Functionally equivalent ages and hearing levels of children with cochlear implants measured with pre-recorded stimuli

Abstract

Three groups of children undertook an interactive computer-based closed-set test of the ability to identify pre-recorded spoken words presented acoustically. The test was completed by 31/39 children with profound hearing loss who had used the Nucleus Spectra-22 cochlear-implant system for at least one year (Group A); by 30 children with normal hearing (Group B); and by 22 children with severe-profound hearing loss who used acoustic hearing aids (Group C). Among the implanted children, those who were younger when implanted and who had used their devices for longer produced higher scores (multiple-r = 0.68). Logistic regression functions were fitted to the data from Group B to describe the relationship between performance and age, and to the data from Group C to describe the relationships between performance and average hearing level (AHL) and aided threshold. By use of the regression equations, the performance of each implanted child was converted into a functionally equivalent (FE) age, an FE AHL and an FE aided threshold. Despite high variability leading to wide confidence intervals, these transformations showed that: (1) mean FE age (3.4 years) lagged mean chronological age (7.4 years), but some implanted children performed within the range expected for children with normal hearing of the same age; (2) mean FE AHL was 94 dB compared with a mean pre-implant AHL of 117 dB; (3) mean FE aided threshold was 45 dB(A) compared with a mean pre-implant aided threshold of 99 dB(A). These results confirm that implantation of appropriate candidates leads to functionally better hearing than would be expected with acoustic hearing aids. The results also demonstrate that many implanted children can participate in interactive tests with pre-recorded speech, thus providing robust data for comparison with future performance.

Comparison of outcomes in children with hearing aids and cochlear implants

“…As early as 1994, Boothroyd and Eran (1994) proposed that children with cochlear implants functioned like children with hearing loss of 88 dB PTA who used hearing aids. Based on speech recognition results, other investigators have confirmed that many children using cochlear implants have a hearing level equivalent to those in the severe hearing loss range (Nakisa et al, 2001;Snik et al, 1997). Blamey et al (2001) concluded that children with implants and an average hearing loss of 106 dB HL performed on speech perception, production, and language measures such as children with hearing aids with an average hearing loss of 78 dB HL.…”

Hearing-Impaired Children in the United Kingdom, I: Auditory Performance, Communication Skills, Educational Achievements, Quality of Life, and Cochlear Implantation

“…Several authors have summarised the results of comparisons between implanted and non-implanted children as a functionally-equivalent hearing level (Osberger et al, 1991;Osberger, Maso, & Sam, 1993;Boothroyd & Eran, 1994;Geers & Moog, 1994;Snik et al, 1997;Meyer et al, 1998;Svirsky & Meyer, 1999;Nakisa et al, 2001;Blamey et al, 2001). This is the unaided AHL of non-implanted children who achieve the same level of outcome as a child with an implant.…”

“…; Tait & Lutman, 1997); cross-sectional with crosssectional controls (e.g. Boothroyd & Eran, 1994;Nakisa et al, 2001); prospective with cross-sectional controls (e.g. Meyer et al, 1998;Osberger et al, 1991;Snik, Vermeulen, Brokx, Beijk, & van den Broek, 1997;Svirsky & Meyer, 1999); and prospective with prospective controls (e.g.…”