Vol 22 No 2 (2013)

Published: 2013-07-29

Review Article(s)

  • XML | views: 153 | pages: 1-16

    Background and Aim: There are four fundamental processes of attention: working memory, topdown sensitivity control, competitive selection, and automatic bottom-up filtering for salient stimuli.Each process makes an essential contribution to attention. Voluntary control operates on the first three processes in a recurrent loop. We reviewed comprehensive researches, theories, mechanisms, and central nervous system functions of auditory attention.
    Methods: In this study, publications on auditory attention from 1953 to 2012 in PubMed, Scopus, ProQuest, Iran Medex, and Goole scholar were reviewed. Keywords were auditory attention and related words.
    Conclusion: In general, auditory attention plays an important role in auditory processing and modulates this process from cochlea to auditory cortex through its four primary components.

Research Article(s)

  • XML | views: 115 | pages: 17-24

    Background and Aim: About 1.5 percent of exceptional children suffer from impaired hearing and this factor affects the teaching and learning process. The aim of this study was to investigate the effect of frequency of knowledge of results (KR) on the learning of children with hearing impairment.
    Methods: Twenty-four individuals with hearing impairment with the mean age of 10.56 with SD 2.53 years (range: 7-14 years) were divided into three homogenous groups according to their records after pre-test. They practiced for eight sessions according to mentioned ways (feedback of 0%, 50% and 100%). The acquisition, learning and translation tests were run. MANOVA with repeated measures and ANOVA were used to analyze the data from the acquisition, retention and transition tests.
    Results: All groups progressed during training and at various stages (acquisition, retention and transition). However, the results of the comparison between means of the three training groups showed significant differences in the acquisition process (p=0.008), learning (p=0.001) and transition (p=0.035). This means that feedback training groups (100%) had better performance in acquisition process, and also in retention and transition (50%).
    Conclusion: According to the results of this study, too much feedback interferes with learning of tasks in individuals with hearing impairment and feedback (50%) had better learning. This finding shows that rules regarding feedback also affect the people with hearing impairment.

  • XML | views: 140 | pages: 25-32

    Background and Aim: Diabetes mellitus is a common disorder and causes a variety of central nervous system complications such as cognitive deficits. P300 auditory event related potential application is a well established neurophysiological approach in the assessment of cognitive performance. In this study, we compared the results of this application in patients with insulindependent (type I) diabetics mellitus and normal individuals.
    Methods: In this non-interventional study, auditory P300 was measured in oddball paradigm by using two tone burst stimuli (1000 and 2000 Hz) on 25 patients with type I diabetics mellitus with the mean age of 28.76 years and 25 age-, education- and sex-matched healthy controls with the mean age of 29.68 years. The participants were enrolled by probable and category random sampling style.
    Results: The mean P300 latency of the patients with type I diabetes mellitus was significantly prolonged compared with that of normal controls at all electrode sites and in both genders (p<0.001). The mean P300 amplitude of these patients was significantly lower compared with that of normal controls at all electrode sites and in both genders (p<0.001).
    Conclusion: Significant prolongation in P300 latency of the patients with type I diabetes mellitus shows that auditory information processing and information categorizing are slower in them. Significant reduction in P300 amplitude of the patients with type I diabetes mellitus demonstrates that working memory in these patients cannot recognize new events and update its context in accordance with them.

  • XML | views: 102 | pages: 33-39

    Background and Aim: The birth of a hearing-impaired child and raising him/her often brings special psychological feelings for parents, especially mothers who spend more time with the child. This study aimed to compare the general health status in mothers of hearing-impaired and hearing children.
    Methods: This was a descriptive-analytic study. General Health Questionnaire was used to identify general health status; and data were analyzed with independent-t test.
    Results: The general health level of mothers of hearing-impaired children was lower than mothers of normal hearing children (p=0.01). The average scores of anxiety (p=0.01), depression (p= 0.01) and physical (p=0.02) symptoms and social function (p=0.01) of mothers of hearing-impaired children was higher than mothers of normal hearing ones (p=0.01).
    Conclusion: Having a child with hearing impairment affects mothers’ general health status. Our findings show that it’s necessary to provide psychological and social support for mothers of hearingimpaired children.

  • XML | views: 101 | pages: 40-46

    Background and Aim: Bilingualism, as one of the discussing issues of psychology and linguistics, can influence the speech processing. Of several tests for assessing auditory processing, dichotic digit test has been designed to study divided auditory attention. Our study was performed to compare the auditory attention between Iranian bilingual and monolingual young adults.
    Methods: This cross-sectional study was conducted on 60 students including 30 Turkish-Persian bilinguals and 30 Persian monolinguals aged between 18 to 30 years in both genders. Dichotic digit test was performed on young individuals with normal peripheral hearing and right hand preference.
    Results: No significant correlation was found between the results of dichotic digit test of monolinguals and bilinguals (p=0.195), and also between the results of right and left ears in monolingual (p=0.460) and bilingual (p=0.054) groups. The mean score of women was significantly more than men (p=0.031).
    Conclusion: There was no significant difference between bilinguals and monolinguals in divided auditory attention; and it seems that acquisition of second language in lower ages has no noticeable effect on this type of auditory attention.

