Investigation of Hearing Aid Provision via the First-fit Efficacy of Three Adaptive Dynamic Range Optimisation (ADRO®) Fitting Methods

Abstract

Objectives: To examine first-fit outcomes of ADRO fitting methods, representing gradients of audiologist and user involvement, to investigate hearing aid provision models. Introduction: Hearing aids are usually fit using compression-based prescriptive procedures dependent on audiologist programming the aids via computers. With global hearing aids meeting less than 10% of need (WHO, 2011) and hearing aid consumers searching for cost-efficient options (Kochkin, 2000, 2002a, 2007), alternative amplification approaches and hearing aid provision models are needed. Adaptive Dynamic Range Optimisation (ADRO®) is an alternative level dependent amplification strategy (Blamey, 2005a, 2006; Martin, Blamey, James, Galvin, & Macfarlane, 2001). With appropriate software, ADRO can be programmed and fine-tuned by hearing professionals or by users themselves. Methods: Twenty computer literate adults, with sensorineural hearing losses, participated in a cross-sectional, laboratory trial of three ADRO fitting methods; ADROpredict (audiogram predicted), participants’ fittings (ADROpredict plus in situ loudness measures) and researcher’s fittings (ADROpredict plus in situ loudness measures and fine-tuning). The trial consisted of first-fit programming and blinded measurement of fitting outcomes using the QuickSINTM (speech intelligibility in noise), Speech Intelligibility Index (SII) via real-ear measures (speech audibility in quiet), sound quality assessments and the Acceptable Noise Level (ANL) test (background noise tolerance). Results: Repeated measures ANOVAs revealed no statistically significant differences between fitting methods in QuickSINTM scores, SII scores, sound quality measures and ANLs. However, data suggested an advantage for the Researcher’s fitting in speech intelligibility in noise and a Participant’s fitting advantage for speech audibility in quiet and sound quality. All three fittings significantly improved unaided speech intelligibility and audibility. Listening safety and comfort issues were identified in one Participant’s and one ADROpredict fitting, respectively. Conclusions: First-fitting of ADRO hearing aids significant aided benefits, irrespective of the fitting method and audiologist or user involvement. Additionally, computer literate users are able to successfully program ADRO hearing aids independently. ADRO hearing aids may have roles in remote rural and developing regions to address hearing services shortages as ADROpredict fittings give comparable first-fit outcomes without need for computer access and/or professional assistance. Further research is required to ascertain if findings are repeatable, hold for long-term outcomes examining the entire fitting process (including alternative ADRO and non-ADRO fitting methods), and are applicable to other hearing impaired populations.