Addendum to "transfer functions and correction factors used in hearing aid evaluation and research".

In an earlier publication, various transformations used in hearing aid research and its application were summarized. As a result of continued interest and requests, additional transfer functions are provided in this addendum.     

Pathways Linking Treatment Intensity and Psychosocial Outcomes among Adult Survivors of Childhood Leukemia

To determine the pathways between treatment intensity (age at diagnosis, dosage of chemotherapy [intrathecal methotrexate; IT-MTX] and cranial radiation [CRT]) and various psychosocial outcomes, review of medical records and structured interviews were carried out in 510 adult survivors of childhood leukemia. Structural equation modeling revealed that higher treatment intensity during childhood (indicated by treatment with high-dose CRT, low-dose IT-MTX, and adjusted by younger age at diagnosis) predicted more health- compromising behaviors as adults through lower educational achievement. Additionally, higher childhood treatment intensity predicted current negative mood both directly and via changes in perceived limitations. The present study's findings suggest that higher treatment intensity during childhood may serve as a risk factor for adult survivors' health-compromising behaviors through neuropsychological deficits that arise from cancer treatment.     

Unexplained symptoms in primary care: perspectives of doctors and patients

This study evaluated unexplained symptoms in primary care from the perspective of both patients and physicians. The data were obtained from two 1998 statewide surveys, one targeting Medicaid patients and the other all primary care physicians in the state. There were 439 patients who responded (45% response rate) and 280 primary care physicians who responded (33% response rate). Half of the patients and half of the physicians were in non-metropolitan counties. Half of the patients reported unexplained symptom usually or always, and 75% of whom sought help for these symptoms. Fifty-two percent of these patients believed their physician was very concerned about their unexplained symptoms. Eighty percent of them rated their physician as providing the best possible care compared to only 49% of patients whose physician did not care about their unexplained symptoms (P=.001). Among the physicians, only 14% reported very good or excellent satisfaction with managing unexplained symptoms as compared to 44% who claimed similar satisfaction in managing psychological problems. Physicians who saw themselves as more effective in dealing with somatoform symptoms were more likely to be in solo practice (P<.005), or in the same location for at least five years (P=.04). Residence in a nonmetropolitan county did not affect patient reporting of symptoms, patient perception of physician concern about symptoms, or physician satisfaction in managing these symptoms. These results indicate the prevalence and importance of unexplained symptoms in the Medicaid population and the comfort of physicians in managing these symptoms. There is an unmet need among primary care physicians to learn how to manage patients with unexplained symptoms.     

A developmental study of gender constancy and parent preference

Children 4–6 years of age were asked which parent they would be when they were older, whether they could be the opposite-sexed parent, and whether they liked their mothers or fathers best. For comparison, a sample of adults were asked these same questions. All but one of the 144 children said they would be the same-sexed parent. Few children said they could switch and be the opposite-sexed parent. These responses did not indicate a simple age trend. Younger children preferred the same-sexed parent, whereas older children and adults tended to prefer their mothers.This research was supported, in part, by Public Health Service grant MH 17072 to P. M. Bentler.     

Fitting hearing aids using clinical measures of loudness discomfort levels: an evidence-based review of effectiveness

Clinical measurement of the loudness discomfort level (LDL) historically has been part of the hearing aid fitting procedure, and this clinical practice remains popular today. LDL measurements also are recommended in contemporary hearing aid fitting protocols. Yet, surveys show that many hearing aid users are dissatisfied with the loudness of their hearing aids. In this evidence-based review article, we evaluate the effectiveness of clinical LDL measurements. Specifically, we asked the question "Are the clinical measurements of LDL for adult patients predictive of aided acceptance and satisfaction of loudness for high inputs in the real world?" Nearly 200 articles were reviewed; three met the criteria set forth in this review. The evidence supported using unaided LDLs for selecting the maximum real-ear output of hearing aids. No study using aided LDLs or aided loudness verification met the criteria. The level of the evidence for the three articles using unaided LDLs was low; no higher than Level 4. The limited number of studies, the level of evidence, and the statistical power of the studies prevents us from making a strong recommendation concerning the clinical use of LDL measures. Additional research in this area, especially research employing randomized controlled trials would be a useful addition to this body of literature.     

Impact of digital labeling on outcome measures

OBJECTIVE: The purpose of this study was to determine whether the label attached to the hearing aid being presented would bias outcome measures towards newer technological designs. DESIGN: Two groups of subjects participated in this investigation. The groups were matched for age, gender, previous hearing aid experience, degree and configuration of hearing loss. Group A wore each of two digital hearing aids for 1 mo; Group B wore the same digital hearing aid for 2 mo, but the subjects were given the impression they were changing hearing aids after 1 mo. In each group the subjects were told that one of the months they were wearing a "digital" hearing aid and one of the months they were wearing a "conventional" hearing aid. Outcome measures consisted of a number of behavioral speech perception tasks and self-report measures, each completed at the onset and after 1 mo use with the hearing aids. RESULTS: Labeling effects were observed for many of the outcome measures. Using a mixed-model factorial analysis of variance to control for irrelevant variables and to explore interaction terms, prejudice (digital versus conventional labeling) was treated as a within-subject factor while the subject group (A or B) and clinician were treated as between-subject factors. Although only the APHAB RV and BN scales showed significant labeling effects on their own, the group of tests used in this study showed a significant labeling effect as a whole (p < 0.01). The total influence of labeling and related interaction terms indicated labeling-related effects accounted for 2 to 32% of the variance in individual outcome measures. DISCUSSION: The results of this investigation indicate a need for double-blinding in hearing aid research aimed at assessing the effectiveness of newer technologies, as well as a need for clinicians to critically evaluate the research describing the potential advantages of certain circuit options.     

Comparison of hearing aids over the 20th century

OBJECTIVE: To measure hearing aid performance using circuitry representative of the major eras of technological advancement during the 20th century. DESIGN: Twenty subjects with audiometric profiles consistent with hearing aid candidacy were fit with each of seven hearing aids. No directional microphones were used and binaural benefit was not assessed. Each hearing aid was fit to the strategy or fitting scheme of the era, or that which was intended by the presenting manufacturer. Electroacoustic and/or real ear measures of gain, output, bandwidth, and distortion were obtained. Objective outcome measures assessing speech perception in backgrounds of noise were obtained. Subjective outcome measures of sound quality and ease of listening were obtained in the laboratory and in real life settings. RESULTS: Electroacoustic and real ear measures indicate that gain and bandwidth have increased, and output and distortion have decreased with current electronic aids. Speech perception ability across the different outcome measures showed significantly poorer performance with the body and linear hearing aids when input levels were high; when input levels were low, outcome measures with hearing aids using a dynamic range compression were not negatively affected. At the most adverse signal to noise ratios, none of the hearing aids was shown to be superior. Measured bandwidth did not correlate highly with speech perception ability for any of the objective outcome measures used. For the subjective measures of sound quality done in a blinded manner, no significant differences were found across different listening situations for current hearing aids. CONCLUSIONS: The two most important factors for aided speech perception appear to be the audibility and distortion of the signal. No current compression scheme proved superior with the outcome measures used in this investigation.