Gap pre-pulse inhibition of the cortical auditory evoked potentials as a possible objective tinnitus assessment tool.

Objectives: The objective assessment tests overcome the variability of subjective methods. Cortical recordings with gap pre-pulse inhibition of the acoustic startle reflex stimulus have been used as objective tinnitus assessments in humans. This study aims to investigate this possible objective tinnitus test and compare gap-induced inhibition in different stimulus parameters and brain regions. Materials & Methods: Twenty People (18-50 years old) without hearing loss and tinnitus were included. The sound stimuli consisted of continuous background noise with a loud startle tone preceded by a silent gap (20 and 40 ms duration, 120 and 150 ms distance from the startle). The N1-P2 complex amplitude and topoplot maps were extracted in 27-channel cortical response recording after signal processing. Four brain regions of interest (ROI) of anterior-frontal, centro-frontal, right, and left temporal were investigated. Results: The results showed that the maximum inhibition occurred in a 40 ms gap duration and 150 ms distance in all 4 ROIs. In comparing ROIs, the centro-frontal and left temporal regions revealed the most inhibition (p<0.05). The decrease in the amplitude of the N1 and P2 in that region could also be traced in the 100 and 200 ms topoplots. Conclusion: Gap-induced inhibition was observed in all gap-embedded stimuli and all ROIs. However, the 40-150 mode and centro-frontal and left temporal regions had maximum inhibition in normal subjects. It provides a promising tool for objectively assessing tinnitus in humans with particular implications in children.

Effects of rehabilitation training on an elderly population with mild to moderate hearing loss: study protocol for a randomised clinical trial.

Background: Age-related hearing loss (presbycusis) is a form of hearing loss in over 60-years-olds and has a negative impact on quality of life. Presbycusis is multifactorial and is predominately characterised with a loss of speech perception in noise. In the cochlea, auditory filters decompose broadband sound into a series of narrowband output signals, which contains two kinds of temporal information: slow changes in overall amplitude envelope (ENV) and faster variations in temporal fine structure (TFS). TFS is important for recognition of target speech in noise. The main aim of the study is to evaluate the effect of TFS rehabilitation training in participants over the age of 60 years with mild to moderate hearing loss. Methods: A randomised clinical trial  conducted on 30 participants with mild (loss of 20-39dB HL) to moderate (40-69dB HL) hearing loss, aged between 60 and 75 years old. Participants with conductive hearing loss, abnormal middle ear pathology and central nervous system disease were excluded. Participants were selected randomly  to an intervention and control group with a 1:1 ratio. Rehabilitation for the intervention Group are 30-minute sessions three times a week for a total five weeks of vowel consonant vowel words that are used to eliminate ENV and keep only TFS. Word in noise test, binaural TFS test, and Speech, Spatial and Qualities of Hearing Scale scores are performed at the beginning and end of study to evaluate the effect of rehabilitation training. Conclusion:  Life expectancy in the elderly has improved, leading to an increased prevalence of age-related diseases including presbycusis. A literature review highlighted that TFS damage is permanent; however, in this study we will attempt to prove that TFS training may lead to speech in noise perception improvement. Trial registration: Registry of Clinical Trials, IRCT2019625044006N1 (7 th August 2019).

A New Speech-in-Noise Test for Measuring Informational Masking in Speech Perception Among Elderly Listeners.

