Clinical Protocols for Hearing Instrument Fitting in the Desired Sensation Level Method

Abstract

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.

Genotype–phenotype correlation of two prevalent GJB2 mutations in chinese newborn infants ascertained from the Universal Newborn Hearing Screening Program

“…Compared with pure-tone audiometry, click-evoked ABR generally overestimates the degree of HI by up to 20 dB depending on many factors [Gorga et al, 1993;Bagatto et al, 2005]. We confirmed this overestimation by measuring the hearing thresholds of 58 control subjects using both click-evoked ABR and pure-tone audiometric measurements.…”

The Influence of Hearing Aid Use on Outcomes of Children With Mild Hearing Loss

“…The audiologist initially conducted probe microphone measures to quantify the real-ear to coupler difference (RECD; Bagatto et al, 2005). An age-related average RECD estimated the acoustic characteristics of the child's occluded ear canal when the RECD could not be measured due to limited cooperation or participant noise.…”

The Desired Sensation Level Multistage Input/Output Algorithm

“…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 characteristics of hearing instruments to optimize children's hearing (Scollie, 2005).…”