Objective: Noise measurement and frequency analysis of commercially available noisy toys were the main purposes of the study.
Materials and Methods: 181 noisy toys commonly found in toy stores in different zones of Tehran were selected and categorized into 10 groups. Noise measurement were done at 2, 25, and 50 cm from toys in dBA. The noisiest toy of each group was frequency analyzed in octave bands.
Results: The highest and the lowest intensity levels belonged to the gun (mean=112 dBA and range of 100-127 dBA) and to the rattle-box (mean=84 dBA and range of 74-95 dBA), respectively. Noise intensity levels significantly decreased with increasing distance except for two toys. Noise frequency analysis indicated energy in effective hearing frequencies. Most of the toys energies were in the middle and high frequency region.
Conclusion: As intensity level of the toys is considerable, mostly more than 90 dBA, and also their energy exist in the middle and high frequency region, toys should be considered as a cause of the hearing impairment.

Background and Aim: Middle latency auditory evoked potentials (MLAEPs) development takes longer time than the auditory brainstem response (ABR) development does, which makes them difficult to record in some children. The purpose of this study was to investigate the age effect on characteristics and detection of MLAEPs in children and adults.
Materials and Methods: This cross sectional study was conducted on 15 children aged   7-12 yr and 31 adults aged 20-50 yr with normal peripheral hearing. To investigate precisely, children were divided in two subgroups of older and younger than 10 years old, as well. The MLAEPs amplitudes and latencies were recorded by conventional protocol and compared.
Results: Adult Na mean latency, 20.86 ms, was less than that of children, 22.86 ms, (p=0.0025).  In contrast, the adult Nb mean latency, 44.93 ms, was longer (p=0.0001). Children Nb mean latency was 42.02 ms. There was no significant difference in MLAEP amplitudes and latencies between two children subgroups, although variance was more in younger children.
Conclusion: MLAEPs are reliably recorded after 7 years old. Characteristics of MLAEPs are different in adults and children so that the primary MLAEPs generators have a course of development extending beyond the first decade of life. As those potentials were recorded in all children, it is suggested to be used in their test batteries for hearing evaluation.

Background and Aim:  Among all auditory assessment tools, auditory steady state response (ASSR) is a modern test. Modulation frequency for this test is usually 80 Hz. The purpose of this study, was to examined adult subjects with 40 Hz and 80 Hz ASSR and compare the results.
Materials and Methods: Thirty adult (60 ears) were evaluated by ASSR and PTA test, Results were divided into three groups: normal hearing, mild and moderate sensorineural hearing loss.
Results: In all groups, forty hertz ASSR thresholds were relatively closer to behavioral threshold than those of 80 Hz ASSR(p<0.05). Besides, the more severe hearing loss, the lower the difference between those two thresholds. Correlation coefficients were also higher in 40 Hz ASSR(p<0.05).
Conclusion: Frequency modulation thresholds with 40 Hz are more likely to be closer to the behavioral thresholds. Moreover, it has better results than the thresholds with 80 Hz.

Background and Aim: Following an early visual deprivation, the neural network involved in processing auditory spatial information undergoes a profound reorganization. In order to investigate this process, event-related potentials provide accurate information about time course neural activation as well as perception and cognitive processes. In this study, the latency and amplitude of auditory P300 were compared in sighted and early blind individuals in age range of 18-25 years old.

Methods: In this cross-sectional study, auditory P300 potential was measured in conventional oddball paradigm by using two tone burst stimuli (1000 and 2000 Hz) on 40 sighted subjects and 19 early blind subjects with mean age 20.94 years old.

Results: The mean latency of P300 in early blind subjects was significantly smaller than sighted subjects (p=0.00.( There was no significant difference in amplitude between two groups (p>0.05).

Conclusion: Reduced latency of P300 in early blind subjects in comparison to sighted subjects probably indicates the rate of automatic processing and information categorization is faster in early blind subjects because of sensory compensation. It seems that neural plasticity increases the rate of auditory processing and attention in early blind subjects.

