Photobiomodulation therapy in improvement of harmful neural plasticity in sodium salicylate-induced tinnitus.

Tinnitus is a common annoying symptom without effective and accepted treatment. In this controlled experimental study, photobiomodulation therapy (PBMT), which uses light to modulate and repair target tissue, was used to treat sodium salicylate (SS)-induced tinnitus in a rat animal model. Here, PBMT was performed simultaneously on the peripheral and central regions involved in tinnitus. The results were evaluated using objective tests including gap pre-pulse inhibition of acoustic startle (GPIAS), auditory brainstem response (ABR) and immunohistochemistry (IHC). Harmful neural plasticity induced by tinnitus was detected by doublecortin (DCX) protein expression, a known marker of neural plasticity. PBMT parameters were 808 nm wavelength, 165 mW/cm2 power density, and 99 J/cm2 energy density. In the tinnitus group, the mean gap in noise (GIN) value of GPIAS test was significantly decreased indicated the occurrence of an additional perceived sound like tinnitus and also the mean ABR threshold and brainstem transmission time (BTT) were significantly increased. In addition, a significant increase in DCX expression in the dorsal cochlear nucleus (DCN), dentate gyrus (DG) and the parafloccular lobe (PFL) of cerebellum was observed in the tinnitus group. In PBMT group, a significant increase in the GIN value, a significant decrease in the ABR threshold and BTT, and also significant reduction of DCX expression in the DG were observed. Based on our findings, PBMT has the potential to be used in the management of SS-induced tinnitus.

Electrophysiological and molecular changes following neuroprotective placental protein administration on tinnitus-induced rats.

Objective: Despite 6%-20% of the adult population suffering from tinnitus, there is no standard treatment for it. Placenta extract has been used for various therapeutic purposes, including hearing loss. Here, we evaluate the effect of a novel neuroprotective protein composition (NPPC) extract on electrophysiological and molecular changes in the medial geniculate body (MGB) of tinnitus-induced rats. Methods: To evaluate the protein analysis by western blot, the rats were divided into three groups: (1) saline group (intraperitoneal injection of 200 mg/kg saline twice a day for 28 consecutive days, (2) chronic Na-Sal group received sodium salicylate as in the first group, and (3) chronic treatment group (received salicylate 200 mg/kg twice daily for 2 weeks, followed by 0.4 mg NPPC daily from day 14 to day 28). Single-unit recordings were performed on a separate group that was treated as in group 4. Gap-prepulse inhibition of the acoustic startle (GPIAS) and pre-pulse inhibition (PPI) was performed to confirm tinnitus in all groups at the baseline, 14th and 28th days. Results: Western blot analysis showed that the expression of γ-Aminobutyric acid Aα1 subunit (GABA Aα1), N-methyl-d-aspartate receptor subtype 2B (NR2B or NMDAR2B), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR1 (GluR1), and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR2 (GluR2) decreased after Na-Sal injection, while NPPC upregulated their expression. MGB units in rats with tinnitus showed decreased spontaneous firing rate, burst per minute, and a spike in a burst. After NPPC administration, neural activity patterns showed a significant positive effect of NPPC on tinnitus. Conclusion: NPPC can play an effective role in the treatment of tinnitus in salicylate-induced rats, and MGB is one of the brain areas involved in these processes. Level of Evidence: NA.

The human neuroprotective placental protein composition suppressing tinnitus and restoring auditory brainstem response in a rodent model of sodium salicylate-induced ototoxicity.

The effect of neuroprotective placental protein composition (NPPC) on the suppression of tinnitus and the restoration of the auditory brainstem response (ABR) characteristics was explored in tinnitus-induced rats. The animals were placed into two groups: (1) the study group, rats received sodium salicylate (SS) at the dose of 200 mg/kg twice a day for two weeks, and then 0.4 mg of the NPPC per day, between the 14th and 28th days, (2) the placebo group, rats received saline for two weeks, and then the NPPC alone between the 14th and 28th days. The gap pre-pulse inhibition of the acoustic startle (GPIAS), the pre-pulse inhibition (PPI), and the ABR assessments were performed on animals in both groups three times (baseline, day 14, and 28). The GPIAS value declined after 14 consecutive days of the SS injection, while NPPC treatment augmented the GPIAS score in the study group on the 28th day. The PPI outcomes revealed no significant changes, indicating hearing preservation after the SS and NPPC administrations. Moreover, some changes in ABR characteristics were observed following SS injection, including (1) higher ABR thresholds, (2) lowered waves I and II amplitudes at the frequencies of 6, 12, and 24 kHz and wave III at the 12 kHz, (3) elevated amplitude ratios, and (4) prolongation in brainstem transmission time (BTT). All the mentioned variables returned to their normal values after applying the NPPC. The NPPC use could exert positive therapeutic effects on the tinnitus-induced rats and improve their ABR parameters.

