The Use of Lexical Neighborhood Test (LNT) in the Assessment of Speech Recognition Performance of Cochlear Implantees with Normal and Malformed Cochlea

Abstract

The present study aims to use the model-based test Lexical Neighborhood Test (LNT), to assess speech recognition performance in early and late implanted hearing impaired children with normal and malformed cochlea. The LNT was administered to 46 children with congenital (prelingual) bilateral severe-profound sensorineural hearing loss, using Nucleus 24 cochlear implant. The children were grouped into Group 1-(early implantees with normal cochlea-EI); n = 15, 31/2–61/2 years of age; mean age at implantation—3½ years. Group 2-(late implantees with normal cochlea-LI); n = 15, 6–12 years of age; mean age at implantation—5 years. Group 3-(early implantees with malformed cochlea-EIMC); n = 9; 4.9–10.6 years of age; mean age at implantation—3.10 years. Group 4-(late implantees with malformed cochlea-LIMC); n = 7; 7–12.6 years of age; mean age at implantation—6.3 years. The following were the malformations: dysplastic cochlea, common cavity, Mondini’s, incomplete partition-1 and 2 (IP-1 and 2), enlarged IAC. The children were instructed to repeat the words on hearing them. Means of the word and phoneme scores were computed. The LNT can also be used to assess speech recognition performance of hearing impaired children with malformed cochlea. When both easy and hard lists of LNT are considered, although, late implantees (with or without normal cochlea), have achieved higher word scores than early implantees, the differences are not statistically significant. Using LNT for assessing speech recognition enables a quantitative as well as descriptive report of phonological processes used by the children.