Communication and noise. Speech intelligibility of airplane pilots with and without active noise compensation

Noise exposure measurements were performed with pilots of the German Federal Navy during flight situations. The ambient noise levels during regular flight were maintained at levels above a 90 dB A-weighted level. This noise intensity requires wearing ear protection to avoid sound-induced hearing loss. To be able to understand radio communication (ATC) in spite of a noisy environment, headphone volume must be raised above the noise of the engines. The use of ear plugs in addition to the headsets and flight helmets is only of limited value because personal ear protection affects the intelligibility of ATC. Whereas speech intelligibility of pilots with normal hearing is affected to only a smaller degree, pilots with pre-existing high-frequency hearing losses show substantial impairments of speech intelligibility that vary in proportion to the hearing deficit present. Communication abilities can be reduced drastically, which in turn can affect air traffic security. The development of active noise compensation devices (ANC) that make use of the "anti-noise" principle may be a solution to this dilemma. To evaluate the effectiveness of an ANC-system and its influence on speech intelligibility, speech audiometry was performed with a German standardized test during simulated flight conditions with helicopter pilots. Results demonstrate the helpful effect on speech understanding especially for pilots with noise-induced hearing losses. This may help to avoid pre-retirement professional disability.     

Self-reported hearing problems in daily life throughout adulthood

The authors assessed age differences on self-reported hearing problems on the performance of auditory tasks in the natural environment. The Your Hearing questionnaire was administered to 265 respondents (aged 20-94 years). Both the degree and variability of self-reported hearing problems were found to increase significantly with age, including those associated with listening to speech under conditions of background noise, the perception of normal and distorted speech, and the perception of short segments of speech and the perception of high-pitched sounds. Experienced hearing problems were greater for Ss who judged their hearing as being of poor quality. Findings suggest that self-report measures can provide valuable insights into the impact of age-related hearing disability on daily life that are not provided by more traditional laboratory-based studies.     

Reliability of monosyllabic discrimination tests in white noise for differentiating among hearing aids

In spite of criticism, monosyllabic discrimination tests are widely employed for hearing aid selection. The current study was designed to investigate the following questions: (1) How reliable is aided speech discrimination of monosyllables in a background of white noise? (2) Can differences among hearing aids be reliably demonstrated by measuring intelligibility of monosyllables in a background of white noise? and (3) Do hearing aids interact with hearing loss? Twenty subjects with mild-moderate sensorineural hearing losses participated in two experimental sessions. Four hearing aids were evaluated using the NU-6 monosyllables in a background of white noise (s/n = +20 dB). Since the standard deviation of the test-retest differences was 6%, differences between aids were not considered significant unless they exceeded 12%. An interaction between subjects and hearing aids was found; that is, the best aid for one person was not the best for all. Measuring monosyllabic word intelligibility in a background of white noise does not reliably identify a single best aid. However, one or more inferior aids were consistently eliminated in 80% of the subjects.     

Benefits of linear amplification and multichannel compression for speech comprehension in backgrounds with spectral and temporal dips

People with cochlear hearing loss have markedly higher speech-receptions thresholds (SRTs) than normal for speech presented in background sounds with spectral and/or temporal dips. This article examines the extent to which SRTs can be improved by linear amplification with appropriate frequency-response shaping, and by fast-acting wide-dynamic-range compression amplification with one, two, four, or eight channels. Eighteen elderly subjects with moderate to severe hearing loss were tested. SRTs for sentences were measured for four background sounds, presented at a nominal level (prior to amplification) of 65 dB SPL: (1) A single female talker, digitally filtered so that the long-term average spectrum matched that of the target speech; (2) a noise with the same average spectrum as the target speech, but with the temporal envelope of the single talker; (3) a noise with the same overall spectral shape as the target speech, but filtered so as to have 4 equivalent-rectangular-bandwidth (ERB) wide spectral notches at several frequencies; (4) a noise with both spectral and temporal dips obtained by applying the temporal envelope of a single talker to speech-shaped noise [as in (2)] and then filtering that noise [as in (3)]. Mean SRTs were 5-6 dB lower (better) in all of the conditions with amplification than for unaided listening. SRTs were significantly lower for the systems with one-, four-, and eight-channel compression than for linear amplification, although the benefit, averaged across subjects, was typically only 0.5 to 0.9 dB. The lowest mean SRT (-9.9 dB, expressed as a speech-to-background ratio) was obtained for noise (4) and the system with eight-channel compression. This is about 6 dB worse than for elderly subjects with near-normal hearing, when tested without amplification. It is concluded that amplification, and especially fast-acting compression amplification, can improve the ability to understand speech in background sounds with spectral and temporal dips, but it does not restore performance to normal.     

