Auditory and Vestibular Research
Volume:31 Issue: 2, Spring 2022

Dichotic listening (DL) test is a non-invasive method used to study hemispheric asymmetry, hemispheric dominance for language processing, or brain lateralization. In addition to the type, concurrence, and the intensity of stimuli presented to the ears, other factors exist that may have less effect on the DL test results. This review study aims to find these factors.

The factors that affects the DL included ear advantage, attention, working memory, gender, and top-down and bottom-up factors. These factors were reviewed and discussed in detail so that more precise test results can be obtained. Moreover, due to the significant effects of each factor on the test results, manipulation of these factors was also reviewed.

According to the results of previous studies, ear advantage, attention, working memory, gender, and top-down and bottom-up factors play an important role in the interpretation of DL results; their negligence during the test can affect the outcomes and provide incorrect brain lateralization results.

This article seeks to examine rights of deaf and unable to hear individuals in international documents as well as domestic Iranian law. In this review, supports in the mentioned documents are discussed and the weaknesses, strengths, objections, and challenges in the laws are analyzed and examined. Lack of access to community facilities lead to marginalization of deaf people. Access to community facilities is an important factor that creates equal opportunities and realizes rights of deaf people.

Iran’s accession to the Treaty on the Rights of disabled people, the Global treaty on Cultural, Public, Economic as well as Children’s title, is one of salient points of these protection laws. By implementing Iran’s national and global commitments regarding titles of the deaf, it is concluded that Comprehensive Law and its executive regulations have been adopted several years before accession to the Contract on the Disability, but they cover most of concepts of the Contract on Education.

Given the Senate and the convention, no significant legal action was taken and the program did not address deaf directly. The lack of an effective mechanism for laws protecting the disabled people right is an institutional as well as structural obstacle for realization of disabled people, especially deaf.

Adolescents with hearing loss face many communication problems and challenges due to their hearing impairment. This study aimed to investigate the effect of psychodrama on communication skills of adolescents with hearing loss.

This is a quasi-experimental study with a pretest/posttest design using a control group. The study population consists of all adolescents with hearing loss aged 12–15 years studying at Naghme School for the Deaf in Yazd, Iran. A total of 24 adolescents were selected using a purposive sampling technique and were randomly assigned into groups of control (n=12) and intervention (n=12). The intervention group received psychodrama at nine sessions of 90 minutes, while the control group received no treatment. The Queendom Communication Skills Test (QCST) was used to collect data. Data were analyzed using descriptive and inferential statistics.

Psychodrama can improve communication skills of adolescents with hearing loss, which is verbal communication.

The mean and standard deviation of the pretest QCST score was 78.75±9.4 for the intervention group. After the treatment, the QCST scores was 105.08±6.28 for the intervention group. The results of ANCOVA showed an improvement in Queendom Communication Skills Test scores of adolescents after intervention (p<0.001).

Consonant development plays a significant role in speech intelligibility which is impaired in children with profound hearing loss. Cochlear implant (CI) can facilitate the development of language comprehension and sound production in children with severe to profound sensorineural hearing loss. This study aimed to compare consonant production skills in children with CI and normal-hearing (NH) children aged 3–5 years.

In this cross-sectional study, participants were 20 children with CI and 20 agematched NH children. The consonant production skills were assessed using the speech intelligibility test in Persian.

There were significant differences between CI and NH children (p<0.05), where the highest percentage of correct production in both groups was related to the manner of articulation of stop and nasal consonants. NH children showed less accuracy only in /r/ and /ʧ/, while children with CI were less accurate in /q/, /x/, /ʤ/, /l/, /j/, and /r/.

Children with CI have lower scores compared to age-matched NH peers, but they have similar consonant production skills.

In a noisy environment, children struggle more than adults to understand speech. Various tests at different levels of cognition are available to evaluate children’s speech perception abilities in a noisy environment. The present study aimed at determining the reliability and equivalency of the Persian version of the quick speech-in-noise (P-Q-SIN) test in 7-12 years old school-aged children.

A total of 120 (60 girls) students with normal hearing were chosen from primary schools in district 2 of Kerman City, Iran. They were in five age groups ranging from 7 to 12 years (24 children per age group). Pure tone audiometry test was performed on the samples, then nine lists of P-Q-SIN of previous studies (Khalili et al. and Shayanmehr et al.) were administered on these participants. To obtain the test-retest reliability, three weeks later, the re-test was performed.

In the test-retest reliability, lists 1 and 4 of Khalili et al. and list 2 of Shayanmehr et al. were highly correlated (p<0.05). There were no significant differences between the scores of girls and boys (p>0.05). The participant’s performance improves as the age increases.

None of the lists of Shayanmehr et al. was reliable and equivalent. List 1 and 4 of Khalili et al. were reliable and equivalent; therefore, they can be used in clinical application for children in the age range of 7 to 12 years by considering the norm of signal-to-noise ratio loss.

Multiple sclerosis (MS) is neurological disease of the central nervous system. Central auditory nervous system can also be affected by MS. The present study aimed to evaluate monaural and binaural auditory processing in patients with MS.

This cross-sectional study was conducted on 45 patients with MS and 45 normal peers as controls aged 25–45 years. They underwent a central auditory processing test battery including the Persian versions of Buffalo model questionnaire (BMQ), staggered spondee word (SSW) test, quick speech in noise test (QSIN), phonemic synthesis test (PST), and twopair dichotic digit test (DDT).