Acoustic and optoacoustic stimulations in auditory brainstem response test in salicylate induced tinnitus.

As a common debilitating disorder worldwide, tinnitus requires objective assessment. In the auditory brainstem response (ABR) test, auditory potentials can be evoked by acoustic or optoacoustic (induced by laser light) stimulations. In order to use the ABR test in the objective assessment of tinnitus, in this study, acoustic ABR (aABR) and optoacoustic ABR (oABR) were compared in the control and tinnitus groups to determine the changes caused by sodium salicylate (SS)-induced tinnitus in rat. In both aABR and oABR, wave II was the most prominent waveform, and the amplitude of wave II evoked by oABR was significantly higher than that of aABR. Brainstem transmission time (BTT), which represents the time required for a neural stimulation to progress from the auditory nerve ending to the inferior colliculus, was significantly shorter in oABR. In the tinnitus group, there was a significant increase in the threshold of both ABRs and a significant decrease in the amplitude of wave II only in the oABR. Based on our findings, the ABR test has the potential to be used in the assessment of SS-induced tinnitus, but oABR has the advantages of producing more prominent waveforms and significantly reducing the amplitude of wave II in tinnitus.

Photobiomodulation therapy in mood disorders: a systematic review.

Mood disorders are common, debilitating and impose a high-cost burden on society. Side effects and resistance to psychiatric drugs justify finding new treatment methods. Photobiomodulation therapy (PBMT) uses photons of light to repair, modulate and improve the function of target tissue. The purpose of this study is to systematically review the use of PBMT for the treatment of mood disorders and to identify the useful parameters of PBMT, the level of evidence of its effectiveness, and the degree of its practical recommendation. "Google scholar," "Pub Med," "Scopus," and "Science direct" online databases were searched based on Preferred Reporting Items for Systematic Reviews and meta-analyses (PRISMA) guidelines. The human or animal studies written in English and published from January 2009 to August 2021 were included. Sixteen studies, which included four randomized controlled trials (RCTs), met the inclusion criteria. Infrared wavelength ranges from 800 to 830 nm, power density of 250 mW/cm2 and energy density of 60 to 120 J/ cm2 were the most used PBMT parameters. Bias risk assessment was performed to evaluate the quality of RCTs in which 2 out of 4 RCTs were evaluated as high quality. Based on grade practice recommendations, PBMT can be classified as strongly recommended for moderate grade of major depressive disorder (MDD) and recommended for anxiety disorder. In bipolar disorder, further studies are needed to recommend this therapeutic method.

Transcranial photobiomodulation in the management of brain disorders.

Transcranial photobiomodulation (tPBM) is the process of delivering light photons through the skull to benefit from its modifying effect. Brain disorders are important health problems. The aim of this review was to determine the existing evidence of effectiveness, useful parameters, and safety of tPBM in the management of traumatic brain injury, stroke, Parkinson, and Alzheimer's disease as the common brain disorders. Four online databases, including Cochrane, Pub Med, Embase, and Google scholar were searched according to the Preferred Reporting Items for Systematic Reviews and meta-analyses (PRISMA) guidelines. 4728 articles were obtained in the initial search. Only those articles that were published until September 2020 and designed as randomized clinical trials (RCTs) or animal-controlled studies were included. 6 RCTs, 2 related supplementary articles, and 38 controlled animal studies met the inclusion criteria of this study. No RCTs were performed in the fields of Alzheimer's and Parkinson's diseases. The human RCTs and animal studies reported no adverse events resulted from the use of tPBM. Useful parameters of tPBM were identified according to the controlled animal studies. Since the investigated RCTs had no homogenous results, making an evidence-based decision for definite therapeutic application of tPBM is still unattainable. Altogether, these data support the need for large confirmatory well-designed RCTs for using tPBM as a novel, safe, and easy-to-administer treatment of brain disorders. EVIDENCE BEFORE THIS STUDY: High prevalence and complications of brain disorders and also side effects of neuropsychiatric medications have encouraged researchers to find alternative therapeutic techniques which tPBM can be one of them. In present review we tried to determine the existing evidence of effectiveness, useful parameters, and safety of tPBM in the management of traumatic brain injury, stroke, Alzheimer, and Parkinson's disease as common brain disorders. Four online databases, including "Cochrane", "Pub Med", "Embase", and "Google scholar" were searched. Only those articles that were published until September 2020 and designed as RCTs or animal-controlled studies were included. Search keywords were the followings: transcranial photobiomodulation" OR "transcranial low-level laser therapy" AND "stroke" OR "traumatic brain injury" OR "Alzheimer" OR "Parkinson". Several studies have confirmed effectiveness of tPBM in treatment of different brain disorders but the level of evidence of its effectiveness remain to be determined. ADDED VALUE OF THIS STUDY: In this study we systematically reviewed human RCTs to determine the existing evidence of tPBM effectiveness in management of four mentioned brain disorders. Since the outcomes of the reviewed RCTs were not homogeneous, further well-designed RCTs are required to decide more definitively on the evidence of this noninvasive and probably safe therapeutic intervention. We hypothesized that non-homogeneous outcomes could be due to inefficiency of PBM parameters. Controlled animal studies have the advantage of using objective tests to evaluate the results and compare them with the control group. We determined useful tPBM parameters based on these studies. IMPLICATIONS OF ALL THE AVAILABLE EVIDENCE: This research is part of our main project of tinnitus treatment using photobiomodulation (PBM). Evidence of central nervous system involvement in tinnitus led us to believe that treatment protocol of tinnitus should also include transcranial PBM. The determined useful parameters can be helpful in designing more efficient tPBM protocols in the management of brain disorders and tinnitus as a common debilitating symptom that can be associated with these disorders.

