Showing papers on "Digital hearing aid published in 1995"
TL;DR: In this article, a programmable customized universal digital listening system is provided with one or more digital signal processor chips which are implemented as one-or more digital filters whose parameters are established by one- or more erasable programmable read-only memories.
Abstract: A programmable customized universal digital listening system is provided with one or more digital signal processor chips which are implemented as one or more digital filters whose parameters are established by one or more erasable programmable read-only memories (EPROMs). The information included in the EPROMs directed to the parameters of the digital filters are determined based upon the user's response to various audio signals provided from an audiologist. Based upon these responses, the EPROMs are programmed. Additionally, this listening system is provided with an additional digital filter which changes its responses based upon the frequency of any background noise.
43 citations
TL;DR: Dynamic range, noise type, and input level were all found to have small, but significant, effects on the deviation of preferred listening level from most comfortable loudness (MCL), and preferred listening levels were close to MCL.
Abstract: Objectiue The purpose of the present experiment was to determine the relationship between most comfortable listening level and preferred listening levels for linear and slow-acting compression hearing aids as a function of variations in speech and noise level. Design A digital hearing aid test system was used to simulate six hearing aids having compression ratios of 1, 1.5, 2, 3, 5, and 10:1. Speech was presented in three different noises (vent, apartment, and cafeteria), with speech input level being varied (55, 70, 85 dB SPL). Subjects were 20 listeners with sensori-neural hearing loss (half with a dynamic range 130 dB and half with a dynamic range > 30 dB). The boundaries of the most comfortable listening range were measured to estimate most comfortable listening level. Preferred listening level was measured by having subjects adjust the output of the hearing aid for satisfactory listening. Results On average, the deviation of preferred listening level from most comfortable loudness (MCL) was less than 5 dB. Dynamic range, noise type, and input level were all found to have small, but significant, effects on the deviation of preferred listening level from MCL. On average, subjects with a small dynamic range listened slightly below MCL, and subjects with a larger dynamic range listened slightly above MCL. For favorable signal-to-noise ratios, preferred listening levels were highest for high input levels and for conditions that resulted in high output levels before level adjustment. Although the pattern of average performance differed slightly at poorer signal-to-noise ratios, all preferred listening levels were close to MCL. Conclusions The gain of a slow-acting compression hearing aid should place the output within 5 dB of MCL. The output for low and medium inputs should approximate MCL and the output for high input levels should be slightly above MCL. This pattern of gain may be obtained with mild compression ratios and a gain rule that places a speech input of 70 dB at MCL.
14 citations
09 May 1995
TL;DR: The principal objectives of the project are to make an easy implementation VLSI system with low consumption for it to be a portable digital hearing aid and to improve their intelligibility.
Abstract: Introduces a digital hearing aid that compensates the signal spoken in sensorineural impaired listeners with the object of improving their intelligibility. The technique used is based on a digital analysis/synthesis of speech; the authors divided the input signal into short time blocks then make a multiband analysis, nonlinear amplification and synthesis based on a sinusoidal model of the voice, according to the subject's dynamic range in that band. This system has been implemented in real-time using a DSP (TMS320C30) based microprocessor board within a host personal computer IBM PC, and one of the principal objectives of the project is to make an easy implementation VLSI system with low consumption for it to be a portable digital hearing aid.
4 citations
30 Oct 1995
TL;DR: The issues described in this paper deal with the development of a true real-time digital hearing aid based on Texas Instruments TMS320C3X, which implements frequency shaping, noise reduction, amplitude compression and various timing options.
Abstract: This paper deals with digital processing of speech as it pertains to the hearing impaired. At present the available hearing aids lag behind the technology curve, both, in terms of algorithm research and available hardware. The issues described in this paper deal with the development of a true real-time digital hearing aid. The system (based on Texas Instruments TMS320C3X) implements frequency shaping, noise reduction, amplitude compression and various timing options. It also provides a testbed for future development.
2 citations
20 Sep 1995
TL;DR: The digital hearing aid designed can slow down speech without any pitch frequency change by using a digital signal processor and was found to be effective for the elderly sensorineural hearing impaired, especially when sentences are spoken rapidly.
Abstract: The digital hearing aid we designed can slow down speech without any pitch frequency change by using a digital signal processor. We have proved that the device is effective for the elderly sensorineural hearing impaired, especially when sentences are spoken rapidly. It also slows down pitch frequency changes, causing the intonation of the speech to become less pronounced. In this paper, we investigated the auditory characteristics of the hearing impaired regarding intonation distinction in order to improve our digital hearing aid. From the results of the auditory tests, it was found that most of the sensorineural hearing impaired could not distinguish the intonation of the word /ame/ which has different meanings depending on its intonation. It was also found that intonation emphasis processed by the digital hearing aid was very effective for distinguishing spoken words which have similar intonations.
2 citations
20 Sep 1995
TL;DR: A digital signal processing based hearing aid has been produced which can be used as a body worn device, with transmitter and receiver in a conventional behind the ear hearing aid case, based on the TMS320C31-27 DSP device.
Abstract: A digital signal processing based hearing aid has been produced which can be used as a body worn device, with transmitter and receiver in a conventional behind the ear hearing aid case. The design is based on the TMS320C31-27 DSP device. Use of this low power chip allows the aid to perform for up to 8 hours without battery replacement and facilitates field testing of different algorithms designed to enhance hearing aid performance.
2 citations
TL;DR: In this article, a battery operated digital processor connected to microphones and receivers located in left and right ear modules was built and used in a hearing aid field trial, where eight hearing impaired individuals with moderate to moderately severe hearing losses served as subjects.
Abstract: A battery‐operated digital processor connected to microphones and receivers located in left and right ear modules was built and used in a hearing aid field trial. Eight hearing impaired individuals with moderate to moderately severe hearing losses served as subjects. All subjects had symmetric hearing losses and were experienced binaural hearing aid users. Four binaural hearing aid algorithms were programmed into the processor for evaluation in the field trial. The algorithms all equalized the magnitude and phase insertion effects of the ear modules, but differed in their gain prescription. Two prescriptions based on the Articulation Index (AI), one on NAL‐R, and a control prescription were evaluated in the two week field trial. Subjects rated each algorithm in seven categories. Objective measures of speech intelligibility in noise, including measures of binaural directional hearing, were taken before and after the field trial. Intelligibility and directional hearing was best with the AI prescriptions, although these prescriptions did not receive the highest subjective ratings. Details of the binaural algorithms and fittings, as well as objective and subjective measures of their benefit will be reported.
1 citations