CLINICS 2011;66(6):1089-1094 REVIEW Diagnosis and management of somatosensory tinnitus: review article Tanit Ganz Sanchez, Carina Bezerra Rocha Department of Otolaryngology, Faculdade de Medicina da Universidade de S a˜o Paulo, S a˜o Paulo/SP, Brazil. Tinnitus is the perception of sound in the absence of an acoustic external stimulus. It affects 10–17% of the world’s population and it a complex symptom with multiple causes, which is influenced by pathways other than the auditory one. Recently, it has been observed that tinnitus may be provoked or modulated by stimulation arising from the somatosensorial system, as well as from the somatomotor and visual–motor systems. This specific subgroup – somatosensory tinnitus – is present in 65% of cases, even though it tends to be underdiagnosed. As a consequence, it is necessary to establish evaluation protocols and specific treatments focusing on both the auditory pathway and the musculoskeletal system. KEYWORDS: auditory pathway; ear; neuroplasticity; myofascial pain syndrome; musculoskeletal. Sanchez TG, Rocha CB. Diagnosis and management of somatosensory tinnitus: review article. Clinics. 2011;66(6):1089-1094. Received for publication on January 16, 2011; First review completed on February 14, 2011; accepted for publication on February 24, 2011 E-mail: tanitsanchez@gmail.com Tel.: 55 11 3021 5251 DOI:10.1590/S1807-59322011000600028 INTRODUCTION Tinnitus is the perception of sound in the absence of an acoustic external stimulus.1 Its prevalence is roughly estimated as being between 10% and 17% of the population2 and it afflicts around a third of North Americans beyond the age of 55.3 For many years, tinnitus was thought to arise almost exclusively out of abnormal neuronal activity within the auditory pathways. However, accumulated evidence suggests that tinnitus-related neural activity is much more complex and multimodal than previously thought. More often than ever, researchers are concluding that tinnitus can be evoked or modulated by inputs from the somatosensory, somatomotor and visual–motor systems in some individuals.4–16 This means that the psychoacoustic attributes of tinnitus (loudness and pitch) might be changed immediately –though only temporarily – by different stimuli, such as the following: forceful muscle contractions of head, neck and limbs;4–6 eye movements in the horizontal or vertical axis,7–9 pressure on myofascial trigger points;10,11 cutaneous stimulation of the hand/fingertip region12 and of the face;13 electrical stimulation of the median nerve and hand;14 or finger movements15 as well as orofacial movements.16 This specific subgroup is called somatosensory tinnitus and it seems to be a good example of central integration of the central nervous system, because an auditory symptom like tinnitus may be modulated immediately after various non-audiology stimuli are presented. The modulation phenomenon is yet to be fully understood, but there is Copyright 2011 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 1089 scientific evidence of existing neural connections between somatosensory and auditory systems, and their "activation" may play a role in this type of tinnitus.17,18 In clinical practice, tinnitus is still considered as an untreatable symptom, and many professionals tell patients that ‘‘there is nothing to be done’’ or that ‘‘you have to learn to live with it’’. Consequently, the practical value of broadening our knowledge of somatosensory tinnitus is that it might make it possible to use various treatment approaches involving a multidisciplinary team (otolaryn- gologists, physiotherapists and dentists). As a result, it is necessary to establish specific protocols for somatosensory tinnitus, for both its diagnosis and treatment. LITERATURE REVIEW Tinnitus modulation Some authors have reported the existence of a connection between the proprioceptive and nociceptive afferents of the neck region as well as the cochlear nucleus – something that could explain ipsilateral correlation with tinnitus in cases of muscular tension.19,20 Furthermore, Levine21 suggested that somatic stimuli can disinhibit the ipsilateral cochlear nucleus, producing the excitatory neuronal activity within the auditory pathway that results in tinnitus. The structure of the auditory pathway consists of several well-defined centers, although precise information about their interaction is still lacking. The cochlear nucleus is the first central nucleus of the auditory pathway, receiving information from the cochlear hair cells. In higher portions of the auditory pathway, the lemniscal system sends received information to the primary cortical auditory areas, whereas the extralemniscal portion of the ascending path- ways transmits auditory information to associated areas. Many neurons of the extralemniscal system receive information from other sensorial tracts, such as the