Development and application of a tool to measure hearing health literacy of young people in the Islamic Republic of Iran.

BACKGROUND: A reliable and valid tool to assess hearing health literacy in Iranian young people is lacking. AIMS: This study aimed to develop a tool to assess the hearing health literacy of young people in the Islamic Republic of Iran and to use the tool to determine the hearing health literacy of a sample of Iranians aged 12-25 years. METHODS: A questionnaire was designed with three skill sections: obtaining health information, evaluating this information and applying it to benefit health. The validity and reliability of the tool were determined. Cluster sampling was used to select 50 urban clusters across the country from which 5000 Iranians aged between 12-25 years old were selected to complete the questionnaire. RESULTS: The final questionnaire had 22 items with scores ranging from 22 to 44. The Cronbach alpha was 0.65, and content validity ratio and index were 0.92 and 0.82, respectively. Of the 5000 questionnaires completed, 4890 were included in the analysis. The mean (standard deviation (SD)) age of the participants was 17 (SD 3) years and 45.9% were males. The mean score on the tool was 30.81 (SD 3.75), indicating inadequate health literacy (score 22-36). Only 137 (2.8%) participants had adequate health literacy (score 37-44). Statistically significant differences in mean hearing health literacy were seen for sex, age, years of education, occupation, marital status and income (P < 0.05). CONCLUSIONS: Given the low level of hearing health literacy in Iranian young people, programmes to improve the ear and hearing health literacy are urgently needed.

Situation Analysis of Ear and Hearing Care Program in Islamic Republic of Iran: System's Challenges and Proper Interventions.

Background: More than 6.8% of the world's population suffer from disabling hearing impairment. Hearing impairment can cause lifelong or even life-threatening problems and has a significant impact on the health and quality of life. This study aimed to analyze the current situation of the ear and hearing care (EHC) in the frame of Iran health system. Methods: This situation analysis was performed over a 5-year period (2013-2017) using the Strengths, Weaknesses, Opportunities, and Threats analysis method. First, after formation of the steering committee, all relevant published and unpublished articles and reports were reviewed and analyzed. In the next step, focused group discussion sessions (FGDs) were held with the participation of the experts, stakeholders, and Steering Committee members. Through the scissor-and-sort technique, the relevant data were highlighted and main categories evolved. Results: The main challenges included inadequate health literacy, weak intrasectoral and intersectoral cooperation, the inadequacy of policy responses, nonintegration of the EHC in the primary health care system, poor standard processes, and resources of EHC, and lack of EHC surveillance system. The 6 major interventions and strategies extracted as identifying the capacities of both the public and private sectors, reinforcement of intersectoral cooperation and intersectoral collaboration, standardizing the processes and integrating of EHC services in the PHC, reorganizing the referral system, promoting hearing health literacy, and minimizing hearing loss risk factors. Conclusion: Implementing the proposed interventions and strategies is essential to improve the situation of Iran EHC management system during the next 5 years.

