A study of the application of a frequency transposition hearing system in children

Abstract

The aim of this retrospective study was to investigate the use of the frequency transposition Transonic FT 40 system in a group of 36 children with profound sensorineural hearing loss. The group comprised 36 children (11 boys, 25 girls) aged between 2.8 and 15.6 years (mean 7.6 years) at fitting of the FT 40 device. At 48 months post-FT 40 fitting, only 11 children (30%) were still wearing the device. The children discontinued wearing the FT 40 for the following reasons: ergonomic (11%); no perceived benefit from the system (11%); cosmetic (17%); and subsequent cochlear implantation (30%). The performance of the long-term FT 40 users was investigated using the following outcome measures: aided soundfield hearing thresholds: closed set speech tests (the E2L toy test and the Manchester Picture Test discrimination test) and a speech intelligibility rating score. The 11 long-term FT 40 users (three boys, eight girls) were aged from 5.3 to 12.9 years (mean 7.2 years) at the time of initial fitting of the FT 40 device. At time of fitting, the aided soundfield thresholds with the FT 40 were significantly better at 500 Hz (p<0.04), 1 kHz (p<0.019), 2 kHz (p<0.001) and 4 kHz (p <0.001) compared to thresholds with conventional hearing aids. Six of 11 children did not show any change in performance on the closed set speech tests and two children had intelligible speech at 48 months' follow-up. A small subgroup of good performers was identified. These children were younger at age of fitting (mean 6.2 years compared to a mean of 7.7 years for the remainder of the group), were predominantly oral communicators and had identified aetiologies for their deafness. The present study suggests that there is a small subgroup of hearing-impaired children who benefit from frequency transposition hearing systems, and future suggested fitting criteria and outcome measures are listed.

Effect of Linear Frequency Transposition on Speech Recognition and Production of School-Age Children

“…Briefly, the majority of these studies were conducted utilizing a frequency compression hearing aid that operated by compressing the whole spectrum by a fixed ratio once a decision on ''voiced'' versus ''voiceless'' sounds was made. The results of these studies showed a lackluster effect of frequency compression (Parent et al, 1998;McDermott and Dean, 2000;McDermott and Knight, 2001;MacArdle et al, 2001). The only exception was the Miller-Hansen et al's (2003) retrospective review where the performance with frequency compression was compared to that of the subjects' own hearing aids.…”

The Importance of High-Frequency Audibility in the Speech and Language Development of Children With Hearing Loss

“…This type of approach has produced mixed results, with some studies showing substantial improvement and others showing no improvement or degradation in performance. [23][24][25][26] However, the signal-processing schemes across studies have differed substantially in concept and implementation. In addition, some studies included subjects who clearly were not candidates for this type of technology.…”

Evaluation of nonlinear frequency compression: Clinical outcomes

“…above 2.5 kHz). Early studies indicated mixed outcomes with the body-worn FT-40 on adults and children, concluding that the FT-40 system was suitable for a select group of listeners (MacArdle et al, 2001; Parent et al, 1997). AVR Sonovations later introduced the ImpaCt behind-the-ear (BTE) hearing aid.…”