to develop a Persian version of the sustained auditory attention capacity test and to study its results in normal children.
Methods: To develop the Persian version of the sustained auditory attention capacity test, like the original version, speech stimuli were used. The speech stimuli consisted of one hundred monosyllabic words consisting of a 20 times random of and repetition of the words of a 21-word list of monosyllabic words, which were randomly grouped together. The test was carried out at comfortable hearing level using binaural, and diotic presentation modes on 46 normal children of 7 to 11 years of age of both gender.
Results: There was a significant difference between age, and an average of impulsiveness error score (p=0.004) and total score of sustained auditory attention capacity test (p=0.005). No significant difference was revealed between age, and an average of inattention error score and attention reduction span index. Gender did not have a significant impact on various indicators of the test.
Conclusion: The results of this test on a group of normal hearing children confirmed its ability to measure sustained auditory attention capacity through speech stimuli.

---

Background and Aim: Preterm birth is one of the risk factors need comprehensive audiological assessment. In this study, the effect of sex and rate of stimulation on response of children with history of preterm birth was investigated by auditory brainstem response (ABR).

Methods: This cross-sectional study was conducted using convinience sampling. Click-evoked a uditory brainstem response test with both low (21.1 c/s) and high (51.1 c/s) stimulus rates was recorded in 30 children with a history of preterm birth and 30 ones with history of term labor, as controls.

Results: Significant differences were observed in inter-peak latencies of I-III in both rates, III-V in the low rate, I-V in the high rate, and absolute latency of III wave between high and low stimulus rates (p<0.05 for all). Rate of stimulus affect on auditory brainstem response of preterm birth group was more than controls. Sex also affected on some parameters of auditory brainstem response test.

Conclusion: Preterm birth group showed longer latencies than normal group in both rates. Rate of stimulus had significant effect on results of children with history of preterm birth compared normal group. These findings may reflect the negative effect of preterm birth on neural synchronization function in response to transient stimuli.

---

Background and Aim: An imbalance between phonatory subsystems may lead to disturbing phonatory muscular balance and consequently voice disorders. Based on theoretical issues, criterion-based laryngeal manual therapy, as a novel treatment method which is supported by classical laryngeal manual therapy, can improve voice quality using manual maneuvers combined with phonatory tasks. The present study aimed to report the treating effects of this method on hyperfunctional voice disorders.

Methods: Twenty adult participants with hyperfunctional voice disorders by the least three months history of voice disorder were selected. The participant’s voices were assessed multidimensionally using acoustic, audio-pecreptual and stroboscopic assessments before and after treatment.

Results: There were a decrease in jitter (p=0.003) and shimmer (p<0.001) and also, increase in harmonic-to-noise ratio (HNR) (p<0.001) of vowel /a/ after treatment. Besides, there was an increase in harmony to noise ratio (p=0.009) and decrease in jitter (p=0.020) of vowel /i/, too. There were not significant changes in shimmer amount of vowel /i/ (p=0.170) after treatment. There were highly significant changes in all aspects of audio-perceptual (p<0.001) and videostroboscopic (p<0.001) parameters.

Conclusion: Using voice-based laryngeal manual therapy can be a treatment method in handling hyperfunctional voice disorders.

---

Background and Aim: Pragmatic impairment is the main cause of communication difficulties in hearing-impaired children and teaching pragmatic skills in these children is too challenging for clinicians. Thus, creating written and formalized therapy plans can be useful for rehabilitation team, clients and therapists.

Methods: A therapy-plan was designed and content validity of it was determined. A single case subject design (a multiple baselines research design) was used to determine the efficacy of the therapy plan to improve four domains of pragmatic in five hearing-impaired children (5 to 8 years). The experiment was divided into three phases including baseline, treatment and follow-up. Treatment phase consisted of 16 sessions and subjects were enrolled in the phase in stair way. The data were analyzed with effect size and visual analysis.

Results: According to expert's opinions, the therapy plan of pragmatic skills was valid. Visual analysis of diagrams showed that all subjects progressed in turn-taking, topic maintenance and response to request for clarification domains and the effect sizes (ES) were high (ES>0.8). Also, there were medium effect sizes (0.8≥ES≥0.2) in certain subjects. In request for clarification domain, some of subjects did not show desired improvement by visual analysis and effect sizes were medium. But, others showed improvement and had high effect sizes.

Conclusion: The therapy plan of pragmatic skills can improve pragmatic skills of moderate-to-severe hearing-impaired children.

---

Background and Aim: Concerning the important role of parents of hearing-impaired children in auditory-verbal therapy, this study mainly focused on preparing a Persian version of the “Parental needs questionnaire” and analyzing its validity and reliability.

Methods: First, the original English version of the questionnaire “the needs of hearing-impaired Children’s Parents in Auditory-Verbal Therapy” translated to Persian, based on the approved translation protocol of International Quality of Life Assessment by world health organization. Then, the Persian version presented to seven experts for validating the content and their feedbacks were applied into the questionnaire. Finally, the questionnaire presented to parents of 51 hearing-impaired children who attend in auditory-verbal therapy, and the collected results were analyzed statistically.

Results: The overall mean of content validity index in 32 items of the questionnaire was 0.87. The overall Cronbach’s alpha of this questionnaire was 0.86 in the test and 0.99 in the re-test phases.

Conclusion: Based on the obtained results, the Persian version of the questionnaire has a satisfactory content validity and reliability and could be used in clinics and medical centers for analysis of parental needs.

---

Background and Aim: Studies have shown that long-term use of monaural hearing aid in symmetrical hearing losses may lead to physiological changes. In this research, the possibility of plasticity occurrence in bilaterally hearing impaired listeners fitted with only one hearing aid was investigated.

Methods: Our study was carried out on 12 elderly listeners with a mean age of 61.92 years who had symmetrical moderate to severe sensory neural hearing loss in both ears. All of the participants had minimum monaural hearing aid experience of 2 years. We used auditory brainstem response (ABR) testing in order to compare absolute latency and amplitude of wave V between the two ears of cases. Air conduction click stimuli were presented monaurally at 80, 90 and 100 dB nHL.

Results: Despite the shorter absolute latency of wave V in the fitted ear, no significant difference was found between the two ears (p>0.389). The difference between wave V amplitude of both ears was greater in 90 dB nHL level (p=0.043). Women showed shorter mean latency than men and the mean amplitude of women was greater than men. Significant gender difference was observed in absolute latency of wave V (p<0.037).

Conclusion: Our findings indicate that the use of monaural hearing aid in symmetrical hearing losses can induce neural plasticity within auditory brainstem pathways which can be displayed by auditory brainstem response test.