Survey of hearing aid fitting practices for children with multiple impairments.

The fitting of amplification on young children with multiple impairments in addition to hearing loss is a challenge faced regularly by audiologists. However, very little has been published on this topic in the audiological literature. The purpose of this survey was to document hearing aid fitting practices for this population within the United States. Specifically, audiologists who regularly serve children were asked to complete a series of questions on their educational preparation and their hearing aid selection, fitting, and verification practices for children with multiple impairments. For purposes of this survey, multiple impairments included vision impairment, mental retardation, physical impairment, and autism spectrum disorders. Findings from this survey suggest that children with special needs in addition to hearing loss are typically fit in the same way and with the same type of amplification as those with hearing loss only. In addition, differences were noted in hearing aid selection, fitting, and verification practices across work settings. Future directions and research needs are suggested.

The role of generic health-related quality of life measures in establishing audiological rehabilitation outcomes.

OBJECTIVE: To review the status of generic functional health measures used with hearing-impaired adults and to summarize the findings of studies that have utilized these outcome measures to assess the benefit of amplification. DESIGN: Four basic generic quality of life measures used with the hearing-impaired population for determining hearing aid benefit are reviewed and discussed. The measures include the Sickness Impact Profile, the Self Evaluation of Life Function, the Medical Outcomes Study, and the Dartmouth COOP Functional Health Assessment Charts. RESULTS: The review of studies concerned with quality of life measures revealed that present day functional health status tools lack the necessary sensitivity to detect clinically meaningful improvements in patients with hearing impairment. CONCLUSIONS: Although we have good reason to believe that hearing aids improve quality of life, available functional health status measures lack the appropriate sensitivity to be used for assessing the benefit of amplification in individuals with hearing impairment. There is an urgent need for additional research to address this important area.

Minimal, progressive, and fluctuating hearing losses in children. Characteristics, identification, and management.

Referring to specific types of hearing loss as "minimal" or "mild" seems to imply that their effects are equally mild or negligible. A growing body of literature, however, supports the notion that such losses can have a significant impact on the communicative and educational development of young children. Although OME is considered a common childhood ailment, mounting evidence suggests that it is not always benign and may contribute to significant educational and communicative difficulties in some young children when accompanied by conductive hearing loss. Even very mild bilateral and unilateral SNHL seems to contribute to problems in the areas of social and emotional function, educational achievement, and communication in some children. Because these hearing losses are so mild, they may not be immediately recognized as the source of such difficulties. The purpose of this report is to heighten the general pediatrician's awareness of the significance of even very mild or minimal hearing losses in children. As the gatekeepers for children's health care, pediatricians are typically the primary recipients of parental expressions of concern and the initiators of evaluations or referrals to address such.

A comparison of the aided performance and benefit provided by a linear and a two-channel wide dynamic range compression hearing aid.

The aided performance and benefit achieved with linear and two-channel wide dynamic range compression (WDRC) in-the-canal (ITC) hearing aids were established in 55 individuals. Study participants had been wearing either linear or adaptive-frequency-response (Bass Increase at Low Levels, BILL) ITC hearing aids for approximately one year before participation in this study. Outcome measures included aided performance and objective benefit in quiet and noise at a variety of speech levels (50, 60, and 75 dB SPL), at various levels of babble background (quiet, signal-to-babble ratios of +5 and +10 dB), and for various types of test materials (monosyllabic words and sentences in connected speech). Several subjective measures of aided performance (sound-quality judgments and magnitude estimates of listening effort) and relative benefit (improvement in listening effort and the Hearing Aid Performance Inventory, HAPI) were also obtained. Finally, self-report measures of hearing-aid use were also obtained using daily logs. Participants completed all outcome measures for the linear ITC hearing aids first, following 2 months of usage, and then repeated all outcome measures for the WDRC instruments after a subsequent 2-month period of use. In general, although both types of hearing aids demonstrated significant benefit, the results indicated that the WDRC instruments were superior to the linear devices for many of the outcome measures. This tended to be the case most frequently when low speech levels were used. Many of the performance differences between devices most likely can be ascribed to differences in gain, and prescriptive approaches (DSL[i/o] vs. NAL-R), for the fixed volume control testing performed in this study.

Children with minimal sensorineural hearing loss: prevalence, educational performance, and functional status.

