Starkey Research & Clinical Blog

Do the benefits of tinnitus therapy increase with time?

Parazzini, M., Del Bo, L., Jastreboff, M., Tognola, G. & Ravazzani, P. (2011). Open ear hearing aids in tinnitus therapy: An efficacy comparison with sound generators. International Journal of Audiology, 50(8), 548-553.

This editorial discusses the clinical implications of an independent research study and does not represent the opinions of the original authors.

Tinnitus management can include a variety of treatment approaches but the most effective usually include a combination of counseling and sound therapy (Jastreboff, 1990; Jastreboff & Hazell, 2004). For many individuals with hearing loss and tinnitus, hearing aids may be the only tinnitus treatment they participate in. Specific treatment recommendations vary depending on a number of patient characteristics, such as degree of hearing loss and severity of the tinnitus disturbance.

Tinnitus Retraining Therapy (TRT; Jastreboff, 1995; Henry et al., 2002, 2003; Jastreboff & Jastreboff, 2006) is a widely known therapeutic approach using counseling and sound therapy, based on the neurophysiological model of tinnitus, that stresses the importance of helping individuals understand their condition, reducing awareness and attention to the tinnitus, providing or restoring appropriate auditory input and eventually training the auditory system to habituate to the tinnitus. Jastreboff & Hazell (2004) have proposed a classification system in which patients are assigned to one of five categories: 0 = mild or recent tinnitus, 1 = normal hearing and severe tinnitus, 2 = significant hearing loss, 3 = hyperacusis and 4 = prolonged worsening of tinnitus or hyperacusis following sound exposure. A patient’s classification on this scale can guide treatment recommendations thereafter. Counseling educates patients about their hearing loss and tinnitus, helping them cope with the stress and annoyance of tinnitus in their everyday lives. Sound therapy treatment aims to help patients habituate to their tinnitus, employing ear-level sound generators for individuals without hearing loss (category 1; described above) whereas hearing aids are recommended for tinnitus sufferers with significant hearing loss (category 2).

Individuals who fall into the borderline area between categories 1 and 2 could theoretically be treated with either sound generators or hearing aids. Presently, there is little evidence to suggest that one of these approaches is superior to the other. Therefore, the purpose of Parazzini et al.’s study was to compare the efficacy of sound therapy treatments with sound generators versus open-fit hearing aids for tinnitus patients whose characteristics fall between categories 1 and 2.

91 participants completed the study. All participants met the requirements for tinnitus categorization between Jastreboff categories 1 and 2, with pure tone thresholds equal to or less than 25dB HL at 2kHz and greater than or equal to 25dB at frequencies higher than 2kHz. None of the participants had used hearing aids or been treated with tinnitus retraining therapy prior to the study. Participants were randomly assigned to one of two treatment groups: those fitted with small, ear-level sound generators (SG group) and those fitted with binaural open fit hearing aids (HA group). All participants used the devices for at least 8 hours per day. Participants completed the Tinnitus Handicap Inventory (THI; Newman et al., 1996) at each of four appointments scheduled at three-month intervals over a year. Structured interviews were completed at each visit. During these interviews the following variables were examined: the effect of tinnitus on life, tinnitus loudness and tinnitus annoyance.

Analysis revealed that participants showed a marked reduction in scores over time, beginning at the first session three months after initiation of therapy and continuing progressively over subsequent measurements every three months up to the last visit at 12 months.  Results with ear-level sound generators and those with hearing aids were essentially identical. All three variables decreased by approximately 50% from the initial assessment to the final session at 12 months. The mean THI score decreased 52% from 57.9 to 27.9, the effect of tinnitus on life decreased 51% from 6.5 to 3.2, and tinnitus loudness ratings decreased from 7 to 3.6, a reduction of 48%. The common clinical criteria for significant improvement on the THI is 20 points (Newman et al., 1998) and 62% of the participants in the current study reached this goal by 6 months and 74% reached it by 12 months. Applying a criterion of 40% improvement to reflect a reduction in tinnitus disturbance—as proposed by P.J. Jastreboff—51% of the subjects achieved the goal by 6 months and 72% reached it by 12 months.

For all recorded variables, the time of treatment was always statistically significant, indicating that subjects were improving steadily over time. There was never a significant difference based on the type of device, indicating that sound generators and open-fit hearing aids were equally successful at alleviating tinnitus symptoms and reactions, at least for the subjects in this population, whose characteristics fell between categories 1 and 2 in Jastreboff & Hazell’s classification system.

Parazzini and colleagues evaluated tinnitus sufferers with mild high frequency hearing loss and measured their responses for up to 12 months. Though there was no evidence of plateaus in the data, it remains unknown whether improvements would continue if treatment were to continue beyond this point. Longer term studies would be valuable to determine at what point improvements plateau and if longer measurement periods yield differences between hearing aids and sound generator devices.