Aberrant Frequency Related Change-Detection Activity in Chronic Tinnitus.

Tinnitus is the perception of sound without the occurrence of an acoustic event. The deficit in auditory sensory or echoic memory may be the cause of the perception of tinnitus. This study considered the mismatch negativity (MMN) to investigate the potential difference between and within groups of persons with normal hearing (NH) and tinnitus. Using an auditory multi-feature paradigm to elicit the MMN, this study considered the MMN peak amplitude at two central frequencies for two MMN subcomponents. These central frequencies were 1 and 5 kHz, which the latter was closer to the perceived tinnitus frequency in the group with tinnitus. The deviants were higher frequency, lower frequency, higher intensity, lower intensity, duration, location (left), location (right), and gap. The pure tone audiometry (PTA) test and distortion product otoacoustic emissions (DPOAE) test showed no meaningful difference between the two groups. For the frontal subcomponent, the mean amplitudes of the MMN peak for the two groups illustrated less negative meaningful MMN peak amplitudes in the group of persons with tinnitus. For the supratemporal component at 5 kHz central frequency, amplitudes were lower for the group of persons with tinnitus, whereas for the central frequency of 1 kHz, most deviants exhibited meaningful differences. Additionally, within-group comparisons indicated that mean amplitudes for both groups were more negative at the central frequency of 1 kHz for the frontal MMN subcomponent. In comparison, the supratemporal component illustrated a lower peak amplitude at 5 kHz central frequency in the group of persons with tinnitus and no difference in the NH group, which is a unique observation of this study. Results of the between-groups are in accordance with previous studies and within-group comparisons consider the probability of decreasing the change detection capability of the brain. The results of this study indicate that increasing the frequency of the stimuli close to the tinnitus perceived frequencies decreases the prediction error, including the prediction error of the silence. Such a decrease may cause the prediction error of the spontaneous neural activity in the auditory pathway to exceed the silence prediction error, and as a result, increases the probability of occurrence of tinnitus in higher frequencies according to the predictive coding model.

Impact of Acamprosate on Chronic Tinnitus: A Randomized-Controlled Trial.

OBJECTIVES: Tinnitus is a common and distressing otologic symptom, with various probable pathophysiologic mechanisms, such as an imbalance between excitatory and inhibitory mechanisms. Acamprosate, generally used to treat alcoholism, is a glutaminergic antagonist and GABA agonist suggested for treating tinnitus. Thus, we aimed to evaluate the efficacy and safety of acamprosate in the treatment of tinnitus. METHODS: The current randomized-controlled trial study included 20 subjects with chronic tinnitus. After performing psycho-acoustic, psychometric and electrophysiological evaluations, all studied tinnitus subjects were randomly divided into two groups of acamprosate and placebo. The first group received oral acamprosate (two tablets of 333 mg/d, three times a day), whereas the second group was given placebo treatment (two tablets, three times a day). After the first 30 days, all evaluations were repeated for the studied groups just in the same manner before the study. Subsequently, the final results of each evaluation were compared together with the baseline values. RESULTS: Nine studied subjects randomly received acamprosate, whereas eleven others received a placebo. There was no significant improvement in the psycho-acoustic tests, except a decrease was observed in the pitch match of tinnitus (P = .039). For those subjects who were receiving acamprosate, a significant reduction was observed in tinnitus handicap inventory (P = .006), tinnitus questionnaire scores (P = .007), and the visual analog scores (P = .007) compared to the placebo group. There was a significant reduction in Action Potential latency (P = .048) as well as an increase in the amplitude of distortion product otoacoustic emissions at 4 kHz (P = .048). CONCLUSIONS: The study results indicated a subjective relief of tinnitus as well as some degree of the electrophysiological improvement at the level of the cochlear and the distal portion of the auditory nerve among the subjects who received the acamprosate. CLINICAL TRIAL REGISTRATION CODE: IRCT2013121115751N1.

The investigation of semantic memory deficit in chronic tinnitus: a behavioral report / Investigação do déficit de memória semântica no zumbido crônico: um relato comportamental

Abstract Introduction: Tinnitus is a central auditory disorder in which different processing systems are involved as a network. One of these networks is memory. Previous studies have demonstrated some deficits in various types of memory in chronic tinnitus. Objectives: The main purpose of the present study was to investigate the semantic memory, which is not yet investigated in the tinnitus population. Methods: In this case-control study, 15 subjects with chronic tinnitus and 16 matched healthy controls were included. 40 semantically related and 40 semantically unrelated word pairs were presented to the participants in a counter-balanced fashion. They were asked to make decision about their semantic relatedness. Then the participants' reaction times and the accuracy of responses were calculated. Results: Mean of reaction times were significantly longer in the tinnitus group (M = 1034 ms, SD = 0.31) compared to the control group (Mean = 1016 ms, SD = 0.13), p < 0.05. However, no significant difference was found for the mean percentage of correct responses between the two groups. Conclusion: The current study provided behavioral evidence that chronic tinnitus can affect the semantic memory. Such behavioral outcomes may provide new insights into more research activities in the field of electrophysiology and neuroimaging in the tinnitus population.

