Recent advances in signal processing offer new opportunities for improving acoustic amplification systems for hearing-impaired persons. This paper provides an overview of the various forms of signal processing for noise reduction that have been developed for hearing aid applications.
Two experiments were carried out to determine how manipulating the compression ratio and release time of a single-band wide dynamic range hearing aid affects sound quality. In experiment I, compression ratio was varied over the range from linear to 10:1 (low compression threshold, attack time = 5 ms, release time = 200 ms). In experiment II, compression ratios of 1.5, 2, and 3:1 were combined with release times of 60, 200, and 1000 ms (attack time = 5 ms). Twenty listeners with sensorineural hearing loss rated the clarity, pleasantness, background noise, loudness, and the overall impression of speech-in-noise (Ventilation, Apartment, Cafeteria) processed through a compression hearing aid. Results revealed that increasing compression ratio caused decreases in ratings on all scales. Increasing release time caused ratings of pleasantness to increase, and ratings of background noise and loudness to decrease. At the 3:1 compression ratio, increasing the release time caused increases in ratings of clarity, pleasantness, and overall impression, and a decrease in background noise. Significant correlations were found between scales. Regression analysis revealed that the contributions of the scales of clarity, pleasantness, background noise, and loudness to the prediction of overall impression differed as a function of the competing noise condition.
Paired-comparison judgments of quality were obtained from 20 hearing-impaired listeners for speech processed through simulated compression hearing aids varying in release time (60, 200, 1000 ms) at three different compression ratios (1.5, 2, 3:1) and for three different background noises (ventilation, apartment, cafeteria). Analysis revealed that the main effect of release time did not have a significant effect on perceived quality. The interaction between release time and noise type was found to be significant. While no significant difference in preference for release times was evident for the ventilation noise, the longer release times (200 and 1000 ms) were preferred for the higher level noises (apartment noise, cafeteria noise). Post hoc testing revealed that the mean preference scores for the 200- and 1000-ms release time were significantly greater than that of the 60-ms release time with the competing cafeteria noise (p < 0.05). Analysis of individual subject data revealed statistically significant preferences that differed from the group mean, suggesting that individualized fitting of this parameter of a compression hearing aid might be warranted.
Paired-comparison judgments of quality were obtained from 20 hearing-impaired listeners (half with a small dynamic range and half with a large dynamic range) for speech-in-noise (vent, apartment, and cafeteria) processed through a slow-acting compression hearing aid. Compression ratio was varied (1, 1.5, 2, 3, 5, and 10:1). Compression threshold, attack time, and release time were fixed. Sound quality judgments were significantly affected by compression ratio, noise, and dynamic range. Preference decreased with increasing compression ratio. The selection of compression ratio. The selection of compression ratios < or = 2:1 was significantly higher than of compression ratios > 3:1. Less compression (no compression or 1.5:1) was preferred with the highest level noise (cafeteria noise) than with the lower level noises (vent or apartment). In particular, the small dynamic range group preferred compression with the vent and apartment noises (noise below the compression threshold), but preferred a linear hearing aid with the cafeteria noise (above the compression threshold). The large dynamic range group showed a slightly greater preference for the linear hearing aid for all three noises.
Background Increasing numbers of adults are receiving cochlear implants (CIs) and many achieve high levels of speech perception and improved quality of life. However, a proportion of implant recipients still struggle due to limited speech recognition and/or greater communication demands in their daily lives. For these individuals a program of aural rehabilitation (AR) has the potential to improve outcomes. Purpose The study investigated the effects of a short-term AR intervention on speech recognition, functional communication, and psychosocial outcomes in post lingually deafened adult CI users. Research Design The experimental design was a multisite clinical study with participants randomized to either an AR treatment or active control group. Each group completed 6 weekly 90-minute individual treatment sessions. Assessments were completed pretreatment, 1 week and 2 months post-treatment. Study Sample Twenty-five post lingually deafened adult CI recipients participated. AR group: mean age 66.2 (48–80); nine females, four males; months postactivation 7.7 (3–16); mean years severe to profound deafness 18.4 (2–40). Active control group: mean age 62.8 (47–85); eight females, four males; months postactivation 7.0 (3–13); mean years severe to profound deafness 18.8 (1–55). Intervention The AR protocol consisted of auditory training (words, sentences, speech tracking), and psychosocial counseling (informational and communication strategies). Active control group participants engaged in cognitive stimulation activities (e.g., crosswords, sudoku, etc.). Data Collection and Analysis Repeated measures ANOVA or analysis of variance, MANOVA or multivariate analysis of variance, and planned contrasts were used to compare group performance on the following measures: CasperSent; Hearing Handicap Inventory; Nijmegen Cochlear Implant Questionnaire; Client Oriented Scale of Improvement; Glasgow Benefit Inventory. Results The AR group showed statistically significant improvements on speech recognition performance, psychosocial function, and communication goals with no significant improvement seen in the control group. The two groups were statistically equivalent on all outcome measures at preassessment. The robust improvements for the AR group were maintained at 2 months post-treatment. Conclusion Results of this clinical study provide evidence that a short-term AR intervention protocol can maximize outcomes for adult post lingually deafened CI users. The impact of this brief multidimensional AR intervention to extend CI benefit is compelling, and may serve as a template for best practices with adult CI users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.