The Desired Sensation Level prescription

The Desired Sensation Level (DSL) Method, developed by Seewald and colleagues, became available as the first software program to assist with hearing aid fitting for young children in 1991. DSL formulae version 3.1 worked with linear hearing aids and included a prescription for hearing aid output limiting (Seewald, Ross, & Spiro, 1985; Seewald, 1991). Similar to the NAL-NL formulae, Seewald sought to prescribe a comfortable level of speech that was associated with maximum speech sound recognition performance in children (based on studies by Erber & Witt, 1977; Kamm, Dirks, & Mickey, 1977; Macrae, 1986; Pascoe, 1978; Pascoe, 1988). These early versions of DSL incorporated children’s ear canal acoustics and child-friendly verification procedures.