Mitochondrial mutations in maternally inherited hearing loss.

BACKGROUND: Although the mitochondrial DNA (mtDNA) mutations m.1555A > G and m.3243A > G are the primary causes of maternally inherited sensorineural hearing loss (SNHL), several other mtDNA mutations are also reported to be associated with SNHL. METHODS: Screening of m.1555A > G and m.3243A > G mutations was performed for 145 probands. Nine probands fulfilled the following criteria: 1) bilateral and symmetric SNHL, 2) ≥ 4 family members with SNHL with a maternal trait of inheritance in ≥ 2 generations, 3) onset of SNHL before the age of 40 years, 4) high-frequency SNHL, and 5) no record of environmental factors related to SNHL. Sequencing of additional mtDNA regions was performed for five subjects meeting the clinical criteria, but the screening results were negative. RESULTS: Among the nine cases meeting the five clinical criteria detailed above, three had the m.1555A > G mutation in MTRNR1, one had a m.3243A > G mutation in MTTL1, and one case had a m.7511T > C mutation in MTTS1. In the family with the m.7511T > C mutation, penetrance of SNHL among maternally related subjects was 9/17 (53%). The age at onset varied from birth (congenital) to adulthood. Hearing levels varied from normal to moderately impaired, unlike previously reported subjects with this mutation, where some maternal family members presented with profound SNHL. Family members with the m.7511T > C mutation and SNHL did not exhibit any specific clinical characteristics distinct from those of other individuals with SNHL and different mtDNA mutations. Among the 136 probands who did not meet the criteria detailed above, one case had the m.1555A > G mutation, and three cases had the m.3243A > G mutation. CONCLUSIONS: Since five of nine probands with the clinical criteria used in this study had mtDNA mutations, these criteria may be helpful for identification of candidate patients likely to have mtDNA mutations.

[Usefulness and Limitation of Thyroglobulin Measurement in Fine Needle Aspirates (FNA-Tg) for Diagnosis of Neck Lymph Node Metastasis from Thyroid Carcinoma].

BACKGROUND: Preoperative diagnosis of lymph node metastasis from thyroid carcinoma is usually confirmed by using fine needle aspiration cytology (FNAC) when thyroid carcinoma is suspected based on the clinical findings. However, the result of FNAC sometimes leads to a false negative, especially in cases of hypocellular lesions such as metastases with cystic change. Thyroglobulin measurement in fine needle aspirates (FNA-Tg) has been shown to be a useful technique to detect the protein specifically secreted by thyroid follicular cells. Elevated FNA-Tg levels in an extra-thyroidal lesion means that the lesion comprises thyroid-originated tissue, most of which suggests the metastasis from thyroid carcinoma. Thus, FNA-Tg is expected to improve the sensitivity of FNAC for the aforementioned purpose. PATIENTS AND METHODS: From 2008 to 2012, 49 extra-thyroidal lesions from 43 patients with thyroid carcinoma were examined using both FNAC and FNA-Tg, followed by surgical resection with a histopathological diagnosis. The results were retrospectively reviewed and analyzed. RESULTS: Among 49 lesions, 47 were metastatic lymph nodes from thyroid carcinoma (46 papillary carcinoma and one follicular carcinoma), one was a metastatic lymph node from submandibular gland adenocarcinoma, and one was an ectopic thyroid gland. In the 47 cases of thyroid carcinoma, the sensitivity of FNAC was 57.4% (27/47), whereas that of FNA-Tg was 76.6% (36/47). When both methods were combined, the sensitivity increased to 93.6% (44/47). Metastasis from submandibular gland adenocarcinoma was considered to be an example of a false positive from FNAC, whereas an ectopic thyroid gland was an FNA-Tg false positive. Three lesions were negative for both FNAC and FNA-Tg, although metastases were suspected by imaging studies and confirmed by histopathological diagnosis, which were consistent with examples of a false negative from both FNAC and FNA-Tg findings. CONCLUSIONS: FNAC reflects whether the lesion has malignant cells, whereas FNA-Tg reflects whether the lesion has thyroid-originated tissue that specifically secrets thyroglobulin. Therefore, FNAC and FNA-Tg are considered to be complementary to each other for the preoperative diagnosis of lymph node metastasis from thyroid carcinoma. FNA-Tg was validated to improve the preoperative diagnostic sensitivity especially when combined with FNAC, however, it is attended with the possibility of a false positive or negative finding, which requires caution in interpretation of the findings.