Resumo Introdução: O zumbido é um distúrbio auditivo central, no qual diferentes sistemas de processamento estão envolvidos como em uma rede. Uma dessas redes é a memória. Estudos anteriores demonstraram alguns déficits em vários tipos de memória no zumbido crônico. Objetivos: Investigar a memória semântica, que ainda não foi investigada na população com zumbido. Método: Neste estudo de caso-controle, 15 indivíduos com zumbido crônico e 16 controles saudáveis pareados foram incluídos; 40 pares de palavras semanticamente relacionados e 40 semanticamente não relacionados foram apresentados aos participantes de forma contrabalançada. Eles foram instruídos a tomar decisões sobre sua relação semântica. Em seguida, os tempos de reação dos participantes e a precisão das respostas foram calculados. Resultados: A média dos tempos de reação foi significativamente maior no grupo com zumbido (M = 1,034 ms, DP = 0,31) em comparação ao grupo controle (média = 1,016 ms, DP = 0,13), p< 0,05. Entretanto, nenhuma diferença significante foi encontrada para a porcentagem média de respostas corretas entre os dois grupos. Conclusão: O presente estudo forneceu evidências comportamentais de que o zumbido crônico pode afetar a memória semântica. Tais resultados comportamentais podem levar a novas percepções em mais atividades de pesquisa no campo da eletrofisiologia e neuroimagem na população com zumbido.

The investigation of semantic memory deficit in chronic tinnitus: a behavioral report.

INTRODUCTION: Tinnitus is a central auditory disorder in which different processing systems are involved as a network. One of these networks is memory. Previous studies have demonstrated some deficits in various types of memory in chronic tinnitus. OBJECTIVES: The main purpose of the present study was to investigate the semantic memory, which is not yet investigated in the tinnitus population. METHODS: In this case-control study, 15 subjects with chronic tinnitus and 16 matched healthy controls were included. 40 semantically related and 40 semantically unrelated word pairs were presented to the participants in a counter-balanced fashion. They were asked to make decision about their semantic relatedness. Then the participants' reaction times and the accuracy of responses were calculated. RESULTS: Mean of reaction times were significantly longer in the tinnitus group (M=1034ms, SD=0.31) compared to the control group (Mean=1016ms, SD=0.13), p<0.05. However, no significant difference was found for the mean percentage of correct responses between the two groups. CONCLUSION: The current study provided behavioral evidence that chronic tinnitus can affect the semantic memory. Such behavioral outcomes may provide new insights into more research activities in the field of electrophysiology and neuroimaging in the tinnitus population.

The efficacy and safety of multiple sessions of multisite transcranial random noise stimulation in treating chronic tinnitus / Eficácia e segurança de múltiplas sessões de estimulação transcraniana por ruído aleatório multissítio no tratamento do zumbido crônico

Abstract Introduction: Random noise stimulation was reported as the more effective and safer type of electrical stimulation techniques in relieving tinnitus symptoms. The multisite protocol of transcranial random noise stimulation has shown additional favorable effects. Objective: Here we will discuss the role of applying eight sessions of multisite transcranial random noise stimulation in decreasing tinnitus loudness and annoyance without exerting additional adverse effects. Methods: Twenty-nine subjects (8 female), the mean age of (45.34 ± 9.57) with chronic tinnitus received transcranial random noise stimulation in the multisite protocol, 10 min of auditory-transcranial random noise stimulation applied over the T3, T4 preceded by 10 min of prefrontal-transcranial random noise stimulation applied over F4, FP1. In the first group, only one session was applied and the multiple-sessions group contained eight repeated sessions. Visual analog scale scores for loudness and distress were recorded before and immediately after the treatment. Multivariate repeated measure ANOVA test was used and minimal detectable change calculated. Results: There was a statistically and clinically significant reduction in tinnitus loudness and annoyance in both groups (p < 0.05, effect size (η 2) > 0.8), while the amount of annoyance suppression in the multiple-sessions group was significantly greater than the single-session group. The patients of the multiple-sessions transcranial random noise stimulation group reported an improvement in their sleep and lower tinnitus handicap inventory scores without experiencing any additional adverse effects of the intervention. Conclusions: The results of this study showed a substantial improvement in tinnitus symptoms by using the multiple sessions of transcranial random noise stimulation in the multisite protocol without producing any additional side effects. We suggest further clinical trials with long-term follow-up be investigated.