The instruments used in Parazzini’s study were either sound generators or hearing aids; none of the devices had both features. Many hearing aids available today offer tinnitus masking stimuli along with traditional amplification features. A similar paradigm examining hearing aids as well as combination devices could offer practical insight into tinnitus treatment options with currently available hearing instrument product lines. Because a goal of tinnitus retraining therapy is to restore auditory inputs to reduce awareness of the tinnitus, hearing aids could have particular benefits over sound generators, because they stimulate the auditory system with meaningful environmental sounds which may more effective at drawing attention away from the tinnitus, in addition to masking the tinnitus with the amplified sound.

Open-fit, behind-the-ear hearing aids appear to be a good solution for tinnitus patients: the ear canal remains open and unoccluded, thereby reducing the likelihood of increased tinnitus awareness. Another consideration is whether receiver-in-canal (RIC) instruments would be an even better choice. RICs are equally as effective as traditional open-fit hearing aids at minimizing occlusion and offer the opportunity to provide a broader high frequency range and more stable high frequency gain than is available when sound is routed thin or standard thickness tubing (Alworth, et al., 2010). This opportunity to provide an extended high-frequency amplification would be expected to increase auditory input in the frequency range where tinnitus is often perceived. Therefore, RICs may more effectively mask the tinnitus via amplification of environmental sounds, reducing tinnitus awareness and potentially, tinnitus annoyance and stress.

Parazzini’s study offers strong support for the use of open-fit hearing aids with tinnitus patients. Advances in hearing aid technology, such as feedback management, automatic signal processing, and the availability of tinnitus masking stimuli may make modern hearing aids even better suited for this purpose. As mentioned earlier, many opportunities exist for research in the treatment of tinnitus with hearing aids: effects of hearing aid style, sound therapy parameters, treatment and counseling strategies, and duration of treatment all remain white space for future researchers.

References

Alworth, L.N., Plyler, P.N., Bertges-Reber, M. & Johnstone, P.M. (2010). Microphone, performance and subjective measures with open canal hearing instruments. Journal of the American Academy of Audiology 21(4), 249-266.

Del Bo, L. & Ambrosetti, U. (2007). Hearing aids for the treatment of tinnitus. Progress in Brain Research 166, 341-345.

Henry J.A., Jastreboff M.M., Jastreboff P.J., Schechter M.A. & Fausti S.A.(2002).  Assessment of patients for treatment with tinnitus retraining therapy. Journal of the American Academy of Audiology, 13, 523 – 44.

Henry J.A., Jastreboff M.M., Jastreboff P.J., Schechter M.A. & Fausti S.A. (2003). Guide to conducting tinnitus retraining therapy initial and follow-up interviews. Journal of Rehabilitation Research and Development 40, 157 – 177.

Jastreboff, P.J. (1990). Phantom auditory perception (tinnitus): Mechanisms of generation and perception. Neuroscience Research 8, 221-254.

Jastreboff, P.J. & Hazell, J.W.P. (2004). Tinnitus Retraining Therapy: Implementing the Neurophysiological Model. Cambridge University Press.

Jastreboff P.J. & Jastreboff M.M. 2006. Tinnitus retraining therapy: A different view on tinnitus. Otorhinolaryngology and Related Specialties 68, 23 – 29.

Newman, C.W., Jacobson, G.P. & Spitzer, J.B. (1996). Development of the Tinnitus Handicap Inventory. Archives of Otolaryngology Head Neck Surgery 122, 143-148.

Newman, C.W., Sandridge, S.A. & Jacobson, G.P. (1998). Psychometric adequacy of the Tinnitus Handicap Inventory (THI) for evaluating treatment outcome. Journal of the American Academy of Audiology 9, 153-160.

Parazzini, M., Del Bo, L., Jastreboff, M., Tognola, G. & Ravazzani, P. (2011). Open ear hearing aids in tinnitus therapy: An efficacy comparison with sound generators. International Journal of Audiology, 50(8), 548-553.

Hearing Aids Alone can be Adjusted to Help with Tinnitus Relief

Shekhawat, G.S., Searchfield, G.D., Kobayashi, K. & Stinear, C. (2013). Prescription of hearing aid output for tinnitus relief. International Journal of Audiology 2013, early online: 1-9.

This editorial discusses the clinical implications of an independent research study and does not represent the opinions of the original authors.

