This study investigated factors that contribute to deficits of elderly listeners in recognizing speech that is degraded by temporal waveform distortion. Young and elderly listeners with normal hear...

Temporal Factors and Speech Recognition Performance in Young and Elderly Listeners

The Desired Sensation Level (DSL) Method was revised to support hearing instrument fitting for infants, young children, and adults who use modern hearing instrument technologies, including multichannel compression, expansion, and multimemory capability. The aims of this revision are to maintain aspects of the previous versions of the DSL Method that have been supported by research, while extending the method to account for adult-child differences in preference and listening requirements. The goals of this version (5.0) include avoiding loudness discomfort, selecting a frequency response that meets audibility requirements, choosing compression characteristics that appropriately match technology to the user's needs, and accommodating the overall prescription to meet individual needs for use in various listening environments. This review summarizes the status of research on the use of the DSL Method with pediatric and adult populations and presents a series of revisions that have been made during the generation of DSL v5.0. This article concludes with case examples that illustrate key differences between the DSL v4.1 and DSL v5.0 prescriptions.

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The Desired Sensation Level Multistage Input/Output Algorithm:

This review provides an overview of recent research that addressed hearing loss and auditory processing problems among elderly people. It focuses on research from the University of Maryland on problems in auditory temporal processing by elderly listeners as assessed in speech perception experiments using temporally altered signals and in psycho-acoustic experiments of duration and rhythm discrimination for simple and complex signals. Some recent studies of perceived hearing disability are also reviewed. The clinical implications of the research findings are discussed in relation to hearing aid performance and use by elderly people as well as potential signal processing strategies that may prove to be beneficial for this population.

Hearing loss and aging: new research findings and clinical implications

The present investigation examined the effect of reverberation and noise on the perception of nonsense syllables by four groups of subjects: younger (≤35 years of age) and older (>60 years of age) ...

Hearing Loss, Aging, and Speech Perception in Reverberation and Noise

Speech is the primary vehicle of human social interaction. In everyday life, speech communication occurs under an enormous range of different environmental conditions. The demands placed on the process of speech communication are great, but nonetheless it is generally successful. Powerful selection pressures have operated to maximize its effectiveness. The adaptability of speech is illustrated most clearly in its resistance to distortion. In transit from speaker to listener, speech signals are often altered by background noise and other interfering signals, such as reverberation, as well as by imperfections of the frequency or temporal response of the communication channel. Adaptations for robust speech transmission include adjustments in articulation to offset the deleterious effects of noise and interference (Lombard 1911; Lane and Tranel 1971); efficient acousticphonetic coupling, which allows evidence of linguistic units to be conveyed in parallel (Hockett 1955; Liberman et al. 1967; Greenberg 1996; see Diehl and Lindblom, Chapter 3); and specializations of auditory perception and selective attention (Darwin and Carlyon 1995). Speech is a highly efficient and robust medium for conveying information under adverse conditions because it combines strategic forms of redundancy to minimize the loss of information. Coker and Umeda (1974, p. 349) define redundancy as “any characteristic of the language that forces spoken messages to have, on average, more basic elements per message, or more cues per basic element, than the barest minimum [necessary for conveying the linguistic message].” This definition does not address the function of redundancy in speech communication, however. Coker and Umeda note that “redundancy can be used effectively; or it can be squandered on uneven repetition of certain data, leaving other crucial items very vulnerable to noise. . . . But more likely, if a redundancy is a property of a language and has to be learned, then it has a purpose.” Coker and Umeda conclude that the purpose of redundancy in speech communication is to provide a basis for error correction and resistance to noise.

The Perception of Speech Under Adverse Conditions

The Modified Rhyme Test (MRT) was processed through a room (volume 165 m3, reverberation time T = 0.4, 0.8, and 1.2 s). For both binaural and monaural earphone listening the tests were recorded with a manikin (Kemar) and equalization filters to compensate for the ear canal effect. Six groups of subjects, ten subjects each, had mean ages of 10, 27, 42, 54, 64, and 72 years and average hearing threshold levels, HTLs (for 0.5, 1, and 2 kHz) of 2.7, 5.6, 6.0, 10.9, 14.4, 17.5 dB, respectively. The individual scores for the MRT without reverberation were between 90% and 100% at 70 dB SPL. Children and the elderly required from 10 to 20 dB higher SPLs than young adults to obtain maximum scores. An analysis of variance showed that all the main effects: T, age, and monaural versus binaural listening were significant. The scores declined with T for all ages. The best scores were obtained by the young adults (27 year olds). The binaural scores were about 5% better than monaural scores. Factors contributing to the results and practical implications for amplification are discussed.

Monaural and binaural speech perception in reverberation for listeners of various ages.

Consonant errors in noise and reverberation were compared. In CVC syllables the variables were 24 initial or 21 final consonants that exist in English words while the constant consonant was /t/ and the vowels were /ɑ/ and /i/. All syllables were produced by a male talker in a carrier sentence: “Mark the /CVC/ again.” The tests were processed through a room with reverberation time, T = 1.2 s or a babble of 20 voices was added. The following conditions were tested: (1) no noise and no reverberation; (2) no noise, T = 1.2 s; and (3) no reverberation, noise at speech‐to‐noise ratio, S/N = + 5 dB. Each condition was tested 20 times by 10 normal hearing subjects. The responses were tabulated in 12 matrices: 2 vowels×2 positions of consonants×3 test conditions. Transmitted information, TI, was calculated for selected distinctive features for each matrix separately. Analysis of variance was performed for each distinctive feature. Many main effects and two‐way interactions were significant. Diffferences in errors in noise and reverberation will be discussed. [Supported by NIH.]

Pauline K. Robinson

Papers

Monaural and binaural speech perception in reverberation for listeners of various ages.

Consonant errors in noise and reverberation