History of Tinnitus Research at the VA National Center for Rehabilitative Auditory Research (NCRAR), 1997-2021: Studies and Key Findings

The Veterans Affairs (VA) Rehabilitation Research & Development (RR&D) National Center for Rehabilitative Auditory Research (NCRAR) was first funded by the RR&D Service in 1997 and has been funded continuously since that time. The overall purpose of the NCRAR is to "improve the quality of life of Veterans and others with hearing and balance problems through clinical research, technology development, and education that leads to better patient care" ( www.ncrar.research.va.gov ). An important component of the research conducted at the NCRAR has been a focus on clinical and rehabilitative aspects of tinnitus. Multiple investigators have received grants to conduct tinnitus research and the present article provides an overview of this research from the NCRAR's inception through 2021.

Sound Therapy to Reduce Auditory Gain for Hyperacusis and Tinnitus

Purpose:

Hyperacusis is the most common of the different types of sound tolerance conditions. It has been defined as physical discomfort or pain when any sound reaches a certain level of loudness that would be comfortable for most people. Because hyperacusis and tinnitus occur together so often, it has been theorized that they have a common neural mechanism. A leading contender for that mechanism is enhancement of auditory gain. The purpose of this tutorial is to review the evidence that sound/acoustic therapy can reduce auditory gain and, thereby, can increase loudness tolerance for people with hyperacusis and/or suppress the percept of tinnitus.

Method:

The scientific literature was informally reviewed to identify and elucidate relationships between tinnitus, hyperacusis, sound therapy, and auditory gain.

Results:

Evidence exists, both in animal and human studies, that enhanced auditory gain is associated with hyperacusis and tinnitus. Further evidence supports the theory that certain forms of sound therapy can reduce neural hyperactivity, thereby reducing auditory gain. The evidence for sound therapy reducing auditory gain is stronger for hyperacusis than it is for tinnitus.

Conclusions:

Based on results from numerous studies, sound therapy clearly has application as a method of desensitization for hyperacusis. Enhanced auditory gain might be responsible for tinnitus, but other mechanisms have been theorized. A review of the relevant literature leads to the conclusion that some form(s) of sound therapy has the potential to suppress or eliminate tinnitus on a long-term basis. Systematic research is needed to evaluate this premise.

Reevaluating the Use of Sound Therapy for Tinnitus Management: Perspectives on Relevant Systematic Reviews

PURPOSE

Tinnitus is a highly prevalent condition that can severely reduce health functioning. In spite of extant clinical practice guidelines (CPGs), implementation of these CPGs is relatively uncommon. As a result, patients seeking professional services for tinnitus often have no assurance of receiving evidence-based care. The purpose of this tutorial was to clarify the evidence for sound therapy so that it may be included in future CPGs for tinnitus.

METHOD

"Best clinical evidence" is obtained from high-quality systematic reviews, which are generally considered the highest level of evidence. Our review of recent, comprehensive, high-quality systematic reviews of interventions for tinnitus concludes that cognitive behavioral therapy is the only effective intervention, though the strength of evidence was generally rated as low in these reviews. Although trials of sound therapy for tinnitus have been included in these reviews, they have been rated as having high risk of bias (RoB) and not included in syntheses or rated as insufficient strength of evidence.

RESULTS

Conclusions from these and other reviews have influenced recommendations made in CPGs for tinnitus. These conclusions, however, can make it appear that an intervention for tinnitus is not effective, even if the opposite is true. We contend that the strict inclusion criteria for these reviews are counterproductive and have the effect of obscuring decades of evidence demonstrating the clinical effectiveness of sound therapies for tinnitus. Ultimately, this process has resulted in many patients not receiving sound therapy, despite what should be sufficient evidence that this is an effective form of intervention.

CONCLUSION

If we rely on systematic reviews using contemporary RoB assessment criteria for studies published prior to these reporting guidelines, then we risk excluding important conclusions regarding interventions that could help patients in need.

Survey of Audiology Graduate Programs: Training Students in Tinnitus Management

Purpose Although tinnitus is highly prevalent among patients receiving audiology services, the extent to which most audiologists are trained in tinnitus management is not well documented. The extent and type of instruction in tinnitus clinical care provided by audiology graduate (AuD) programs is not clear, nor is it known whether training programs are consistent in their recommendations. It is certainly true that widely accepted standards do not exist to ensure that all tinnitus clinical services are supported by adequate scientific evidence, which may result in unsatisfactory outcomes and unnecessary expense for patients. The purpose of this clinical focus article is to describe the results of an informal survey of AuD programs to determine their level of training for tinnitus management. Method A short survey was sent to all 75 American Speech-Language-Hearing Association-accredited AuD programs to assess the extent and type of tinnitus training their students receive. Conclusions The 32 AuD programs that responded to our survey provide tinnitus training using a variety of settings and methods. Further research could explore in more detail the extent of training in specific methods provided by these programs, and aim to elicit responses from a greater number of programs and from the students themselves.