Optimal management of single‐sided deafness

Current trends in auditory rehabilitation for single-sided deafness (SSD) reflect a renewed interest in the functional impact of unilateral hearing loss and also in the advances in technologies for SSD that make interventions more effective and more appealing to patients. Clinicians are now equipped with an array of therapeutic options ranging from Bluetooth contralateral routing of signal (CROS) devices to in-the-ear TransEar hearing aids (Ear Technology Corp., Johnson City, TN), as well as bone-anchored hearing aids (BAHA). Even unilateral cochlear implantation represents a current investigational intervention that may offer yet another option to patients in the future. A prominent deficiency in this field is the absence of concise and evidence-based guidelines for patient and intervention selection. Factors to consider when recommending the best treatment include functional handicapping due to SSD, speech understanding in noise, localization, ease of use, the need for surgery and cost. This article seeks to review the pertinent literature on this topic and offer a best-practice framework. Both BAHA and CROS devices enable patients to pick up sound from the deaf side, thus effectively expanding the sound field.1 Patients are bothered by the occlusion effect a CROS device presents by having an ear mold in their better hearing ear, whereas some reject the BAHA because of the need for surgery. Niparko et al.1 compared both objective and subjective measures on 10 patients with SSD who underwent a 1-month trial period with a conventional CROS device and subsequent BAHA implantation. All quality-of-life measure tests showed greater subjective satisfaction with the BAHA compared to the CROS device. The localization test showed poor performance across the board, with no statistical difference among unaided, CROS device, and BAHA, but the BAHA was superior for speech discrimination in noise. It was conjectured that the speech in noise performance was better with the BAHA compared to the CROS device due to the tighter and more efficient transcranial routing of sound from osseointegration. The TransEar hearing aid offers a nonsurgical bone-conduction hearing aid option that can be inserted in the algorithm in addition to the BAHA and CROS device for some patients. The TransEar requires a deeply fitted ear mold that allows bone transmission of sound by means of an in-the-ear hearing aid but eliminates occlusion in the better hearing ear as in the CROS device. To date, there remains a paucity of data about its use in the literature, and audiologic familiarity/expertise is required to make this an effective hearing rehabilitative option. A prospective pilot study conducted in Europe by Hol et al.2 had 10 subjects with SSD use all three devices: the BAHA soft band, CROS device, and a device that is placed completely in the canal (CIC), in a random order for an 8-week trial period each. The localization was poor across the board, but the results on quality-of-life issues were mixed with some surprising benefits with the CIC device. At the end of trying all three devices, only 3/10 of the patients chose to proceed with BAHA implantation and 1/10 for a CROS device. The authors emphasized that all patients derived some form of benefit for each device, but there is a real need for a sufficient trial period for patients before making an informed decision. Complications and long-term satisfaction with the BAHA needs to be considered before committing to a surgery. Gluth et al.3 summarized a long-term satisfaction and complication rate of the BAHA, with average use duration of 3.5 years. Seventy percent of all users thought their overall quality of life improved, which was maintained at long term with an 81% continued-user rate for the BAHA. For complications, 38% of patients experienced skin reactions, whereas 66.7% required the processor to be repaired. This article highlights the fact that patient satisfaction with the BAHA is maintained even at long term, but that diligent care for the abutment site is required due to frequent skin reaction. Patients need to be aware of such requirement as well as high rate of processor failure preoperatively. Sophono (Sophono, Inc., Boulder, CO) is a newer bone-conduction device that is implanted underneath the skin without any percutaneous abutment. This not only eliminates the cosmetic concerns that patients have with an abutment but also the need for a meticulous cleaning of the abutment site and associated wound issues.4 A Danish prospective study5 of 59 patients with SSD after translabyrinthine acoustic neuroma (AN) resection focused on functional impairment of AN resection 2 to 3 years after the surgery and what their satisfaction rate was following a trial of a BAHA headband. These data showed that 80% of the respondents experienced and perceived a hearing handicap, but eventually only 54% of those who tried decided to proceed with the implantation, citing insufficient benefit. The authors showed the significant hearing handicap these patients experience with SSD. However, they argued that the BAHA should not be routinely offered as a part of tumor resection, but rather that the patient should be given some time to decide whether or not to pursue a hearing intervention. As a best practice, it is reasonable to consider a sequential interventional approach for SSD patients that takes into consideration the degree of invasiveness or risk associated with each intervention. For example, an initial trial of a CROS or TransEar type hearing aid can be recommended as a nominal risk, noninvasive option for patients with SSD. If those trials prove unsatisfactory, the patient might then be considered an appropriate candidate for an implantable bone conduction device (e.g., BAHA or Sophono). Extensive counseling about peri- and postoperative care as well as complication rates for the BAHA need to be discussed with the patient preoperatively. Those patients likely to require magnetic resonance imaging (MRI) should also be counseled against Sophono implantation due to MRI incompatibility. Finally, patients should understand the realistic benefits offered by hearing interventions (whether CROS, TransEar, BAHA, or Sophono). There is no cost-effectiveness analysis comparing the use of the BAHA versus other modalities. One study involved prospective randomized trial thus qualifying for level I evidence. Three studies used prospective cohort observational studies which fall under level II. One study is level IV.