Tinnitus as an early indicator of permanent hearing loss. A 15 year longitudinal study of noise exposed workers

A retrospective study was designed to evaluate tinnitus (ringing or other sounds in the ears or head) as a potential early indicator of permanent hearing loss in a population of noise exposed workers. Data were examined from 91 male employees working in environments with noise levels ranging from 8 hour time weighted averages of 85 to 101 dBA over a period of 15 years. Results of annual audiometric testing were obtained as part of an ongoing hearing conservation program conducted since 1971 by ESCO Corporation, a steel foundry located in the Portland, Oregon metropolitan area. Results indicate the prevalence of tinnitus increases more than two and one half times for workers experiencing maximum threshold shifts > or = 15 decibels in hearing level (dBHL). Results also provide evidence that reports of tinnitus at the time of annual audiometric testing may be useful in identifying workers at greater risk for developing significant shifts in hearing thresholds.     

Speech enhancement based on a sinusoidal model

Sinusoidal modeling is a new procedure for representing the speech signal. In this approach, the signal is divided into overlapping segments, the Fourier transform computed for each segment, and a set of desired spectral peaks is identified. The speech is then resynthesized using sinusoids that have the frequency, amplitude, and phase of the selected peaks, with the remaining spectral information being discarded. Using a limited number of sinusoids to reproduce speech in a background of multi-talker speech babble results in a speech signal that has an improved signal-to-noise ratio and enhanced spectral contrast. The more intense spectral components, assumed to be primarily the desired speech, are reproduced, whereas the less intense components, assumed to be primarily background noise, are not. To test the effectiveness of this processing approach as a noise suppression technique, both consonant recognition and perceived speech intelligibility were determined in quiet and in noise for a group of subjects with normal hearing as the number of sinusoids used to represent isolated speech tokens was varied. The results show that reducing the number of sinusoids used to represent the speech causes reduced consonant recognition and perceived intelligibility both in quiet and in noise, and suggests that similar results would be expected for listeners with hearing impairments.     

Disability and identity: A study of identity patterns in adolescents with hearing impairments.

Some children with physical disabilities are encouraged to identify exclusively with nondisabled persons, relinquishing any identity with others who have disabilities. The implications of such a personal identification on adjustment were examined by measuring identity choice in 111 students (aged 15–19 yrs) at a state school for persons with hearing impairments. Ss were classified into 3 groups: those with a predominant hearing identity (able-bodied identity), those with a primary deaf identity (disabled identity), and those who identified with both groups (dual identity). Analyses focused on the relationship between the Ss' identity and indicators of the Ss' social relations, self-evaluations, academic achievement, and perceived family acceptance of their disability. Data indicate that an able-bodied identity was consistently associated with poorer outcomes and a dual identity with better outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory perception with level-dependent hearing protectors. The effects of age and hearing loss

Auditory perception with hearing protectors was assessed in three groups of subjects, two with normal hearing, but differing in age, and one with moderate bilateral sensorineural hearing loss. Individuals were tested with the ears unoccluded, and fitted with each of two level-dependent ear muffs and their conventional level-independent counterparts. One of the former devices provided limited amplification. In each of these five ear conditions, the threshold of audibility for one-third octave noise bands centered at 500, 1,000, 2,000 and 4,000 Hz, consonant discrimination, and word recognition were measured in quiet and in a continuous impulse noise background. The results showed that the attenuation of sounds (i.e. the difference between protected and unoccluded thresholds) in quiet did not vary as a function of age or hearing loss for any of the four protectors. In noise, the difference between protected and unoccluded listening was close to zero, as long as hearing was normal. With hearing loss as a factor, there was a significant increment in the protected threshold, the amount determined by the device. Word recognition in quiet was adversely affected in normal-hearing listeners by the three attenuating devices but improved in noise relative to unoccluded listening. Amplification had a deleterious effect for both consonant discrimination and word recognition in noise. In hearing-impaired listeners, speech perception was impeded by all four muffs but less so in quiet with limited amplification.     

Word discrimination for listeners with flat sensorineural hearing losses

This study examined discrimination scores among listeners (742 ears) with flat sensorineural hearing losses. The discrimination data were analyzed in terms of degree of hearing impairment and subject age. Contrary to previous findings, the results showed that the average subject exhibited a discriminative ability of 70% or better for hearing levels less than 60 dB. A 10 to 20% decline in intelligibility, however, was found for losses 60 dB and greater. Listeners' performance decreased somewhat as a function of age especially for subjects with the greatest hearing losses. Finally, a subject's word discrimination was similar whether hearing loss was based on a three- or a five-frequency average.     

