Auditory and Vestibular Research
Volume:20 Issue: 2, 2011

It is well established that adult sensory systems can reorganize following environmental changes; hearing aid stimulates a deprived auditory system resulting in changes in received stimuli and may be capable of inducing changes within the auditory system abilities such as difference limen for intensity. Hearing aid fitting induces perceptual and physiological modifications. The present study was conducted to evaluate the effects of hearing aid use on the intensity discrimination performance. The study group consisted of 30 monaural users of hearing aid with symmetrical moderate or moderately severe sensorineural hearing loss in both ears (15 males, 15 females), aged 45-65 years old with the mean of 57.73 and SD of 8.12 years. difference limen for intensity was measured at two frequencies, 500 Hz, 2000 Hz, and two intensity levels (10 dB SL, 40 dB SL). The results of fitted ears were compared with not-fitted ones. The results of the study showed better difference limen for intensity scores at high frequency and high intensity levels. A significant lower difference limen for intensity in fitted ears was observed compared with not-fitted ears (p<0.05), while there was no significant difference between the difference limen for intensity in the two groups at 500 Hz with 10 dB SL intensity (p=0.132). Hearing aid use affects intensity discrimination performance. Besides, perceptual modification following use of hearing aid is confirmed by our study which suggests a possible functional plasticity due to hearing aid use. However, further

Specific language impairment (SLI) is one of the most prevalent developmental language disorders which is less considered in Persian researches. The aim of this study was to investigate the differences in some morpho-syntactic features of speech and other language skills between Persian children with specific language impairment and their normal age-matched peers. Moreover, the usefulness of the test of language development-3 (TOLD-3), Persian version, as a tool in identifing Persian-speaking children with this impairment, was investigated. In a case-control study, the results of the test of language development and speech samples analysis of 13 Persian-speaking children (5 to 7 years old) with specific language impairment were compared with 13 age-matched normal children. The results of this study showed that there were significant differences between the scores of specific language impairment group and control group in all measured aspects of the TOLD-3 (p<0.001); the children with specific language impairment had a shorter mean length of utterance (p<0.001) and made less use of functional words in their speech (p=0.002) compared with their peers. Such as specific language impairment children in other languages, all language abilities of Persian-speaking children with specific language impairment are less than expected stage for their age. Furthermore, the Persian version of TOLD-3 is a useful assessment instrument in identifying children with specific language impairment which is comparable to the.

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 blinds in temporal discrimination over sighted subjects. In this study, temporal processing was compared in congenital blind subjects with sighted controls via gap in noise test (GIN). This analytic-prescriptive non-invasive cohort study was conducted on 22 congenital blinds (11 males and 11 females) with a mean age of 26.22 years and 22 sighted control subjects (11 males and 11 females) with a mean age of 24.04 years with normal hearing in faculty of Rehabilitation Tehran University of Medical Sciences. Gap in noise test results, approximate threshold and percent of corrected answers, were obtained and then, were analyzed by Mann-Whitney non-parametric statistical test. There was a significant difference in the approximate threshold and the percent of corrected answers between congenital blinds and sighted control subjects (p<0.05). However, there was no significant difference between males and females in this regard (p>0.05). Auditory temporal resolution ability, the lower approximate threshold and the more corrected answers in gap in noise, in blind subjects is better than the sighted control group and it might be related to the compensative neuroplasticity after visual deprivation.

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. 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. 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(. 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.

Regarding the importance of employment in social and emotional status of individuals, it would be important for the deaf. The purpose of the present study was to assess the employment status of the members of Tehran deaf community. This descriptive study was performed on all members of Tehran deaf community. A researchers-made questionnaire which had three parts (demographic information, employment status of the deaf members and their attitudes regarding employment) was used in this study. The obtained data were analyzed using descriptive methods. Majority of deaf community members were adult (ages ranging between 18 and 30). Sixty-eight of them (52.5%) were female and 53 (47.5%) were male, from our participants, 56.2% were unemployed and 43.8% were employed. Main problems were: having no access to facilities regarding their disability (14.5%), communication problems (9.4%), lower salaries because of their disability (12.4%), being far from the working place (15.4%), disproportion of working environment to their disability (11.4%), maltreatment of their coworkers (13.2%), maltreatment of their employer (12.5%) and discrimination because of their disability (11.2%), the attitudes of the deaf members were positive regarding the employment in all areas: 90% of them considered it as an essential part of life versus 10% of them mentioned not very important issue. Our findings showed that most of the deaf were supported by their family members, but not by the social facilities or their past education. The social policies should be reformed to support employment of the deaf.

Phonological working memory is an important factor in speech and language development and the treatment of related disorders. Assessment of this kind of memory is based on non word repetition. The aim of this study was providing a non word repetition test to examine the capacity of phonological working memory and determining its validity and reliability. This is a cross-sectional study. Initially 60 words were selected based on common Persian syllable structures. Then non words were created by changing one or two phonemes in each of the words. Words and non words were assessed by experts for the content validity and 25 non words were selected. 16 boys and 14 girls aged 4 years to 4 years and eleven months were selected by non-probability sampling from the childcares centers in regions 2 and 6 of Tehran. The test was performed twice by a single examiner to evaluate the reliability of test. Children non word repetition scores were determined and correlation analysis was conducted using the Pearson's correlation coefficient. Our results show that a high coefficient correlation between different performances 0.76 (p<0.001). These findings show that non word repetition test has high validity and reliability.