The American Tinnitus Association (ATA) reports that approximately 50 million people in the United States experience some degree of tinnitus.About one third of tinnitus sufferers consider it severe enough to seek medical attention. Fortunately only a small proportion of tinnitus sufferers experience symptoms that are debilitating enough that they feel they cannot function normally. But even if it does not cause debilitating symptoms, for many tinnitus still causes a number of disruptive effects such as sleep interference, difficulty concentrating, anxiety, frustration and depression  (Tyler & Baker, 1983; Stouffer & Tyler, 1990; Axelsson, 1992; Meikle 1992; Dobie, 2004).

Therapeutic treatments for tinnitus include the use of tinnitus maskers, tinnitus retraining therapy, biofeedback and counseling . Though these methods provide relief for many the tendency for tinnitus to co-occur with sensorineural hearing loss (Hoffman & Reed, 2004) leads the majority of individuals to attempt management of tinnitus with the use of hearing aids alone (Henry, et al., 2005; Kochkin & Tyler, 2008; Shekhawat et al., 2013).  There are a number of benefits that hearing aids may offer for individuals with tinnitus:  audiological counseling during the fitting process may provide the individual with a better understanding of hearing loss and tinnitus (Searchfield et al., 2010); hearing aids may reduce the stress related to struggling to hear and understand; amplification of environmental sound may reduce perceived loudness of tinnitus (Tyler, 2008).

Prescriptive hearing aid fitting procedures are designed to improve audibility and assist hearing loss rather than address tinnitus concerns. Yet the majority of studies show that hearing aids alone can be useful for tinnitus management (Shekhawat et al., 2013). The Better Hearing Institute reports that approximately 28% of hearing aid users achieve moderate to substantial tinnitus relief with hearing aid use (Tyler, 2008). Approximately 66% of these individuals said their hearing aids offered tinnitus relief most or all the time and 29% reported that their hearing aids relieved their tinnitus all the time. However, little is known about how hearing aids should be adjusted to optimize this apparent relief from tinnitus. In a study comparing DSL I/O v4.0 and NAL-NL1, Wise (2003) found that low compression kneepoints in the DSL formula reduced tinnitus awareness for 80% of subjects, but these settings also made environmental sounds more annoying. Conversely, they had higher word recognition scores with NAL-NL1 but did not receive equal tinnitus reduction. The proposed explanation for this was the increased low-intensity, low-frequency gain of the DSL I/O formula versus the increased high frequency emphasis of NAL-NL1. Based on these findings, the author suggested the use of separate programs for regular use and for tinnitus relief.

Shekhawat and his colleagues began to address the issue of prescriptive hearing aid fitting for tinnitus by studying how output characteristics should be tailored to meet the needs of hearing aid users with tinnitus.  Specifically, they examined how modifying the high frequency characteristics of the DSL v5 (Scollie et al., 2005) prescription would affect subjects’ short term tinnitus perception.  Speech files with variable high frequency cut-offs and gain settings were designed and presented to subjects in matched pairs to arrive at the most favorable configuration for tinnitus relief.

Twenty-five participants mild to moderate high-frequency sensorineural hearing loss were recruited for participation. None of the participants had used hearing aids before but all indicated interest in trying hearing aids to alleviate their tinnitus.  All subjects had experienced chronic, bothersome tinnitus for at least two years and the average perception of tinnitus loudness was 62.6 on a scale from 1-100, where 1 is very faint and 100 is very loud. Subjects had a mean Tinnitus Functional Index (TFI; Meikle et al., 2012) score of 39.30. Six participants reported unilateral tinnitus localized to the left side, 15 had bilateral tinnitus and 4 reported tinnitus that localized to the center of the head, which is likely to be present bilaterally though not necessarily symmetrical.  The majority (40%) of the subjects reported their tinnitus quality as tonal, whereas 28% described it as noise, 20% as crickets and 12% as a combination of sound qualities. Tinnitus pitch matching was conducted using pairs of tones in which subjects were repeatedly asked to indicate which of the tones more closely matched the pitch of their tinnitus. The average matched tinnitus pitch was 7.892kHz with a range from 800Hz to 14.5kHz. When asked to describe the pitch of their tinnitus, most subjects defined it as “very high pitched”, some said “high pitched” and some said “medium pitched”.

There were 13 speech files, based on sentences spoken by a female talker, with variable high frequency characteristics. There were three cut-off frequencies (2, 4 and 6kHz) and four high frequency gain settings (+6, +3, -3 and -6dB). Stimuli were presented via a master hearing aid with settings programmed to match DSL I/O v5.0 prescriptive targets for each subject’s hearing loss.  Pairs of sentences were presented in a round robin tournament procedure  and subjects were asked to choose which one interfered most with their tinnitus and made it less audible. A computer program tabulated the number of “wins” for each sentence and collapsed the information across subjects to determine a “winner”, or the sentence that was most effective at reducing tinnitus audibility.  Real-ear measures were used to compare DSL v5 prescribed settings with the characteristics of the winning sentence and outputs were recorded from 250Hz to 6000Hz.

