Severe-Profound Hearing Losses

A severe or profound hearing loss is typically characterized by a very narrow dynamic range, reduced spectral resolution, altered masking properties, special need for lip-reading support etc. These aspects contribute to particular problems in speech perception which must be considered in hearing-aid fitting, and there is also an extended need for connectivity to assistive devices. In many countries, including Sweden, there are currently no guidelines specifying how hearing aids should be programmed and fitted for patients with severe or profound hearing losses. These aspects have been addressed in a series of studies at ORCA Europe.
Severe profound hearing loss: Sound quality and loudness

Aim

The main aim of this study was to investigate how participants with Severe to Profound hearing losses rated sound quality and loudness using recordings of speech and music processed through hearing aids from four different manufacturers. Additional aims were to compare these ratings with ratings made by participants with Mild to Moderate hearing loss and with Normal Hearing. Also, to compare the results with applicable predictive methods for measuring sound quality and distortion.

Main Outcomes

31 persons participated in the listening tests. They were divided into three groups; Severe to Profound (N=11), Mild to Moderate (N=11), and Normal Hearing (N=9). Ratings were made using the assessment tool SenseLab Online (DELTA-report, 2013). The study confirmed that it is important to rely on persons with relevant hearing loss in sound quality assessment. But for overall sound quality, normal hearing listeners may provide indicative judgments that are valid also for hearing impaired listeners, at least regarding rank orders between the hearing aids. Also, informative differences between ratings from the different listener groups appeared when the results were analyzed from specific sound attributes and sound stimuli. This was most prominent for judgements of Distortion and Clarity of speech. Relations between subjectively rated and predicted sound quality were ambiguous. For subjectively rated sound quality in speech there was a rather high correlation with predicted sound quality measurement (PESQ) for all groups. The predictive audio quality measure (PEAQ) and the signal-to-distortion ratio (SDR) measure showed no correlation with subjectively rated sound quality.

Publications and Presentations

Audionomdagarna (National Swedish conference for Audiologists), Stockholm (Sweden), 2014.

Severe Profound Fitting Range 

Aim

The aim of the project was to conduct a literature search on to explore existing hearing aid fitting guidelines for people with severe to profound hearing loss. The aim was also to investigate the features and default settings that are provided by manufactures. The aim was also to find answers to if these settings differ compared to default settings for a milder loss, and what amplification is provided when performing box measurements on a selection of devices fitted for severe and profound hearing losses.

Main Outcomes

The literature search showed that there was no specific prescription method used for this group of users. Box measurements showed that there were large differences in provided gain and output between different devices fitted for the same audiogram. All devices had noise reduction of some kind as well as feedback cancellation enabled. Most devices had directionality as default setting.

Hearing-aid fittings for patients with severe or profound hearing loss - Audiologists’ experiences

Aim

In many countries including Sweden, there are currently no guidelines specifying how hearing aids should be programmed and fitted for patients with severe or profound hearing losses. The aim of this study was to evaluate audiologists’ experiences of hearing aid fittings for patients with severe or profound hearing losses by interview, in order to highlight important aspects of the hearing aid fittings from the audiologists’ perspective.

Main Outcomes

Seven categories (“prescription”, “features”, “hearing aid choice”, “technical aspects of hearing aid change”, “pedagogical aspects of hearing aid change”, “hearing aid limitations” and “the patient group’s extensive needs”) with 21 sub-categories were identified in the interviews. The audiologists’ experienced that many specific considerations were needed in the hearing aid fittings for patients with a severe or profound hearing loss, both regarding technical and pedagogical parts of the work. Clearer guidelines for hearing aid settings and fittings are needed to facilitate the audiologists’ work with the patient group.

Publications and Presentations

Audionomdagarna (National Swedish conference for Audiologists), Luleå (Sweden), 2013.

Andersson, K. (2013). Hörapparatutprovningar för patienter med grav hörselnedsättning. Audionomers erfarenheter. (MSc), Karolinska Institutet Stockholm.  

ORCA EUROPE

Maria Bangata 4
SE-118 63 STOCKHOLM
SWEDEN

Tel: +46 8 455 67 60

E-mail: orca@orca-eu.info

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