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Tinnitus is a very common oto-neurological disorder of the perception of sound when no sound is present. To improve understanding of the scope, strengths and weaknesses of New Zealand tinnitus research, a critical scoping review was undertaken. The aim was to help develop priorities for future research. A review of the literature was undertaken using a 6-stage scoping review framework of Scopus and Pub Med were searched in May 2023 with the combination of following key word [Tinnitus] and country of affiliation [New Zealand]. The search of PubMed resulted in 198 articles and that of Scopus 337 articles. After initial consideration of title relevance to the study (165 from PubMed and 196 from Scopus) removal of duplicates and after reading the articles and adding from references, 208 studies were chosen for charting of data. Nine themes were identified and described: A. Epidemiology; B. Models; C. Studies in animals; D. Mechanisms; E. Assessment and prognosis; F. Pharmacotherapy; G. Neuromodulation; H. Sensory therapies; I. Clinical practice. An urgent priority for future tinnitus research in NZ must be to address the absence of cultural and ethnic diversity in participants and consideration of traditional knowledge. [ABSTRACT FROM AUTHOR]

Tinnitus is a hearing disorder that is characterized by the perception of sounds in the absence of an external source. Currently, there is no pharmaceutical cure for tinnitus, however, multiple therapies and interventions have been developed that improve or control associated distress and anxiety. We propose a new Artificial Intelligence (AI) algorithm as a digital prognostic health system that models electroencephalographic (EEG) data in order to predict patients' responses to tinnitus therapies. The EEG data was collected from patients prior to treatment and 3-months following a sound-based therapy. Feature selection techniques were utilised to identify predictive EEG variables with the best accuracy. The patients' EEG features from both the frequency and functional connectivity domains were entered as inputs that carry knowledge extracted from EEG into AI algorithms for training and predicting therapy outcomes. The AI models differentiated the patients' outcomes into either therapy responder or non-responder, as defined by their Tinnitus Functional Index (TFI) scores, with accuracies ranging from 98%–100%. Our findings demonstrate the potential use of AI, including deep learning, for predicting therapy outcomes in tinnitus. The research suggests an optimal configuration of the EEG sensors that are involved in measuring brain functional changes in response to tinnitus treatments. It identified which EEG electrodes are the most informative sensors and how the EEG frequency and functional connectivity can better classify patients into the responder and non-responder groups. This has potential for real-time monitoring of patient therapy outcomes at home. [ABSTRACT FROM AUTHOR]

Objective: This randomized single-blind controlled trial tested the hypothesis that a prototype digital therapeutic developed to provide goal-based counseling with personalized passive and active game-based sound therapy would provide superior tinnitus outcomes, and similar usability, to a popular passive sound therapy app over a 12 week trial period. Methods: The digital therapeutic consisted of an app for iPhone or Android smartphone, Bluetooth bone conduction headphones, neck pillow speaker, and a cloud-based clinician dashboard to enable messaging and app personalization. The control app was a popular self-help passive sound therapy app called White Noise Lite (WN). The primary outcome measure was clinically meaningful change in Tinnitus Functional Index (TFI) between baseline and 12 weeks of therapy. Secondary tinnitus measures were the TFI total score and subscales across sessions, rating scales and the Client Oriented Scale of Improvement in Tinnitus (COSIT). Usability of the US and WN interventions were assessed using the System Usability Scale (SUS) and the mHealth App Usability Questionnaire (MAUQ). Ninety-eight participants who were smartphone app users and had chronic moderate-severe tinnitus (>6 months, TFI score > 40) were enrolled and were randomly allocated to one of the intervention groups. Thirty-one participants in the USL group and 30 in the WN group completed 12 weeks of trial. Results: Mean changes in TFI for the USL group at 6 (16.36, SD 17.96) and 12 weeks (17.83 points, SD 19.87) were clinically meaningful (>13 points reduction), the mean change in WN scores were not clinically meaningful (6 weeks 10.77, SD 18.53; 12 weeks 10.12 points, SD 21.36). A statistically higher proportion of USL participants achieved meaningful TFI change at 6 weeks (55%) and 12 weeks (65%) than the WN group at 6 weeks (33%) and 12 weeks (43%). Mean TFI, rating and COSIT scores favored the US group but were not statistically different from WN. Usability measures were similar for both groups. Conclusions: The USL group demonstrated a higher proportion of responders than the WN group. The usability of the USL therapeutic was similar to the established WN app. The digital polytherapeutic demonstrated significant benefit for tinnitus reduction supporting further development. [ABSTRACT FROM AUTHOR]

