A comparison of NAL and DSL prescriptive methods for paediatric hearing-aid fitting: Predicted speech intelligibility and loudness
Date
2013Author
Johnson, Earl E.
Hou, Sanna
Dillon, Harvey
Zhang, Vicky
Burns, Lauren
Van Buynder, Patricia
Wong, Angela
Flynn, Christopher
Metadata
Show full item recordAbstract
OBJECTIVE—To examine the impact of prescription on predicted speech intelligibility and
loudness for children.
DESIGN—A between-group comparison of Speech Intelligibility Index (SII) and loudness, based
on hearing aids fitted according to NAL-NL1, DSL v4.1, or DSL m[i/o] prescriptions. A withingroup
comparison of gains prescribed by DSL m[i/o] and NAL-NL2 for children in terms of SII
and loudness.
STUDY SAMPLE—Participants were 200 children , who were randomly assigned to first
hearing-aid fitting with either NAL-NL1, DSL v4.1, or DSL m[i/o]. Audiometric data and hearing
aid data at 3 years of age were used.
RESULTS—On average, SII calculated on the basis of hearing-aid gains were higher for DSL
than for NAL-NL1 at low input level, equivalent at medium input level, and higher for NAL-NL1
than DSL at high input level. Greater loudness was associated with DSL than with NAL-NL1,
across a range of input levels. Comparing NAL-NL2 and DSL m[i/o] target gains revealed higher
SII for the latter at low input level. SII was higher for NAL-NL2 than for DSL m[i/o] at mediumand
high-input levels despite greater loudness for gains prescribed by DSL m[i/o] than by NALNL2.
CONCLUSION—The choice of prescription has minimal effects on speech intelligibility
predictions but marked effects on loudness predictions.