Resumo Introdução: Tem sido relatado que a estimulação transcraniana por ruído aleatório é um tipo mais eficaz e seguro de técnica de estimulação elétrica no alívio dos sintomas do zumbido. O protocolo multissítio da estimulação transcraniana por ruído aleatório mostrou efeitos favoráveis adicionais. Objetivo: Discutir o papel da aplicação de oito sessões de estimulação transcraniana por ruído aleatório multissítio na diminuição da intensidade (loudness) do som e incômodo (annoyance) do zumbido sem causar efeitos adversos adicionais. Método: Vinte e nove indivíduos com zumbido crônico (oito do sexo feminino), com média de 45,34 ± 9,57 anos, receberam estimulação transcraniana por ruído aleatório no protocolo multissítio, 10 minutos de estimulação transcraniana por ruído aleatório-auditivo aplicado no T3, T4 precedido por 10 min de estimulação transcraniana por ruído aleatório pré-frontal aplicado sobre F4, FP1. No primeiro grupo, apenas uma sessão foi aplicada e o grupo de múltiplas sessões recebeu oito sessões. Os escores da escala visual analógica para a intensidade do som (loudness) e incômodo (annoyance) do zumbido foram registrados antes e imediatamente após o tratamento. O teste Anova multivariada para medidas repetidas foi utilizado e a mudança mínima detectável foi calculada. Resultados: Houve uma redução estatisticamente e clinicamente significante na intensidade e incômodo do zumbido em ambos os grupos (p < 0,05; tamanho do efeito (η2) > 0,8), embora o nível de supressão do incômodo no grupo de sessões múltiplas tenha sido significantemente maior do que no grupo de sessão única. Os pacientes do grupo estimulação transcraniana por ruído aleatório com múltiplas sessões relataram uma melhoria no sono e menores escores no tinnitus handicap inventory, sem experimentar quaisquer efeitos adversos adicionais da intervenção. Conclusão: Os resultados deste estudo mostraram uma melhora substancial nos sintomas do zumbido utilizando múltiplas sessões de estimulação transcraniana por ruído aleatório no protocolo multissítio sem produzir quaisquer efeitos colaterais adicionais. Sugerimos que novos ensaios clínicos com seguimento de longo prazo sejam realizados.

Toward An Exploration of Habituating to Tinnitus: Perspectives on Sensory Gating.

BACKGROUND: Some tinnitus participants habituate to their tinnitus, but some others do not and complain of its annoyance so much. It has been suggested that tinnitus is a habituation deficit. Habituation and the ability to ignore a sensory input depend on the normal function of filtering mechanism of sensory gating. PURPOSE: The purpose of this study was to compare behavioral aspects of sensory gating in normal and tinnitus participants to search for the reason why some tinnitus participants habituate to their tinnitus but some others do not. RESEARCH DESIGN: This investigation was an observational case-control study. STUDY SAMPLE: There were 60 tinnitus participants who were categorized into two tinnitus groups (30 compensated tinnitus participants and 30 decompensated tinnitus participants) based on the complaint of tinnitus annoyance, visual analog scale (VAS) for tinnitus loudness, annoyance, and awareness, scores on Tinnitus Questionnaire (TQ), and Tinnitus Handicap Inventory (THI). Also, there were 30 normal hearing participants without tinnitus as the normal control group. DATA COLLECTION AND ANALYSIS: Sensory Gating Inventory (SGI), TQ, THI, and VAS was obtained from all participants. THI, TQ, VAS, and SGI total scores and their factors were compared among the groups. Correlations between SGI scores with THI, TQ, and VAS score were calculated. RESULTS: The results showed that SGI total score and the scores of its four factors were significantly higher in decompensated tinnitus participants compared with compensated tinnitus participants and normal controls. Also, there was a positive correlation between SGI perceptual modulation factor and TQ emotional distress factor and with the VAS for loudness in decompensated tinnitus group. CONCLUSIONS: These results suggested that tinnitus associated with behavioral aspects of sensory gating and decompensated tinnitus may be a result of deficient sensory gating.

