Lockwood et al. continue the description of findings originally presented in 1998, which suggest that plastic reorganization within the brain could be associated with tinnitus. Their findings further support Jastreboff’s postulate from 1990 that tinnitus is the phantom auditory perception.

Neuroanatomy of tinnitus. Lockwood AH, Salvi RJ, Burkard RF, Galantowicz PJ, Coad ML, Wack DS. Department of Neurology, VA Western New York Healthcare System and State University of New York, University at Buffalo, 14215, USA. alan@petnet.buffalo.edu. Scand Audiol Suppl 1999;51:47-52

We tested the hypothesis that tinnitus was due to excessive spontaneous activity in the central auditory system by seeking cerebral blood flow (CBF) changes that paralleled changes in the loudness of tinnitus in patients able to alter the loudness of their tinnitus. We found CBF changes in the left temporal lobe in patients with right ear tinnitus, in contrast to bilateral temporal lobe activity associated with stimulation of the right ear. The tones activated more extensive portions of the brain in patients than controls. We conclude that tinnitus is not cochlear in origin and associated with plastic transformations of the central auditory system. We suggest that tinnitus arises as a consequence of these aberrant new pathways and may be the auditory system analog to phantom limb sensations in amputees.

Somatic (craniocervical) tinnitus and the dorsal cochlear nucleus hypothesis. Levine RA. Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston 02114-3096, USA. Am J Otolaryngol 1999 Nov-Dec;20(6):351-62

PURPOSE: Of all nonauditory sensory systems, only the somatosensory system seems to be related to tinnitus (eg, temporomandibular joint syndrome and whiplash). The purpose of this study is to describe the distinguishing characteristics of tinnitus associated with somatic events and to use these characteristics to develop a neurological model of somatic tinnitus. MATERIALS AND METHODS: Case series. RESULTS: Some patients with tinnitus, but no other hearing complaints, share several clinical features including (1) an associated somatic disorder of the head or upper neck, (2) localization of the tinnitus to the ear ipsilateral to the somatic disorder, (3) no vestibular complaints, and (4) no abnormalities on neurological examination. Pure tone and speech audiometry of the 2 ears is always symmetric and usually within normal limits. Based on these clinical features, it is proposed that somatic (craniocervical) tinnitus, like otic tinnitus, is caused by disinhibition of the ipsilateral dorsal cochlear nucleus. Nerve fibers whose cell bodies lie in the ipsilateral medullary somatosensory nuclei mediate this effect. These neurons receive inputs from nearby spinal trigeminal tract, fasciculus cuneatus, and facial, vagal, and glossopharyngeal nerve fibers innervating the middle and external ear. CONCLUSIONS: Somatic (craniocervical) modulation of the dorsal cochlear nucleus may account for many previously poorly understood aspects of tinnitus and suggests novel tinnitus treatments.

Similarities between severe tinnitus and chronic pain. Moller AR. University of Texas at Dallas, School of Human Development, Callier Center for Communication Disorders, 75235, USA. J Am Acad Audiol 2000 Mar;11(3):115-24

The symptoms and signs of severe tinnitus and chronic pain have many similarities and similar hypotheses have been presented regarding how the symptoms are generated. Pain and tinnitus have many different forms. The severity of the symptoms of both varies within wide limits, and it is not likely that all forms have the same pathology. Some individuals with severe tinnitus perceive sounds to be unpleasant or painful. This may be similar to what is known as allodynia, which is a painful sensation of normally innocuous stimulation of the skin. Many individuals with chronic pain experience a worsening of their pain from repeated stimulation (the "wind-up" phenomenon). This is similar to the increasingly unpleasant feeling from sounds that are repeated that many individuals with severe tinnitus experience. There are also similarities in the hypotheses about the generation of pain and tinnitus. Although less severe tinnitus may be generated in the ear, it is believed that severe tinnitus in many cases is caused by changes in the nervous system that occur as a result of neural plasticity. Acute pain caused by tissue injury is generated at the site of injury but chronic pain is often generated in the central nervous system, yet another similarity between chronic pain and severe tinnitus. The changes in the nervous system consist of altered synaptic efficacy including opening of dormant synapses. For pain, this is believed to occur in the wide dynamic range neurons of the spinal cord and brain stem. Less is known about the anatomic location of the changes that cause severe tinnitus but there are indications that it may be the inferior colliculus. It is also possible that other auditory systems than the classical ascending pathways may be involved in severe tinnitus.

Acupuncture continues to attract attention, in spite of a series of reports showing lack of its effectiveness. Recent papers presented below are typical - open studies show some promise, but double blind studies did not demonstrate any beneficial effect of acupuncture.

