The Desired Sensation Level (DSL) Method was revised to support hearing instrument fitting for infants, young children, and adults who use modern hearing instrument technologies, including multichannel compression, expansion, and multimemory capability. The aims of this revision are to maintain aspects of the previous versions of the DSL Method that have been supported by research, while extending the method to account for adult-child differences in preference and listening requirements. The goals of this version (5.0) include avoiding loudness discomfort, selecting a frequency response that meets audibility requirements, choosing compression characteristics that appropriately match technology to the user's needs, and accommodating the overall prescription to meet individual needs for use in various listening environments. This review summarizes the status of research on the use of the DSL Method with pediatric and adult populations and presents a series of revisions that have been made during the generation of DSL v5.0. This article concludes with case examples that illustrate key differences between the DSL v4.1 and DSL v5.0 prescriptions. et al., 1995).Since that revision, DSL[i/o] has been evaluated in both adult and pediatric populations in a number of studies. In this chapter, we will summarize the current status of DSL evaluation work in children and adults and argue the need for different prescriptive targets for adults and children. We will also present research describing electroacoustic and signal processing issues that have motivated us to make modifications to the input/output structure of the DSL target functions. These modifications will be described, and several case studies will illustrate the magnitude and type of changes to prescriptive targets in DSL v5.0. Outcomes for ChildrenStudies using the DSL Method with the pediatric population have been done with various aims and purposes. Some studies have sought to determine whether DSL-related outcomes differ from those of alternative fittings (Snik and Stollman, 1995;Ching et al., 1997;Scollie et al. 2000) or to compare subversions of DSL such as linear vs nonlinear (Jenstad et al., 1999;Jenstad et al., 2000). Other studies have used DSL as the fitting method within general pediatric hearing and amplification research, such as when evaluating signal processing options or audibility effects in children with hearing loss (Moeller et al., 1996;Bamford et al., 1999;Christensen, 1999;Gravel et al., 1999;Hanin, 1999;Lear et al., 1999;Pittman and Stelmachowicz, 2000;Stelmachowicz et al., 2000;Stelmachowicz et al., 2001;Condie et al., 2002;Stelmachowicz et al., 2002). Other authors incorporate the DSL Method, including the associated clinical procedures described by Bagatto et al., 2005, within recommended clinical guidelines for pediatric amplification (e.g., The Pediatric Working Group 1996; American Academy of Audiology, 2004). Ongoing research will, therefore, likely always strive to determine the best methods for prescribing the signal processing ch...

This study evaluated prototype multichannel nonlinear frequency compression (NFC) signal processing on listeners with high-frequency hearing loss. This signal processor applies NFC above a cut-off frequency. The participants were hearing-impaired adults (13) and children (11) with sloping, high-frequency hearing loss. Multiple outcome measures were repeated using a modified withdrawal design. These included speech sound detection, speech recognition, and self-reported preference measures. Group level results provide evidence of significant improvement of consonant and plural recognition when NFC was enabled. Vowel recognition did not change significantly. Analysis of individual results allowed for exploration of individual factors contributing to benefit received from NFC processing. Findings suggest that NFC processing can improve high frequency speech detection and speech recognition ability for adult and child listeners. Variability in individual outcomes related to factors such as degree and configuration of hearing loss, age of participant, and type of outcome measure.

A discussion of the protocols used particularly in the clinical application of the Desired Sensation Level (DSL) Method is presented in this chapter. In the first section, the measurement and application of acoustic transforms is described in terms of their importance in the assessment phase of the amplification fitting process. Specifically, the implications of individual ear canal acoustics and their impact on accurately defining hearing thresholds are discussed. Detailed information about the statistical strength of the real-ear-to-coupler difference (RECD) measurement and how to obtain the measure in young infants is also provided. In addition, the findings of a study that examined the relationship between behavioral and electrophysiologic thresholds in real-ear SPL is described. The second section presents information related to the electroacoustic verification of hearing instruments. The RECD is discussed in relation to its application in simulated measurements of real-ear hearing instrument performance. In particular, the effects of the transducer and coupling method during the RECD measurement are described in terms of their impact on verification measures. The topics of insertion gain, test signals, and venting are also considered. The third section presents three summary tables that outline the hearing instrument fitting process for infants, children, and adults. Overall, this chapter provides both clinical and scientific information about procedures used in the assessment and verification stages of the DSL Method.

There is a growing trend for hearing aids to incorporate wide dynamic range compression. The input/output (I/O) hearing aid formula, presented in this report, is a general frequency-specific mathematical approach which describes the relationship between the input level of a signal delivered to a hearing aid and the output level produced by the hearing aid. The I/O formula relates basic psychoacoustic parameters, including hearing threshold level and uncomfortable listening level, to the electroacoustic characteristics of hearing aids. The main design goal of the I/O formula was to fit the acoustic region corresponding to the "extended" normal auditory dynamic range into the hearing-impaired individual's residual auditory dynamic range. The I/O approach can be used to fit hearing aids utilizing linear gain, linear compression or curvilinear compression to a hearing-impaired individual's residual auditory area.

This document describes the protocol for the provision of amplification to infants and preschool children registered with the Ontario infant hearing program (OIHP) in Canada. The provision of amplification includes the prescription and dispensing of hearing instruments to infants and preschool children identified with permanent childhood hearing impairment (PCHI) in the province of Ontario. The first section deals with the structure and processes of the program, while the second section specifies the clinical procedures that are applied in providing hearing instruments to infants and young children with hearing impairment.