An evaluation of frequency transposition for hearing-impaired school-age children

Abstract

A key objective when fi tting hearing aids to children is to maximize the audibility of high frequency speech cues which are critical in the understanding of spoken English. Recent advances in digital signal processing have enabled the development of hearing aids which offer linear frequency transposition as a new way of accessing these important speech sounds. This study examined the changes in aided performance observed in children with hearing impairment who trialed the alternative hearing aid technology. The rationale behind the research was to evaluate the benefi ts of this new technology, as applied in the commercially available Widex Inteo hearing aid, for a group of children with sloping high frequency sensori-neural hearing loss (n = 6). The participants were aged between 9 and 14 years and all attended mainstream schools. Outcome measures were comprised of tests of speech perception and speech production and questionnaires. Speech perception abilities were measured using CNC word and phoneme tests, with and without frequency transposition in both the audiovisual and visual alone modalities at 6 weekly intervals for 24 weeks. The Goldman-Fristoe 2 Test of Articulation was the chosen measure of speech production and was administered prior to the new aid fi tting and after 24 weeks of frequency transposition use. Results showed statistically signifi cant improvements for the group as a whole on both these measures. These results were supported by positive reporting on the questionnaires completed by key stakeholders.

An Evidence-Based Systematic Review of Frequency Lowering in Hearing Aids for School-Age Children With Hearing Loss

“…Additionally, scores after 6 and 3 weeks of training with the FT settings were significantly better than scores with FT at baseline for consonant and vowel recognition at 30 dB HL (see Table 3). Smith et al (2009) found statistically significant differences ( p ≤ .01) on tests of word and phoneme perception for participants using frequency lowering after 12 weeks over previous scores with CP HAs.…”

“…Two sets of researchers (Auriemmo et al, 2009; Smith, Dann, & Brown, 2009) studied the use of FT, two (Glista et al, 2009; Wolfe et al, 2010, 2011) investigated NLFC, and one (Miller-Hansen, Nelson, Widen, & Simon, 2003) used FC with DCB. As a result of the heterogeneity (e.g., differences in specific outcome measures used, differences in severity of hearing loss, differences in compression thresholds and stimulus input levels) and small number of included studies for each clinical question, effect sizes were not averaged across studies.…”

“…Two studies (Auriemmo et al, 2009; Smith et al, 2009) investigated the effect of FT as found in the Widex Inteo 9 and 19 HAs compared to CP in the same or a previously worn device. Both studies were repeated measures design studies with quality appraisal scores of 2/7 (see Table 1).…”

“…In Auriemmo et al (2009), speech recognition, speech production, and self-report outcome measures were collected for the study HAs in CP and FT settings at baseline and /or after 3- or 6-week acclimatization and training periods. In the study by Smith and colleagues (2009), speech recognition and speech production outcome measures were obtained after 12 and 24 weeks, respectively, for the study aids in FT mode as compared to the children’s previous performance with their own CP HAs.…”

“…Both Auriemmo et al (2009) and Smith et al (2009) investigated differences in speech production outcomes after use of FT. Smith et al noted significant differences ( p = .01) in the children’s scores on the Goldman-Fristoe Test of Articulation—Second Edition (Goldman & Fristoe, 2000) after 24 weeks of HAs with FT as compared to their previous scores without FT. Children in the Auriemmo et al study also demonstrated significantly better ( p < .05) production of /s/ and /z/ in reading and conversation after 6 weeks of auditory training with FT as compared to their previous productions after 3 weeks of training without FT.…”