A comparison of three approaches to verifying aided Baha output

The objective of the present study was to compare three methods of estimating the audibility of aided speech using the Baha.

23 Adult Baha users with primarily bilateral conductive hearing loss were recruited from the Bone Conduction Amplification Program at the Institute for Reconstructive Sciences in Medicine in Edmonton, Alberta, Canada.

A test Baha was set to each subject's preferred listening level. The same Baha was used to assess the audibility of the long-term average speech spectrum (LTASS) for each of the following three approaches: 1) Aided soundfield thresholds, 2) Real Ear SPL, and 3) Real Head Acceleration Level.

Significant differences were discovered between the three approaches. Aided soundfield thresholds consistently over-estimated the sensation level of aided speech. The Real Ear SPL approach provided reasonable estimates in the mid-frequencies. However, low- and high-frequency estimates for the Real Ear approach have significant limitations.

The Real Head Acceleration Level appears to be the most accurate method of determining aided audibility with the Baha.