Brainstem Correlates of Comodulation Masking Release for Speech in Normal Hearing Adults

BACKGROUND AND OBJECTIVES: Weak signals embedded in fluctuating masker can be perceived more efficiently than similar signals embedded in unmodulated masker. This release from masking is known as comodulation masking release (CMR). In this paper, we investigate, neural correlates of CMR in the human auditory brainstem. SUBJECTS AND METHODS: A total of 26 normal hearing subjects aged 18-30 years participated in this study. First, the impact of CMR was quantified by a behavioral experiment. After that, the brainstem correlates of CMR was investigated by the auditory brainstem response to complex sounds (cABR) in comodulated (CM) and unmodulated (UM) masking conditions. RESULTS: The auditory brainstem responses are less susceptible to degradation in response to the speech syllable /da/ in the CM noise masker in comparison with the UM noise masker. In the CM noise masker, frequency-following response (FFR) and fundamental frequency (F0) were correlated with better behavioral CMR. Furthermore, the subcortical response timing of subjects with higher CMR was less affected by the CM noise masker, having higher stimulus-to-noise response correlations over the FFR range. CONCLUSIONS: The results of the present study revealed a significant link between brainstem auditory processes and CMR. The findings of the present study show that cABR provides objective information about the neural correlates of CMR for speech stimulus.

Effects of Age on Speech-in-Noise Identification: Subjective Ratings of Hearing Difficulties and Encoding of Fundamental Frequency in Older Adults

BACKGROUND AND OBJECTIVES: Numerous studies have indicated deterioration of speech perception in noisy conditions among the elderly even those with normal hearing capabilities. The aim of this study was to investigate the effects of age on the speech-in-noise identification by speech-in-noise (SIN) test, subjective ratings of hearing difficulties by speech, spatial, and qualities of hearing scale (SSQ) questionnaire and encoding of fundamental frequency (F0) by Speech auditory brainstem response (ABR) in the elderly and comparing the results with young people. SUBJECTS AND METHODS: The present study was conducted on 32 elderly people aged over 60 years old (17 male and 15 female) with the mean age of 68.9 (standard deviation=6.33) possessing normal peripheral hearing and 32 young subjects (16 male and 16 female) aged 18-25 years old. RESULTS: Findings showed that the score of SIN test is lower among the elderly people as compared with young people in signal-to-noise ratios of 0 and -10 based on Iranian version of SSQ questionnaire (p < 0.001). The range of F0 amplitude in the elderly people is also lower than young people (p < 0.001) in Speech ABR. CONCLUSIONS: It seems that speech processing in older people is deteriorated comparing with young people regardless of their normal peripheral auditory thresholds. This decrease will result in weaker perception and improper segregation of speech from other competing sources.

Relation between working memory capacity and auditory stream segregation in children with auditory processing disorder

Background: This study assessed the relationship between working memory capacity and auditory stream segregation by using the concurrent minimum audible angle in children with a diagnosed auditory processing disorder [APD]

Methods: The participants in this cross-sectional, comparative study were 20 typically developing children and 15 children with a diagnosed APD [age, 9-11 years] according to the subtests of multiple-processing auditory assessment. Auditory stream segregation was investigated using the concurrent minimum audible angle. Working memory capacity was evaluated using the non-word repetition and forward and backward digit span tasks. Nonparametric statistics were utilized to compare the between-group differences. The Pearson correlation was employed to measure the degree of association between working memory capacity and the localization tests between the 2 groups

Results: The group with APD had significantly lower scores than did the typically developing subjects in auditory stream segregation and working memory capacity. There were significant negative correlations between working memory capacity and the concurrent minimum audible angle in the most frontal reference location [0[degree sign] azimuth] and lower negative correlations in the most lateral reference location [60[degree sign] azimuth] in the children with APD

Conclusion: The study revealed a relationship between working memory capacity and auditory stream segregation in children with APD. The research suggests that lower working memory capacity in children with APD may be the possible cause of the inability to segregate and group incoming information

Review paper: introduction of pediatric balance therapy in children with vestibular dysfunction: review of indications, mechanisms, and key exercises

The veStibular system is important for the development of normal movement reactions, motion tolerance, and motor control for poStural alignment, balance, and vision

A veStibular system that is damaged by disease or injury in childhood can have a major impact on a child's development In addition, the emergence of veStibular lesions may also lead to cognitive deficits, including attention deficit Despite the advances in testing and documentation of veStibular deficits in children, the veStibular problems continue to be an overlooked entity. Many children do not receive treatment that could significantly improve function and address the developmental delays caused by veStibular disorders

VeStibular rehabilitation therapy [VRT] has been defined as an effective modality for moSt individuals with disorders of the veStibular or central balance system disorders. The basis for the success of VRT is the use of existing neural mechanisms in the human brain for adaptation, plasticity, and compensation. The veStibular syStem cannot be considered as a separate entity ignoring other balance subsystems. Hence, a modified VRT program, named pediatric balance therapy with special modifications in exercises, was developed for children with veStibular disorders, in accordance to the whole balance system

effect of working memory training on auditory stream segregation in auditory processing disorders children

This study investigated the efficacy of working memory training for improving working memory capacity and related auditory stream segregation in auditory processing disorders children. Fifteen subjects [9-11 years], clinically diagnosed with auditory processing disorder participated in this non-randomized case-controlled trial. Working memory abilities and auditory stream segregation were evaluated prior to beginning and six weeks after completing the training program. Ten control subjects, who did not participate in training program, underwent the same battery of tests at time intervals equivalent to the trained subjects. Differences between the two groups were measured using a repeated measures analysis of variance. The results of this study indicated children who received auditory working memory training performed significantly better on working memory abilities and auditory stream segregation task than children do not received training program. Results from this case-control study support the benefits of working memory training for children with auditory processing disorders and indicate that training of auditory working memory is especially important for this population

Evaluation of Saccular Function Pre-Post Cochlear Implant Surgery Using VEMPs

Objectives: The aim of present study was evaluation of saccular function in cochlear implant candidates with severe to profound sensory neural hearing loss. Before and after cochlear implantation

Methods: In this study 35 Cochlear Implant [CI] candidates with bilateral severe to profound sensory neural hearing loss before and about 30 days after cochlear implantation and 20 normal-hearing cases as a control group underwent VEMP test. Both groups were matched based on gender and age.

Results: VEMP responses were absent bilaterally in 10 out of 35 patients. 4 patients were excluded from the study because they did not receive CI during present study. From 21 remaining patients, 5 cases lost VEMP response in their implanted ear after surgery. In control group, VEMP responses were present bilaterally.

Discussion: The results of present study show that saccular dysfunction in CI candidates is extremely probable and this is possible that saccule get impaired after CI.