Reference equivalent threshold sound pressure levels for the Wireless Automated Hearing Test System.

This paper presents reference equivalent threshold sound pressure levels (RETSPLs) for the Wireless Automated Hearing Test System (WAHTS), a recently commercialized device developed for use as a boothless audiometer. Two initial studies were conducted following the ISO 389-9 standard [ISO 389-9 (2009). "Acoustics-Reference zero for the calibration of audiometric equipment. Part 9: Preferred test conditions for the determinations of reference hearing threshold levels" (International Organization for Standardization, Geneva)]. Although the standard recruitment criteria are intended to yield otologically normal test subjects, the recruited populations appeared to have slightly elevated thresholds [5-10 dB hearing level (HL)]. Comparison of WAHTS thresholds to other clinical audiometric equipment revealed bias errors that were consistent with the elevated thresholds of the RETSPL populations. As the objective of RETSPLs is to ensure consistent thresholds regardless of the equipment, this paper presents the RETSPLs initially obtained following ISO 389-9:2009 and suggested correction to account for the elevated HLs of the originally recruited populations. Two additional independent studies demonstrate the validity of these corrected thresholds.

Clinical Effectiveness of an At-Home Auditory Training Program: A Randomized Controlled Trial.

OBJECTIVES: To investigate the effectiveness of an at-home frequent-word auditory training procedure for use with older adults with impaired hearing wearing their own hearing aids. DESIGN: Prospective, double-blind placebo-controlled randomized trial with three parallel branches: an intervention group who received the at-home auditory training; an active control group who listened to audiobooks using a similar platform at home (placebo intervention); and a passive control group who wore hearing aids and returned for outcomes, but received no intervention. Outcome measures were obtained after a 5-week period. A mixed research design was used with a between-subjects factor of group and a repeated-measures factor of time (pre- and post-treatment) to evaluate the effects of the at-home auditory training program. The intervention was completed in participants' own homes. Baseline and outcomes measures were assessed at a university research laboratory. The participants were adults, aged 54 to 80 years, with the mild-to-moderate hearing loss. Of the 51 identified eligible participants, 45 enrolled as a volunteer sample and 43 of these completed the study. Frequent-word auditory training regimen completed intervention at home over a period of 5 weeks. The active control group listened to audiobooks (placebo intervention) and the passive control group completed no intervention. The primary outcome measure is a Connected Speech test benefit. The secondary outcome measure is a 66-item self-report profile of hearing aid performance. RESULTS: Participants who received the at-home training intervention demonstrated significant improvements on aided recognition for trained materials, but no generalization of these benefits to nontrained materials was seen. This was despite reasonably good compliance with the at-home training regimen and careful verification of hearing aid function throughout the trial. Based on follow-up post-trial evaluation, the benefits observed for trained materials in the intervention group were sustained for a period of at least 8.5 months. No improvement was seen for supplemental outcome measures of hearing aid satisfaction, hearing handicap, or tolerance of background noise while listening to speech. CONCLUSIONS: The at-home auditory training procedure utilizing frequently occurring words was effective for the trained materials used in the procedure. No generalization was seen to nontrained materials or to perceived benefit from hearing aids.

The Effects of Service-Delivery Model and Purchase Price on Hearing-Aid Outcomes in Older Adults: A Randomized Double-Blind Placebo-Controlled Clinical Trial.

OBJECTIVES: The objectives of this study were to determine efficacy of hearing aids in older adults using audiology best practices, to evaluate the efficacy of an alternative over-the-counter (OTC) intervention, and to examine the influence of purchase price on outcomes for both service-delivery models. DESIGN: The design of this study was a single-site, prospective, double-blind placebo-controlled randomized trial with three parallel branches: (a) audiology best practices (AB), (b) consumer decides OTC model (CD), and (c) placebo devices (P). Outcome measures were obtained after a typical 6-week trial period with follow-up 4-week AB-based trial for those initially assigned to CD and P groups. SETTING: Older adults from the general community were recruited via newspaper and community flyers to participate at a university research clinic. PARTICIPANTS: Participants were adults, ages 55-79 years, with mild-to-moderate hearing loss. There were 188 eligible participants: 163 enrolled as a volunteer sample, and 154 completed the intervention. INTERVENTION(S): All participants received the same high-end digital mini-behind-the-ear hearing aids fitted bilaterally. AB and P groups received best-practice services from audiologists; differing mainly in use of appropriate (AB) or placebo (P) hearing aid settings. CD participants self-selected their own pre-programmed hearing aids via an OTC model. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome measure was a 66-item self-report, Profile of Hearing Aid Benefit (Cox & Gilmore, 1990). Secondary outcome measure was the Connected Speech Test (Cox, Alexander, & Gilmore, 1987) benefit. Additional measures of hearing-aid benefit, satisfaction, and usage were also obtained. RESULTS: Per-protocol analyses were performed. AB service-delivery model was found to be efficacious for most of the outcome measures, with moderate or large effect sizes (Cohen's d). CD service-delivery model was efficacious, with similar effect sizes. However, CD group had a significantly (p < .05) lower satisfaction and percentage (CD: 55%; AB: 81%; P: 36%) likely to purchase hearing aids after the trial. CONCLUSIONS: Hearing aids are efficacious in older adults for both AB and CD service-delivery models. CD model of OTC service delivery yielded only slightly poorer outcomes than the AB model. Efficacious OTC models may increase accessibility and affordability of hearing aids for millions of older adults. Purchase price had no effect on outcomes, but a high percentage of those who rejected hearing aids paid the typical price (85%). TRIAL REGISTRATION: Clinicaltrials.gov: NCT01788432; https://clinicaltrials.gov/ct2/show/NCT01788423.

The effects of dosage and duration of auditory training for older adults with hearing impairment.

This study explored a range of training dosages and durations for a word-based auditory-training procedure for older adults with hearing impairment. Three groups received a different "dose": 2x/week; 3x/week; no training. Fifteen training sessions comprised a "cycle" which was repeated three times for each dosage. Groups that completed training performed significantly better than controls for speech-in-noise materials included in the training regimen, with no significant difference observed between the 2x or 3x/week training groups. Based on these results, as well as prior literature on learning theory, training 2x or 3x/week for 5-15 weeks appears to be sufficient to yield training benefits with this training regimen.