Background. Attention and habituation are two domains known to play key roles in the perception and maintenance of tinnitus. The heterogeneous nature of tinnitus and the methodologies adopted by various studies make it difficult to generalize findings. The current review aims at assessing and synthesizing evidence on the possible roles of attention and habituation in continuous subjective tinnitus. Methodology. The literature search included five databases (PubMed, Scopus, Web of Sciences, CINAHL and ProQuest) that resulted in 1,293 articles, published by July 2019. Studies on attention and/or habituation in individuals with tinnitus using either behavioural or electrophysiological tests were included in the review after a quality assessment. Results. Seventeen studies on attention in tinnitus were included in the narrative synthesis. Two meta-analyses were performed to assess the role of attention in tinnitus using a behavioural methodology (z = 4.06; p < 0.0001) and P300 amplitude (z = 2.70; p = 0.007) with 531 participants. With respect to habituation, the review indicates the lack of quality articles for habituation inclusion in the narrative synthesis. Conclusions. The review highlights that selective domains of attention were consistently impaired in individuals with tinnitus. Habituation, on the other hand, needs further exploration. [ABSTRACT FROM AUTHOR]

Subjective tinnitus is the conscious perception of sound in the absence of any acoustic source. The literature suggests various tinnitus mechanisms, most of which invoke changes in spontaneous firing rates of central auditory neurons resulting from modification of neural gain. Here, we present an alternative model based on evidence that tinnitus is: (1) rare in people who are congenitally deaf, (2) common in people with acquired deafness, and (3) potentially suppressed by active cochlear implants used for hearing restoration. We propose that tinnitus can only develop after fast auditory fiber activity has stimulated the synapse formation between fast-spiking parvalbumin positive (PV) intemeurons and projecting neurons in the ascending auditory path and coactivated frontostriatal networks after hearing onset. Thereafter, fast auditory fiber activity promotes feedforward and feedback inhibition mediated by PV+ intemeuron activity in auditory-specific circuits. This inhibitory network enables enhanced stimulus resolution, attention-driven contrast improvement, and augmentation of auditory responses in central auditory pathways (neural gain) after damage of slow auditory fibers. When fast auditory fiber activity is lost, tonic PV+ intemeuron activity is diminished, resulting in the prolonged response latencies, sudden hyperexcitability, enhanced cortical synchrony, elevated spontaneous y oscillations, and impaired attention/stress-control that have been described in previous tinnitus models. Moreover, because fast processing is gained through sensory experience, tinnitus would not exist in congenital deafness. Electrical cochlear stimulation may have the potential to reestablish tonic inhibitory networks and thus suppress tinnitus. The proposed framework unites many ideas of tinnitus pathophysiology and may catalyze cooperative efforts to develop tinnitus therapies. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to provide proof-of-concept of a single session of tinnitus instruction and counselling with and without homework. Design: A mixed-method design using questionnaires and thematic evaluation of qualitative data was implemented. Study sample: Sixteen participants received instruction in a single, one-to-one counselling session; eight participants additionally undertook homework consisting of either positive visualisation augmented by sound or a workbook of written and drawing activities supporting the instruction provided in the counselling session. All participants completed questionnaires just before and 3 weeks after the intervention, half were interviewed 3 weeks following the intervention. Results: Average tinnitus functional index (TFI) scores were 45 (SD 25) before and 29 (SD 23) following counselling, with a change of 4.8 or greater recorded in 75% and change of 13 points or greater in 50% of participants. Both counselling and counselling with homework showed similar changes in the TFI. This finding was supported by the qualitative analysis from which a model consisting of the themes of counselling benefit, content, application and homework benefit was derived. Conclusions: This study provides proof-of-concept of a single tinnitus instruction and counselling session, based on an ecological model of tinnitus. [ABSTRACT FROM AUTHOR]

A scoping review was undertaken to explore research investigating early interactions and integration of auditory and visual stimuli in the human brain. The focus was on methods used to study low-level multisensory temporal processing using simple stimuli in humans, and how this research has informed our understanding of multisensory perception. The study of multisensory temporal processing probes how the relative timing between signals affects perception. Several tasks, illusions, computational models, and neuroimaging techniques were identified in the literature search. Research into early audiovisual temporal processing in special populations was also reviewed. Recent research has continued to provide support for early integration of crossmodal information. These early interactions can influence higher-level factors, and vice versa. Temporal relationships between auditory and visual stimuli influence multisensory perception, and likely play a substantial role in solving the 'correspondence problem' (how the brain determines which sensory signals belong together, and which should be segregated). [ABSTRACT FROM AUTHOR]

