Research Centre
Research Excellence
Research Excellence



Improving Outcomes for Patients Who Wear Bone Conduction Hearing Aids Through Prescription and Verification

Dr. Bill Hodgetts, Principal Investigator

Bone conduction hearing devices are used for individuals with chronic middle ear problems or for individuals who do not have a normal ear canal. Instead of sending signals to the ear through the eardrum, bone conduction devices vibrate the entire head. To date more than 100,000 patients have been treated with this type of technology worldwide. 

When I joined iRSM and entered the field of bone conduction, there was no valid method of measuring the output of a device on an individual basis.  This led to two primary knowledge-to-action gaps in the field of bone conduction devices (BCDs). First, clinicians did not have sufficient tools or knowledge on how to verify the output of BCDs (verification). Second, clinicians were forced to rely on manufacturers’ settings rather than independently validated prescriptive approaches and procedures for fitting the BCDs (prescription). For a hearing aid fitting to be successful, there should be a “good match” between all of the known auditory needs of the individual seeking hearing help and the acoustical/mechanical characteristics of the device. 

Our desired sensation level (DSL) prescription and verification approach was developed to close these knowledge-to-action gaps.  It allows clinicians to apply the type of fitting rules that govern best (and oftentimes mandated) practice in the field of Audiology that we prescribe and verify the output of the hearing aid on an individual basis. DSL provides guiding targets, frequency response recommendations and compression characteristics that aim to maximize speech understanding with a BCD. 

Our prescriptive method has already been transferred to several manufacturers of bone conduction devices who have included it in their software so that any clinician fitting a bone conduction device has the option of using our prescription. Additionally, the targets have been transferred to a hearing aid analyzer company that provides verification tools for the audiologist. This means that a clinician in a bone conduction centre anywhere, now has the option of prescribing an individual's output according to our prescriptive rationale and also has available to them a valid approach to compare prescribed vs. measured targets on an individual basis with a hearing aid analyzer and a skull simulator. All of this culminates in benefits for the patients as hearing aid fittings become more successful given the “good match” between all of the known auditory needs of the individual seeking hearing help and the mechanical characteristics of the device.