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: Neuroimaging techniques in audiovisual speech processing are innovative approach to neuroscience investigation that steadily influences the deep survey of highly mechanisms involved in this process. The purpose of this study was to evaluate brain activity via functional magnetic resonance imaging throughout audiovisual speech perception in Persian language.
Methods: Functional MRI was used to assess 19 normal 20-30 year old women while they had been presented syllable /ka/ visually and /pa/ auditory using block design method, in which it would provide two series of imaging, functional and T1-weighted. Subsequently, the results were analyzed and compared by FSL software.
Results: The results of this study pointed out that both middle and cortical regions of brain are activated in visual stimuli and its middle regions are activated in response to auditory stimuli. Hence, left anterior supramarginal, some parts of motor speech system including insular and cingulate cortex-precentral cortex were stimulated with visual stimulus and left posterior supramarginal as well as right supramarginal gyrus were stimulated with auditory stimulus. Moreover, in this investigation, McGurk effect was behaviorally proven in fifteen subjects.
Conclusion: It was hypothesized that the activation of unique region, supramarginal gyrus, with both audio and visual stimuli indicated the presence of commonplace region for phonologic processing of sensory inputs. In addition, auditory stimuli develop more intense activity and on the other hand, broaden-maximum voxel-as well as extra regions are demonstrated in response to visual stimuli. These points represent the unfamiliarity of normal individual brain to percept visual speech stimuli.

Background and Aim: Conventional balance tests such as electronystagmography and videonystagmography, which are vision-dependant, are not practical in blind patients. Instead, vestibular evoked myogenic potential , not needing any vision, seems to be a more appropriate test for evaluating the vestibular system, in these patients. This study aimed to assess the prevalence and the latencies of p13 and n23 waves among congenitally blind and sighted participants evaluated by vestibular evoked myogenic potential.
Methods: In a cross-sectional study, vestibular evoked myogenic potential was recorded for 20 sighted and 20 congenitally blind subjects, aged 18 to 30 years old, using 500 Hz-tone bursts (95 dBnHL).
Results: Vestibular evoked myogenic potentials responses were present in all (100%) of the participants. Considering the results of the both ears, there was no significant difference between mean p13 and n23 latencies of the two groups (p>0.05).
Conclusion: Formation of vestibular evoked myogenic potentials reflex arc and neural pathway in congenitally blind patients is similar to sighted individuals hence, the development of this pathway is independent of the visual system. Vestibular evoked myogenic potentials test is a useful test to assess vestibular function of the blinds.

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 and Aim: 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.
Methods: 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&aposs correlation coefficient.
Results: Our results show that a high coefficient correlation between different performances 0.76 (p<0.001).
Conclusion: These findings show that non word repetition test has high validity and reliability.

Background and Aim: The relationship between language and stuttering is an important issue in development of children because initiation of stuttering is generally contemporaneous with the period of rapid language development in children. Phonological awareness is part of language function which simultaneously develops with language and is the basis for oral and aural skills. The purpose of this research is to evaluate the relationship between stuttering and phonological awareness and the importance of phonological awareness in the process of evaluation and treatment of stuttering.
Methods: It was a cross-sectional comparative study. Conducted on 53 children aged 4 to 8 years in Tehran. Participants&apos profile was made by examiner through interview with participants&apos therapist, parents and instructor. Voice of stutterer children was recorded and the phonological awareness test was performed. Obtained data was analyzed.
Results: Regarding the scores of phonological awareness test there were significant differences between stutterer and non-stutterer groups and also between different ages (p<0.05). Scores of phonological awareness test in children with different stuttering severities were not significantly different. Children younger than 4 years had the least scores while children older than 7 years had the most and the differences were statistically significant (p<0.05). This shows that the score improves by aging.
Conclusion: Phonological awareness, age, type and severity of stuttering should be considered in assessment and treatment of Persian stutterer children aged 4 to 8 years old.

Background and Aim: Due to defects of auditory feedback, children with hearing loss have inappropriate speech intonation. Consistently, results of previous studies have shown that cochlear-implanted children have some difficulties in their intonation. Intonation shows the type of the sentence which can be statement or question sentences. The purpose of this study was comparison of speech intonation in cochlear-implanted children and normal hearing children.
Methods: The present study was performed on 25 cochlear-implanted children and 50 normal hearing children. Different pictures were shown to the subjects and they said statement and question sentences. All sentences were heard by eight speech therapists and perceptually judged. Using praat software mean base frequency and pitch alterations were measured.
Results: In cochlear-implanted group, mean speech base frequency was higher and mean pitch alteration was lower than the control group. Mean experts&apos scores in cochlear-implanted group were lower than the control group. Differences in all three variables were statistically significant (p<0.05). There was a significant direct correlation between duration of time that the children had cochlear implant and perceptual judgment scores (p<0.05).
Conclusion: According to the results, cochlear implant prosthesis has limited efficacy in improving speech intonation although their ability to produce speech intonation improves by increasing duration of the time that children have cochlear implant. Thus speech therapists should consider intervening on speech intonation in treatment program of cochlear-implanted children.