Low prevalence of hearing aid use among older adults with hearing loss: the Epidemiology of Hearing Loss Study

OBJECTIVES: To measure the prevalence of hearing aid use among older adults with hearing loss and to identify factors associated with those currently using hearing aids. DESIGN: Population-based cohort study. SETTING: The south-central Wisconsin community of Beaver Dam. PARTICIPANTS: A total of 1629 adults, aged 48 to 92 years, who have hearing loss and are participating in the Epidemiology of Hearing Loss Study and the Beaver Dam Eye Study. MEASUREMENTS: A hearing-related risk factor and medical history questionnaire, the Hearing Handicap Inventory for the Elderly (screening version), screening tympanometry, pure-tone air- and bone-conduction audiometry, and word recognition tests were administered by trained examiners using standard protocols. RESULTS: The prevalence of current hearing aid use among those with a hearing loss (pure-tone average > 25 decibels hearing level over 500, 1000, 2000, and 4000 Hertz, worse ear) was 14.6%. The prevalence was 55% in a subset of the most severely affected participants. In univariate analyses, current hearing aid use was associated with age, severity of loss, word recognition scores, self-reported hearing loss, self-perceived hearing handicap, and history of noise exposure. Factors associated with current hearing aid use in multivariate logistic regression models were age, severity of loss, education, word recognition scores, Hearing Handicap Inventory for the Elderly (screening version) score, and self-report of a hearing loss. CONCLUSIONS: Few older adults with hearing loss are currently utilizing hearing aids. Improved screening and intervention programs to identify older adults who would benefit from amplification are needed to improve hearing-related quality of life for this large segment of the population.     

Life satisfaction of people with physical disabilities: Relationship to personal assistance, disability status, and handicap.

Investigated 3 possible moderating factors associated with physical disabilities and with life satisfaction, including level of disability, level of handicap, and self-appraised adequacy of personal assistance. 45 persons with various physical disabilities who use personal assistance were given the Life Satisfaction Index Form A, selected subscales from the Arthritis Impact Measurement Scale, the Craig Handicap Assessment and Report Technique, and a 19-item measure of personal assistance satisfaction. There were significant positive correlations between life satisfaction and both handicap and personal assistance satisfaction. Life satisfaction and degree of disability were not significantly correlated. There was no interaction between disability and personal assistance satisfaction with respect to either life satisfaction or handicap. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection and prevention of childhood disability with the help of Anganwadi workers

OBJECTIVES: To evaluate the role of Anganwadi Workers (AWW) for detection and prevention of disability in children below 6 years of age. DESIGN: Cross sectional and longitudinal follow up. SETTING: Ten Anganwadi Centers in ICDS Urban Project. METHODS: Trained AWWs identified disabilities and instituted preventive measures like immunization and supplementary nutrition. Simultaneous independent verification by pediatricians. Repeat survey after 6 mo of follow-up. Results: Amongst the 1545 children, AWW identified disability in 126 subjects which were verified in 118 cases by pediatricians. The disability rate was 7638 per 100,000 population. Visual, mental, orthopedic, speech and hearing disabilities rates were 4790, 2654, 583, 518 and 453 per 100,000 population, respectively. In the repeat survey, 35 of the 74 children with visual disability (mostly xerophthalmia), 4 of the 9 with orthopedic disability and 3 of the 7 with hearing disability could be managed satisfactorily. CONCLUSIONS: AWW can help in early detection and appropriate management of incipient and preventable childhood disabilities.     

A comparison of various methods of soft tissue management following the immediate placement of implants into extraction sockets

This study included 10 subjects with sensorineural hearing loss. They had not previously used hearing aids. The hearing aid fitting with "behind-the-ear' aids was based on the NAL method. Judging the sounds in their ordinary home environment, three sound situations (programmes) were selected, permitting the subjects to listen to one programme with speech, another with music and a third with "background noise'. For the group as a whole, significant differences were found between the sound quality judgements with and without the hearing aid. When the judgements of the programmes with background noise were excluded in the analysis, there were significant differences over time in the group as a whole on the scales for clarity and total impression.     

An adaptive noise canceller for hearing aids using two nearby microphones

An adaptive noise cancellation scheme based on two-stage adaptive filtering as proposed by Van Compernolle [Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing (IEEE, New York, 1990)] was tested for two identical directional microphones mounted in an endfire configuration within a single behind-the-ear (BTE) hearing aid. Speech intelligibility tests were carried out with two normal hearing subjects and three hearing aid users with moderate hearing losses, in a realistic test environment using open set words and sentences. A significant improvement, on average more than 5 dB, of speech reception threshold (SRT) in background noise was obtained.     