[Long-term effects of tinnitus retraining therapy involving monaural noise generators].

We have previously reported on the effects of tinnitus retraining therapy (TRT) involving monaural noise generators (NGs) up to 24 months after the start of treatment (Eur Arch Otorhinolaryngol. 2013 Feb; 270(2) : 443-8.) but very few reports exist about the long-term effects of TRT for periods of over 2 years. The aim of this study was to report the effects of TRT involving monaural NGs more than 24 months after the start of treatment. Thirty-three patients with chronic tinnitus were included in this study. All received directive counseling and monaural NGs without any other combination treatment. Effects were evaluated with the Tinnitus Handicap Inventory (THI) at their final visits to our clinic (average 31 months after the start of treatment). The average THI scores significantly improved from 55.3 +/- 19.7 at baseline to 33.5 +/- 23.3 at their final visits. Seventeen patients (52%) improved by more than 20 points from the baseline. Eleven patients who were treated with TRT for more than 3 years were individually observed in a detailed manner. Some of them experienced aggravation of their symptoms after 2 years' successful treatments. This study suggests that, although TRT seems effective more than 2 years after the start of treatment, the clinical course of each patient can vary and we need to follow them periodically depending on their situations and symptoms.

Moderate hearing loss associated with a novel KCNQ4 non-truncating mutation located near the N-terminus of the pore helix.

Genetic mutation is one of the causative factors for idiopathic progressive hearing loss. A patient with late-onset, moderate, and high-frequency hearing loss was found to have a novel, heterozygous KCNQ4 mutation, c.806_808delCCT, which led to a p.Ser260del located between S5 and the pore helix (PH). Molecular modeling analysis suggested that the p.Ser269del mutation could cause structural distortion and change in the electrostatic surface potential of the KCNQ4 channel protein, which may impede K+ transport. The present study supports the idea that a non-truncating mutation around the N-terminus of PH may be related to moderate hearing loss.

Can the effectiveness of tonsillectomy for PFAPA syndrome be predicted based on clinical factors.

OBJECTIVES: To evaluate the clinical factors associated with the outcome of tonsillectomy in children with periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome, thereby clarifying who would most likely benefit from that surgery. METHODS: This was a case-control study of 53 PFAPA patients who underwent tonsillectomy and were divided into a complete-resolution group and a postoperative-fever group. Logistic regression analyses were performed using 17 clinical factors as variables to identify factors associated with the surgical outcome. Hierarchical cluster analysis was also performed to evaluate for relationships between phenotypes and surgical outcomes. RESULTS: Thirty-nine (73.6%) patients had complete resolution after tonsillectomy. In simple logistic regression analysis, the surgical outcome showed significant positive trends with late-onset (odds ratio [OR] 7.1, P = 0.02) and presence of headache (OR 6.5, P = 0.01). In stepwise multiple logistic regression analysis adjusted for age at onset, presence of headache was significantly associated with complete resolution (OR 6.5, P = 0.01). The complete resolution rates for each combination of headache status and age at onset were as follows: presence of headache/age at onset ≥36 months, 100% (14/14); presence of headache/age at onset <36 months, 76.9% (10/13); absence of headache/age at onset ≥36 months, 75.0% (6/8); and absence of headache/age at onset <36 months, 43.8% (7/16). In hierarchical cluster analysis, complete resolution, age at onset, and headache were in the same cluster. CONCLUSIONS: PFAPA patients with headache and late onset responded well to tonsillectomy. The mechanisms underlying this association may warrant further investigation.

Expression and function of Sox21 during mouse cochlea development.

The development of the inner ear is an orchestrated process of morphogenesis with spatiotemporally controlled generations of individual cell types. Recent studies have revealed that the Sox gene family, a family of evolutionarily conserved HMG-type transcriptional factors, is differentially expressed in each cell type of the mammalian inner ear and plays critical roles in cell-fate determination during development. In this study, we examined the expression pattern of Sox21 in the developing and adult murine cochlea. Sox21 was expressed throughout the sensory epithelium in the early otocyst stage but became restricted to supporting cells during adulthood. Interestingly, the expression in adults was restricted to the inner phalangeal, inner border, and Deiters' cells: all of these cells are in direct contact with hair cells. Evaluations of the auditory brainstem-response revealed that Sox21(-/-) mice suffered mild hearing impairments, with an increase in hair cells that miss their appropriate planar cell polarity. Taken together with the previously reported critical roles of SoxB1 families in the morphogenesis of inner ear sensory and neuronal cells, our results suggest that Sox21, a counteracting partner of the SoxB1 family, controls fine-tuned cell fate decisions. Also, the characteristic expression pattern may be useful for labelling a particular subset of supporting cells.