Efficacy of acupuncture as a treatment for tinnitus: a systematic review. Park J, White AR, Ernst E. Department of Complementary Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, England. J.B.Park@exeter.ac.uk. Arch Otolaryngol Head Neck Surg 2000 Apr;126(4):489-92

BACKGROUND: Tinnitus is a prevalent condition for which patients may seek treatment with acupuncture since no conventional treatment has been shown to be effective. OBJECTIVE: To summarize and critically review all randomized controlled trials on the efficacy of acupuncture as a treatment for tinnitus. DATA SOURCES: Four independent computerized literature searches (MEDLINE, Cochrane Controlled Trials Register, Embase, and CISCOM) were conducted in December 1998 using the key words acupuncture and tinnitus. STUDY SELECTION: All randomized controlled trials that compared any form of acupuncture with any control intervention in the treatment of tinnitus were included. DATA EXTRACTION: Data were extracted by 2 authors independently. The methodological quality of the included randomized controlled trials was assessed using the Jadad score. DATA SYNTHESIS: Six randomized controlled trials were included in the review, 4 of which used crossover design. Four studies used manual acupuncture and 2 used electroacupuncture. Five of 6 studies used inconsistent acupoints. Three studies scored 3 points or more on the Jadad scale. MAIN OUTCOME MEASURES: Outcome measurements were visual analog scale scores for loudness, annoyance, and awareness of tinnitus; subjective severity scale scores for tinnitus; or Nottingham Health Profile scores. RESULTS: Two unblinded studies showed a positive result, whereas 4 blinded studies showed no significant effect of acupuncture. CONCLUSION: Acupuncture has not been demonstrated to be efficacious as a treatment for tinnitus on the evidence of rigorous randomized controlled trials.

[The effect of traditional Chinese acupuncture on severe tinnitus. A double-blind, placebo-controlled clinical study with an open therapeutic surveillance]. [Article in Danish] Nielsen OJ, Moller K, Jorgensen KE. Horeklinikken, Vejle Sygehus. Ugeskr Laeger 1999 Jan 25;161(4):424-9

The aim of the present study was to determine the effect of intensive acupuncture on severe tinnitus. The structure of the study was a randomized, double-blind, clinical investigation with open therapeutic surveillance and included 54 patients. All were subjected to 25 treatment sessions over a period of two months, each treatment lasting 30 minutes. Fifty-two patients completed the study. The variables used for self-registration were based on the Visual Analogue Scale, where annoyance, loudness and awareness of the tinnitus were assessed. These were recorded twice daily over a four month period starting one month before the first treatment and ending one month after the last treatment. Questionnaires, interviews and audiometry were carried out repeatedly. No statistically significant differences were found between the acupuncture group and the placebo group.

A study of the noise hazard to employees in local discotheques. Lee LT. Department of Industrial Health, Ministry of Manpower, Singapore. Singapore Med J 1999 Sep;40(9):571-4

AIM OF STUDY: There is growing concern that amplified music in discotheques can cause hearing loss. This study attempts to evaluate the noise hazard of employees exposed to amplified music in our discotheques. METHOD: Employees comprising of disc jockeys, bartenders, waiters, cashiers and security officers of five selected discotheques were used for the study. Personal noise dosimetry was carried out on 40 employees throughout their workshift. The audiometric examination results of another 46 employees were compared with 37 subjects from a non-exposed match control group. RESULTS: The range of exposure to noise level above 85 dBA for the employees is 3.6 to 6.9 hours with a mean of 5.1 hours. All the occupational groups are exposed to noise level of at least 89 dBA Leq for their whole work shift. The discotheque group has statistically significant higher prevalence (41.9%) of early sensorineural hearing loss compared to the control group (13.5%). A higher proportion of employees in the older age group (above 30 years old) and working longer (above 1 year) suffer from hearing loss. A significant proportion of the discotheque study subjects (21%) also complained of recurrent tinnitus compared to 2.7% in the control group. The younger (< 30 years) and those with shorter exposure duration (< 1 year) appeared to complain of tinnitus more. CONCLUSION: The study shows that all the employees regardless of occupations are exposed to noise above the permissible level of 85 dBA Leq A high proportion of them also suffer from early sensorineural hearing loss and tinnitus.

