Functional gain of already implanted hearing devices in patients with sensorineural hearing loss of varied origin and extent: Berlin experience.
OBJECTIVE: The evaluation process of patients with sensorineural hearing loss (SNHL) as candidates for an implantable hearing device is a complex matter. Different criteria have to be considered, such as audiologic, psychological, and socioeconomic issues, presently fitted hearing aids, and the patient's satisfaction with hearing aids. The objective of this study was to describe the evaluation process to select candidates for implantation of the Vibrant Soundbridge system (Symphonix Devices, Inc., San Jose, CA, U.S.A.) in a capital area such as Berlin, where approximately 4 million people live. STUDY DESIGN: Retrospective chart review with additional clinical and audiologic testing and extensive interview of the patients. SETTING: The study was conducted at two referral centers. PATIENTS: A total of 45,350 pure-tone audiograms (PTAs) and speech audiograms (samples from 1987 to 1999) of patients with different extents and types of SNHL were screened. MAIN OUTCOME MEASURES: The PTA, speech audiograms, Abbreviated Profile of Hearing Aid Benefit questionnaire, and a telephone interview served as major criteria. However, several additional criteria in the evaluation and in the decision-making process were included and are described in detail. RESULTS: Of 45,350 patients' charts with their PTA, 346 patients appeared to be possible implant candidates (0.76%) because of their hearing loss. At the time of the hearing screening, 255 patients (0.56%) were possible candidates for the P-type Soundbridge audio processor, and 91 patients (0.2%) were possible candidates for the HF-type processor. Out of the initial 346 patients, 84 (24.3%) were not interested in being further tested or interviewed and declared their lack of interest in the implant technology for several reasons (e.g., satisfaction with their present hearing aid fitting, anxiety to be operated on). A total of 126 patients (36.4%) could be contacted neither by mail nor by telephone. A total of 61 patients (0.13%) declared that they were basically interested, but wanted to wait for further technological refinements (e.g., fully implantable devices). The remaining 75 patients (i.e., 0.16% of the total population screened) could be clinically reevaluated with regard to our standardized protocol. Because of clinical and other reasons, another 33 patients (0.07%) had to be excluded from this study. The resulting 42 patients (0.09%) were undergoing the final ABHAB interview and were ready to be implanted. CONCLUSION: The number of patients in a stochastic population who are realistic implant candidates for an implantable hearing device is limited. Although there are many more patients suffering from SNHL who meet the requirements of the implant system because of their audiograms, the complexity of a careful evaluation process extremely limits the number of implant candidates. Moreover, reimbursement restrictions in the present health economy worldwide have to be considered.