Multisite transcranial Random Noise Stimulation (tRNS) modulates the distress network activity and oscillatory powers in subjects with chronic tinnitus.

Tinnitus is a common disorder in which auditory and non-auditory areas are involved as a network. Therefore, the multisite protocol of brain stimulation (tRNS) seems effective in relieving tinnitus symptoms. This study aimed to verify the modulatory effects of multisite tRNS on the tinnitus network. Thirty-two tinnitus-suffering patients received two consecutive sessions of tRNS (SHAM+ REAL) applied over the T3, T4 (the auditory cortex group) and F4, FP1 followed by T3, T4 (the multisite group). A 3-min resting-state EEG was recorded before and immediately after each session. After the multisite-tRNS real session, there was a significantly increased power in the alpha-1 band at the auditory and prefrontal cortex accompanied by decreased power in the delta and beta-2 bands in the prefrontal cortex. Standardized low-resolution brain electromagnetic tomography (sLORETA) showed a significant decrease in beta-2 activity in the prefrontal cortex, anterior cingulate cortex, and the parahippocampus and decreased alpha connectivity between the right prefrontal cortex and the left auditory cortex. No significant effects were noticed for the sham session. This study showed that tRNS has modulatory effects on the electrical activity of the brain and that targeting prefrontal and auditory areas in sequence could modulate the distress network and multiple hubs in the tinnitus network.

The potential role of auditory prediction error in decompensated tinnitus: An auditory mismatch negativity study.

INTRODUCTION: Some tinnitus subjects habituate to their tinnitus but some others do not and complain of its annoyance tremendously. Normal sensory memory and change detection processes are needed for detecting the tinnitus signal as a prediction error and habituation to tinnitus. The purpose of this study was to compare auditory mismatch negativity as the index of sensory memory and change detection among the studied groups to search for the factors involving in the perception of tinnitus and preventing habituation in decompensated tinnitus subjects. METHODS: Electroencephalography was recorded from scalp electrodes in compensated tinnitus, decompensated tinnitus, and no tinnitus control subjects. Mismatch negativity was obtained using the oddball paradigm with frequency, duration, and silent gap deviants. Amplitude, latency, and area under the curve of mismatch negativities were compared among the three studied groups. RESULTS: The results showed lower mismatch negativity amplitude and area under the curve for the higher frequency deviant and for the silent gap deviant in decompensated tinnitus group compared to normal control and compensated tinnitus group. CONCLUSIONS: This study revealed a deficit in sensory memory and change detection processing in decompensated tinnitus subjects. This causes persistent prediction errors; tinnitus signal is consistently detected as a new signal and activates the brain salience network and consequently prevents habituation to tinnitus. Mismatch negativity is proposed as an index for monitoring tinnitus rehabilitation.

Acoustic Analysis of Crying Signal in Infants with Disabling Hearing Impairment.

OBJECTIVE: Crying is a multimodal, dynamic behavior and the first way to communicate. Early identification of hearing impairment is critical for prevention of speech and language disorders. The present study aimed to assess the acoustic features of infant's cry signals to find possible differences between two groups including hearing-impaired (HI) infants and normal hearing (NH) control. METHODS: The data were collected from 34 (17 HI, 17 NH) infants under 2 months of age. Recording of the infant cry signals was collected during the examination of the Babinski reflex and was subsequently submitted for acoustic analysis. The total duration of the recording for each infant was approximately 30 seconds. The acoustical features included fundamental frequency (F0), formants (F1, F2, and F3), intensity, jitter, shimmer, ratios of F2/F1 and F3/F1, ratio of harmonic to noise, and voice break. The recording device was an Olympus ws-321M voice recorder with 44,100 Hz sampling frequency in the stereo form. Praat analysis software (version 27, 3, 5) was used to analyze the crying signals. The data were then statistically analyzed using SPSS version 21. RESULTS: Acoustic analysis of the crying signals showed that HI infants have lower intensity and higher F0 and voice break than NH infants. However, the other differences were not statistically significant. CONCLUSION: The results of the present study demonstrated that the acoustic components including F0, intensity, and voice break may be used as indices to discriminate HI infants from NH infants under 2 months of age. These findings can be increased our knowledge concerning the functional mechanisms of the vocal organ in HI and NH infants.

The efficacy and safety of multiple sessions of multisite transcranial random noise stimulation in treating chronic tinnitus.