[Acute hearing loss and tinnitus caused by amplified recreational music]. [Article in German] Metternich FU, Brusis T. Hals-Nasen-Ohrenklinik des Universitatskrankenhauses Hamburg-Eppendorf. Laryngorhinootologie 1999 Nov;78(11):614-9

BACKGROUND: Hearing loss resulting from exposure to permanent or repeated amplified music in professional musicians and music consumers is described in literature. The risk of hearing loss does not exist only after prolonged exposure to music. Short-term exposure to very high sound levels, for example in concerts, can also cause hearing loss and tinnitus. PATIENTS: The retrospective study includes 24 patients who required rheologic therapy between 1994 and 1997 due to a music related acoustic trauma. The type, intensity, and length of music exposure as well as the distance and the position to the source of noise were examined. The type of hearing damage and its development during rheological treatment was studied by pure-tone audiometry. RESULTS: In the majority of examined patients (67%) the hearing loss developed on the basis of one-time exposure at a rock concert or pop concert, followed by hearing loss from attending discotheques (17%) or parties (12%), and music exposure from personal cassette players (4%). The majority of patients showed a maximum hearing loss of 40-60 dB (A) in a frequency between 3 kHz and 4 kHz. Pure-tone audiometry in 58% of the patients exhibited a unilateral threshold in a frequency between 3 kHz and 4 kHz combined with ipsilateral tinnitus of the same frequency. Twenty-one percent of the patients showed a symmetric bilateral threshold and tinnitus between 3 kHz and 4 kHz. In 8% there was a unilateral tinnitus, and in 13% a bilateral tinnitus without any hearing loss. All patients improved their hearing loss during rheologic treatment. Improvement in the tinnitus was only achieved in 33% of the examined cases. CONCLUSION: The risk of permanent hearing loss resulting from short-term exposure to amplified music is low compared to the risk of continuous tinnitus. Given the lack of acceptance of personal ear protectors, the risk of acute hearing damage due to amplified music could be reduced by avoiding the immediate proximity to the speakers.

Aural symptoms and signs of temporomandibular disorder in association with treatment need and visits to a physician. Kuttila S, Kuttila M, Le Bell Y, Alanen P, Jouko S. Department of Otorhinolaryngology, Otonhammas, Jyvaskyla, Finland. Laryngoscope 1999 Oct;109(10):1669-73

OBJECTIVES: To analyze associations between aural symptoms and clinical signs of and treatment need for temporomandibular disorders, as well as visits to a physician, in a Finnish population. STUDY DESIGN: A longitudinal study of a random sample of adults. METHODS: Four hundred eleven subjects (203 men and 208 women aged 25, 35, 45, 55, or 65 years at baseline) were examined and interviewed at three consecutive examinations at 12-month intervals, and a questionnaire on visits to physician during the preceding 12 months was completed. RESULTS: The aural symptoms were common. The prevalence of otalgia without infection varied between 12% and 16%, while the prevalence of tinnitus and fullness of ears was 12% to 17% and 5% to 9%, respectively. Women had more aural symptoms than men. When compared with the other subjects, the subjects with aural symptoms more often had masticatory muscles that were tender to palpation or temporomandibular joint signs. Subjects with obvious treatment need for temporomandibular disorders had more aural symptoms than subjects in the other treatment need subgroups. They also visited a physician more often because of otalgia than the subjects with otalgia in the other treatment need subgroups. CONCLUSIONS: In patients with otalgia, infectious otolaryngologic diseases should be ruled out. Then the patients without infection should be remitted to a dentist with stomatognathic experience. In the absence of temporomandibular disorders, further medical consultations (e.g., otorhinolaryngological, neurological, physiatric, and psychiatric) are indicated.

[Tinnitus and deafness]. [Article in French] Dauman R. Unite d'audiologie, INSERM EMI 99-27, CHU de Bordeaux Universite Victor-Segalen-Bordeaux 2 Hopital Pellegrin. Rev Prat 2000 Jan 15;50(2):165-8

The relationships between tinnitus and hearing loss are studied from a clinical prospect. Five critical points are discussed. 1. Some degree of hearing loss is found in the vast majority of tinnitus patients; but an individual may well have a sensorineural hearing loss and no tinnitus at all. 2. A minor adjunction to the neurophysiological model of Jastreboff is proposed to take account of the association between tinnitus and hearing loss. 3. Tinnitus appears to cause more distress when hearing loss is marked. 4. Self-reported hearing loss should be considered when implementing habituation sound therapy. 5. According to McKinney, the rate of success on tinnitus that can be expected with habituation sound therapy is not significantly affected by hearing level.