Introduction Elderly listeners have reported concerns about speech perception in noisy environments. This partly occurs because of their increased informational masking (IM). This study aimed to develop a Persian coordinate response measure (CRM) corpus and a novel speech-in-noise test for measuring IM. Material and methods A cross-sectional validation study was conducted in two parts. Part one was the determination of the validity and reliability of the Persian CRM corpus. Part two consisted of measuring the IM at five signal-to-noise ratio (SNR; -6,-3, 0, +3, and +6) in two conditions: one with the target and masker speaker of the same sex and one with the target and masker speaker of different sexes. In each condition, the IM measurements were performed at a 45° separation angle of target and maskers and as a co-location of the speakers. A group of young listeners aged 20 to 40 years and a group of elderly listeners aged 60 to 75 years were recruited (50 study participants in part one and 47 in part two). The study was conducted from July 2018 to March 2019 at the Iran University Medical Sciences audiology clinic. Content validity ratio, content validity index, impact score, Spearman's test, and Mann-Whitney's test were used for statistical analysis. Results The Persian CRM corpus showed acceptable validity and reliability in each group (p < 0.001). The results suggested that in both azimuth locations and at SNRs of 0, -3, and -6, the IM amount in the elderly group was significantly higher (p < 0.003) than in the young group at conditions of target and masker speakers of opposite-sex. However, in cases where both target and masker speakers were of the same sex, a significant difference was observed at an SNR of 0 in angular separation and SNRs of +3 and 0 at co-located situations (p < 0.001). Conclusion A validated Persian CRM corpus has been collected for use in IM measurement studies. Overall, the IM of elderly listeners was higher than younger listeners in low-cue situations such as lower SNR. Therefore, a novel speech-in-noise test for measuring IM was validated to use in speech perception studies in the elderly population.

The effects of auditory spatial training on informational masking release in elderly listeners: a study protocol for a randomized clinical trial.

Background: Regarding the strong auditory spatial plasticity capability of the central auditory system and the effect of short-term and long-term rehabilitation programs in elderly people, it seems that an auditory spatial training can help this population in informational masking release and better track speech in noisy environments. The main purposes of this study are developing an informational masking measurement test and an auditory spatial training program. Protocol: This study will be conducted in two parts. Part 1: develop and determine the validity of an informational masking measurement test by recruiting two groups of young (n=50) and old (n=50) participants with normal hearing who have no difficulty in understanding speech in noisy environments. Part 2 (clinical trial): two groups of 60-75-year-olds with normal hearing, who complain about difficulty in speech perception in noisy environments, will participate as control and intervention groups to examine the effect of auditory spatial training. Intervention: 15 sessions of auditory spatial training. The informational masking measurement test and Speech, Spatial and Qualities of Hearing Scale will be compared before intervention, immediately after intervention, and five weeks after intervention between the two groups. Discussion: Since auditory training programs do not deal with informational masking release, an auditory spatial training will be designed, aiming to improve hearing in noisy environments for elderly populations. Trial registration: Iranian Registry of Clinical Trials ( IRCT20190118042404N1) on 25 th February 2019.

Comparison of the Minimum Plateau Width by Plateau and a New Method in People with Conductive Hearing Loss.

BACKGROUND AND OBJECTIVES: In clinical masking, the plateau is a state in which the non-test ear (NTE) is completely masked by the noise and tone is heard only by the test ear (TE). At least 15 to 20 dB of plateau width is needed to obtain valid threshold. In the study, a part of plateau after initial masking level known as the minimum plateau width (mPW) was determined and compared by a new formula and the plateau searching method. Subjects and. METHODS: Minimum plateau widths of air conduction were obtained in 29 participants with unilateral and 30 participants with bilateral conductive hearing loss (CHL) aged 20 to 45 years old by using step by step plateau method and mPW estimation by the formula between two points of masking diagram [mPW=(N2-N1)-(T2-T1)] and then the mPW of two methods was compared for each frequency. RESULTS: There was no significant difference between the minimum plateau width obtained by the plateau and formula methods for two given point of masking diagram in people with unilateral and bilateral CHL at octave frequencies from 500 Hz to 4,000 Hz. CONCLUSIONS: Threshold obtaining of TE by two tones for two noise levels delivered to the NTE is enough to estimate the mPW between these two noise points and it is not necessary that for clinicians to know the actual values of masking diagram components.

