1

Introduction

Tinnitus is a frequently bothersome symptom defined as the perception of sound without an external source, varying in loudness, pitch, and quality in each affected individual. Up to 85% of patients suffering from tinnitus have associated hearing loss . Currently, most treatments for tinnitus in patients with hearing loss involve addressing the auditory deprivation through the use of hearing aids or masking devices in combination with cognitive behavioral therapy. It is thought that amplification of external sounds may reverse or reduce the factors responsible for pathological changes in the central auditory system associated with hearing loss, such as increased gain or auditory cortex reorganization, possibly by strengthening lateral inhibitory connections. Another theory is that increased neuronal activity resulting from amplified sounds may reduce the contrast between tinnitus activity and background activity, thus reducing audibility and awareness of the tinnitus . In their review of 17 studies evaluating the effect of hearing aids on tinnitus, Shekhawat et al. concluded that hearing aids were beneficial in reducing tinnitus . However, for patients with severe to profound single sided hearing loss and tinnitus such conventional therapies may be limited by the magnitude of the hearing loss.

In recent years, numerous reports have established the effectiveness of osseointegrated auditory implants in treatment of single sided deafness . However there are no reports to date of a prospective study analyzing the effect of OAIs on tinnitus severity. In the present study, we investigated the degree of tinnitus in patients with SSD prior to surgery and evaluated the changes in tinnitus with OAI use.

2

Materials and methods

The study was approved by the Virginia Commonwealth University Institutional Review Board (HM 13638) and written informed consent was obtained from all participants. Patients were included if they suffered from stable unilateral severe to profound hearing loss and ipsilateral tinnitus for greater than 12 months. Pediatric patients (< 18 years old) or any patient with any contralateral hearing loss were excluded. All patients were initially fit with contralateral routing of signal (CROS) hearing aids, and those that were dissatisfied were offered a trial of the osseointegrated device on a headband. Those patients satisfied with the osseointegrated device subsequently proceeded with implantation of a percutaneous OAI.

Preoperative hearing assessment including pure tone audiometry, and hearing loss was described by means of a 3-tone pure tone average (PTA), the average of the hearing thresholds at 0.5, 1, and 2 kHz. Speech discrimination scores were also obtained and recorded. Subjects were asked to complete the Tinnitus Reaction Questionnaire (TRQ) and the Tinnitus Handicap Inventory (THI) pre-operatively, 6 months post-fitting, and 12 months post-fitting. Results from each questionnaire were recorded and analyzed using linear mixed mode, with time as fixed effect for longitudinal data with repeated measures. The difference of least square means among the three time points for each of the two measures (TRQ and THI) was tested, where P ≤ 0.05 was considered significant.

Subgroup analysis was carried out by dividing the patients into two groups according to the degree of hearing loss. Group A was considered the profound SNHL group, and contained 3 patients (S1, S9, S10) with PTA of 70 or greater. Group B was considered the severe SNHL group, and contained 7 patients (S2–S8) with PTA less than 70 and poor discrimination.

2

Materials and methods

The study was approved by the Virginia Commonwealth University Institutional Review Board (HM 13638) and written informed consent was obtained from all participants. Patients were included if they suffered from stable unilateral severe to profound hearing loss and ipsilateral tinnitus for greater than 12 months. Pediatric patients (< 18 years old) or any patient with any contralateral hearing loss were excluded. All patients were initially fit with contralateral routing of signal (CROS) hearing aids, and those that were dissatisfied were offered a trial of the osseointegrated device on a headband. Those patients satisfied with the osseointegrated device subsequently proceeded with implantation of a percutaneous OAI.

Preoperative hearing assessment including pure tone audiometry, and hearing loss was described by means of a 3-tone pure tone average (PTA), the average of the hearing thresholds at 0.5, 1, and 2 kHz. Speech discrimination scores were also obtained and recorded. Subjects were asked to complete the Tinnitus Reaction Questionnaire (TRQ) and the Tinnitus Handicap Inventory (THI) pre-operatively, 6 months post-fitting, and 12 months post-fitting. Results from each questionnaire were recorded and analyzed using linear mixed mode, with time as fixed effect for longitudinal data with repeated measures. The difference of least square means among the three time points for each of the two measures (TRQ and THI) was tested, where P ≤ 0.05 was considered significant.

Subgroup analysis was carried out by dividing the patients into two groups according to the degree of hearing loss. Group A was considered the profound SNHL group, and contained 3 patients (S1, S9, S10) with PTA of 70 or greater. Group B was considered the severe SNHL group, and contained 7 patients (S2–S8) with PTA less than 70 and poor discrimination.