Cochlear Promontory Stimulation for Treatment of Tinnitus

Candidate subjects will undergo a temporal bone Computed Tomography (CT) scan, contrast enhanced head Magnetic Resonance Imaging (MRI), audiogram with immittance testing, pitch and level matching of tinnitus, Distortion Product Otoacoustic Emissions (DPOAE) and Auditory Brainstem Response (ABR) testing prior to promontory stimulation. Head MRI, DPOAE, audiogram and immittance testing are considered clinically routine for assessment of asymmetric tinnitus. Temporal bone CT, ABR, tinnitus pitch, level matching, masking levels and residual inhibition testing are not standard clinical assessments for asymmetric tinnitus. In addition, subjects will complete the Tinnitus Handicap Inventory (THI), Tinnitus Functional Index (TFI) and Visual Analog Scale (VAS) questionnaires three separate times within the week prior to promontory stimulation testing. Additional testing for comorbid anxiety and depressive conditions will be a screening Generalized Anxiety Disorder (GAD7), Patient Health Questionnaire (PHQ8), and short Health Anxiety Inventory (HAI-S). The NEO Personality Inventory (NEO PI) will be administered to provide baseline information. The initial session of promontory stimulation will define optimal stimulation parameters (i.e., location, current level, pulse-width, phase polarity), where maximal tinnitus suppression occurs with minimal or no auditory percept. After these parameters are established, the patient will complete the THI, TFI, and VAS immediately prior to stimulation, during stimulation, and following completion of stimulation at 10-minutes, 1-hour, 24-hours, 48-hours, and 1-week following completion of stimulation. In addition, pitch and level matching of tinnitus will be completed immediately upon completion of each promontory stimulation session. Each patient will undergo three successive treatments separated by 1-week. Prior to each treatment, the patient will receive an audiogram and DPOAE testing to document interval safety. At the conclusion of the study, subjects will be asked about their willingness to undergo surgical implantation of a device capable of long-term scheduled or on-demand electrical stimulation for tinnitus suppression

Inclusion criteria

• Normal to moderate sensorineural hearing loss (based on pure tone audiometry (PTA) of 500, 1000 and 2000 Hz) and a word recognition score equal to or greater than 60%
• Asymmetric or unilateral subjective tonal tinnitus
• Tinnitus that is disruptive

• Determined by THI score (in the severe range i.e. ≥56/100)
• TFI (in the severe range i.e. ≥52/100)
• Tinnitus VAS (≥ 5/10 )
• Tinnitus that is intractable, and has not been ameliorated by conventional measures such as a hearing aid or masking
• Normal contrast-enhanced MRI of the head

Exclusion criteria

• Tinnitus present less than 6 months or longer than 12 years; it is permissible to include people who have had intermittent or constant tinnitus longer than 12 years as long as it was not perceived as severe longer than 12 years
• History of brain or major ear surgery
• Prior major head trauma
• Ongoing clinical diagnosis of depression or anxiety; for the purposes of this study, it is permissible to include people who: 1. have a past history of clinically diagnosed depression or anxiety that is no longer currently active; or 2. people who have depressive or anxious symptoms that are thought to primarily result from severe tinnitus

a. Determined by screening using the GAD 7, PHQ8, and HAI-S

• GAD7 > 9 (indicates clinically significant anxiety)
• PHQ > 9 (indicates clinically significant depression)
• HAI-S > 25 (hypochondriacal level illness anxiety)
• Inability to assess, continue or complete trial
• Currently on regularly scheduled antidepressants, anxiolytics or antipsychotics; for this study, it is permissible to include people who use such medications at lower doses as a sleep aid or for people who intermittently use such medications for situational anxiety (e.g., Ativan before airplane travel)
• Active use of other tinnitus treatments; for the purposes of this study it is permissible to include people who prefer to use a hearing aid to amplify ipsilateral hearing loss
• Known pregnancy