An Examination of Standardized Measures of Vocabulary in Children with Hearing Loss

The purpose of this study was to explore the effects of word type, phonotactic probability, word frequency, and neighborhood density on the vocabularies of children with mild-to-moderate hearing loss compared to children with normal hearing. This was done by assigning values for these parameters to each test item on the Peabody Picture Vocabulary Test (Version III, Form B) to quantify and characterize the performance of children with hearing loss relative to that of children with normal hearing. It was expected that PPVT IIIB scores would: 1) Decrease as the degree of hearing loss increased. 2) Increase as a function of age 3) Be more positively related to nouns than to verbs or attributes. 4) Be negatively related to phonotactic probability. 5) Be negatively related to word frequency 6) Be negatively related to neighborhood density. All but one of the expected outcomes was observed. PPVT IIIB performance decreased as hearing loss increased, and increased with age. Performance for nouns, verbs, and attributes increased with PPVT IIIB performance, whereas neighborhood density decreased. Phonotactic probability was expected to decrease as PPVT IIIB performance increased, but instead it increased due to the confounding effects of word length and the order of words on the test. Age and hearing level were rejected by the multiple regression analyses as contributors to PPVT IIIB performance for the children with hearing loss. Overall, the results indicate that there is a 2-year difference in vocabulary age between children with normal hearing and children with hearing loss, and that this may be due to factors external to the child (such as word frequency and phonotactic probability) rather than the child's age and hearing level. This suggests that children with hearing loss need continued clinical services (amplification) as well as additional support services in school throughout childhood.