Background and Aim: Neurotologic signs and symptoms, especially vestibular symptoms, are common in migraine patients. The goal of this study was to investigate some parts of the central vestibular system using some subtests of videonystagmographic evaluation, including spontaneous nystagmus, gaze-evoked nystagmus, and smooth pursuit between their attacks of migraine.
Methods: Thirty patients with migraine and 38 healthy volunteers of 18-48 years of age were included in this study. Spontaneous nystagmus, gaze-evoked nystagmus toward the right, left and upward, and also smooth pursuit using three different velocities were performed in both groups.
Results: Five normal subjects and five migraine patients had spontaneous nystagmus, which was less than three degrees there was no statistically significant difference between the two groups. No gaze-evoked nystagmus was seen in both groups. In one velocity of smooth pursuit evaluation, gain and phase were significantly different. The statistical difference in gain and phase was not clinically important as it was in normal range of the device. Another statistically significant parameter was saccadic morphology of smooth pursuit which was seen in migraine patients.
Conclusion: These results suggest the presence of subtle otoneurological abnormalities in migraine patients that is probably due to deficiency of oculomotor function with vestibulocerebellar origin.

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: The temporal processing is one of the critical features in central auditory processing system the gap in noise (GIN) test is the appropriate clinical tool for appraisal of temporal resolution which in people with multiple sclerosis may encounter with complications. Consequently, the aim of this study was to compare the results of gap in noise test in 18 to 40-year-old patients with multiple sclerosis and normal participants.
Methods: This cross-sectional non-invasive cohort study was conducted on 20 patients with relapsing-remitting multiple sclerosis (mean age: 28.9 years) and 26 healthy normal hearing participant (mean age: 27.7 years) in the age range 18 to 40 years. The approximate threshold and percent of corrected responses were obtained and then were analyzed using Student&aposs t-test.
Results: There was an increase in gap detection and decrease in percent of corrected responses in gap in noise test within multiple sclerosis patients in comparison with normal people (p<0.0001). Moreover, there were a correlation of 78% between increasing disease duration and approximate threshold and also a correlation of 82% between increasing disease duration and corrected responses (p<0.0001).
Conclusion: Based on the findings of this study, it seems that people with multiple sclerosis suffer from some degree of disorder in the temporal resolution which might be due to involvement of central nerve system and, somehow, deficit in central auditory processing. Therefore, for evaluating the temporal resolution in people with multiple sclerosis, gap in noise test could be useful.

Bachground and Aim: The involvement of central auditory nervous system is relatively prevalent in patients suffering from multiple sclerosis (MS). To understand cortex function and to investigate cognitive impairment, event related potential is considered as a valuable tool. This study was aimed to compare the amplitude and latency of the event related potentials of P300 in MS patients and normal individuals.
Methods: This cross sectional study was conducted on 21 MS patients and 27 normal cases aged 18-50 years. Auditory P300 was recorded with oddball paradigm, using two tone burst stimuli (1000 and 2000).
Results: In MS patients, mean latencies were significantly longer (p<0.001) and mean amplitude were significantly lower (p<0.001), in both males and females. Sex did not affect P300 latencies and amplitudes significantly.
Conclusion: MS patients show some degree of event related potential abnormalities. Combination of auditory P300 and neuropsychological tests may be useful to investigate cognitive impairment in MS patients.

Background and Aim: Auditory temporal processing reveals an important aspect of auditory performance, in which a deficit can prevent the child from speaking, language learning and reading. Temporal resolution, which is a subgroup of temporal processing, can be evaluated by gap-in-noise detection test. Regarding the relation of auditory temporal processing deficits and phonologic disorder of children with dyslexia-dysgraphia, the aim of this study was to evaluate these children with the gap-in-noise (GIN) test.
Methods: The gap-in-noise test was performed on 28 normal and 24 dyslexic-dysgraphic children, at the age of 11-12 years old. Mean approximate threshold and percent of corrected answers were compared between the groups.
Results: The mean approximate threshold and percent of corrected answers of the right and left ear had no significant difference between the groups (p>0.05). The mean approximate threshold of children with dyslexia-dysgraphia (6.97 ms, SD=1.09) was significantly (p<0.001) more than that of the normal group (5.05 ms, SD=0.92). The mean related frequency of corrected answers (58.05, SD=4.98%) was less than normal group (69.97, SD=7.16%) (p<0.001).
Conclusion: Abnormal temporal resolution was found in children with dyslexia-dysgraphia based on gap-in-noise test. While the brainstem and auditory cortex are responsible for auditory temporal processing, probably the structural and functional differences of these areas in normal and dyslexic-dysgraphic children lead to abnormal coding of auditory temporal information. As a result, auditory temporal processing is inevitable.