The most preferred output for interfering with tinnitus perception was a 6dB reduction at 2kHz, which was chosen by 26.47% of the participants.  A 6dB reduction at 4kHz was preferred by 14.74% of the subjects, followed by a 3dB reduction at 2kHz, which was preferred by 11.76%.  There were no significant differences between the preferences for any of these settings.

They found that when tinnitus pitch was lower than 4kHz, the preferred setting had lower output than DSL v5 across the frequency range. The difference was small (1-3dB) and became smaller as tinnitus pitch increased. When tinnitus pitch was between 4-8kHz, subjects preferred slightly less output than DSL v5 for high frequencies and slightly more output for low frequencies, though these differences were minimal as well. When tinnitus pitch was higher than 8kHz, participants preferred output that was slightly greater than DSL v5 at three frequencies: 750Hz, 1kHz and 6kHz. From these results a trend emerged: as tinnitus pitch increased, preferred output became lower than DSL v5 though the differences were not statistically significant.

Few studies investigating the use of hearing aids for tinnitus management have considered the perceived pitch of the tinnitus or the prescriptive method of the hearing aids (Shekhawat et al., 2013). The results of this study suggest that DSL v5 could be an effective prescriptive formula for hearing aids used in a tinnitus treatment plan, though the pitch of the individual’s tinnitus might affect the optimal output settings. In general, they found that the higher the tinnitus pitch, the more the preferred output matched with DSL I.O v5.0 targets. This study agrees with an earlier report by Wise (2003) in which subjects preferred DSL v5 over NAL-NL1 for interfering with and reducing tinnitus. It is unknown how NAL-NL2 targets would fare in a similar comparison, though the NAL-NL2 formula may provide more tinnitus relief than its predecessor because it tends to prescribe slightly higher gain for low frequencies and lower compression ratios which could potentially provide more of a masking effect from environmental sounds. The NAL-NL2 formula should be studied as it pertains to tinnitus management, perhaps along with consideration of other factors including degree of loss, gender and prior experience with hearing aids, since these affect the targets prescribed by the updated formula (Keidser & Dillon, 2006; Keidser et al., 2008). The subjects in the present study had similar degrees of loss and all lacked prior experience with amplification; the NAL-NL2 formula takes these factors into consideration, prescribing slightly different gain based on degree of loss or for those who have used hearing aids before.

The authors recommend offering separate hearing aid programs for use when the listener desires tinnitus relief. Most fitting formulae are designed to optimize speech intelligibility and audibility, and based on previous reports, an individual might prefer one formula when speech understanding and communication is their top priority, and may prefer another, used with or without an added noise masker, when their tinnitus is bothering them.

They also propose that tinnitus pitch matching should be considered when programming hearing aids, though there is often quite a bit of variability in results and testing needs to be repeated several times to increase reliability.  Still, their study agrees with prior work in suggesting that the pitch of the tinnitus affects how likely hearing aids are to reduce it and whether output adjustments can impact how effective the hearing aids are to this end. Schaette (2010) found that individuals with tinnitus pitch lower than 6kHz showed more reduction of tinnitus with hearing aid use than did subjects whose pitch was higher than 6kHz. This makes sense because of the typical bandwidth of hearing aids, in which most gain is delivered below this frequency range. Not surprisingly, another study reported that hearing aids were most effective at reducing tinnitus when the pitch of the tinnitus was within the frequency response range of the hearing aids (McNeil et al., 2012).  Though incorporating tinnitus pitch matching into a clinical protocol might seem daunting or time consuming, it is probably possible to use an informal bracketing procedure, similar to one used for MCLs, to get an idea of the individual’s tinnitus pitch range. Testing can be repeated at subsequent visits to eventually arrive at a more reliable estimate.  If pitch matching measures are not possible, clinicians can question the patient about their perceived tinnitus pitch range and, with reference the current study, adjust outputs in the 2kHz to 4kHz range to determine if the individual experiences improvement in tinnitus relief.

Proposed are a series of considerations for fitting hearing instruments on tinnitus sufferers and for employing dedicated tinnitus programs:

- noise reduction should be disabled;

- fixed activation of omnidirectional microphones introduce more environmental noise;

- in contrast to the previous recommendation, full-time activation of directional microphones will increase the hearing aid noise floor;

- lower compression knee points increase amplification for softer sounds;

- expansion should be turned off to increase amplification of low-level background sound;

- efforts should be made to  minimize occlusion, which can emphasize the perception of tinnitus;

- ensuring physical comfort of the devices can minimize the user’s general awareness of their ears and the hearing aids, potentially reducing their attention to the tinnitus as well (Sheldrake & Jastreboff, 2004; Searchfield, 2006);

- user controls are important as they allow access to alternate hearing aid programs and sound therapy options.