  • XML | views: 147 | pages: 47-54

    Background and Aim: Time compressed speech test is one of the most common types of monaural central auditory processing tests assesses the temporal resolution. The aim of the present study was to evaluate the impact of compression rate and sex on results of this test among the young individuals with normal hearing.
    Methods: The Persian version of time compressed speech test with six lists of 25 monosyllabic words was prepared in three compression rates of 0, 40 and 60 percent. 36 young people with normal hearing and age range of 18 to 30 years were assessed with time compressed speech test in the most comfortable level in each ear separately. Then scores were compared between two ears, genders and three compression rates.
    Results: There was a significant difference between word recognition scores of three compression rates (p<0.0001). Significant difference was revealed between word recognition scores of both ears, just in the 60% compression rates. No significant difference was found between the word recognition scores of the two genders.
    Conclusion: Word recognition scores decreases with increase of the presentation rate of speech stimuli. Time compressed speech test accompany with other audiologic tests can be used to examin the auditory temporal processing and speed of speech processing as a test battery.

  • XML | views: 132 | pages: 56-62

    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 with 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.

  • XML | views: 108 | pages: 63-72

    Background and Aim: Patients with systemic lupus erythematosus (SLE) may develop hearing and balance disorders as a result of the immune-mediated inner ear damage. Vestibular evoked myogenic potential (VEMP) is a new vestibular test assesses the vestibulospinal tract. Balance disorders such as endolymphatic hydrops may occur as a result of perisaccular deposition of immune complexes in these patients. Although the vestibular system abnormality in the patients has been demonstrated, the function of the part of vestibular system including vestibulospinal tract has not been investigated so far. This study aimed to compare the vestibular evoked myogenic potentials between patients with inactive stage of systemic lupus erythematosus and normal individuals.
    Methods: In this cross-sectional study, vestibular evoked myogenic potential was recorded between 26 healthy subjects and 20 patients with lupus erythematosus in inactive stage of disease aged 20 to 50 years old, using 500 Hz-tone bursts at 95 dB nHL.
    Results: Vestibular evoked myogenic potentials responses were present in all (100%) of the participants. There was no significant difference in mean peak to peak amplitude and assymetry ratio between two groups. The mean p13 and n23 latencies were significantly higher in patients (p<0.05). Duration of disease had no effect on test parameters.
    Conclusion: According to the prolonged latency of vestibular evoked myogenic potentials response in patients with lupus erythematosus, lesions in the retrolabyrinthine, especially in the vestibulospinal tract is suspected. Due to small sample size, there is no possibility for generalizing this result to all patients with lupus lupus erythematosus.

  • XML | views: 93 | pages: 73-82

    Background and Aim: Learning and memory are two high level cognitive performances in human that hearing loss influences them. In our study, mini-mental state examination (MMSE) and Ray auditory-verbal learning test (RAVLT) was conducted to study cognitive status and lexical learning and memory in deaf adults using sign language.
    Methods: This cross-sectional comparative study was conducted on 30 available congenitally deaf adults using sign language in Persian and 46 normal adults aged 19 to 27 years for both sexes, with a minimum of diploma level of education. After mini-mental state examination, Rey auditory-verbal learning test was run through computers to evaluate lexical learning and memory with visual presentation.
    Results: Mean scores of mini-mental state examination and Rey auditory-verbal learning test in congenitally deaf adults were significantly lower than normal individuals in all scores (p=0.018) except in the two parts of the Rey test. Significant correlation was found between results of two tests just in the normal group (p=0.043). Gender had no effect on test results.
    Conclusion: Cognitive status and lexical memory and learning in congenitally deaf individuals is weaker than in normal subjects. It seems that using sign language as the main way of communication in deaf people causes poor lexical memory and learning.

  • XML | views: 113 | pages: 83-93

    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 auditory 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.

  • XML | views: 145 | pages: 94-103

    Background and Aim: Patients with type I diabetes mellitus commonly complain about dizziness, floating sensation, tinnitus, weakness, and sweating. The aim of this study was comparing vestibular evoked myogenic potentials (VEMPs) between these patients and normal people.
    Methods: Twenty-four patients with type I diabetes mellitus and twenty-four healthy volunteers with the age range of 15-40 years were enrolled in this study. A tone burst of 500 Hz, with the intensity of 95 dB nHL, was delivered through a insert earphone and vestibular evoked myogenic potential was recorded. The t-test was used to compare the results between the two groups. To investigate the effect of glycated hemoglobin (HbA1c) on VEMP responses (latency, absolute and relative amplitude), the regression analysis was used.
    Results: The mean p13 and n23 latency were significantly more in patients with type Ι diabetes mellitus (for P13 latency, p=0.013 in right and p=0.010 in left ear, and for n23 latency, p<0.001 in right and p=0.005 in left ear). There was no significant difference between two groups in absolute and relative amplitude and prevalence of the VEMP (p>0.050). There was no correlation between VEMPs and HbA1c in patients with type 1 diabetes mellitus (p>0.05).
    Conclusion: Prolonged latencies of the VEMP in patients with type 1 diabetes mellitus suggest lesions in the retrolabyrinthine, especially in the vestibulospinal tract. Nevertheless, due to the limited number of examined samples, further investigation with more patients should be performed.

Case Report(s)

  • XML | views: 125 | pages: 104-109

    Background: Balance disorders are common in patients following stroke. There are a number of physiotherapy modalities to treat balance impairments, one of which is vibration. The effects of vibration on balance disorders after stroke have not been investigated. This case report demonstrates the short-term effects of plantar vibration on the balance impairment of a patient with stroke.
    Case presentation: A 72-years-old man with right hemiplegia resulted from stroke was admitted for vibration therapy after not responding to standard rehabilitation interventions. He complained of balance problems despite walking independently. Main studied outcomes were timed up and go test and posturography. Foot sensation, ankle plantar flexor spasticity, and the passive range of ankle dorsiflexion were assessed, as well. Vibration with a frequency of 100 Hz was introduced to the sole of the affected foot for 5 minutes. After intervention, all tests were improved compared to the baselines.
    Conclusion: This case showed that the vibration was effective for improving balance disorder after stroke.