Speech and language development in a population of Swedish hearing-impaired pre-school children, a cross-sectional study.

OBJECTIVE: There is little information on speech and language development in pre-school children with mild, moderate or severe hearing impairment. The primary aim of the study is to establish a reference material for clinical use covering various aspects of speech and language functions and to relate test values to pure tone audiograms and parents' judgement of their children's hearing and language abilities. METHODS: Nine speech and language tests were applied or modified, both classical tests and newly developed tests. Ninety-seven children with normal hearing and 156 with hearing impairment were tested. Hearing was 80 dB HL PTA or better in the best ear. Swedish was their strongest language. None had any additional diagnosed major handicaps. The children were 4-6 years of age. The material was divided into 10 categories of hearing impairment, 5 conductive and 5 sensorineural: unilateral; bilateral 0-20; 21-40; 41-60; 61-80 dB HL PTA. The tests, selected on the basis of a three component language model, are phoneme discrimination; rhyme matching; Peabody Picture Vocabulary Test (PPVT-III, word perception); Test for Reception of Grammar (TROG, grammar perception); prosodic phrase focus; rhyme construction; Word Finding Vocabulary Test (word production); Action Picture Test (grammar production); oral motor test. RESULTS: Only categories with sensorineural loss showed significant differences from normal. Word production showed the most marked delay for 21-40 dB HL: 5 and 6 years p<0.01; for 41-60 dB: 4 years p<0.01 and 6 years p<0.01 and 61-80 dB: 5 years p<0.05. Phoneme discrimination 21-40 dB HL: 6 years p<0.05; 41-60 dB: 4 years p<0.01; 61-80 dB: 4 years p<0.001, 5 years p<0.001. Rhyme matching: no significant difference as compared to normal data. Word perception: sensorineural 41-60 dB HL: 6 years p<0.05; 61-80 dB: 4 years p<0.05; 5 years p<0.01. Grammar perception: sensorineural 41-60 dB HL: 6 years p<0.05; 61-80 dB: 5 years p<0.05. Prosodic phrase focus: 41-60 dB HL: 5 years p<0.01. Rhyme construction: 41-60 dB HL: 4 years p<0.05. Grammar production: 61-80 dB HL: 5 years p<0.01. Oral motor function: no differences. The Word production test showed a 1.5-2 years delay for sensorineural impairment 41-80 dB HL through 4-6 years of age. There were no differences between hearing-impaired boys and girls. Extended data for the screening test [E. Borg, A. Risberg, B. McAllister, B.M. Undemar, G. Edquist, A.C. Reinholdsson, et al., Language development in hearing-impaired children. Establishment of a reference material for a "Language test for hearing-impaired children", Int. J. Pediatr. Otorhinolaryngol. 65 (2002) 15-26] are presented. CONCLUSIONS: Reference values for expected speech and language development are presented that cover nearly 60% of the studied population. The effect of the peripheral hearing impairment is compensated for in many children with hearing impairment up to 60 dB HL. Above that degree of impairment, language delay is more pronounced, probably due to a loss of acuity. The importance of central cognitive functions, speech reading and signing for compensation of peripheral limitations is pointed out.

Language development in hearing-impaired children. Establishment of a reference material for a 'Language test for hearing-impaired children', LATHIC.

OBJECTIVE: In Sweden, there has previously been no normalised test material for the evaluation of language development in individual hearing-impaired children, and for the assessment of various methods of auditory habilitation. The purpose of the present study was to compose, apply and evaluate a test for language development in hearing-impaired children, and to establish the first set of reference values related to age, sex, type and degree of hearing impairment. METHODS: A test consisting of nine subtests was assembled and developed for, and subsequently applied to, hearing-impaired children in the age range 4-6 years. The inclusion criteria were a pure tone average of 80 dBHL or less and oral language (Swedish) as the first language. Two hundred and eleven hearing-impaired children and 87 normal hearing control children were tested. RESULTS: The results show that: (1) children with hearing impairment-also unilateral-have a delayed language development; (2) the delay is greater in children with larger losses and tends to decrease with increasing age; (3) 6-year-olds with hearing loss greater than 60 dB have not reached the level of the control group; (4) no difference between right- or left sided deafness with respect to language development was observed; (5) a reference material, applicable during clinical assessment, was established for the most common types of hearing impairment. CONCLUSIONS: The test designed gave graded measures of important aspects of language development in hearing-impaired children. The results merit further application of the test material.

Electrophonic Hearing and Cochlear Implants.

It has been difficult to explain the good speech understanding obtained by some cochlear implant patients fitted with a single-channel electrode and analog transmissions of the speech signal (Vienna/3M implant). It has also been difficult to explain the variation in results reported by different groups using the same implant. One hypothesis asserts that the above differences can be explained by the observation that electric stimulation with an implanted electrode might result in two different auditory sensations, the first resulting from the stimulation of the remaining hair cells (electrophonic component) and the second from the electric stimulation of the auditory nerve (electro-neural component). The two sensations are very different. As a result of different definitions of total deafness (functional or threshold definition), patients with remaining hair cells are operated on by some groups, but not by other groups. Some published results from different studies are discussed with reference to the above hypothesis and the possible consequences for the selection of the patients, the use of extra-or intracochlear electrodes, and the selection of the speech coding strategy are discussed.