[Thyroglobulin concentration measurement in fine-needle aspiration fluid from cystic cervical lymph node metastases of papillary thyroid carcinoma].

BACKGROUND: Combining ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI) and fine-needle aspiration cytology (FNAC) usually results in the best preoperative diagnosis of cervical masses, including neoplasms. This may not be true, however, especially in occult papillary thyroid carcinoma (PTC) associated with single cystic cervical lymph node metastasis. We assessed the role of thyroglobulin measurement in FNA fluid (FNATg) in differentially diagnosing cystic cervical mass lesions, including PTC cystic lymph node metastasis. METHODS: We reviewed the records of 17 subjects with cervical cystic masses undergoing both FNATg measurement and surgery. FNA was done under ultrasonographic guidance. We also measured FNATg concentrations from extrathyroid lesions, consisting of cystic cervical lymph node metastases and benign cystic lesions. RESULTS: Pathological diagnosis involved 5 PTC lymph node metastases, 3 lateral cervical cysts, 7 thyroglossal duct cysts, and 2 squamous cell carcinoma (lung and oropharynx) lymph node metastases. FNATg of PTC lymph node metastasis was much higher than the reference range of blood serum thyroglobulin, although much lower for the lateral cervical cyst detection threshold. FNAC and FNATg measurement are thought to be mutually complementary in the differential diagnosis of PTC cystic lymph node metastasis. CONCLUSION: High concentrations of FNATg in a cystic cervical mass is considered specific to PTC lymph node metastasis, indicating its usefulness in distinguish PTC cystic metastasis from other cystic lesions. Including FNATg measurement with FNAC may thus improve preoperative diagnosis accuracy without additionally stressing subjects with PTC cystic lymph node metastasis.

Trk agonist drugs rescue noise-induced hidden hearing loss.

TrkB agonist drugs are shown here to have a significant effect on the regeneration of afferent cochlear synapses after noise-induced synaptopathy. The effects were consistent with regeneration of cochlear synapses that we observed in vitro after synaptic loss due to kainic acid-induced glutamate toxicity and were elicited by administration of TrkB agonists, amitriptyline, and 7,8-dihydroxyflavone, directly into the cochlea via the posterior semicircular canal 48 hours after exposure to noise. Synaptic counts at the inner hair cell and wave 1 amplitudes in the auditory brainstem response (ABR) were partially restored 2 weeks after drug treatment. Effects of amitriptyline on wave 1 amplitude and afferent auditory synapse numbers in noise-exposed ears after systemic (as opposed to local) delivery were profound and long-lasting; synapses in the treated animals remained intact 1 year after the treatment. However, the effect of systemically delivered amitriptyline on synaptic rescue was dependent on dose and the time window of administration: it was only effective when given before noise exposure at the highest injected dose. The long-lasting effect and the efficacy of postexposure treatment indicate a potential broad application for the treatment of synaptopathy, which often goes undetected until well after the original damaging exposures.

An antibody to RGMa promotes regeneration of cochlear synapses after noise exposure.

Auditory neuropathy is caused by the loss of afferent input to the brainstem via the components of the neural pathway comprising inner hair cells and the first order neurons of the spiral ganglion. Recent work has identified the synapse between cochlear primary afferent neurons and sensory hair cells as a particularly vulnerable component of this pathway. Loss of these synapses due to noise exposure or aging results in the pathology identified as hidden hearing loss, an initial stage of cochlear dysfunction that goes undetected in standard hearing tests. We show here that repulsive axonal guidance molecule a (RGMa) acts to prevent regrowth and synaptogenesis of peripheral auditory nerve fibers with inner hair cells. Treatment of noise-exposed animals with an anti-RGMa blocking antibody regenerated inner hair cell synapses and resulted in recovery of wave-I amplitude of the auditory brainstem response, indicating effective reversal of synaptopathy.