The words are the symbolic tools for communication. Nouns are the initial and the most frequent components of language that children acquire and use during the procedure of language development. Therefore, this study aimed to determine the noun perception and expression abilities in Persian-speaking children, as well as gathering the normative data for two picture-pointing and picture-naming tests. In this cross-sectional study, 110 normal Persian-speaking children (54 girls and 56 boys), 2.5 to 4 year-old in four groups, were selected randomly throughout Arak kindergartens. Two pictorial perception and expression tests were performed in this study. Mean scores of perception and expression was statistically different between all age groups, except 3 and 3.5 year-old groups (p<0.05). There was no statistically difference between mean scores of girls and boys. In addition, a significant positive correlation between mean scores of perception and expression was shown (p=0.001, r=0.896). The perception and expression abilities are different in 4 age groups. The two picture-pointing and picture-naming tests can show these differences. Regardless of rapid development of perception, perception and expression abilities develop in parallel, and the ability of girls and boys shows similar trends.

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.

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.

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.

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.

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. 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. 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. 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.

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. 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. 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/. 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/.

The dichotic auditory-verbal memory test (DAVMT) is useful in detecting auditory-verbal memory deficits and differences in memory function between the brain hemispheres. The purpose of this study was to prepare the Persian version of dichotic auditory-verbal memory test and to obtain its results in 18- to 25-year old normal individuals of both genders in Iran. The Persian version of dichotic auditory-verbal memory test like the original one consisted of 18 lists of ten words. The lists were arranged such that 10 words were presented to one ear, with the reverse words simultaneously were presented to the other ear, constituting a dichotic test situation. After preparing the 18 lists, content validity was assessed by a panel of eight experts and then, the words of each list were recorded on CD in a dichotic mode. Thereafter, it was performed on one hundred and ten normal individuals with ages ranging from 18 to 25 years (mean age: 21.3 SD 1.9 years) and the scores were recorded on a specially designed scoring sheet. There was no significant difference between mean scores of 18 lists of the dichotic auditory-verbal memory test. The overall mean of CVI was 96% for the 18 lists and the mean score of dichotic auditory-verbal memory test was 6.5 SD 1.0 in the normal group. Based on the obtained results, the Persian version of dichotic auditory-verbal memory test has a good content validity and can be used in detecting the auditory-verbal memory deficits.

Hearing-impaired students have some delays in learning language skills such as reading because of hearing loss. To study the effect of promoting educational level on the development of reading comprehension, the students of the 4th grade of elementary and last year guidance school were compared based on international test of reading literacy. The project was cross-sectional and the tool used was the international standard booklet of PIRLS 2001. Thirty-six students selected with moderately severe and severe hearing loss from the 4th grade of elementary and last year guidance school from Shahriar, Robatkarim, Karaj and Hashtgerd, Iran, exceptional schools. Comparative statistical analysis was performed using t-test. The first level (focus on and retrieve explicity information) showed a meaningful difference between the last year guidance school and the 4th grade of elementary students (p<0.05), but there were no significant differences in other levels, make straightforward information-interpret and integrate ideas-examine and evaluate content, (p> 0.05). Hearing-impaired students have difficulties in understanding in deep levels of reading despite promoting educational level. Thus, in making policies for special trainings, continuing the rehabilitation in guidance and high school levels to promote the complex levels of comprehension should be taken more into consideration.

Research conducted since the early 1900s has consistently identified differences between deaf and hearing children on performance of a wide variety of motor tasks, most notably balance. Our study was performed to test static and dynamic balance skills in congenital severe to profound hearing impaired children in comparison with normal age-matched children. This cross-sectional study was conducted on 30 severe to profound hearing impaired and 40 normal children with age 6 to 10 years old. Bruininks-Oseretsky test of motor proficiency 2, balance subset with 9 parts was used for evaluation of balance skills. Hearing-impaired children showed 16.7 to 100% fail results in 7 parts of the balance subset. In normal children fail result was revealed just in 3 parts of the balance subset from 2.5 to 57.5%, and differences between two groups were significant (p<0.0001). There was a significant difference between two groups in two static balance skills of standing on one leg on a line and standing on one leg on a balance beam with eyes closed (p<0.0001). It seems that development of static balance skills are longer than dynamic ones. Because severe to profound hearing-impaired children showed more weakness than normal children in both static and dynamic balance abilities, functional tests of balance proficiency can help to identify balance disorders in these children.

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. 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, rabbit's 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. 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). 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.

Vocal cord nodule is one of the voice disorders causes hoarseness and breathy voice. Voice therapy is one of the treatment approaches. We aimed to find out the effects of voice therapy on vocal acoustic characteristics in these patients. In this case series, five women with vocal nodule (14 to 45-year-old) participated in a 9-week voice therapy program developed by Boone. Vocal hygiene and voice practices were measured every day using a questionnaire. Moreover, structure and movements of vocal folds were examined using videolaryngostroboscope by a laryngologist before and after voice therapy to evaluate the effectiveness of program. For collecting voice samples we used sustained /æ/ in comfortable loudness for all patients and data were analyzed using Speech Studio. After voice therapy, fundamental frequency in four of five subjects were decreased but it was not significant (p=0.225). However, jitter in all of five subjects was significantly decreased (p=0.043). After voice therapy, shimmer in three of five subjects were decreased that was not significant (p=0.345). Voice therapy can be used for the remedy of acoustic vocal characteristics and elimination or contraction of vocal cord nodule.

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. 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.