INTRODUCTION: Random noise stimulation was reported as the more effective and safer type of electrical stimulation techniques in relieving tinnitus symptoms. The multisite protocol of transcranial random noise stimulation has shown additional favorable effects. OBJECTIVE: Here we will discuss the role of applying eight sessions of multisite transcranial random noise stimulation in decreasing tinnitus loudness and annoyance without exerting additional adverse effects. METHODS: Twenty-nine subjects (8 female), the mean age of (45.34±9.57) with chronic tinnitus received transcranial random noise stimulation in the multisite protocol, 10min of auditory-transcranial random noise stimulation applied over the T3, T4 preceded by 10min of prefrontal-transcranial random noise stimulation applied over F4, FP1. In the first group, only one session was applied and the multiple-sessions group contained eight repeated sessions. Visual analog scale scores for loudness and distress were recorded before and immediately after the treatment. Multivariate repeated measure ANOVA test was used and minimal detectable change calculated. RESULTS: There was a statistically and clinically significant reduction in tinnitus loudness and annoyance in both groups (p<0.05, effect size (η2)>0.8), while the amount of annoyance suppression in the multiple-sessions group was significantly greater than the single-session group. The patients of the multiple-sessions transcranial random noise stimulation group reported an improvement in their sleep and lower tinnitus handicap inventory scores without experiencing any additional adverse effects of the intervention. CONCLUSIONS: The results of this study showed a substantial improvement in tinnitus symptoms by using the multiple sessions of transcranial random noise stimulation in the multisite protocol without producing any additional side effects. We suggest further clinical trials with long-term follow-up be investigated.

Correlation Analysis of the Tinnitus Handicap Inventory and Distress Network in Chronic Tinnitus: An EEG Study.

INTRODUCTION: Tinnitus is a common disorder with a considerable amount of distress that affects the patient's daily life. No objective tools were approved for measuring tinnitus distress. It can be estimated only by subjective scales and questionnaires, albeit, the Electroencephalography (EEG) studies have reported some alterations regarding tinnitus distress network. This study aimed to investigate the correlation between Tinnitus Handicap Inventory (THI) and the recorded EEG data. METHODS: A total of 33 chronic tinnitus cases (9 females) with the mean age of 42.67 years were recruited. Their THI scores were collected, and a 3-minute EEG recorded with eye closed at resting-state. The correlation analysis was performed on THI scores and the current density in the selected Region of Interests (ROIs) concerning the distress network for the eight frequency bands. The patients grouped depending on the THI cutoff point of 56 into low and high THI groups, and then the groups were compared for source analysis and functional connectivity between ROIs using standardized low-resolution brain electromagnetic tomography. RESULTS: A significant positive correlation was seen between THI scores and the electrical activity in the Anterior Cingulate Cortex (ACC), the prefrontal cortex, and the parahippocampus for an alpha band (P<0.05) and in the ACC for beta (P<0.01). Source analysis showed significant differences with increased activity in the high THI group for alpha, beta and gamma bands. Functional connectivity was also elevated in the high THI group between the ROIs in alpha and beta bands. CONCLUSION: THI can be a useful tool for measuring tinnitus distress, and it has a high correlation with EEG data.

Developing the Persian Version of Sensory Gating Inventory and Assessing Its Validity and Reliability.

INTRODUCTION: Sensory Gating Inventory (SGI) measures behavioral aspects of Sensory Gating (SG), which filters irrelevant sensory inputs into the higher cortex. It modifies sensitivity to sensory stimuli. Abnormal SG leads to overloading of information in the brain and its subsequent dysfunction. Electrophysiological techniques cannot assess the behavioral aspects of SG. We aimed to design the Persian version of SGI with high validity and reliability. METHODS: After a forward and then backward translation of the original SGI, we assessed the content validity and construct validity of the Persian version. A total of 405 participants filled the Persian version of SGI. To assess test-retest reliability, 100 participants filled the inventory again 7-10 days later. The content validity ratio and index, as well as confirmatory factor analysis, were computed, too. Finally, the Cronbach's alpha, Cohen's kappa, and intraclass correlation coefficients were calculated. RESULTS: The content validity ratios of all items of the inventory were more than 60%, which means that they were necessary according to the experts' opinions. Confirmatory factor analysis confirmed the fitness of the 4-factor structure of the original Inventory. The test-retest reliability using the intraclass correlation coefficient and Cronbach's alpha coefficients were also high for the four subscales. The Cohen's kappa coefficients revealed moderate to substantial level of agreement between the first and second scores for all items. CONCLUSION: The Persian version of SGI has good and acceptable psychometric properties. It can be used as a valid and reliable tool for studying behavioral aspects of SG in Persian speaking population.