Single nucleotide polymorphisms in tinnitus patients exhibiting severe distress.

The association between distress caused by tinnitus and psychological factors such as depression and anxiety has been examined and reported. However, prognostic factors remain poorly understood because there are only a few reports on genetic associations. We theorized there might be an association between the grade of tinnitus distress and the genetic background related to psychological factors which might lead us to identify prognostic markers. We enrolled 138 patients who had suffered from tinnitus for over 3 months. Using Tinnitus Handicap Inventory (THI) scores, we examined the association between tinnitus distress and a genetic background related to depression or anxiety. A significant association between single nucleotide polymorphism rs131702 of the Breakpoint Cluster Region (BCR) gene and the severe THI score was identified. In addition, there was an association with the severity of the State-Trait Anxiety Inventory, an index of state anxiety severity. No association was found with the Self-Rating Depression Scale, an index of depression severity. It is reported that rs131702 of BCR in Japanese patients are related to bipolar II depression characterized by fluctuation between abnormal mood states of mania and depression. Our results indicate that rs131702 of BCR is independent of depression in this study and is, therefore, a prognostic factor unique to tinnitus. We conclude that the severity of tinnitus is associated with genes related to depression.

Age-related change of auditory functional connectivity in Human Connectome Project data and tinnitus patients.

BACKGROUND: We reported that tinnitus patients showed reduced levels of auditory functional connectivity (FC) in comparison with normal hearing control subjects, and that we succeeded in objective diagnosis of tinnitus with 86% sensitivity and 74% specificity by focusing only on auditory-related FC. However, the age-related change of auditory FC is not clarified. In this study, we examine age-related change of the auditory FC using the database of Human Connectome Project (HCP) and compared with our database of tinnitus patients. METHOD: From the HCP database HCP Lifespan Pilot project, we studied five age groups, 8 to 9 years old, 14 to 15, 25 to 35, 45 to 55, and 65 to 75. We also applied our tinnitus patients' resting-state functional magnetic resonance imaging (fMRI) database, which is divided into three generations; 20 to 40 years old, 40 to 60, and 60 to 80 to compare with the HCP database. The resting state fMRI analyses were performed using the CONN toolbox version 18. As auditory-related regions, Heschl's gyrus, planum temporale, planum polare, operculum, insular cortex, and superior temporal gyrus were set as the regions of interest from our previous reports. RESULT: Auditory FC is strongest among adolescents and reduces with age. But the auditory FC of tinnitus patients were significantly less than those of HCP data in each generation. CONCLUSION: Although auditory FC decreases with age, tinnitus patients have less auditory FC compared with age-matched controls. The age-matched cutoff values are necessary for an objective diagnosis of tinnitus with resting state fMRI.

Outpatient chemotherapy with S-1 for recurrent head and neck cancer.

BACKGROUND: This retrospective study evaluates the efficacy and safety of S-1 chemotherapy or S-1 followed by low-dose docetaxel chemotherapy for recurrent head and neck cancer. PATIENTS AND METHODS: S-1 was administered to 21 patients with recurrent head and neck cancer, in outpatient settings. Of these 21 patients, 8 were additionally administered a low dose of docetaxel fortnightly. RESULTS: The survival rate of patients with squamous cell carcinoma of the head and neck was 59.1% for 12 months and 17.5% for 24 months, with a median survival time of 18 months. Time to progression of more than 12 months was shown by 4 patients (22.2%). Most adverse events were mild (up to grade 2). CONCLUSION: S-1 therapy is considered a safe and effective treatment option. From the viewpoint of tumour dormancy, S-1 therapy is a useful vigorous anticancer treatment that can be provided while maintaining patients' quality of life in recurrent cases.

Auditory Related Resting State fMRI Functional Connectivity in Tinnitus Patients: Tinnitus Diagnosis Performance.