Dr. Shekhawat and his colleagues also underscore the importance of counseling tinnitus sufferers who choose hearing aids. Clinicians need to ensure that these patients have realistic expectations about the potential benefits of hearing aids and that they know the devices will not cure their tinnitus. Follow-up care is especially important to determine if adjustments or further training is necessary to improve the performance of the aids for all of their intended purposes.

Currently, little is known about how to optimize hearing aid settings for tinnitus relief and there are no prescriptive recommendations targeted specifically for tinnitus sufferers. Shekhawat and his colleagues propose that the DSL v5 formula may be an appropriate starting point for these individuals, as their basic program and/or in an alternate program designated for use when their tinnitus is particularly bothersome.  Most importantly, however, are the observations that intentional manipulation of parameters common to most hearing aid fittings may increase likelihood of tinnitus relief with hearing aid use. Further investigation into the optimization of these fitting parameters may reveal a prescriptive combination that audiologists can leverage to benefit individuals with hearing loss who also seek relief from the stress and annoyance of tinnitus.

 

References

American Tinnitus Association (ATA) reporting data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES), conducted by the Centers for Disease Control and Prevention (CDC). www.ata.org, retrieved 9-10-13.

Axelsson, A. (1992). Conclusion to Panel Discussion on Evaluation of Tinnitus Treatments. In J.M. Aran & R. Dauman (Eds) Tinnitus 91. Proceedings of the Fourth International Tinnitus Seminar (pp. 453-455). New York, NY: Kugler Publications.

Cornelisse, L.E., Seewald, R.C. & Jamieson, D.G. (1995). The input/output formula: A theoretical approach to the fitting of personal amplification devices. Journal of the Acoustical Society of America 97, 1854-1864.

Dobie, R.A. (2004). Overview: Suffering From Tinnitus. In J.B. Snow (Ed) Tinnitus: Theory and Management (pp.1-7). Lewiston, NY: BC Decker Inc.

Henry, J.A., Dennis, K.C. & Schechter, M.A. (2005). General review of tinnitus: Prevalence, mechanisms, effects and management. Journal of Speech, Language and Hearing Research 48, 1204-1235.

Hoffman, H.J. & Reed, G.W. (2004). Epidemiology of tinnitus. In: J.B. Snow (ed.) Tinnitus: Theory and Management. Hamilton, Ontario: BC Decker.

Keidser, G. & Dillon, H. (2006). What’s new in prescriptive fittings down under? In: Palmer, C.V., Seewald, R. (Eds.), Hearing Care for Adults 2006. Phonak AG, Stafa, Switzerland, pp. 133-142.

Keidser, G., O’Brien, A., Carter, L., McLelland, M. & Yeend, I. (2008). Variation in preferred gain with experience for hearing aid users. International Journal of Audiology 47(10), 621-635.

Kochkin, S. & Tyler, R. (2008). Tinnitus treatment and effectiveness of hearing aids: Hearing care professional perceptions. Hearing Review 15, 14-18.

McNeil, C., Tavora-Vieira, D., Alnafjan, F., Searchfield, G.D. & Welch, D. (2012). Tinnitus pitch, masking and the effectiveness of hearing aids for tinnitus therapy. International Journal of Audiology 51, 914-919.

Meikle, M.B. (1992). Methods for Evaluation of Tinnitus Relief Procedures. In J.M. Aran & R. Dauman (Eds.) Tinnitus 91: Proceedings of the Fourth International Tinnitus Seminar (pp. 555-562). New York, NY: Kugler Publications.

Meikle, M.B., Henry, J.A., Griest, S.E., Stewart, B.J., Abrams, H.B., McArdle, R., Myers, P.J., Newman, C.W., Sandridge, S., Turk, D.C., Folmer, R.L., Frederick, E.J., House, J.W., Jacobson, G.P., Kinney, S.E., Martin, W.H., Nagler, S.M., Reich, G.E., Searchfield, G., Sweetow, R. & Vernon, J.A. (2012). The Tinnitus Functional Index:  Development of a new clinical measure for chronic, intrusive tinnitus. Ear & Hearing 33(2), 153-176.

Moffat, G., Adjout, K., Gallego, S., Thai-Van, H. & Collet, L. (2009). Effects of hearing aid fitting on the perceptual characteristics of tinnitus. Hearing Research 254, 82-91.

Schaette, R., Konig, O., Hornig, D., Gross, M. & Kempter, R. (2010). Acoustic stimulation treatments against tinnitus could be most effective when tinnitus pitch is within the stimulated frequency range. Hearing Research 269, 95-101.

