Device and Fitting Protocol for a Transitional Intervention for Debilitating Hyperacusis.

PURPOSE: This report describes a hearing device and corresponding fitting protocol designed for use in a transitional intervention for debilitating loudness-based hyperacusis. METHOD: The intervention goal is to transition patients with hyperacusis from their typical counterproductive sound avoidance behaviors (i.e., sound attenuation and limited exposure to healthy low-level sounds) into beneficial sound therapy treatment that can expand their dynamic range to the point where they can tolerate everyday sounds and experience an improved quality of life. This requires a combination of counseling and sound therapy, the latter of which is provided via the hearing device technology, signal processing, and precision fitting approach described in this report. The device combines a miniature behind-the-ear sound processor and a custom earpiece designed to maximize the attenuation of external sounds. Output-limiting loudness suppression is used to restrict exposure to offending high-level sounds while unity gain amplification maximizes exposure to healthy and tolerable lower level sounds. The fitting process includes measurement of the real-ear unaided response, the real-ear measurement (REM) system noise floor, the real-ear occluded response, real-ear insertion gain, and the output limit. With these measurements, the device can achieve the prescribed unity gain needed to provide transparent access to comfortable sound levels. It also supports individualized configuration of the therapeutic noise from an on-board sound generator and adaptive output limiting based on treatment-induced increases in dynamic range. RESULTS AND CONCLUSION: The utility of this device and fitting protocol, in combination with structured counseling, is highlighted in the outcomes of a successful 6-month trial of the transitional intervention described in a companion report in this issue.

Counseling Protocol for a Transitional Intervention for Debilitating Hyperacusis.

INTRODUCTION: This clinical focus article describes a structured counseling protocol for use with protected sound management and therapeutic sound in a transitional intervention for debilitating hyperacusis. The counseling protocol and its associated visual aids are crafted as a teaching tool to educate affected individuals about hyperacusis and encourage their acceptance of a transitional intervention. DESCRIPTION OF COUNSELING COMPONENTS: The counseling protocol includes five components. First, the patient's audiometric results are reviewed with the patient, and the transitional intervention is introduced. An overview of peripheral auditory structures and central neural pathways and the concept of central gain are covered in the second and third components. Maladaptive hyper-gain processes within the auditory neural pathways, which underlie the hyperacusis condition, and associated connections with nonauditory processes responsible for negative reactions to hyperacusis are covered in the fourth component. Detrimental effects from misused hearing protection devices (HPDs) and the necessity to wean the patient from overuse of HPDs are also discussed. In the fifth component, the importance of therapeutic sound is introduced as a tool to downregulate hyper-gain activity within the auditory pathways; its implementation in uncontrolled and controlled sound environments is described. It is explained that, over the course of the transitional intervention, recalibration of the hyper-gain processes will be ongoing, leading to restoration of normal homeostasis within the auditory pathways. In turn, associated activation of reactive nonauditory processes, which contribute to hyperacusis-related distress, will be reduced or eliminated. As recalibration progresses, there will be less need for protected sound management and sound therapy. Sound tolerance will improve, hyperacusis will subside, and daily activities in typical healthy sound environments will again become routine. RESULTS AND CONCLUSION: The combination of counseling with protected sound management and therapeutic sound is highlighted in companion reports, including a summary of the outcomes of a successful trial of the transitional intervention.

Background and Rationale for a Transitional Intervention for Debilitating Hyperacusis.

