Implantable Devices for Rehabilitation of Persons with Hearing Loss

Implantable devices are an integral part of the armamentarium of hearing healthcare. In this issue, findings are examined in two categories of devices, bone-anchored cochlear stimulators and cochlear implants (CIs), that are widely recognized as the standard of care for a variety of hearing loss diagnoses. At this time, the category of middle ear implants is more diverse, and several of the devices described are in clinical trials; therefore, their application is not yet at the same routine level as that of Baha and CIs. Thus, middle ear implants are not yet—as a category—considered standard of care.

User satisfaction is one of the themes of this issue. Soha Ghossaini, Jaclyn Spitzer, and Julia Borik review the efficacy of Baha and present preliminary findings of long-term follow-up of users of the device. The authors had participants respond to questions using a 5-point rating scale, ranging from 1 (disagree strongly) to 5 (agree strongly), or answering “not applicable” to assess both hearing performance—listening in groups, listening to music, localization, listening in large venues—and the pragmatic use of the device. For many of the areas assessed, the majority of participants reported agreeing or agreeing strongly that the Baha provided satisfactory experiences in such domains as the pleasantness of their own voice and other speakers' voices, naturalness of environmental sounds, speech understanding in small groups, enjoyment of music, and the pragmatic use of the Baha device.

Craig Newman, Sharon Sandridge, and Lisa Oswald examine the relationship between patient expectations and satisfaction for Baha users with single-sided deafness (SSD). In this focused study, measures confirmed that actual satisfaction exceeded initial expectations. The authors emphasize the importance of establishing realistic expectations preoperatively and throughout the rehabilitative process.

On the horizon, emerging technologies will affect many persons with hearing loss who do not fit into either the Baha or CI categories. An expansion of targeted candidates will result from the broader application of middle ear implants, as described by Marc Bassim and José Fayad. In their review of current implantable middle ear hearing devices (IMEHDs), the authors describe the mechanical concepts and design of IMEHDs, as well as the indications and latest outcomes in their application. As the safety and efficacy of this category of implantable devices are demonstrated, many persons with hearing loss will have the option to choose a surgically implanted alternative to conventional hearing aids.

The factors influencing localization assessment for implantable devices are discussed by John Preece. Although improvement in horizontal localization is taken by some clinicians as axiomatic, Dr. Preece examines some of the factors that make this area complex and draws attention to the methodological variations in the literature studying localization performance. He also brings into focus the situation that frequently occurs clinically: a CI user may be employing a single implant or a combination of devices, either two CIs or a combination of CI and hearing aid contralaterally.

Another theme of this issue is that implantation with sophisticated technology is not an endpoint in the rehabilitative process. Linda Thibodeau points out that patient management encompasses use of ancillary devices with implanted technologies. She describes common components and coupling arrangements for frequency modulated (FM) instrumentation to be used in conjunction with CIs. In addition, the author discusses methods of verification of the mating of FM systems with implanted technologies to enhance speech recognition. This work focuses on the goal of maximizing acoustic input in adverse listening conditions, such as the classroom and large group venues.

This issue of Seminars in Hearing represents a “slice of time” in an aspect of Audiology and Otology that is changing rapidly. The use of these devices is a means to an end, the end being improvements in communication and quality of life for individuals with diverse hearing impairments. As a field, we will continue to explore these dimensions—safety, efficacy, user satisfaction, enhancement in adverse acoustic conditions, and training methodologies—as the implantable device technologies develop further.