Principles of functional magnetic resonance imaging: application to auditory neuroscience. Cacace AT, Tasciyan T, Cousins JP. Department of Surgery, Albany Medical College, New York 12208, USA. J Am Acad Audiol 2000 May;11(5):239-72

Functional imaging based on magnetic resonance methods is a new research frontier for exploring a wide range of central nervous system (CNS) functions, including information processing in sensory, motor, cognitive, and linguistic systems. Being able to localize and study human brain function in vivo, in relatively high resolution and in a noninvasive manner, makes this a technique of unparalleled importance. In order to appreciate and fully understand this area of investigation, a tutorial covering basic aspects of this methodology is presented. We introduce functional magnetic resonance imaging (fMRI) by providing an overview of the studies of different sensory systems in response to modality-specific stimuli, followed by an outline of other areas that have potential clinical relevance to the medical, cognitive, and communicative sciences. The discussion then focuses on the basic principles of magnetic resonance methods including magnetic resonance imaging, MR spectroscopy, fMRI, and the potential role that MR technology may play in understanding a wide range of auditory functions within the CNS, including tinnitus-related activity. Because the content of the material found herein might be unfamiliar to some, we provide a broad range of background and review articles to serve as a technical resource.

Henry and Meikle’s review paper confirms the consensus that neither tinnitus loudness nor other psychoacoustic measures of tinnitus are related to its severity or perceived tinnitus loudness. This postulate was one of the bases of the neurophysiological model of tinnitus and of Tinnitus Retraining Therapy.

Psychoacoustic measures of tinnitus. Henry JA, Meikle MB. VA RR&D National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Oregon 97207, USA. J Am Acad Audiol 2000 Mar;11(3):138-55

This report reviews research from the 1930s to the present that has extended our understanding by investigating the characteristics of tinnitus that can be studied using psychoacoustic techniques. Studies of tinnitus masking and residual inhibition began in the 1970s, leading to the therapeutic use of tinnitus masking and a consequent increase in research devoted to tinnitus measurement. In 1981, the CIBA Foundation symposium on tinnitus advocated general adoption of four tinnitus measures: (1) pitch, (2) loudness, (3) maskability, and (4) residual inhibition. Since then, psychoacoustic research into all four topics has proliferated, yielding many valuable insights and controversies concerning the details of measurement techniques. A consensus has emerged that neither the loudness nor other psychoacoustic measures of tinnitus bear a consistent relation to the severity or perceived loudness of tinnitus. Nevertheless, quantification is needed in clinical trials of proposed treatments and in a variety of other types of tinnitus research. Standardization of techniques for specifying the acoustic parameters of tinnitus thus continues to be an important research goal.

The acoustic reflex threshold: not predictive for loudness perception in normally-hearing listeners. Olsen SO, Rasmussen AN, Nielsen LH, Borgkvist BV. Department of Otorhinolaryngology, Head and Neck Surgery, Copenhagen University Hospital, Rigshospitalet, Denmark. Audiology 1999 Nov-Dec;38(6):303-7

The working hypothesis of an ongoing study is that the quick and reliable procedure of acoustic reflex threshold (ART) determination in conjunction with measurements of HTL may yield accurate estimates of loudness. The aim of this study was to investigate whether differences in loudness in normally-hearing subjects are reflected in the ARTs and to collect normal material with respect to pure-tone elicited ART and loudness categories. Categorical loudness scaling (CLS) and ART measurements were performed at frequencies of 0.5, 1, 2 and 4 kHz in 60 normally-hearing subjects (HTL<20 dB HL, 26 males, 34 females, aged 21-63 years) with no history or sequelae of middle ear disease. Subjects reporting disturbing tinnitus were excluded. The results show that the ART is not a predictor of individual loudness perception for normally-hearing subjects. Using a numerical scale (HTL=0, 'very soft'=5, 'soft'=15, 'OK'=25, 'loud'=35, 'very loud'=45 and 'too loud'=50) loudness for pure tones grows almost linearly at approximately 0.4 arbitrary loudness units per dB below the 'loud' category. Above the 'loud' category the slope is around 1 unit per dB. The median ART was 85 dB HL at frequencies of 0.5, 1, 2 and 4 kHz. No differences in loudness perception across frequencies were found.

One-year audiologic monitoring of individuals exposed to the 1995 Oklahoma City bombing. Van Campen LE, Dennis JM, Hanlin RC, King SB, Velderman AM. Department of Otorhinolaryngology, University of Oklahoma School of Medicine, Oklahoma City, USA. J Am Acad Audiol 1999 May;10(5):231-47

This longitudinal study evaluated subjective, behavioral, and objective auditory function in 83 explosion survivors. Subjects were evaluated quarterly for 1 year with conventional pure-tone and extended high-frequencies audiometry, otoscopic inspections, immittance and speech audiometry, and questionnaires. There was no obvious relationship between subject location and symptoms or test results. Tinnitus, distorted hearing, loudness sensitivity, and otalgia were common symptoms. On average, 76 percent of subjects had predominantly sensorineural hearing loss at one or more frequencies. Twenty-four percent of subjects required amplification. Extended high frequencies showed evidence of acoustic trauma even when conventional frequencies fell within the normal range. Males had significantly poorer responses than females across frequencies. Auditory status of the group was significantly compromised and unchanged at the end of 1-year postblast.

