An Examination of Sources of Variability Across the Consonant-Nucleus-Consonant Test in Cochlear Implant Listeners

The 10 consonant-nucleus-consonant (CNC) word lists are considered the gold standard in the testing of cochlear implant (CI) users. However, variance in scores across lists could degrade the sensitivity and reliability of them to identify deficits in speech perception. This study examined the relationship between variability in performance among lists and the lexical characteristics of the words. Data are from 28 adult CI users. Each subject was tested on all 10 CNC word lists. Data were analyzed in terms of lexical characteristics, lexical frequency, neighborhood density, bi-, and tri-phonemic probabilities. To determine whether individual performance variability across lists can be reduced, the standard set of 10 phonetically balanced 50-word lists was redistributed into a new set of lists using two sampling strategies: (a) balancing with respect to word lexical frequency or (b) selecting words with equal probability. The mean performance on the CNC lists varied from 53.1% to 62.4% correct. The average ...