Auditory and Vestibular Research
Volume:19 Issue: 2, 2010

Hearing aid users complain about a phenomenon called "occlusion effect". The aim of this study was to compare the occlusion effect in normal hearing individuals and those with slight and mild sensory neural hearing loss via Real Ear Measurement. Sixty volunteers (30 male, 30 female) aged 18-55 years were enrolled in this study. Subjects were instructed to vocalize /e/ and /i/ for 5 seconds. Sound pressure level was measured by a probe- microphone and recorded in the ear canal. Occlusion effect and the frequency in which maximum occlusion effect occurs were obtained for each individuals for further analysis. The peak of occlusion effect for /e/ was 10.25 dB and 9.77 dB respectively in 751.9 Hz and 542.98 Hz frequencies in female and male individuals. The maximum occlusion effect occurred with 19.03 dB and 19.10 dB for /i/ and in 518.88 Hz and 440.28 Hz in female and male individuals, in respect. In addition, no significant difference was seen among hearing levels and between genders. The peak of occlusion effect varies significantly among hearing aid users so that the hearing aid must be tuned. Probe-microphone measures will assist in determination where frequency- specific adjustments are needed.

Vestibular-Evoked Myogenic Potentials (VEMP) is a new vestibular function test that assesses the vestibulospinal pathway.Although many studies have investigated different inner ear pathologies by using VEMP, the role of this test in brainstem pathologies and demyelinating processes of central nervous system is still remained to be defined and discussed.The aim of this study was to compare VEMP in multiple sclerosis patients and normal individuals.

We carried out a cross-sectional study in 21 patients (15 female, 6 male) fulfilling diagnostic criteria of clinically definite multiple sclerosis, and 20 normal individuals (15 female, 6 male). ages ranging from 17 to 50 years old.The VEMPs was recorded using 500 Hz short tone burst (STB). The p13 and n23 latencies and p13-n23 peak-to-peak amplitude were the studied parameters.

VEMP results were abnormal in 47.6% of patients. P13 latency and p13-n23 peak to peak amplitude in both ears showed significant difference between the two groups (p<0.05). P13 latency was delayed in 14 ears (of nine patients). VEMPs were unilaterally absent in two patients.

VEMPs thus represent a new method of the brainstem in multiple sclerosis disease. VEMP abnormalities in these patients might be due to impairment in vestibulocollic pathway.

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. 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. 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. 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.

Reading skill is one of the most important necessities of student's learning in everyday life. This skill is referred to the ability of comprehension, comment and conclusion from texts and receiving the meaning of the massage which is composed. Educational development in any student has a direct relation with the ability of the comprehension. This study is designed to investigate the effects of hearing loss on reading comprehension in hearing-impaired students compared to normal-hearing ones. Seventeen hearing-impaired students in 4th year of primary exceptional schools in Karaj, Robatkarim and Shahriyar, Iran, were enrolled in this cross-sectional study. Seventeen normal-hearing students were randomly selected from ordinary schools next to exceptional ones as control group. They were compared for different levels of reading comprehension using the international standard booklet (PIRLS 2001). There was a significant difference in performance between hearing-impaired and normal- hearing students in different levels of reading comprehension (p<0.05). Hearing loss has negative effects on different levels of reading comprehension, so in exceptional centers, reconsideration in educational planning in order to direct education from memorizing to comprehension and deeper layers of learning seems necessary.

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. 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. 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). 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.

Cued speech as a kind of communication method, is a system which utilizes several hand configurations and locations to supplement the normal visible manifestations of speech. This study was aimed to investigate the effects of Persian cued speech on the speech discrimination scores of hearing impaired children.

Sixteen 9-12 years old profoundly hearing impaired children were divided into two matched-groups of cases and controls. Cases were taught cued speech in a five-month period of 45-60 minutes daily therapy. Speech discrimination score test was tested pretest, post-test and three-week follow-up test in both groups. Mixed repeated measurement was used to analyze the repeated measures data.

There was a significant difference between pretest (without cued speech) and the other two tests of post-test and follow-up (both with cued speech) in cases. The speech perception scores of the cases were almost completed (p=0.001) after cued speech practicing but no significant difference was seen in speech perception scores of control group.(p>0.05)

The results indicate that Persian cued speech is an efficient tool to increase speech discrimination scores of hearing impaired children.