PURPOSE: This report provides the experimental, clinical, theoretical, and historical background that motivated a patented transitional intervention and its implementation and evaluation in a field trial for mitigation of debilitating loudness-based hyperacusis (LH). BACKGROUND AND RATIONALE: Barriers for ameliorating LH, which is differentiated here from other forms of hyperacusis, are delineated, including counterproductive management and treatment strategies that may exacerbate the condition. Evidence for hyper-gain central auditory processes as the bases for LH and the associated LH-induced distress and stress responses are presented. This presentation is followed by an overview of prior efforts to use counseling and therapeutic sound as interventional tools for recalibrating the hyper-gain LH response. We also consider previous efforts to use output-limiting sound-protection devices in the management of LH. This historical background lays the foundation for our transitional intervention protocol and its implementation and evaluation in a field trial. CONCLUSIONS: The successful implementation and evaluation of a transitional intervention, which we document in the outcomes of a companion proof-of-concept field trial in this issue, build on our prior efforts and those of others to understand, manage, and treat hyperacusis. These efforts to overcome significant barriers and vexing long-standing challenges in the management and treatment of LH, as reviewed here, are the pillars of the transitional intervention and its primary components, namely, counseling combined with protective sound management and therapeutic sound, which we detail in separate reports in this issue.

Results of a 6-Month Field Trial of a Transitional Intervention for Debilitating Hyperacusis.

PURPOSE: We present results from a 6-month field trial of a transitional intervention for debilitating primary hyperacusis, including a combination of structured counseling; promotion of safe, comfortable, and healthy sound exposure; and therapeutic broadband sound from sound generators. This intervention is designed to overcome barriers to successful delivery of therapeutic sound as a tool to downregulate neural hyperactivity in the central auditory pathways (i.e., the maladaptive mechanism believed to account for primary hyperacusis) and, together with the counseling, reduce the associated negative emotional and physiological reactions to debilitating hyperacusis. METHOD: Twelve adults with normal or near-normal audiometric thresholds, complaints consistent with their pretreatment loudness discomfort levels ≤ 75 dB HL at multiple frequencies, and hearing questionnaire scores ≥ 24 completed the sound therapy-based intervention. The low-level broadband therapeutic sound was delivered by ear-level devices fitted bilaterally with either occluding earpieces and output-limiting loudness suppression (LS; to limit exposure to offensive sound levels) or open domes to maximize comfort and exposure to sound therapy. Thresholds for LS (primary outcome) were incrementally adjusted across six monthly visits based on treatment-driven change in loudness judgments for running speech in sound field. Secondary outcomes included categorical loudness judgments, speech understanding, and questionnaires to assess the hyperacusis problem, quality of life, and depression. An exit survey assessed satisfaction with and benefit from the intervention and the counseling, therapeutic sound, and LS components. RESULTS: The mean change in LS (34.8 dB) was highly significant (effect size = 2.045). Eleven of 12 participants achieved ≥ 16-dB change in LS, consistent with highly significant change in sound-based questionnaire scores. Exit surveys indicated satisfaction with and benefit from the intervention. CONCLUSION: The transitional intervention was successful in improving the hyperacusis conditions of 11 of 12 study participants while reducing their sound avoidance behaviors and reliance on sound protection.

Reliability of the Minimum Masking Level as Outcome Variable in Tinnitus Clinical Research.

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2-3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation (r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.

Amplitude modulated S-tones can be superior to noise for tinnitus reduction.

PURPOSE: Recent evidence has suggested that amplitude modulated tones might have some advantages over broadband noise. METHOD: Fifty-six subjects listened to S-Tones at a carrier frequency matched at the tinnitus pitch (amplitude modulation rate of 40 Hz) and to broadband noise. Subjects rated their tinnitus loudness before, during, and after a 120-s duration masker. RESULTS: The results suggested that S-Tones were generally more effective at reducing tinnitus loudness than noise. In about one third (21/56) of the subjects, there was no significant effect from any masker. In other subjects, 54.3% (19/35) showed a greater reduction for the S-Tones, 20% (7/35) showed a greater reduction with the noise, and 25.7% (9/35) showed similar performance between the 2 stimuli. The S-Tones showed a statistically significant benefit ( p < .01) versus noise at reducing the patient's tinnitus perception. Using low-level stimuli that were rated much softer than the subjects' baseline tinnitus, the S-Tones reduced the tinnitus loudness by 1.9 times the amount that noise did (about 28% on average, whereas the noise reduced the tinnitus by about 15%). CONCLUSION: S-Tones at the tinnitus pitch-match frequency are more likely to be effective than broadband noise at reducing tinnitus loudness.