The article by Jastreboff offers and outline of the neurophysiological model fo tinnitus and TRT, written purposefully for the audience of audiologist. Rauschecker’s review present compelling evidence of the high level of plasticity within human auditory system, presence of which is essential for developing tinnitus habituation.

Tinnitus Retraining Therapy (TRT) as a method for treatment of tinnitus and hyperacusis patients. Jastreboff PJ, Jastreboff MM. Tinnitus and Hyperacusis Center, Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. J Am Acad Audiol 2000 Mar;11(3):162-77

The aim of this paper is to provide information about the neurophysiologic model of tinnitus and Tinnitus Retraining Therapy (TRT). With this overview of the model and therapy, professionals may discern with this basic foundation of knowledge whether they wish to pursue learning and subsequently implement TRT in their practice. This paper provides an overview only and is insufficient for the implementation of TRT.

Auditory cortical plasticity: a comparison with other sensory systems. Rauschecker JP. Georgetown Institute for Cognitive and Computational Sciences, Washington, DC 20007, USA. Trends Neurosci 1999 Feb;22(2):74-80

The auditory cortex has a crucial role in higher cognitive functions, including the perception of speech, music and auditory space. Cortical plasticity, as in other sensory systems, is used in the fine tuning of the auditory system for these higher functions. Auditory cortical plasticity can also be demonstrated after lesions of the cochlea and it appears to participate in generating tinnitus. Early musical training leads to an expansion in the representation of complex harmonic sounds in the auditory cortex. Similarly, the early phonetic environment has a strong influence on speech development and, presumably, on the cortical organization of speech. In auditory spatial perception, the spectral cues generated by the head and outer ears vary between individuals and have to be calibrated by learning, which most probably takes place at the cortical level. The neural mechanisms of plasticity are likely to be the same across all cortical regions. It should be useful, therefore, to relate some of the findings and hypotheses about auditory cortical plasticity to previous studies of other sensory systems.

Pharmacology

Salicylate is a gold standard for inducing tinnitus in animals. The comprehensive article by Cazals’ offer an excellent review of data relating salicylate and tinnitus, and will be of great use for those working on animals models of tinnitus.

Auditory sensori-neural alterations induced by salicylate. Cazals Y. Inserm EPI 9902 Pathologies de l'oreille interne et rehabilitation, Laboratoire Otologie NeuroOtologie, Faculte de Medecine Nord, Univ. Mediterranee Aix-Marseille II, Boulevard Pierre Dramard, 13916 20, Marseille Cedex, France. Prog Neurobiol 2000 Dec 15;62(6):583-631

Early after the development of aspirin, almost 150 years ago, its auditory toxicity has been associated with high doses employed in the treatment of chronic inflammatory diseases. Tinnitus, loss of absolute acoustic sensitivity and alterations of perceived sounds are the three auditory alterations described by human subjects after ingestion of large doses of salicylate. They develop over the initials days of treatment but may then level off, fluctuate or decrease, and are reversible within a few days of cessation of treatment. They may also occur within hours of ingestion of an extremely large dose. Individual subjects vary notably as to their susceptibility to salicylate-induced auditory toxicity. Tinnitus may be the first subjective symptom, and is often described as a continuous high pitch sound of mild loudness. The hearing loss is slight to moderate, bilaterally symmetrical and affects all frequencies with often a predominance at the high frequencies. Alterations of perceived sounds include broadening of frequency filtering, alterations in temporal detection, deterioration of speech understanding and hypersensitivity to noise. Behavioral conditioning of animals provides evidence for mild and reversible hearing loss and tinnitus, similar to those observed in humans. Anatomical examinations revealed significant alterations only at outer hair cell lateral membrane. Electrophysiological investigations showed no change in endocochlear resting potential, and small changes in the compound sensory potentials, cochlear microphonic and summating potential, at low acoustic levels. Measures of cochlear mechanical responses to sounds indicated a clear loss of absolute sensitivity and an associated broadening of frequency filtering, both of a magnitude similar to audiometric alterations in humans, but at extremely high salicylate levels. Otoacoustic emissions demonstrated changes in the mechano-sensory functioning of the cochlea in the form of decrease of spontaneous emissions and reduced nonlinearities. In vitro measures of isolated outer hair cells showed reduction of their fast motile responses which are thought to be at the origin of cochlear absolute sensitivity and associated fine filtering. Acoustically evoked neural responses from the eighth nerve to the auditory cortex showed reversible and mild losses of absolute sensitivity and associated broadening of frequency filtering. There is no evidence of a direct alteration of cochlear efferent innervation. Evidence was obtained for decreases in cochlear blood supply under control of autonomous innervation. Spontaneous neural activity of the auditory nerve revealed increases in firings and/or in underlying temporal synchronies. Similar effects were found at the inferior colliculus, mostly at the external nucleus, and at the cortex, mostly at the anterior and less at the secondary auditory cortex but not at the primary auditory cortex. These changes in spontaneous activity might underlie tinnitus as they affect mostly neural elements coding high frequencies, can occur without a loss of sensitivity, are dose dependent, develop progressively, and are reversible. Biochemical cochlear alterations are poorly known. Modifications of oxydative phosphorylation does not seem to occur, involvement of inhibition of prostaglandin synthesis appears controversial but could underlie changes in blood supply. Other biochemical alterations certainly also occur at outer hair cells and at afferent nerve fibers but remain unknown.