Rhyme awareness is an important criterion for speech, language and writing processing. In Iran, there is no auditory tasks of rhyme awareness available for assessment of 5-6 year-old Persian-speaking children. The aim of this study was to develop and to evaluate Persian rhyme awareness tasks in 5-6 year-old Persian-speaking children.

A hundred normal 5-6 year-old Persian-speaking children (50 girls and 50 boys) were randomly selected. The two rhyme awareness tasks of this study were rhyme detection and rhyme production. The validity and reliability of these tasks were studied by content validity index, intraclass correlation coefficient, and standard error of measurement. The correlation between tasks was studied by Pearson correlation and the mean scores of two sections were compared by easiness level method. The comparison of mean scores of girls and boys were evaluated by independent t-test.

The results showed that the proposed tasks had appropriate validity and reliability. The ability of children in production section was significantly more than in detection section. The correlation of each of two sections with total tasks was significant (p<0.05). In addition, the mean scores of girls and boys were not statistically different (p>0.05).

The proposed tasks are appropriate for assessment of rhyme awareness skills with appropriate validity and reliability in both genders. Two Sections of the tasks had significant correlations and influence on together. The abilities of girls and boys were the same.

The voice of human being changes during lifetime with different patterns in males and females. In addition to assessment of changes due to aging, some studies examined the voice changes among various languages and ethnical groups. This study is performed to evaluate the fundamental frequency changes in normal 9-50 year-old Persian (Farsi) speaking individuals.

In this cross-sectional study, 320 voice samples in normal voiceless environment were recorded. The mean of fundamental frequency of vowels and counting is measured by Dr Speech software (real analysis program). Data analysis was performed by MANOVA test and the profiles of their changes were plotted.

The profile of mean of fundamental frequency changes was different in males and females. The mean of fundamental frequency was equal in both genders until 13 years old and the samples of voice had low pitch (Mean: higher than 200 Hz). MFF after 13 years old significantly decreased in males specially in vowels (p<0.001). The changes in vowels and counting were similar. The mean of fundamental frequency in both genders, between 20-40 years old had relative constancy.

The mean of fundamental frequency changes of vowels and counting in females and males result from diverse dimensions of larynx and other anatomical differences. Significant changes of mean of fundamental frequency in both genders after 13 years old result from puberty in males. The proportional consistence of mean of fundamental frequency between 20-40 years old is probably due to the uniformity of body in this age range.

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.

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.

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).

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.

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.

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.

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).

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.

Vocal abuse and misuse are the most frequent causes of voice disorders. Consequently some therapy is needed to stop or modify such behaviors. This research was performed to study the effectiveness of vocal hygiene program on perceptual signs of voice in people with dysphonia.

A Vocal hygiene program was performed to 8 adults with dysphonia for 6 weeks. At first, Consensus Auditory- Perceptual Evaluation of Voice was used to assess perceptual signs. Then the program was delivered, Individuals were followed in second and forth weeks visits. In the last session, perceptual assessment was performed and individuals’ opinions were collected. Perceptual findings were compared before and after the therapy.

After the program, mean score of perceptual assessment decreased. Mean score of every perceptual sign revealed significant difference before and after the therapy (p≤0. 0001). «Loudness» had maximum score and coordination between speech and respiration indicated minimum score. All participants confirmed efficiency of the therapy.

The vocal hygiene program improves all perceptual signs of voice although not equally. This deduction is confirmed by both clinician-based and patient-based assessments. As a result, vocal hygiene program is necessary for a comprehensive voice therapy but is not solely effective to resolve all voice problems.

Asking questions is one of the basic skills for getting information. “What”, “Who”, “Where”, “Why”, “How much”, “How, etc. are question words frequently used for asking questions. Studies on the sequence of acquisition of question words in English speaking children follow a unique sequence. “What” is the first question word used by these children. We aimed to study whether Persian speaking children follow a unique pattern in the acquisition and use of question words as well.Case: Two normal Persian speaking children (a boy and a girl) who were sent to the kindergarten of Faculty of Rehabilitation Sciences, Iran University of Medical Sciences by their parents were investigated. Children’s spontaneous speech from 12 to 36 months was videotaped, and question words were extracted from phonetic transcription of both children’s speech. In order to ask a question, both children initially used rising tone with /m/ or /hum/ before saying the first question word. Two first question words were “what” and “where” in both children’s speech samples. Asking about the time with the question word /when/ was not appeared in their speech samples until 36 months. These two Persian speaking children also used Wh-question sequentially. The result of this study was consistent with the results of other studies on English speaking children.