Shekhawat, G.S., Searchfield, G.D., Kobayashi, K. & Stinear, C. (2013). Prescription of hearing aid output for tinnitus relief. International Journal of Audiology 2013, early online: 1-9.

Shekhawat, G.S., Searchfield, G.D. & Stinear, C.M. In press (2013). Role of hearing aids in tinnitus intervention: A scoping review. Journal of the American Academy of Audiology.

Searchfield, G.D. (2006). Hearing aids and tinnitus. In: R.S. Tyler (ed). Tinnitus Treatment, Clinical Protocols. New York: Thieme Medical Publishers, pp. 161-175.

Searchfield, G.D., Kaur, M. & Martin, W.H. (2010). Hearing aids as an adjunct to counseling: Tinnitus patients who choose amplification do better than those that don’t. International Journal of Audiology 49, 574-579.

Sheldrake, J.B. & Jastreboff, M.M. (2004). Role of hearing aids in management of tinnitus. In: J.B. Sheldrake, Jr. (ed.) Tinnitus: Theory and Management. London: BC Decker Inc, pp. 310-313.

Stouffer, J.L. & Tyler, R. (1990). Characterization of tinnitus by tinnitus patients. Journal of Speech and Hearing Disorders 55, 439-453.

Tyler, R.S.(Ed). (2008). The Consumer Handbook on Tinnitus. Auricle Ink Publishers., Sedona, AZ.

Tyler, R. & Baker, L.J. (1983). Difficulties experienced by tinnitus sufferers. Journal of Speech and Hearing Disorders 48, 150-154.

Wise, K. (2003). Amplification of sound for tinnitus management: A comparison of DSL i/o and NAL-NL1 prescriptive procedures and the influence of compression threshold on tinnitus audibility. Section of Audiology, Auckland: University of Auckland.

 

The Tinnitus Functional Index (TFI): A New and Improved way to Evaluate Tinnitus

Meikle, M.B., Henry, J.A., Griest, S.E., Stewart, B.J., Abrams, H.B., McArdle, R., Myers, P.J., Newman, C.W., Sandridge, S., Turk, D.C., Folmer, R.L., Frederick, E.J., House, J.W., Jacobson, G.P., Kinney, S.E., Martin, W.H., Nagler, S.M., Reich, G.E., Searchfield, G., Sweetow, R. & Vernon, J.A. (2012). The Tinnitus Functional Index:  Development of a new clinical measure for chronic, intrusive tinnitus. Ear & Hearing 33(2), 153-176.

This editorial discusses the clinical implications of an independent research study and does not represent the opinions of the original authors.

The practice of clinical audiology can arguably be described as having two primary goals: the diagnosis of auditory and vestibular disorders, followed by verifiable, effective treatment and rehabilitation. There are well established, objective diagnostic tests for hearing and vestibular disorders and their treatment methods can be verified with objective and subjective tools. The evaluation and treatment of tinnitus, though equally important, is more complicated. There are test protocols for matching perceived tinnitus characteristics, but the impact of tinnitus on the individual must be measured subjectively with self-assessment questionnaires.  There are several published questionnaires to evaluate tinnitus severity and the impact it has on an individual’s activities, emotions and relationships. However, most of these questionnaires were not designed specifically to measure the effect of tinnitus treatments (Kamalski et al., 2010), so their value as follow-up measures is unknown.

Tinnitus affects as many as 50 million Americans and can have disabling effects including: sleep interference, difficulty concentrating and attending, anxiety, frustration and depression (for review see Tyler & Baker, 1983; Stouffer & Tyler, 1990; Axelsson, 1992; Meikle 1992; Dobie, 2004b). There are numerous methods of treatment available, including hearing aids, tinnitus maskers, tinnitus retraining therapy, biofeedback, counseling and others. Because there is currently no standard assessment tool to evaluate tinnitus treatment outcomes, the effectiveness of tinnitus treatment methods is difficult to verify and compare. The Tinnitus Functional Index (TFI) was developed as a collaborative effort among researchers and clinicians to develop a validated, standard questionnaire that can be used clinically for intake assessments and follow-up measurements and in the laboratory as a way of comparing treatment efficacy and identifying subject characteristics.

The developers of the TFI aimed for this inventory to be used in three ways:

1. As an intake evaluation tool to identify individual differences in tinnitus patients.
2. As a reliable and valid measurement of multiple domains of tinnitus severity.
3. As an outcome measure to assess treatment-related change in tinnitus.