OBJECTIVE: The purpose of the present study was to investigate functional connectivity in tinnitus patients with and without hearing loss, and design the tinnitus diagnosis performance by resting state functional magnetic resonance imaging (rs-fMRI). SUBJECTS AND METHODS: Nineteen volunteers with normal hearing without tinnitus, 18 tinnitus patients with hearing loss, and 11 tinnitus patients without hearing loss were enrolled in this study. The subjects were evaluated with rs-fMRI, and region of interests (ROIs) based correlation analyses were performed using the CONN toolbox version 16 and SPM version 8. The correlation coefficients from individual level results were converted into beta values. RESULTS: With a beta threshold of more than 0.2, 91% of all possible connections between auditory-related ROIs (Heschl's gyrus, planum temporale, planum polare, operculum, insular cortex, superior temporal gyrus) in the control group remained intact, whereas 83 and 66% of such connections were present in the hearing loss and the normal-hearing tinnitus group. However, between non-auditory-related ROIs, the rates of intact connections at a beta threshold of more than 0.2 were 17% in the control group, and 16 and 15% in the tinnitus groups. When resting state fMRI positive is defined as less than 9% of all possible connections between auditory-related ROIs with a beta threshold of more than 0.7, the sensitivity and specificity of tinnitus diagnosis is 86 and 74%, respectively. CONCLUSIONS: The associations between auditory-related networks are weakened in tinnitus patients, even if they have normal hearing. It is possible that rs-fMRI can be a tool for objective examination of tinnitus, by focusing the auditory-related areas.

Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice.

Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K+ circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.

Hearing Loss Controlled by Optogenetic Stimulation of Nonexcitable Nonglial Cells in the Cochlea of the Inner Ear.

Light-gated ion channels and transporters have been applied to a broad array of excitable cells including neurons, cardiac myocytes, skeletal muscle cells and pancreatic ß-cells in an organism to clarify their physiological and pathological roles. Nonetheless, among nonexcitable cells, only glial cells have been studied in vivo by this approach. Here, by optogenetic stimulation of a different nonexcitable cell type in the cochlea of the inner ear, we induce and control hearing loss. To our knowledge, deafness animal models using optogenetics have not yet been established. Analysis of transgenic mice expressing channelrhodopsin-2 (ChR2) induced by an oligodendrocyte-specific promoter identified this channel in nonglial cells-melanocytes-of an epithelial-like tissue in the cochlea. The membrane potential of these cells underlies a highly positive potential in a K+-rich extracellular solution, endolymph; this electrical property is essential for hearing. Illumination of the cochlea to activate ChR2 and depolarize the melanocytes significantly impaired hearing within a few minutes, accompanied by a reduction in the endolymphatic potential. After cessation of the illumination, the hearing thresholds and potential returned to baseline during several minutes. These responses were replicable multiple times. ChR2 was also expressed in cochlear glial cells surrounding the neuronal components, but slight neural activation caused by the optical stimulation was unlikely to be involved in the hearing impairment. The acute-onset, reversible and repeatable phenotype, which is inaccessible to conventional gene-targeting and pharmacological approaches, seems to at least partially resemble the symptom in a population of patients with sensorineural hearing loss. Taken together, this mouse line may not only broaden applications of optogenetics but also contribute to the progress of translational research on deafness.

Auditory resting-state functional connectivity in tinnitus and modulation with transcranial direct current stimulation.

CONCLUSIONS: The functional connectivity (FC) between the right and left auditory cortex is weak in tinnitus patients. Transcranial direct current stimulation (tDCS) over the auditory cortex has potential as a tool to modulate auditory-based FC. OBJECTIVE: This study investigated the effects of applying tDCS in tinnitus patients, and searched for modulation of brain networks in resting-state functional magnetic resonance imaging (rs-fMRI) through an analysis of FC with the stimulated brain region. SUBJECTS AND METHODS: Nine male patients with chronic tinnitus and 10 male volunteers with normal hearing were enrolled. The subjects were evaluated with rs-fMRI immediately before and after tDCS. The tinnitus patients filled out the self-evaluation questionnaires designed to measure tinnitus conditions before tDCS treatment and 1 week afterwards. RESULTS: The FC between the right and left auditory cortex was significantly weaker in tinnitus patients than in controls. After tDCS treatment, in the tinnitus group, the primary auditory cortex showed a reduction in the amount of statistically significant connectivity with the somatosensory area and motor area, but maintained strong significant connectivity (p < 0.005) with the auditory area and insular cortex. In contrast, in the control group, there remained strong significant connectivity between the primary auditory cortex and the somatosensory area, motor area, insular cortex, and auditory area.

