Research paper Acoustic stimulation treatments against tinnitus could be most effective when tinnitus pitch is within the stimulated frequency range Roland Schaette a, b, c, * ,1 , Ovidiu König d,1 , Dirk Hornig d , Manfred Gross d , Richard Kempter a, b, e a Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43,10115 Berlin, Germany b Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115 Berlin, Germany c UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, United Kingdom d Department of Audiology and Phoniatrics, Charité, Medical Faculty of Berlin, Augustenburger Platz 1, 13353 Berlin, Germany e Neuroscience Research Center, Charité, Medical Faculty of Berlin, Charitéplatz 1,10117 Berlin, Germany article info Article history: Received 7 July 2009 Received in revised form 22 June 2010 Accepted 28 June 2010 Available online 7 July 2010 abstract Acoustic stimulation with hearing aids or noise devices is frequently used in tinnitus therapy. However, such behind-the-ear devices are limited in their high-frequency output with an upper cut-off frequency of approximately 5e6 kHz. Theoretical modeling suggests that acoustic stimulation treatments with these devices might be most effective when the tinnitus pitch is within the stimulated frequency range. To test this hypothesis, we conducted a pilot study with 15 subjects with chronic tinnitus. Eleven subjects received hearing aids and four subjects noise devices. Perceived tinnitus loudness was measured using a visual analog scale, and tinnitus-related distress was assessed using the Tinnitus Questionnaire. After six months of device usage, reductions of perceived tinnitus loudness were seen only in subjects with a tinnitus pitch of less than 6 kHz. When subjects were grouped by tinnitus pitch, the group of patients with a tinnitus pitch of less than 6 kHz (n ¼ 10 subjects) showed a significant reduction in perceived tinnitus loudness (from 73.4  6.1 before to 56.4  7.4 after treatment, p ¼ 0.012), whereas in subjects with a tinnitus pitch of 6 kHz or more (n ¼ 5 subjects) tinnitus loudness was slightly increased after six months of treatment (65.0  4.7 before and 70.6  5.9 after treatment), but the increase was not significant (p ¼ 0.063). Likewise, tinnitus-related distress was significantly decreased in the low-pitch group (from 31.6  4.3 to 20.9  4.8, p ¼ 0.0059), but not in the group with high-pitched tinnitus (30.2  3.3 before and 30.0  5.1 after treatment, p ¼ 1). Overall, reductions in tinnitus-related distress in our study were less pronounced than those reported for more comprehensive treatments. However, the differences we observed between the low- and the high-pitch group show that tinnitus pitch might influence the outcome of acoustic stimulation treatments when devices with a limited frequency range are used. Ó 2010 Elsevier B.V. All rights reserved. 1. Introduction Tinnitus, the perception of a phantom sound in the absence of a corresponding external acoustic stimulus, is a frequent phenomenon; its prevalence in adults is estimated to be about 10e15% (Hoffman and Reed, 2004; Henry et al., 2005). In most cases, tinnitus is not experienced as bothersome, but for about 1e2% of the population, tinnitus symptoms seriously affect the quality of life (Axelsson and Ringdahl, 1989; Pilgramm et al., 1999). Several lines of evidence point to a relation between tinnitus and hearing loss: The majority of tinnitus patients have a certain degree of hearing loss (Axelsson and Ringdahl, 1989; Nicolas-Puel et al., 2002), the hearing thresholds of subjects with tinnitus have been reported to be elevated compared to age-matched controls (Roberts et al., 2008), and signs of limited cochlear deafferentation could be demonstrated in subjects with normal audiograms and tinnitus (Weisz et al., 2006). Furthermore, the slopes of the audiograms of subjects with noise-induced hearing loss and tinnitus have been found to be significantly steeper than those of subjects with noise-induced hearing loss without tinnitus (König et al., 2006). Finally, the perceived pitch of the tinnitus sensation usually corresponds to frequencies where hearing is impaired (Henry et al., 1999; Noreña et al., 2002; König et al., 2006; Roberts et al., 2008). * Corresponding author. UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, United Kingdom. Tel.: þ44 2076798946; fax: þ44 2076798990. E-mail address: r.schaette@ucl.ac.uk (R. Schaette). URL: http://www.dr-koenig-hno.de 1 Both authors contributed equally. Contents lists available at ScienceDirect Hearing Research journal homepage: www.elsevier.com/locate/heares 0378-5955/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.heares.2010.06.022 Hearing Research 269 (2010) 95e101