To the Editor:

We were pleased to see the article bySindhusake et al on ‘Factors predicting sever-ity of tinnitus: a population-based assess-ment,’ published in a recent issue of the Jour-nal of the American Academy of Audiology(Sindhusake et al, 2004). Population-basedstudies like the Blue Mountains HearingStudy and the Epidemiology of Hearing LossStudy can provide valuable informationregarding prevalence of tinnitus and associ-ated risk factors.

There are two errors, however, in theSindhusake et al article that we would liketo bring to the attention of your readers. Inthe introduction (page 271) of Sindhusake etal, our recent paper, ‘Prevalence and 5-yearincidence of tinnitus among older adults: theEpidemiology of Hearing Loss Study’ (Non-dahl et al, 2002) is discussed. In that dis-cussion, Sindhusake et al report that ourstudy defined tinnitus as “tinnitus of at leastmoderate intensity, which was defined astinnitus that caused difficulty in fallingasleep.” Later in the same report (page 275),Sindhusake et al write that our definition oftinnitus was “tinnitus of at least moderateannoyance that causes difficulty in fallingasleep.” These two descriptions of Nondahlet al definitions are quite different, and unfor-tunately, both are incorrect. In Nondahl etal (2002), a person was classified as havingsignificant tinnitus if “their tinnitus was atleast moderate in severity or caused diffi-culty in falling asleep.”

The distinction is important. Increasingtinnitus severity does not always lead to dif-ficulties in falling asleep (Coles, 1984; Axels-son and Ringdahl, 1989). In our study, 308participants in our baseline examinationwere classified as having significant tinnitus.Among these, 285 (92.5%) rated their tinni-tus as moderate or severe, with only 46 of the285 (16.1%) having difficulties falling asleepas a result of their tinnitus. The remaining23 did not rate their tinnitus as moderate orsevere, but did have difficulties falling asleepdue to their tinnitus and so were classified ashaving significant tinnitus due to the func-tional impact of the tinnitus on their lives.

There is no single agreed upon definitionof tinnitus in the literature, so it is particu-larly important to be precise about definitionsused when making comparisons across stud-ies. Thank you for this opportunity to informyour readers about the above errors so thatfuture cross-study comparisons with resultsfrom the Epidemiology of Hearing Loss Studyare not based on misinformation that couldlead to incorrect conclusions.

David M. NondahlBarbara E. K. Klein

Ronald KleinDepartment of Ophthalmology

and Visual SciencesUniversity of Wisconsin Medical School

Karen J. CruickshanksTed S. Tweed

Department of Ophthalmology and Visual Sciences

Department of Population Health SciencesUniversity of Wisconsin Medical School

Terry L. WileyDepartment of Speech and Hearing Science

Arizona State University

REFERENCES

Axelsson A, Ringdahl A. (1989) Tinnitus---a study ofits prevalence and characteristics. Brit J Audiol23:53-62.

Coles RRA. (1984) Epidemiology of tinnitus: (1) preva-lence. J Laryngol Otol 9 (suppl.):7-15.

Nondahl DM, Cruickshanks KJ, Wiley TL, Klein R,Klein BEK, Tweed TS. (2002) Prevalence and 5-yearincidence of tinnitus among older adults: theEpidemiology of Hearing Loss Study. J Am AcadAudiol 13:323-331.

Sindhusake D, Golding M, Wigney D, Newall P,Jakobsen K, Mitchell P. (2004) Factors predictingseverity of tinnitus: a population-based assessment.J Am Acad Audiol 15:269-280.

Reply to Nondahl et al:

J Am Acad Audiol 16:196-197 (2005)

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Letters to the Editor