A review of evidence in support of a role for 5-HT in the perception of tinnitus. Simpson JJ, Davies WE. Department of Pharmacology, Division of Neuroscience, Medical School, University of Birmingham, Vincent Drive, B15 2TT, Birmingham, UK. Hear Res 2000 Jul;145(1-2):1-7

Tinnitus is a debilitating condition from which some 0.5-1% of the population of the Western world suffer sufficiently badly as to interfere with their normal working and leisure life. There is no satisfactory treatment at the present time and the uncertainty surrounding the mechanism of its generation makes it difficult to devise an effective cure. After much debate, the consensus of opinion amongst researchers regarding its site of origin is that it is primarily a central nervous system pathology although there certainly exists a class of patients whose tinnitus is peripherally based. In this paper, we provide some speculative ideas on how an initial auditory insult can be translated into central neurological substrates that represent tinnitus. Plastic changes arising from sensory deprivation trigger a change in synaptology and neurotransmission with a consequent change in receptor configuration. From neuroanatomical considerations and analogies with other clinical conditions, we postulate the involvement of serotonin (5-HT) in these plastic changes and consider the evidence available from the use of serotonergic drugs in different conditions. A possible relationship between 5-HT and lidocaine is also discussed.

Changes in Blood Serotonin in Patients with Tinnitus and Other Vestibular Disturbances. Sachanska T. National Center of Hygiene, Medical Ecology, and Nutrition, Sofia, Bulgaria. Int Tinnitus J 1999;5(1):24-26

The role of serotonin as a mediator and stress hormone and its function in vessel tonus regulation is proved. The aim of the work is to study the concentration of serotonin in blood in patients with vestibular disturbances before and after vestibular provocation and in patients with tinnitus. The study was performed on 134 persons distributed among three groups: group I, 35 patients with vestibular disturbances; group II, 75 healthy persons; group III, 24 patients with tinnitus. Serotonin was examined twice in patients with vestibular disturbances (group I) and in healthy persons (group II), before and 15 minutes after vestibular provocation realized by a cold caloric test, and once in patients with tinnitus (group III). Vestibular loading provokes changes in blood serotonin: In vestibularly stable persons, serotonin decreases and comparatively weaker vestibular vegetative reactions develop. The role of serotonin in the compensatory mechanisms of the organism related to vestibular crisis is discussed. We recommend its inclusion with routine neurootological examinations for selecting candidates for work in conditions that overload the vestibular analyzer. Patients with tinnitus have serotonin blood values that significantly exceed the referent ones.

Endogenous Dynorphins: Possible Role in Peripheral Tinnitus. Sahley TL, Nodar RH, Musiek FE. Departments of Speech and Hearing, and Biology, Cleveland State University, Cleveland OH. Int Tinnitus J 1999;5(2):76-91