The study, supported by a grant from the Tinnitus Research Consortium (TRC), had three stages. The first stage involved consultation with 21 tinnitus experts, including audiologists, otologists and hearing researchers. The panel of experts evaluated 175 items from nine previously published tinnitus questionnaires and judged them based on their relevance to 10 tinnitus negative impact domains as well as their expected responsiveness, or ability to measure treatment-related improvement. After analyzing the content validity, relevance and potential responsiveness of the 175 items (Haynes et al., 1995), 43 items were selected for the first questionnaire prototype. The TRC initially required that 10 domains of negative tinnitus impact be covered by the TFI but this expert panel added three additional domains so that the first prototype of the TFI covered 13 domains of tinnitus impact. The TRC also recommended avoiding overly negative items (such as those referring to suicidal thoughts or feeling victimized or helpless), items referring to hearing loss without mentioning tinnitus and items referring to more than one subtopic. Each domain had at least three or four items, based on recommendations for achieving adequate reliability (Fabrigar et al., 1999; Moran et al., 2001).  Each questionnaire item probed respondents for a rating on a scale of 0 to 10, based on how they experienced their tinnitus “over the past week”. For example, a typical question read, “Over the past week, how easy was it for you to cope with your tinnitus?” with potential responses from 0 being “very easy to cope” and 10 being “impossible to cope”.

During the second stage of the study, TFI Prototype 1 was tested on 326 tinnitus patients at five independent clinical sites.  The goals for the second stage were to determine the responsiveness of items or their ability to reflect changes in tinnitus status, to evaluate the 13 tinnitus impact domains and to determine the TFI’s ability to scale tinnitus severity. The questionnaire was administered at the initial intake assessment, after 3 months and after 6 months.  In addition to completing the TFI, at the initial encounter the subjects completed a brief tinnitus history questionnaire, The Tinnitus Handicap Inventory (THI; Newman et al., 1996) and the Beck Depression Inventory-Primary Care (BDEI-PC; Beck et al., 1997).  The TFI was re-administered to 65 subjects after 3 months and again to 42 subjects after 6 months.

The researchers found that subjects had very few problems responding to the 43 selected items and that most questionnaires were fully completed. There were no floor or ceiling effects, indicating that there were no items for which responses clustered at either end of the scale, reducing the potential responsiveness of the item.  The TFI had very high convergent validity, which means it agreed well with other published scales of tinnitus severity, such as the THI.  There were large effect sizes, demonstrating that the Prototype 1 items had good responsiveness for treatment-related change and supporting use of the TFI as an outcome measure. Factor analysis of the 13 initial tinnitus impact domains yielded 8 clearly structured domains, which were retained for the second prototype.

The third stage of the study involved development and evaluation of TFI Prototype 2, which was modified based on validity and reliability measurements from the first prototype. Prototype 2 included the 30 best-functioning items from the first version, categorized according to 8 tinnitus impact domains. It was administered to 347 new participants at the initial assessment. Follow-up data were obtained from 155 participants after 3 months and from 85 participants after 6-months. Encouragingly, the results from clinical evaluation of Prototype 2 again showed good performance for all of the validity and reliability measurements, supporting its use for scaling tinnitus severity.

The best performing items from Prototype 2 were used to create the final version of the TFI, which contains 25 items in 8 domains or sub-scales: Intrusive, Sense of Control, Cognitive, Sleep, Auditory, Relaxation, Quality of Life and Emotional. Seven of the domains contain 3 items and the Quality of Life domain contains 4 items.

When used during the initial assessment, the TFI categorizes tinnitus severity according to five levels: not a problem, a small problem, a moderate problem, a big problem or a very big problem.  As a screening tool, this allows a clinician to determine the overall severity of the tinnitus to help formulate a treatment plan and consider whether referrals to other clinical professionals are needed. For example, an individual who scores in the “not a problem” level may require only brief reassurance and counseling and may be asked to follow-up only if symptoms progress. In contrast, an individual who scores in the “big problem” or “very big problem” categories will likely need referrals for additional diagnostic and therapeutic services right away.

The developers of the TFI acknowledge that their study is preliminary and more research is needed to determine the TFI’s value as an outcome measurement tool. However, based on their analyses they recommend that a change in TFI score of 13 should be considered meaningful. In other words, a decrease of 13 or more indicates an improvement based on treatment recommendations or an increase in 13 or more indicates a significant exacerbation of symptoms.

Most tinnitus self-report questionnaires were designed to assess tinnitus impact but do not specifically measure treatment outcomes. The Tinnitus Handicap Inventory (THI; Newman et al., 1996), however, has shown some promise as an initial evaluation tool and as a way to measure treatment outcome.  After formulation of the final version of the TFI, the effect sizes of the TFI were compared to the THI. Overall, the TFI had greater responsiveness, indicating that it could potentially yield statistically significant differences with fewer subjects than the THI would require. Evaluation of subs-scale domains yielded some differences between the TFI and THI, primarily related to the “Catastrophic” subscale of the THI. Most of these items were not included in the TFI, based on the TRC’s recommendations to avoid questions dealing with negative ideation. The TRC recommended against inclusion of items relating to despair inability to escape tinnitus and fear of having a terrible disease, because they may suggest to people with mild tinnitus that they will eventually have these concerns, creating feelings of negativity before treatment has started.  Because these items on the THI correlated only moderately with the more neutrally worded items on the TFI, the authors suggested that the THI Catastrophic subscale might measure a different severity domain than the TFI and may be useful in combination with the THI as an outcome measure.