Horizontal Localization in Simulated Unilateral Hearing Loss

BACKGROUND AND OBJECTIVES: The ability to localize a sound source is one of the binaural hearing benefits in a horizontal plane based on interaural time difference and interaural intensity difference. Unilateral or bilateral asymmetric hearing loss will affect binaural hearing and lead to sound locating errors. In this cross sectional analytical descriptive study, the localization error was investigated when participants turned their heads to the sound source with closed eyes and after simulating unilateral hearing loss by placing earplugs inside the right ear canal. SUBJECTS AND METHODS: This cross sectional analytical descriptive study was carried out on 30 right-handed adults, 22 female and 8 male (average: 25 years, standard deviation: 3.16). They were selected with the available random access method. Horizontal localization was evaluated with five speakers located at 0, ±30, and ±60 degree azimuths at a 1-meter distance from the examinee. Narrow-band noise signals were delivered at 35 dB SL in two “without earplug” and “with earplug” situations and the results were compared. The study was performed between September and December 2016 in Tehran, Iran. RESULTS: Significant differences were observed in localization errors between the “with earplug” and “without earplug” situations. The localization differences were greater for left-side speakers (-30 and -60 degrees) compared with right-side speakers (+30 and +60 degrees). The differences were more apparent at 4,000 and 6,000 Hz, which confirmed the effect of unilateral simulated hearing loss on interaural latency differences. CONCLUSIONS: Simulating hearing loss by using an earplug in one ear (right) increased localization errors at all frequencies. The errors increased at higher frequencies.

Satisfaction with Hearing Aids Based on Technology and Style among Hearing Impaired Persons.

INTRODUCTION: Hearing loss is one of the most disabling impairments. Using a hearing aid as an attempt to improve the hearing problem can positively affect the quality of life for these people. This research was aimed to assess satisfaction of hearing impaired patients with their hearing aids regarding the employed technology and style. MATERIALS AND METHODS: This descriptive-analytic cross-sectional research was conducted on 187 subjects with hearing loss who were using a hearing aid. The subjects were over 18 years of age and were using a hearing aid for at least 6 months. The Persian version of Satisfaction with Amplification in Daily Life (SADL) questionnaire was the instrument which was used for assessing satisfaction with the hearing aid. Cronbach's alpha was calculated to be 0.80 for instrument reliability. RESULTS: A significant difference was observed among satisfaction subscales' mean scores with hearing aid technology. Also a significant difference was observed between the total satisfaction score and the hearing aid model. With respect to the analysis of satisfaction with the hearing aid and its style, cost and services was the only subscale which showed a significant difference (P=0.005). CONCLUSION: Respondents using hearing aids with different technology and style were estimated to be quite satisfied. Training audiologists in using more appropriate and fitting hearing aids in addition to using self-reporting questionnaires like SADL for estimating patients' social condition and participation in their life can essentially change their disability condition and countervail their hearing loss.

Satisfaction with Hearing Aids among Aged Patients with Different Degrees of Hearing Loss and Length of Daily Use.

BACKGROUND AND OBJECTIVES: The evaluation of subjective benefits and positive effects of hearing aids in daily is important for measuring the treatment outcome. The aim of this project was to investigate the degree of satisfaction of aged users with their hearing aids using the Satisfaction with Amplification in Daily Life (SADL) scale, which emphasizes non-auditory factors contributing to satisfaction as well as benefit. SUBJECTS AND METHODS: The Persian version of SADL scale was completed by 40 patients who received monaural hearing aid fitting at south of the Iran from December 2013 and March 2014. SADL subscales of the SADL were evaluated according to the type and degree of hearing loss, the pure tone audiogram pattern and shape and type of the hearing aid. RESULTS: The results associated with the SADL subscales revealed a greater satisfaction associated with the Positive Effect and Service and Costs subscales. Subjects with different degree of hearing loss were very satisfied in terms of positive effect subscale. CONCLUSIONS: Participants reported a considerable level of satisfaction with their hearing aids. Appropriate guidance for using hearing aids and spending more time for counseling can improve the satisfaction level of this age group.