The results of SSW test, QSIN test, PST, DDT and BMQ in the MS group were significantly different than in the control group (p≤0.001). The results showed the poor performance of patients compared to controls in some monaural and binaural auditory processing skills.

Central auditory processing disorder is common among patients with MS. The BMQ is a suitable screening tool for identifying affected people. Dichotic listening skills, phonemic processing and speech perception in noise are impaired in MS patients which can have significant impacts on their quality of life.

Background noise as a serious challenge mainly affects the speech perception in people with hearing loss. One of the methods used to control noise is digital noise reduction (DNR) technique. The present study aimed to investigate the effect of DNR program (activated and deactivated) on the frequency gain of basic and advanced behind-the-ear (BTE) Oticon hearing aids, using different DNR strategies to reduce background noise.

Two behind-the-ear Oticon hearing aids (Opn1 S105 and GetP) were used in this study. The Affinity 2.0 test box was first used to measure their DNR (off/on) gains using the national acoustic laboratories-non linear2 (NAL-NL2) and desired sensation level multi-stage [input/output] (DSLm[I/O]) formulas at sound pressure levels of 45, 65 and 85 dB SPL at a frequency range of 250-8000 Hz for three hearing loss (HL) patterns using the international speech test signal and broad band noise.

There was a significant difference in DNR performance between the Opn1 S105 and GetP models for all three HL patterns at 45 and 65 dB SPL and most frequencies.

The DNR performance of advanced and basic hearing aids is different for different HLs at 45 and 65 dB SPL and most frequencies. The performance of advanced hearing aids is significant using the DSLm[I/O] formula at most frequencies

Caffeine intake enhances concentration through affecting brain functions. It also improves attention to the signal which is believed to be associated with increased noise tolerance and improved speech perception. This study aimed to evaluate the long-term effects of caffeine intake on simultaneous speech and sound perception in people with normal hearing.

This double-blind study was conducted on 90 people aged 18-34 years (45 males and 45 females), randomly assigned to two intervention groups (receiving 3 and 5 mg/kg caffeine) and a control group (receiving placebo). The acceptable noise level (ANL) test was conducted before and five hours after intervention.

Comparison of ANL scores before and after intervention showed a significant difference in the 3 mg/kg caffeine group (p=0.002), but not in the placebo (p=0.497) and 5 mg/kg caffeine (p=0.146) groups. Between-group analysis showed a significant difference between the placebo and 3 mg/kg caffeine groups in the ANL five hours after (p=0.005), while the difference was not significant between the placebo and the 5 mg/kg caffeine groups (p=0.139). Moreover, there was no significant difference in the ANL between the 3 and 5 mg/kg caffeine groups (p=0.148).

Caffeine intake affects noise tolerance, depending on the dose of caffeine. The ANL and speech tolerance improve five hours after consuming 3 mg/kg of caffeine.

Hearing loss is considered a main cause of speech-language delay and academic performance retardation. This study aimed to detect the prevalence of hearing loss diagnosed for the first time in primary school children.

A cross-sectional study has involved 624, randomly chosen, primary school children. The children have undergone hearing screening using tympanometry, and pure tone audiometry screening in order to detect the children with undiagnosed hearing loss.

Six hundred and twenty-four children underwent tympanometry which showed that 481 children have type A Tympanogram, 39 have type C, 16 have type A in one ear and type C in the other, 78 have type B, and 10 of them have type B in one ear and type C in the other. Then all children underwent pure tone audiometry screening and this showed that 565 children have responded to 20 dB for all frequencies, 42 have not responded to 20 dB at any frequency, 27 of them are from those children with type B Tympanogram, 10 children have not responded to 20 dB for frequencies >2000 Hz, 7 of them have not responded to 20 dB at any frequency in one ear with normal responses in the other.

School age hearing screening is an important procedure to detect hearing loss in children in order to manage hearing loss as early as possible and avoid its consequences.

The deficit in cognitive functions and central executive function is one of the popular hypotheses on the underlying cause of tinnitus. These factors are not only the complications of tinnitus but are also involved in the generation of it. In this study, bifrontal transcranial Direct Current Stimulation (tDCS) and conflict processing will be used in the form of auditory Stroop training to improve cognitive performance and inhibition control for tinnitus management.

This study will be carried out on 34 chronic tinnitus patients. The initial evaluations include the tinnitus psychoacoustic evaluations, determination of the tinnitus handicap through tinnitus handicap inventory, and examining the annoyance and loudness of tinnitus through the visual analog scale after which the participants will be investigated in two groups. The first group will receive sessions of tDCS followed by six sessions of conflict processing training. The second group will first receive tDCS in the form of sham, to be followed by six sessions of auditory Stroop. The evaluations will be repeated after each intervention.

Studies have shown that successive sessions of conflict processing training can enhance cognitive plasticity and inhibition function. As conflict processing training has not been addressed as rehabilitation training in the people suffering from tinnitus, these processes will be designed in four tasks as rehabilitation exercises in Farsi language and applied along with tDCS to the people with chronic tinnitus to decrease and control tinnitus by improving cognitive and inhibition control.
Trial registration: Iranian Registry of Clinical Trials (IRCT20120215009014N366) on Sep 17th, 2020.