Background and Aim: One of the common problems in many types of aphasia syndromes is word retrieval and/or production difficulty. So, designing a valid test that can examine this problem based on related processes and influencing factors is important. Picture confrontation naming is a typical method for assessing and treatment of word retrieval impairments. The aim of this study was determining the validity and reliability of oral picture-naming test in assessing word retrieval ability of aphasic adults.
Methods: Content and face validity of the test, that contains the line drawings of 115 Persian nouns, were assessed by speech therapists, graphists and painters. Then, the test was administered on 10 aphasics and 30 age-, gender- and education-matched normal subjects in two steps. Construct validity and internal consistency of test were investigated. External consistency was analyzed by test-retest method.
Results: The content and face validity of all items were more than 90 and 85 percents, respectively. There was a statistically significant difference between the mean scores of patients and normal subjects (p<0.001). The internal consistency of 0.98 was determined for the test. The intra-class correlation coefficient of this test was 0.98.
Conclusions: The oral picture-naming test had good content, face and construct validity. Also, internal and external consistencies were high. So, this test is a valid instrument for assessing naming ability of aphasic patients by a variety and big set of picture.

Background and Aim: Temporal lobe epilepsy (TLE) is one of the most frequent epileptic syndromes in adults. Some patients with epilepsy, especially TLE, have central auditory disorders, such as temporal processing, even though they have normal peripheral auditory function. The Gaps-in-Noise (GIN) test is one of the new tests for assessing auditory temporal resolution. The aim of this study was to evaluate temporal resolution ability in patients with unilateral temporal lobe epilepsy.
Methods: In this cross-sectional and descriptive-analytic study, 25 subjects with temporal lobe epilepsy (11 patients with right temporal lobe epilepsy and 14 patients with left temporal lobe epilepsy) and 18 normal control subjects of 15 to 50 years of age were assessed by the GIN test. Parameters of GIN test were analyzed by one-way ANOVA and compared between the three groups.
Results: There was a significant difference in the mean of approximate threshold and percentage of correct answer in GIN test in the right ear, left ear, and mean of both ears between patients with temporal lobe epilepsy and normal subjects (p<0.05). However, difference between right and left temporal lobe epilepsy groups were not significant (p>0.05).
Conclusion: The lower percentage of correct answer and higher approximate threshold in patients with temporal lobe epilepsy in comparison with the normal control group revealed temporal processing deficiencies especially in temporal resolution abilities. This may be due to involvement of structures related to temporal processing.

Background and Aim: Multiple sclerosis (MS) is characterized with inflammation, demyelization and gliosis. It may be relapsing, remitting, or progressive. Cognitive impairment is relatively prevalent in patients wit h multiple sclerosis and as duration of disease is longer as cognition impairment is more. To understand the cognitive impairment, event related potential can be considered as a valuable tool. This study aimed to investigate the influence of duration of disease and expanded disability status scale (EDSS) on the amplitude and latency of the event related potentials of P300 in patients with multiple sclerosis.

Methods: In this cross-sectional and non-intervention study, 21 patients with multiple sclerosis with mean age of 27.8 with SD 7.1 years (between 18 to 50 years) were enrolled. The patients were selected randomly. The correlation of P300 event-related potential and oddball paradigm was assessed, using two 1000 and 2000 Hz tone burst stimulus.

Results: There was a significant correlation between the latency of P300 wave and duration of disease and expanded disability status scale (p < 0.05) there was high correlation in both electrode sites (r>0.50). The correlation of amplitude of P300 and duration of disease and expanded disability status scale was not significant (p>0.05).

Conclusion: Significant correlation between the latency of P300 and the duration of multiple sclerosis and expanded disability status scale can be a sign of central nervous system changes. Besides, there is a relation between physical disability and cognitive impairments.