OBJECTIVE: This study was designed to determine the prevalence of minimal sensorineural hearing loss (MSHL) in school-age children and to assess the relationship of MSHL to educational performance and functional status. DESIGN: To determine prevalence, a single-staged sampling frame of all schools in the district was created for 3rd, 6th, and 9th grades. Schools were selected with probability proportional to size in each grade group. The final study sample was 1218 children. To assess the association of MSHL with educational performance, children identified with MSHL were assigned as cases into a subsequent case-control study. Scores of the Comprehensive Test of Basic Skills (4th Edition) (CTBS/4) then were compared between children with MSHL and children with normal hearing. School teachers completed the Screening Instrument for Targeting Education Risk (SIFTER) and the Revised Behavior Problem Checklist for a subsample of children with MSHL and their normally hearing counterparts. Finally, data on grade retention for a sample of children with MSHL were obtained from school records and compared with school district norm data. To assess the relationship between MSHL and functional status, test scores of all children with MSHL and all children with normal hearing in grades 6 and 9 were compared on the COOP Adolescent Chart Method (COOP), a screening tool for functional status. RESULTS: MSHL was exhibited by 5.4% of the study sample. The prevalence of all types of hearing impairment was 11.3%. Third grade children with MSHL exhibited significantly lower scores than normally hearing controls on a series of subtests of the CTBS/4; however, no differences were noted at the 6th and 9th grade levels. The SIFTER results revealed that children with MSHL scored poorer on the communication subtest than normal-hearing controls. Thirty-seven percent of the children with MSHL failed at least one grade. Finally, children with MSHL exhibited significantly greater dysfunction than children with normal hearing on several subtests of the COOP including behavior, energy, stress, social support, and self-esteem. CONCLUSIONS: The prevalence of hearing loss in the schools almost doubles when children with MSHL are included. This large, education-based study shows clinically important associations between MSHL and school behavior and performance. Children with MSHL experienced more difficulty than normally hearing children on a series of educational and functional test measures. Although additional research is necessary, results suggest the need for audiologists, speech-language pathologists, and educators to evaluate carefully our identification and management approaches with this population. Better efforts to manage these children could result in meaningful improvement in their educational progress and psychosocial well-being.

A comparison of the benefit provided by well-fit linear hearing aids and instruments with automatic reductions of low-frequency gain.

In this clinical study, 110 patients seen at three different clinical facilities were fit binaurally with linear, in-the-canal (ITC) hearing aids. All patients were new hearing aid users. Each of the hearing aids was equipped with an adjustable control that could be set by one of the audiologists (Audiologist A) at each site to convert it from a linear instrument to an experimental nonlinear one with automatic reduction of low-frquency gain at high input levels (or base increase at low levels, BILL). Both the patient and the audiologist performing the outcome testing at each site (Audiologist B) were blind as to the present setting of the hearing aid. Each participant was enrolled in the study for a total of 12 weeks, with the hearing aid set to either the linear or BILL-processing mode of operation for the first 8 weeks and the opposite setting for a subsequent 4-week period. In summary, this was a prospective, doubleblind, crossover study of 110 new hearing aid users. Outcome measures focused on hearing-aid benefit and included both objective and subjective measures. Objective measures were derived from scores on the Northwestern University Auditory Test NO. 6 (NU-6) and the Connected Speech Test (CST) obtained for all possible combinations of two speech presentation levels (60 and 75 dB SPL) two types of background noise (cafeteria noise and multitalker babble), and two signal-to-noise ratios (+5 and +10 dB). Subjective outcome measures included magnitude estimation of listening effort (MELE), the abbreviated form of the Hearing Aid Performance Inventory (HAPI), and estimations of hearing-aid usage based on daily-use logs kept by the participants. All of these measures were used to evaluate the benefit provided by linear amplification and the benefit resulting from the experimental BILL processing. Participant preferences for the experimental BILL-processing scheme or linear processing were also examined by using a paired-comparison task at the end of the study. Results were analyzed separately for three subgroups of patients (mild, moderate, severe) formed on the basis of their average hearing loss at 500, 1000, 2000, and 4000 Hz. In all three subgroups, significant improvement in performance was observed for linear amplification and for BILL processing when compared to unaided performance. There were no significant differences in aided performance, however, between linear processing and the experimental BILL processing.

A gene for autosomal dominant nonsyndromic hereditary hearing impairment maps to 4p16.3.

Mapping genes for nonsyndromic hereditary hearing impairment may lead to identification of genes that are essential for the development and preservation of hearing. We studied a family with autosomal dominant, progressive, low frequency sensorineural hearing loss. Linkage analysis employing microsatellite polymorphic markers revealed a fully linked marker (D4S126) at 4p16.3, a gene-rich region containing IT15, the gene for Huntington's disease (HD). For D4S126, the logarithm-of-odds (lod) score was 3.64 at theta = 0, and the overall maximum lod score was 5.05 at theta = 0.05 for D4S412. Analysis of recombinant individuals maps the disease gene to a 1.7 million base pair (Mb) region between D4S412 and D4S432. Genes for two types of mutant mice with abnormal cochleovestibular function, tilted (tlt) and Bronx waltzer (bv), have been mapped to the syntenic region of human 4p16.3 on mouse chromosome 5. Further studies with the goals of cloning a gene for autosomal nonsyndromic hearing impairment and identifying the murine homologue may explain the role of this gene in the development and function of the cochlea.