Purpose: Tinnitus is a common oto-neurological complaint often accompanying hearing loss. In this perspective on rehabilitation we describe a framework for sound therapy and aural rehabilitation of tinnitus based on the ecological model of tinnitus. Method: A thematic network analysis-based approach was used to relate aural rehabilitation methods to the ecological model of tinnitus and the client-oriented scale of improvement in tinnitus. Results: Aural rehabilitation methods were mapped to concepts of: (1) Context, (2) presence of sound and (3) reaction to sound. A global theme was: adaptation to sound. The framework is the result of an iterative and cumulative research program exploring tinnitus as the outcome of the relationship between individual psychoacoustics and psychosocial factors including context of perception. Conclusions: The intent of this framework is to help guide audiologists managing tinnitus. The framework has been useful in our clinic as illustrated by a case study. The benefits of this approach relative to standard care needs to be independently ascertained. Tinnitus is a common oto-neurological complaint that when severe can be very disabling. Tinnitus is very heterogeneous as a consequence of this no one treatment is suitable for everyone. The sound therapy and aural rehabilitation for tinnitus framework is designed to assist audiologists in clinical planning that addresses individual needs. The framework is the result of an iterative and cumulative research program exploring tinnitus as the outcome of the relationship between individual psychoacoustics and psychosocial factors including context of perception. [ABSTRACT FROM AUTHOR]

Background: There is a need to develop methods to help clinicians work with clients to select and personalize tinnitus therapies. The use of validated measures to determine treatment success is also essential for research and clinical practice. A goal planning method widely used in audiologic rehabilitation is the client oriented scale of improvement (COSI). A modified version of the COSI has been used to identify tinnitus treatment goals and outcomes (client oriented scale of improvement in tinnitus [COSIT]). Purpose: The aims of this study were to identify treatment goals in a clinic sample and ascertain the convergent validity of the COSIT to three widely used standardized questionnaires. Research Design: A retrospective evaluation of client treatment goals using thematic analysis and correlational analysis of secondary research data comparing the COSIT to tinnitus handicap questionnaire (THQ), tinnitus handicap inventory (THI), and tinnitus functional index (TFI). Study Sample: One hundred and twenty-two adult patients and research participants attending the University of Auckland Hearing and Tinnitus Clinic. Results: Specific treatment goals were categorized into 11 themes. The most common treatment goals (>10% of responses) were: (1) Reducing tinnitus' effects on Hearing. (2) Improved wellbeing and being less depressed. (3) Coping with or controlling the tinnitus. (4) Managing the effect of the environment (context) on tinnitus. (5) Improving sleep. (6) Understanding tinnitus. Individuals differed in their complaints and priorities for treatment. The COSIT showed moderate convergent validity with the THQ, THI, and TFI indicating that the total scores measured similar constructs. Conclusions: The COSIT is a pragmatic method for determining tinnitus treatment goals and priorities in a format that should be familiar to audiologists. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the feasibility of predictable or unpredictable amplitude-modulated sounds for tinnitus therapy. Design: The study consisted of two parts. (1) An adaptation experiment. Loudness level matches and rating scales (10-point) for loudness and distress were obtained at a silent baseline and at the end of three counterbalanced 30-min exposures (silence, predictable and unpredictable). (2) A qualitative 2-week sound therapy feasibility trial. Participants took home a personal music player (PMP). Study sample: Part 1: 23 individuals with chronic tinnitus and part 2: seven individuals randomly selected from Part 1. Results: Self-reported tinnitus loudness and annoyance were significantly lower than baseline ratings after acute unpredictable sound exposure. Tinnitus annoyance ratings were also significantly lower than the baseline but the effect was small. The feasibility trial identified that participant preferences for sounds varied. Three participants did not obtain any benefit from either sound. Three participants preferred unpredictable compared to predictable sounds. Some participants had difficulty using the PMP, the average self-report hours of use were low (less <1 h/day). Conclusions: Unpredictable surf-like sounds played using a PMP is a feasible tinnitus treatment. Further work is required to improve the acceptance of the sound and ease of PMP use. [ABSTRACT FROM AUTHOR]