Hypertrophic chronic pachymeningitis associated with chronic otitis media and mastoiditis.

We describe the case history of a 70-year-old female patient presenting with bilateral hearing disturbance, facial paralysis, and vertigo. Radiological tests of temporal bone revealed soft tissue in the mastoid and tympanic cavities, and T1 weighted MRI revealed prominent Gd enhancement of the middle skull basal meninges. Middle ear inflammation appeared to induce pachymeningitis and to exacerbate associated symptoms, leading to a decline in the patient's overall condition. Bilateral mastoidectomies were effective in improving her general condition. Her hearing improved only on the right side because ossiculoplasty was performed only on that side. Her facial movement progressively improved and pachymeningitis diminished over time. We speculate that removal of the infectious granulation within the middle ears and mastoids ameliorated the acute inflammation. The etiology remains unknown in this case.

A psychometric validation of the Japanese versions of new questionnaires on tinnitus (THI-12, TRS, TRSw, TSS, and TSSw).

CONCLUSION: The Japanese version of the Tinnitus Handicap Inventory-12 (THI-12), Tinnitus Rating Scale (TRS), TRS 1-week version (TRSw), Tinnitus Severity Scale (TSS), and TSS 1-week version (TSSw), which were developed in this study, showed high reliability and validity, suggesting their usefulness in clinical practice. Based on the THI severity grades, we propose that the severity grades of THI-12 (draft) are categorized into four groups: 0-4 points, 5-9 points, 10-14 points, and 15-24 points. OBJECTIVES: We developed Japanese versions of new questionnaires for evaluating the level of psychological distress and difficulty in activities of daily living due to tinnitus, and performed their psychometric validation to determine the reliability and validity. The THI-12 is an assessment consisting of 12 items, each of which is rated on a 3-point scale that was created by reducing the number of questions from the 25 items of the THI. The TRS, TRSw, TSS, and TSSw, which were self-evaluation questionnaires of tinnitus on an 11-grade integer Likert scale from 0 to10 points, were used as additional instruments to assess tinnitus severity and distress. METHODS: The subjects were healthy adults, and patients with subjective tinnitus who were examined at the Otolaryngology Department of Keio University Hospital, Osaka City University Hospital, or Nagoya City University Hospital with a chief complaint of tinnitus between September 2010 and January 2011. In all, 38 healthy adult subjects and 113 patients with subjective tinnitus were included. We examined the reproducibility and the internal consistency for reliability. We also examined the relationship with the available scales (THI and Hospital Anxiety and Depression Scale, HADS) and group divergence for validity. RESULTS: The psychometric validation showed high reliability and validity of the THI-12, TRS, TRSw, TSS, and TSSw.

Repetitive transcranial magnetic stimulation (rTMS) for treatment of chronic tinnitus.

OBJECTIVE: There is compelling evidence that tinnitus is associated with functional alterations in the central nervous system. Repetitive transcranial magnetic stimulation (rTMS) is a potent tool for modifying neural activity at the stimulated area and at a distance along the functional anatomical connections. Depending on the stimulation parameters, cortical networks can be functionally disturbed or modulated in their activities. Low-frequency rTMS has been shown to result in a decrease in cortical excitability. The technique can alleviate tinnitus by modulating the excitability of neurons in the auditory cortex. We aimed to investigate the effects of low-frequency rTMS in patients and determine the factors that predict a beneficial outcome with rTMS treatment. METHODS: Sixteen patients (male 10, female 6) with chronic tinnitus underwent low-frequency (1Hz) rTMS (intensity: 110% motor threshold; number of stimuli: 1200) to the left auditory cortex. The treatment outcome was assessed with a visual analog scale (VAS) of loudness, annoyance and duration, loudness balance test, and tinnitus handicap inventory (THI). Therapeutic success was studied according to the patients' clinical characteristics. RESULTS: A significant reduction in the VAS (loudness and annoyance) occurred immediately after rTMS, with a gradual return to pretreatment levels after 7 days. The tinnitus patients with sudden deafness were significant resistant to rTMS treatment compared with those diagnosed with age-related hearing loss. CONCLUSION: These results support the potential of rTMS as a new therapeutic tool for the treatment of chronic tinnitus. Because this study was performed with a small sample size and showed high interindividual variability in treatment effects, further development of the technique is needed before it can be recommended for clinical applications.