Tinnitus has been defined as the perceptual correlate of altered spontaneous neural activity occurring without an external auditory stimulus. Hyperacusis, defined as a collapse of tolerance to sound, is present in 40-86% of those who suffer from disabling forms of tinnitus. Both phenomena often are induced or exacerbated by physical or psychological stress. Biological systems known to regulate the body's overall response to stress use and release endogenous neuroactive opioid peptides. These stress-related neuromodulators consist of products derived from three genetically distinct precursor hormones. Two of these precursor hormones are proenkephalin and prodynorphin. Enkephalin and dynorphin-related peptides exist within the efferent olivocochlear systems (lateral and medial) of several mammalian species, including humans. Prodynorphin derivatives, however, may be restricted exclusively to lateral efferent neurons. Descending lateral efferent axons terminate solely on primary (type I) auditory dendrites innervating cochlear inner hair cells in most species. This action indicates that they play an important role in modulating auditory nerve sensitivity and spontaneous discharge. In a fashion similar to that exhibited by the observed excitatory mechanism of action of dynorphins in the spinal cord, sodium salicylate (aspirin) recently was shown to facilitate the excitatory effects of glutamate in the cochlea. This article provides support for a neurochemical model in which endogenous dynorphins may induce hyperacusis and can contribute to the induction, maintenance, or exacerbation of tinnitus in the auditory periphery by altering auditory type I neural excitability to glutamate.

Detrimental effects of alcohol on tinnitus. Stephens D. Welsh Hearing Institute, University Hospital of Wales, Heath Park, Cardiff, UK. Clin Otolaryngol 1999 Apr;24(2):114-6

The present study has examined the detrimental effects which alcohol has on tinnitus in a consecutive series of 51 patients seen in a tinnitus clinic and reporting such an effect. Eighty-four per cent of those studied reported that the level of the tinnitus was increased by the alcohol, 73% that they became more aware of it, and 47% that it increased the effect of the alcohol on their sleep. Compared with patients reporting beneficial effects on tinnitus, they consumed less alcohol, they comprised a higher proportion of younger females, and they were more likely to report that their tinnitus was worse the next day. There were no marked differences between the effects of different types of alcohol.

Recently there has been a renewed interest in lidocaine administration for tinnitus, with the goal of achieving long term positive effects. While the short term effectiveness of lidocaine in attenuationg tinnitus perception has been well established in past, at the moment there are no data supporting the long term effectiveness of lidocaine treatment. Papers by Weinmeister and Staffen offer an attempt to investigate the validity of such an approach.

Local gentamicin administration is one of popular approaches for Meniere disease which by definition involves a specific subtype of tinnitus with unique mechanisms based on endolymphatic hydrops. Eklund et al. report indicate a beneficial effect of this treatment for this specific type of tinnitus. However, their data cannot be directly transformed and applied to tinnitus not associated with Menieres, which presumably has totally different mechanisms of generation.

Prolonged suppression of tinnitus after peripheral nerve block using bupivacaine and lidocaine. Weinmeister KP. Department of Anesthesiology, Mayo Clinic Hospital, Phoenix, Arizona 85054, USA. Reg Anesth Pain Med 2000 Jan-Feb;25(1):67-8

OBJECTIVE: The local anesthetic lidocaine has been shown to suppress tinnitus, albeit very temporarily, when administered intravenously. Long-term suppression by local anesthetics has not been reported. Bupivacaine has not been studied. Here we report a case of prolonged (1-month) suppression of tinnitus following a peripheral nerve block performed with lidocaine and bupivacaine. CASE REPORT: A 57-year-old man undergoing facet and sacroiliac infiltration with lidocaine and bupivacaine experienced symptoms of systemic local anesthetic toxicity. He described significant perioral numbness. Shortly after this the patient noted that his long-standing and severe tinnitus was completely gone. Follow-up 1 month later revealed the tinnitus had not returned. Longer-term follow-up was not possible because the patient died. CONCLUSIONS: There are no reports regarding the use of bupivacaine for suppression of tinnitus. Although previous reports studying lidocaine for this purpose have shown only a brief effect, the use of bupivacaine or a combination of lidocaine and bupivacaine, as in this case, may represent a treatment for tinnitus that is worth further investigation. There currently is no effective long-term therapy for this debilitating problem.

The effect of lidocaine on chronic tinnitus: a quantitative cerebral perfusion study. Staffen W, Biesinger E, Trinka E, Ladurner G. Neurological Department, Landesnervenklinik Salzburg, Austria. Audiology 1999 Jan-Feb;38(1):53-7

The cerebral perfusion of a 55-year-old female patient with chronic tinnitus was investigated quantitatively by single photon emission computed tomography (SPECT) with the xenon133 inhalation method. The first investigation was performed under standard conditions, the second during suppression of tinnitus with intravenous injection of lidocaine. As a reference a healthy volunteer was included under the same conditions. The global cortical perfusion was identical on both sides except for increased perfusion in the auditory cortex, especially on the right side when tinnitus lasted during the first measurement. The second investigation under treatment with lidocaine and during the tinnitus-free interval showed a decrease of the global cortical perfusion with a slightly higher value at the temporal cortex bilaterally. In comparison to the first investigation, a difference between right and left auditory cortex could no longer be demonstrated, and also the difference between regional and global perfusion decreased. A cerebral effect under treatment of tinnitus with lidocaine was shown by the quantitative measurement of brain perfusion. It is debatable whether this effect on cerebral activity results from the medication or as a reaction to the tinnitus-free interval.

