Confidence Limits of Word Identification Scores Derived Using Nonlinear Quantile Regression

The relation between degree of sensorineural hearing loss and maximum speech identification scores (PB(max)) is commonly used in audiological diagnosis and rehabilitation. It is important to consider the relation between the degree of hearing loss and the lower boundary of PB(max), as the PB(max) varies largely between subjects at a given degree of hearing loss. The present study determines the lower boundary by estimating the lower limit of the one-tailed 95% confidence limit (CL) for a Dantale I, word list, in a large group of young and older subjects with primarily sensorineural hearing loss. PB(max) scores were measured using Dantale I, at 30 dB above the speech reception threshold or at the most comfortable level from 1,961 subjects with a wide range of pure-tone averages. A nonlinear quantile regression approach was applied to determine the lower boundary (95% CL) of PB(max) scores. At a specific pure-tone average, if the measured PB(max) is poorer than the lower boundary (95% CL) of PB(max), it may be considered disproportionately poor.