Development and evaluation of a procedure for fitting multi-channel compression hearing aids

Hearing aids with multi-channel compression are often fitted on the basis of loudness scaling data obtained using narrow bands of noise or tones. Here, we report the development and evaluation of an alternative fitting procedure based on the use of speech signals. The parameters of the hearing aid (the gains in each channel for high and low input levels) are adjusted adaptively under computer control on the basis of the listener's responses. The goal is that speech at 85 dB SPL should be judged as 'loud', speech at 60 dB SPL should be judged as 'quiet', and speech at both levels should be judged as 'neither tinny nor boomy'. The procedure was evaluated using a two-channel compression hearing aid, the remote control of which allowed two programs to be stored. One program was based on our fitting procedure. The other was either based on the manufacturer's recommended full fitting procedure (which included loudness scaling with bands of noise), or was based on the audiogram alone, using the manufacturer's algorithm. After an acclimatization period of at least two weeks, subjects were then asked to fill in a questionnaire about their experiences with the two programs in different listening situations. The results generally indicated a preference for the program based on our adaptive fitting procedure. We also conducted laboratory measurements of speech intelligibility, in quiet and in a background of a single competing talker. These showed no clear difference between programs, although scores overall were very high. We conclude that our adaptive procedure gives very satisfactory results in everyday life. Parameter values giving good comfort also give good intelligibility. The procedure typically takes between five and 10 minutes per ear, which is quicker than most loudness scaling procedures.     

Use of glycopyrrolate in the treatment of Meniere's disease

OBJECTIVES/HYPOTHESIS: The objective of this study was to determine whether glycopyrrolate is useful as a vestibular suppressant in patients with Meniere's disease. The tested hypotheses were that glycopyrrolate would decrease the perception of dizziness measured by the Dizziness Handicap Inventory in patients with Meniere's disease and that placebo would cause no such decrease. STUDY DESIGN: Randomized, prospective. METHODS: Thirty-seven subjects with a diagnosis of Meniere's disease were administered either 2 mg of glycopyrrolate or placebo twice daily as needed for vertigo. All were also administered the regimen of 1500 mg sodium/day diet and diuretic. The following indices were examined: Dizziness Handicap Inventory, Tinnitus Handicap Inventory, Modified Somatic Perception Questionnaire, Beck Depression Inventory, hearing examination, and electronystagmography. After 4 to 6 weeks of the drug regimen, Dizziness Handicap Inventory, Tinnitus Handicap Inventory, Modified Somatic Perception Questionnaire, and Beck Depression Scale were reexamined. Paired t tests were performed to verify the significance of improvement before and after treatment. RESULTS: Subjects who received glycopyrrolate had statistically significant reduction in Dizziness Handicap Inventory, Beck Depression Score, and Modified Somatic Perception Score. In the placebo group, no improvement in any index was found. CONCLUSIONS: The hypothesis that glycopyrrolate is a useful vestibular suppressant in patients with Meniere's disease was statistically verified.     

Antibody-directed enzyme prodrug therapy: pharmacokinetics and plasma levels of prodrug and drug in a phase I clinical trial

OBJECTIVE: The objective of the study was to determine the major factors that underlie auditory/audiological performance measures in an elderly population, with particular emphasis on finding those factors responsible for speech understanding under specific conditions of interference. DESIGN: Audiological status and auditory performance of a group of elderly (60- to 81-yr-old) and normal-hearing young (18- to 30-yr-old) individuals was determined through a test battery. When present, the hearing loss of elderly subjects was symmetrical in the two ears and, at most, moderate. The battery included tests of speech intelligibility on the word and sentence levels, with and without the presence of interfering speech. In addition to pure-tone and speech reception thresholds, perception of spectrally or temporally distorted speech as well as auditory resolution of frequency, time, and space were tested. Two tests received special consideration: the Speech Perception In Noise Test and the Modified Rhyme Reverberation Test. Taking the overall results as well as various subsets of the results, principal component analyses were conducted to identify major factors underlying auditory performance. RESULTS: The factors extracted by the principal component analyses present a portrayal of the auditory performance profile in which effects of interference, high-frequency hearing, and basic auditory function play a major role. Interference factors include general susceptibility to noise as well as segregation of concurrent speech sounds on the basis of temporal dissimilarities and spatial separation. Comparison of factors extracted from various subsets of tests indicate that factors underlying the decline of the "cocktail party effect" in the elderly are addressed mostly by tests specifically designed to assess speech understanding in spatially distributed babble or in a reverberant environment. CONCLUSIONS: Factor analysis of test measures obtained from a group of elderly individuals with normal hearing or mild-to-moderate hearing loss led to two main findings. First, it portrayed hearing loss as a component of different factors rather than as a factor on its own. Second, the independence of measures of speech understanding in babble or reverberation from other measures suggests that such tests should become an integral part of audiological test batteries designed to assess auditory functions in aging.     