Achieving prescribed gain/frequency responses with advances in hearing aid technology.

Technological limitations have restricted the capability of older generation in-the-ear (ITE) hearing aids to closely match prescribed real ear gain/frequency responses. Newer technology, widely available in currently marketed ITE hearing aids, has considerably improved this capability. Data for 60 ears are presented comparing the real ear insertion gain (REIG) actually achieved to the target REIG, using ITE hearing aids having: 1) older generation narrow-band receivers, and amplifiers with single-pole-filter low frequency tone control and a class A amplifier output stage (n = 30), and 2) newer generation amplifiers with a two- or four-pole-filter low frequency tone control, and wide band receivers, containing a class D amplifier output stage (n = 30). With the newer technology ITE hearing aids, the means and ranges of deviation from target gain were reduced. Capability for achieving prescription REIG with ITE hearing aids can be further improved with multichannel amplifiers. Examples of the latter are shown for several difficult-to-fit audiograms.

Ability to achieve gain/frequency response and SSPL-90 under three prescription formulas with in-the-ear hearing aids.

Custom in-the-ear (ITE) hearing aids (standard linear amplifiers with single-pole-filter low-frequency tone control and a class A amplifier output stage) were fit to 90 ears using the revised National Acoustics Laboratories' formula (NAL-R), and to 20 ears each using Prescription of Gain/Output II (POGO II) and Memphis State University (MSU) formulas. Both real-ear insertion gain and 2-cc coupler gain were evaluated. Examination of differences between prescribed gain and that actually achieved in the fittings revealed that too much gain was often given in the low- and mid-frequency range and insufficient gain in the high frequencies. There was little difference among the formulas in the degree of deviation from target. For some fittings, the deviation resulted in poorer predicted speech recognition scores (modified Speech Transmission Index). For the POGO II and MSU methods, underfitting of prescribed SSPL-90 values was far more common than overfitting.

Identification and management of children with minimal hearing loss.

Throughout the last two decades, we have witnessed a gradual change in the audiological profile of the hearing-impaired child. The number of children with severe to profound hearing losses seems to be declining, while those with minimal losses seems to be increasing. Such losses include unilateral sensorineural, mild bilateral sensorineural, and bilateral conductive hearing loss. Historically, children with minimal hearing loss have received limited attention from physicians, audiologists, or educators. It has been assumed that minimally hearing-impaired children will exhibit few, if any, handicaps and require no special assistance in the academic setting. Recent evidence challenges that assumption, however, and suggests that, in fact, children with minimal hearing loss can demonstrate significant academic and communicative difficulties. It is recommended that children with minimal hearing impairment be considered at high risk for communication and educational difficulties and that assessments be made early in order to identify problems and implement management programs.

Deriving criteria for hearing impairment in the elderly: a functional approach.

We describe a method for deriving criteria for hearing impairment in the elderly based on self-reported handicap. Using the Sickness Impact Profile (SIP) and Hearing Handicap Inventory for the Elderly - Screening (HHIE-S) version as functional measures of handicap, the analysis proceeded in five steps: 1. Audiometric thresholds at various frequencies were inter-correlated. This was done both within and between ears. 2. Better and poorer ear thresholds were determined for each frequency, and these were correlated with the HHIE-S and SIP scores. 3. Using the HHIE-S and SIP scores as dependent variables, stepwise multiple linear regressions were used to select the frequencies that explained the most variance in the functional scales. 4. Using the HHIE-S and SIP as standards, receiver operating curves were constructed for each frequency to select the threshold level that provided the best test accuracy. 5. The newly-derived criteria were then compared against four other "traditional" criteria of hearing impairment. In general, the newly-derived criteria combined a relatively low frequency with a relatively high frequency, with the low frequency being functionally more important. Depending on the functional scale used, the threshold level was in the 25 to 35-dB range for the lower frequencies and 40 to 45-dB for the higher frequencies. These features provide a suitable compromise to the current debate over which threshold levels comprise the best discrimination of aged persons who are hearing-impaired. Future research should focus on developing consensus standards for functional hearing impairment and handicap in the elderly.

Comparing criteria of hearing impairment in the elderly: a functional approach.