Abstract: Long‐term potentiation is a form of synaptic plasticity thought to play an important role in learning and memory. Recently noninvasive methods have been developed to induce and measure activity similar to long‐term potentiation in humans. Sensory tetani (trains of quickly repeating auditory or visual stimuli) alter the electroencephalogram in a manner similar to electrical stimulation that results in long‐term potentiation. This review briefly covers the development of long‐term potentiation research before focusing on in vivo human studies that produce long‐term potentiation‐like effects using auditory and visual stimulation. Similarities and differences between traditional (animal and brain tissue) long‐term potentiation studies and human sensory tetanization studies will be discussed, as well as implications for perceptual learning. Although evidence for functional consequences of sensory tetanization remains scarce, studies involving clinical populations indicate that sensory induced plasticity paradigms may be developed into diagnostic and research tools in clinical settings. Individual differences in the effects of sensory tetanization are not well‐understood and provide an interesting avenue for future research. Differences in effects found between research groups that have emerged as the field has progressed are also yet to be resolved. [ABSTRACT FROM AUTHOR]

Background: Advances in digital signal processing have made it possible to provide a wide-band frequency response with smooth, precise spectral shaping. Several manufacturers have introduced hearing aids that are claimed to provide gain for frequencies up to 10-12 kHz. However, there is currently limited evidence and very few independent studies evaluating the performance of the extended bandwidth hearing aids that have recently become available. Purpose: This study investigated an extended bandwidth hearing aid using measures of speech intelligibility and sound quality to find out whether there was a significant benefit of extended bandwidth amplification over standard amplification. Research Design: Repeated measures study designed to examine the efficacy of extended bandwidth amplification compared to standard bandwidth amplification. Study Sample: Sixteen adult participants with mild-to-moderate sensorineural hearing loss. Intervention: Participants were bilaterally fit with a pair of Widex Mind 440 behind-the-ear hearing aids programmed with a standard bandwidth fitting and an extended bandwidth fitting; the latter provided gain up to 10 kHz. Data Collection and Analysis: For each fitting, and an unaided condition, participants completed two speech measures of aided benefit, the Quick Speech-in-Noise test (QuickSIN™) and the Phonak Phoneme Perception Test (PPT; high-frequency perception in quiet), and a measure of sound quality rating. Results: There were no significant differences found between unaided and aided conditions for QuickSIN™ scores. For the PPT, there were statistically significantly lower (improved) detection thresholds at high frequencies (6 and 9 kHz) with the extended bandwidth fitting. Although not statistically significant, participants were able to distinguish between 6 and 9 kHz 50% better with extended bandwidth. No significant difference was found in ability to recognize phonemes in quiet between the unaided and aided conditions when phonemes only contained frequency content,6 kHz. However significant benefit was found with the extended bandwidth fitting for recognition of 9-kHz phonemes. No significant difference in sound quality preference was found between the standard bandwidth and extended bandwidth fittings. Conclusions: This study demonstrated that a pair of currently available extended bandwidth hearing aids was technically capable of delivering high-frequency amplification that was both audible and useable to listeners with mild-to-moderate hearing loss. This amplification was of acceptable sound quality. Further research, particularly field trials, is required to ascertain the real-world benefit of high-frequency amplification. [ABSTRACT FROM AUTHOR]

Objective: To compare preference for and performance of manually selected programmes to an automatic sound classifier, the Phonak AutoSense OS. Design: A single blind repeated measures study. Participants were fit with Phonak Virto V90 ITE aids; preferences for different listening programmes were compared across four different sound scenarios (speech in: quiet, noise, loud noise and a car). Following a 4-week trial preferences were reassessed and the users preferred programme was compared to the automatic classifier for sound quality and hearing in noise (HINT test) using a 12 loudspeaker array. Study sample: Twenty-five participants with symmetrical moderate-severe sensorineural hearing loss. Results: Participant preferences of manual programme for scenarios varied considerably between and within sessions. A HINT Speech Reception Threshold (SRT) advantage was observed for the automatic classifier over participant’s manual selection for speech in quiet, loud noise and car noise. Sound quality ratings were similar for both manual and automatic selections. Conclusions: The use of a sound classifier is a viable alternative to manual programme selection. [ABSTRACT FROM AUTHOR]