Effect of intratympanic gentamicin on hearing and tinnitus in Meniere's disease. Eklund S, Pyykko I, Aalto H, Ishizaki H, Vasama JP. Am J Otol 1999 May;20(3):350-6. Department of Otolaryngology, University Hospital of Helsinki, Finland.

OBJECTIVE: The objective of this study was to examine the effect of intratympanically applied gentamicin (GM) (30 mg/mL) on hearing and tinnitus in patients with intractable Meniere's disease. STUDY DESIGN: A prospective study was conducted on 93 subjects treated with intratympanically applied GM. The mean pure-tone average (PTA) at speech frequencies was measured before the treatment and after 2 weeks, 1 month, 3 months, 6 months, 1 year, and 2 years after injections. Tinnitus was surveyed with a questionnaire. The mean duration of Meniere's disease was 9.8 years (range, 1-33 years). PATIENTS: The study group consisted of 28 men and 65 women. The mean age was 50.9 years (range, 19-74 years). RESULTS: The mean PTA at speech frequencies for the group worsened from 60 dB to 68 dB, which was statistically significant. Ten ears were deafened. The mean tinnitus handicap score before treatment was 2.92; 2 years after treatment, it was 2.26, indicating significant abatement of tinnitus during the course of the treatment. CONCLUSIONS: The authors found that the average frequency of deafening was 10% and it was dose dependent. GM caused alleviation of tinnitus in the majority of the patients.

Savastano & Maron’s paper offers another support to consensus non-auditory aspects being related with tinnitus severity (see Henry & Meikle abstract).

Importance of Behavior in Response to Tinnitus Symptoms. Savastano M, Maron MB. Ear, Nose, and Throat Department, Padua University, Padua, Italy. Int Tinnitus J 1999;5(2):121-124

Among subjects affected by tinnitus, two groups are distinguished: patients who can cope positively with the symptom and patients who cannot cope with it. These differing attitudes suggest the necessity to study affected patients' "illness behavior" (i.e., a subjective interpretation of symptoms concerning body functioning). Our study considered 125 idiopathic tinnitus sufferers who requested a visit by an otorhinolaryngologist expressly for this symptom. All patients were invited to complete the illness behavior questionnaire (IBQ). IBQ mean score results were lower for affective inhibition and irritability and resulted in higher denial. Patients with more psychological suffering presented higher levels of hypochondria, disease convinction, and dysphoria. Results revealed a correlation between psychological suffering and tinnitus intensity: The group of patients with stronger psychological suffering included more subjects with a higher intensity level. The other group included more subjects with a moderate intensity level. Within the psychological evaluation of tinnitus sufferers, the IBQ results demonstrated particular sensitivity in revealing patients' nonadaptation area in coping with the symptom.

The influence of training on tinnitus perception: an evaluation 12 months after tinnitus management training. Dineen R, Doyle J, Bench J, Perry A. School of Human Communication Sciences, La Trobe University, Bundoora, Victoria, Australia. Br J Audiol 1999 Feb;33(1):29-51

Sixty-five subjects were reviewed 12 months after tinnitus management training, which had been comprised variously of information, relaxation training and a therapeutic noise strategy. Seventy-four per cent of subjects reported increased habituation to tinnitus (n = 48), 65% reported reduced tinnitus annoyance (n = 42), and 52% reported an increased ability to cope with tinnitus (n = 34). Twenty-five per cent of subjects reported deterioration in coping ability (n = 16), 23% reported reduced habituation to tinnitus (n = 15) and 8% reported increased tinnitus-related annoyance (n = 5). None of the management strategies were found to be significantly more effective than others in facilitating improved coping or habituation to tinnitus. Subjects who reported reduced coping and habituation to tinnitus experienced greater levels of general life stress than subjects who reported increased habituation and coping ability. The use of relaxation therapies as applied in this study did not appear to influence the level of tinnitus distress or the level of life stress. Thirty-seven per cent of subjects given long-term low-level white noise (LTWN) stimulation reported benefit. However, LTWN stimulation did not significantly alter tinnitus awareness or the minimum masking level (MML) of tinnitus. Long-term low-level white noise stimulation appeared to influence cognitive reaction to tinnitus rather than its physical perception. Subjects who initially had low ability to cope with tinnitus and preferred a more active coping style reported significantly greater benefit from LTWN stimulation than subjects whose primary approach to coping was to regulate the emotional impact of tinnitus.