We determined and compared the associations of four commonly used audiometric criteria of hearing impairment with two functional outcome measures in 152 aged persons screened in primary care medicine practices. The outcome measures were the Sickness Impact Profile (SIP, a measure of global function), and the Hearing Handicap Inventory for the Elderly-Screening Version (HHIE-S, a communication-specific measure of functional impairment). There were five main findings. (1) The four criteria of hearing loss were not independent. (2) The criterion of loss chosen depends on the functional measure of impairment. (3) Functional hearing impairment may also be classified by the number of criteria met. (4) A large subset (21%) of aged persons met one criterion but had little in the way of communicative or global dysfunction. (5) Hearing handicap as measured by the HHIE-S was directly associated with global dysfunction as measured by the SIP.

Hearing impairment as a determinant of function in the elderly.

This clinical, practice-based study explores the research question: Is there a relationship between hearing loss and functional disturbance in elderly patients? We analyzed the impact of hearing impairment on 153 patients over 65 years of age screened in primary care practice. Functional and psychosocial impairment were measured using the Sickness Impact Profile (SIP), a standardized measure for assessing sickness related dysfunction. Hearing level was determined with pure tone audiometry. Multiple linear regression was used to adjust for patient case-mix differences and other clinical variables. After adjustment, a 10 dB increase in hearing loss was found to result in a 2.8 point increase in Physical SIP scores (95% confidence interval = 1.8-3.8), a 2.0 point increase in psychosocial SIP scores (95% confidence interval = 0.8-3.2) and a 1.3 point increase in overall SIP scores (95% confidence interval = 0.1-2.5). Poor hearing was associated with higher SIP scores and increased dysfunction. Thus, hearing impairment is an important determinant of function in the elderly.

Impact of recurrent otitis media on middle ear function, hearing, and language.

Whether recurrent otitis media in infants and young children is followed by delayed language development was addressed by following 210 normal subjects longitudinally through the first 2 years of life with pneumatic otoscopy and tympanometry performed at every physician encounter. Otitis accounted for 26% of the medical visits. One hundred fifty-six of these children had speech and hearing evaluation at 2 years of age. Thirty percent of the children with recurrent otitis media had a mild or moderate hearing loss. However, after multiple speech and language tests, we could not identify a delay in language acquisition in the otitis-prone children. At 3 to 4 years old, 36 children, including nine with a hearing loss at 2 years of age, were retested; all nine had normal hearing. Recurrent otitis media induced a temporary decrease in hearing sensitivity demonstrable at 2 years of age, which appeared to resolve as the children matured and which was not associated with delay in language acquisition.

Diagnostic performance of the hearing handicap inventory for the elderly (screening version) against differing definitions of hearing loss.

The diagnostic performance of the Hearing Handicap Inventory for the Elderly--Screening Version (HHIE-S) was evaluated against five definitions of hearing loss in 178 elderly subjects screened in primary care. Hearing loss was assessed by pure-tone audiometry. Using a score of greater than 8 as a cut point, the HHIE-S had sensitivities ranging from 53 to 72% and specificities ranging from 70 to 84% with the different definitions. The HHIE-S receiver-operating characteristics and likelihood ratios were similar regardless of hearing loss definition used. The HHIE-S is a valid, robust test for identifying hearing-impaired elderly, irrespective of the audiometric definition used to finally diagnose hearing difficulties.

Validation of screening tools for identifying hearing-impaired elderly in primary care.

Two instruments for the detection of hearing impairment, the Welch-Allyn audioscope (Welch-Allyn Inc, Skaneateles Falls, NY) and the Hearing Handicap Inventory for the Elderly--Screening Version (HHIE-S), were validated against pure tone audiometry in 178 patients over 65 years old screened in primary care practice. The prevalence of hearing impairment in this sample was 30%. The audioscope yielded reproducible results in the physicians' offices and a hearing center. The sensitivity of the audioscope was 94% in both locations, while its specificity was 90% in the hearing center and 72% in the physicians' offices. The HHIE-S yielded reproducible results between the two test locations. An HHIE-S score from 0 to 8 resulted in a likelihood ratio of 0.36 (95% confidence interval, 0.19 to 0.68), and a score of 26 or more yielded a likelihood ratio of 12.00 (95% confidence interval, 2.62 to 55.00) for predicting the presence of hearing impairment. Used together, the two instruments had a test accuracy of 83%. The audioscope and HHIE-S are valid, reliable, inexpensive tools for detecting hearing impairment in the elderly.

Performance and management of children with unilateral sensorineural hearing loss.

This paper reviews the status of children with unilateral sensorineural hearing loss. There is mounting evidence to show that some unilaterally hearing-impaired children experience difficulty in school. Furthermore, these children may have trouble understanding speech in noise, exhibit poor localization skills, and display behavior problems in school and at home. Suggested management strategies for this population are discussed.