The Tinnitus Functional Index (TFI), like other previously published tinnitus questionnaires, shows promise as a tool to measure and classify tinnitus severity. It is easy for respondents to understand the test items and can be administered briefly at or prior to the initial appointment. An additional benefit of the TFI appears to be its validity as an outcome measure of treatment effectiveness. This is critically important for guiding clinical decisions and modifying ongoing treatment plans. It also suggests that the TFI could be useful in laboratory research as a standardized way to evaluate and compare tinnitus treatment methods or to identify subject characteristics for inclusion in treatment groups. For instance, if a treatment is expected to affect the negative emotional impact of tinnitus more than the functional impact, the TFI could be useful in identifying appropriate subject candidates who are experiencing strong emotional reactions to their tinnitus. The Tinnitus Functional Index (TFI) is one of the most systematically validated methods of assessing a patient’s reaction to their tinnitus. Ease of application and interpretation place the TFI among the most compelling assessment options for clinicians working with tinnitus patients.

If you would like to use the TFI. It is now available on a website posted by Oregon Health & Science University (OHSU). OHSU owns the copyright to the TFI and permission is required by OHSU to use the TFI. The request form takes 3 minutes to complete and allows you access to the TFI form and instructions. You will then be able to use the TFI with no fee.

http://www.ohsu.edu/xd/health/services/ent/services/tinnitus-clinic/tinnitus-functional-index.cfm

References

Axelsson, A. (1992). Conclusion to Panel Discussion on Evaluation of Tinnitus Treatments. In J.M. Aran & R. Dauman (Eds) Tinnitus 91. Proceedings of the Fourth International Tinnitus Seminar (pp. 453-455). New York, NY: Kugler Publications.

Beck, A.T., Guth, D. & Steer, R.A. (1997). Screening for major depression disorders in medical in patients with the Beck Depression Inventory for Primary Care. Behavioral Research and Therapy 35, 785-791.

Dobie, R.A. (2004b). Overview: Suffering From Tinnitus. In J.B. Snow (Ed) Tinnitus: Theory and Management (pp.1-7). Lewiston, NY: BC Decker Inc.

Fabrigar, L.R., Wegeners, D.T. & MacCallum, R.C. (1999). Evaluating the use of exploratory factor analysis in psychological research. Psychological Methods 4, 272-299.

Kamalski, D.M., Hoekstra, C.E. & VanZanten, B.G. (2010). Measuring disease-specific health-related quality of life to evaluate treatment outcomes in tinnitus patients: A systematic review. Otolaryngology Head and Neck Surgery 143, 181-185.

Meikle, M.B. (1992). Methods for Evaluation of Tinnitus Relief Procedures. In J.M. Aran & R. Dauman (Eds.) Tinnitus 91: Proceedings of the Fourth International Tinnitus Seminar (pp. 555-562). New York, NY: Kugler Publications.

Meikle, M.B., Henry, J.A., Griest, S.E., Stewart, B.J., Abrams, H.B., McArdle, R., Myers, P.J., Newman, C.W., Sandridge, S., Turk, D.C., Folmer, R.L., Frederick, E.J., House, J.W., Jacobson, G.P., Kinney, S.E., Martin, W.H., Nagler, S.M., Reich, G.E., Searchfield, G., Sweetow, R. & Vernon, J.A. (2012). The Tinnitus Functional Index:  Development of a new clinical measure for chronic, intrusive tinnitus. Ear & Hearing 33(2), 153-176.

Moran, L.A., Guyatt, G.H. & Norman, G.R. (2001). Establishing the minimal number of items for a responsive, valid, health-related quality of life instrument. Journal of Clinical Epidemiology 54, 571-579.

Newman, C.W., Jacobson, G.P. & Spitzer, J.B. (1996). Development of the Tinnitus Handicap Inventory. Archives of Otolaryngology Head and Neck Surgery 122, 143-148.

Stouffer, J.L. & Tyler, R. (1990). Characterization of tinnitus by tinnitus patients. Journal of Speech and Hearing Disorders 55, 439-453.

Tyler, R. & Baker, L.J. (1983). Difficulties experienced by tinnitus sufferers. Journal of Speech and Hearing Disorders 48, 150-154.