Sound-Field Speech Evoked Auditory Brainstem Responsein Cochlear-Implant Recipients

Background and Objectives@#Currently limited information is available on speech stimuli processingat the subcortical level in the recipients of cochlear implant (CI). Speech processing inthe brainstem level is measured using speech-auditory brainstem response (S-ABR). The purposeof the present study was to measure the S-ABR components in the sound-field presentationin CI recipients, and compare with normal hearing (NH) children. Subjects and Methods:In this descriptive-analytical study, participants were divided in two groups: patients withCIs; and NH group. The CI group consisted of 20 prelingual hearing impairment children (meanage=8.90 ± 0.79 years), with ipsilateral CIs (right side). The control group consisted of 20healthy NH children, with comparable age and sex distribution. The S-ABR was evoked bythe 40-ms synthesized /da/ syllable stimulus that was indicated in the sound-field presentation. @*Results@#Sound-field S-ABR measured in the CI recipients indicated statistically significantdelayed latencies, than in the NH group. In addition, these results demonstrated thatthe frequency following response peak amplitude was significantly higher in CI recipients,than in the NH counterparts (p<0.05). Finally, the neural phase locking were significantlylower in CI recipients (p<0.05). Conclusions: The findings of sound-field S-ABR demonstratedthat CI recipients have neural encoding deficits in temporal and spectral domains atthe brainstem level; therefore, the sound-field S-ABR can be considered an efficient clinicalprocedure to assess the speech process in CI recipients. J Audiol Otol 2020;24(2):71-78

Central Auditory Processing Tests as Diagnostic Tools for the Early Identification of Elderly Individuals with Mild Cognitive Impairment

BACKGROUND AND OBJECTIVES: Mild cognitive impairment (MCI) is a disorder that usually occurs in the elderly, leading to dementia in some progressive cases. The purpose of this study is to examine the utility of central auditory processing tests as early diagnostic tools for identifying the elderly with MCI. SUBJECTS AND METHODS: This study was conducted on 20 elderly patients with MCI and 20 healthy matched peers. The speech perception ability in a quiet environment and in the presence of background noise and also temporal resolution were assessed by using Speech Perception in Noise (SPIN) and Gap in Noise (GIN) tests, respectively. RESULTS: The results indicated that the ability to understand speech in a quiet environment did not differ significantly between the two groups. However, SPIN at the three signal-tonoise ratios and the temporal resolution scores were significantly different between the two groups (p<0.001). CONCLUSIONS: Individuals with MCI appear to have poorer speech comprehension in noise and a lower temporal resolution than those of the same age, but without cognitive defects. Considering the utility of these tests in identifying cognitive problems, we propose that since the GIN test seems to be less influenced by intervening factors, this test can therefore, be a useful tool for the early screening of elderly people with cognitive problems.

[Protection against noise-induced cochlear hair cell loss in conditioned guinea pigs]

Since noise-induced hearing loss is a common problem and its prevention is important, we aimed to evaluate whether previous exposure to moderate level of noise could prevent subsequent high level noise-induced cochlear damage. This study was conducted on 10 guinea pigs randomly divided into two groups [n=5, each]. Animals in control group exposed to 4 kHz, 105 dB SPL octave band noise for 4 hours, while in conditioned group animals exposed to 85 dB SPL, 4 kHz octave band noise, 6 hours/day for 5 days before exposing to 105 dB noise. One week later, the subjects euthanized for histological evaluation and the remaining and lost outer hair, inner hair and supporting cells were compared. Our results showed that outer hair cells row 1 was injured the most. A massive damage around the second turn of the cochlea was observed in control group. Conditioning significantly reduced the amount of hair cell loss. In conditioned group, the amount of hair cell loss was significantly reduced when compared to control [p<0/05]. Our findings confirmed that conditioning protects against noise-induced cochlear hair cell loss

[Hearing status of the blind school boys]

Objective: A survey on hearing state of blind schoolboys in Tehran

Method and Material: This cross-sectional descriptive survey was conducted on 640 ears of 320 blind schoolboys of 5-23 years old as a hearing screening in Tehran blind schools, 2000-01

Results: 20.94% was hearing-impaired of whom 13.75% had bilateral and 7.19% had unilateral hearing loss. 15.16% of students suffered from sensory-neural hearing loss [SNHL], 1.56% from conductive hearing loss [CHL] and 0.62% from mixed hearing loss [MHL], that is, SNHL occurred 10 times more than CHL. Hearing loss was often mild and moderate, and audiogram configuration was primarily high tone loss [HTL]. On the whole, 8.13% of students needed medical treatment, 15.13% needed audiological rehabilitation and 3.44% of them were in need of both medical and rehabilitation Intervention. General information about hearing problem was very low among students, their parents and teachers, which was 26.87%, 20.9% and 22.39%, respectively. There is significant relation between SNHL and parents and apos relationship

Conclusion: The prevalence of hearing loss in blinds is higher than in normal-visions. It is often sensorineural. So, it is important to identify these children through hearing screening [Using more high frequencies] and to conduct medical as well as rehabilitative intervention