Effects of lexical factors on word recognition among normal-hearing and hearing-impaired listeners

An investigation was conducted to examine the effects of lexical difficulty on spoken word recognition among young normal-hearing and middle-aged and older listeners with hearing loss. Two word lists, based on the lexical characteristics of word frequency and neighborhood density and frequency (Neighborhood Activation Model [NAM]), were developed: (1) lexically "easy" words with high word frequency and a low number and frequency of words phonemically similar to the target word and (2) lexically "hard" words with low word frequency and a high number and frequency of words phonemically similar to the target word. Simple and transformed up-down adaptive strategies were used to estimate performance levels at several locations on the performance-intensity functions of the words. The results verified predictions of the NAM and showed that easy words produced more favorable performance levels than hard words at an equal intelligibility. Although the slopes of the performance-intensity function for the hearing-impaired listeners were less steep than those of normal-hearing listeners, the effects of lexical difficulty on performance were similar for both groups.