The effects of decreased audibility produced by high-pass noise masking on cortical event-related potentials to speech sounds/ba/and/da

This study investigated the effects of decreased audibility produced by high-pass noise masking on cortical event-related potentials (ERPs) N1, N2, and P3 to the speech sounds /ba/and/da/presented at 65 and 80 dB SPL. Normal-hearing subjects pressed a button in response to the deviant sound in an oddball paradigm. Broadband masking noise was presented at an intensity sufficient to completely mask the response to the 65-dB SPL speech sounds, and subsequently high-pass filtered at 4000, 2000, 1000, 500, and 250 Hz. With high-pass masking noise, pure-tone behavioral thresholds increased by an average of 38 dB at the high-pass cutoff and by 50 dB one octave above the cutoff frequency. Results show that as the cutoff frequency of the high-pass masker was lowered, ERP latencies to speech sounds increased and amplitudes decreased. The cutoff frequency where these changes first occurred and the rate of the change differed for N1 compared to N2, P3, and the behavioral measures. N1 showed gradual changes as the masker cutoff frequency was lowered. N2, P3, and behavioral measures showed marked changes below a masker cutoff of 2000 Hz. These results indicate that the decreased audibility resulting from the noise masking affects the various ERP components in a differential manner. N1 is related to the presence of audible stimulus energy, being present whether audible stimuli are discriminable or not. In contrast, N2 and P3 were absent when the stimuli were audible but not discriminable (i.e., when the second formant transitions were masked), reflecting stimulus discrimination. These data have implications regarding the effects of decreased audibility on cortical processing of speech sounds and for the study of cortical ERPs in populations with hearing impairment.     

Use of technology by people with physical disabilities in Australia

PURPOSE: This study aimed to quantify the extent to which computers and assistive devices were being used by people with physical disabilities and the levels of computer training being undertaken by this group. METHOD: With the help of Queensland disability associations a written survey was distributed to people over 15 years in age with physical disabilities living in the greater Brisbane metropolitan area. Responses were received from 82 people (comprising spinal cord injuries (n = 71), cerebral palsy (n = 8), muscular dystrophy (n = 3)). RESULTS: Indicate that 60% of respondents were computer users, while only 15 respondents used assistive devices. Computer ability was correlated to age and time of disability onset. Respondents with quadriplegia had higher levels of computer ability than those with paraplegia. The study indicates that while many people with disabilities have used computers and assistive devices, many have not. CONCLUSIONS: The low rate of assistive device use by people with high-level quadriplegia is of concern. This study suggests that increased levels of training in the use of computers and assistive devices needs to be provided to people with physical disabilities.     

Determination of hearing loss and disability assessment from pure tone audiometry and speech audiometry in occupational noise-induced hearing loss

BACKGROUND: Occupational hearing loss is the most accepted occupational disease. The assessment should be conducted in accordance with the "K?nigsteiner Merkblatt" which appeared in the fourth completely revised edition in 1996. Determination of degree of disability is mainly based on speech audiometry. Adapted complete word understanding is most important. In special cases only sinus-tone audiometry is used for the assessment. Knowledge about common and uncommon schedules is important for the assessment. METHODS AND PATIENTS: The results of 200 audio metrical examinations in case of professional hearing loss have been evaluated with eight different schedules. Four of these schedules for determination of hearing loss are based on sinus tone audiometry. Boenninghaus and R?ser's schedule uses speech audiometry under consideration of simple and adapted complete word understanding. Lehnhardt's schedule uses sinus-tone and speech audiometry for determination of degree of disability. Further on it is shown that the complete word understanding is the most important parameter for the quantitative determination of permanent noise induced hearing loss. It is even possible to determine the degree of disablement only using the complete word understanding. For all cases, the eight schedules were used to calculate the average hearing loss and the average degree of disability. Further on it was shown in how many cases-according to each schedule-a degree of disability of less than 10%, 10 to 15%, 20%, and more than 20% was calculated. RESULTS AND CONCLUSION: Comparing these eight schedules, it was shown that the use of adaptec complete word understanding increases the number of cases with 10% and 20% degree of disability. Using R?ser's schedule of 1980, the number of minimal handicap increases. With the new "K?nigsteiner Merkblatt" a 10% degree of disability is reached more easily than it was previously.