Objective: To undertake a preliminary evaluation of the test–retest reliability, and accuracy of an iPad audiometer app using commercial earphones as a low-cost alternative to a clinical audiometer in a restricted sample of normal hearing participants.Design: Twenty participants self-reporting normal hearing undertook four pure-tone audiometry tests in a single session. Two tests were performed with a 2-channel Type 1 audiometer (GSI-61) using EAR insert earphones and two tests with an iPad based app (Audiogram Mobile) using Apple earbud headphones.Study sample: Twenty normal hearing participants (13 female and seven male participants, aged 21–26 years) were recruited for the test–retest and accuracy evaluations.Results: The app resulted in different thresholds to the audiometer (F(1, 19) = 16.635,p < 0.001). However test–retest reliability was similar. The app froze or quit unexpectedly over 25% of times used.Conclusions: Audiometer apps have great potential for clinical settings, especially in resource scarce environments, but reliability should not be assumed. While a low cost-alternative to standard transducers, issues of accuracy and calibration of consumer headphones need to be addressed before such combinations can be used with confidence. [ABSTRACT FROM AUTHOR]

Objectives: A randomized cross-over trial in 18 participants tested the hypothesis that nature sounds, with unpredictable temporal characteristics and high valence would yield greater improvement in tinnitus than constant, emotionally neutral broadband noise. Study Design: The primary outcome measure was the Tinnitus Functional Index (TFI). Secondary measures were: loudness and annoyance ratings, loudness level matches, minimum masking levels, positive and negative emotionality, attention reaction and discrimination time, anxiety, depression and stress. Each sound was administered using MP3 players with earbuds for 8 continuous weeks, with a 3 week wash-out period before crossing over to the other treatment sound. Measurements were undertaken for each arm at sound fitting, 4 and 8 weeks after administration. Qualitative interviews were conducted at each of these appointments. Results: From a baseline TFI score of 41.3, sound therapy resulted in TFI scores at 8 weeks of 35.6; broadband noise resulted in significantly greater reduction (8.2 points) after 8 weeks of sound therapy use than nature sounds (3.2 points). The positive effect of sound on tinnitus was supported by secondary outcome measures of tinnitus, emotion, attention, and psychological state, but not interviews. Tinnitus loudness level match was higher for BBN at 8 weeks; while there was little change in loudness level matches for nature sounds. There was no change in minimum masking levels following sound therapy administration. Self-reported preference for one sound over another did not correlate with changes in tinnitus. Modeled under an adaptation level theory framework of tinnitus perception, the results indicate that the introduction of broadband noise shifts internal adaptation level weighting away from the tinnitus signal, reducing tinnitus magnitude. Nature sounds may modify the affective components of tinnitus via a secondary, residual pathway, but this appears to be less important for sound effectiveness. The different rates of adaptation to broadband noise and nature sound by the auditory system may explain the different tinnitus loudness level matches. In addition to group effects there also appears to be a great deal of individual variation. A sound therapy framework based on adaptation level theory is proposed that accounts for individual variation in preference and response to sound. [ABSTRACT FROM AUTHOR]

Purpose: It has been suggested that frequency lowering may be a superior tinnitus reducing digital signal processing (DSP) strategy in hearing aids than conventional amplification. A crossover trial was undertaken to determine if frequency compression (FC) was superior to wide dynamic range compression (WDRC) in reducing tinnitus.Method: A 6–8-week crossover trial of two digital signal-processing techniques (WDRC and 2 WDRC with FC) was undertaken in 16 persons with high-frequency sensorineural hearing loss and chronic tinnitus.Results: WDRC resulted in larger improvements in Tinnitus Functional Index and rating scale scores than WDRC with FC. The tinnitus improvements obtained with both processing types appear to be due to reduced hearing handicap and possibly decreased tinnitus audibility.Conclusions: Hearing aids are useful assistive devices in the rehabilitation of tinnitus. FC was very successful in a few individuals but was not superior to WDRC across the sample. It is recommended that WDRC remain as the default first choice tinnitus hearing aid processing strategy for tinnitus. FC should be considered as one of the many other options for selection based on individual hearing needs.Implications of RehabilitationHearing aids can significantly reduce the effects of tinnitus after 6–8 weeks of use.Addition of frequency compression digital signal processing does not appear superior to standard amplitude compression alone.Improvements in tinnitus were correlated with reductions in hearing handicap. [ABSTRACT FROM PUBLISHER]

Objective: Scoping reviews of existing literature were conducted to identify key personality traits relevant to tinnitus, and examine the relationship between affective disorders and tinnitus.Design: The methodological framework of Arksey and O’Malley was followed.Study sample: Sixty studies were chosen for charting the data, 14 studies examined personality traits exclusively, 31 studies examined affective disorders exclusively, and 15 studies investigated both.Results: The presence of one or more specific personality traits of high neuroticism, low extraversion, high stress reaction, higher alienation, lower social closeness, lower well-being, lower self control, lower psychological acceptance, presence of a type D personality, and externalized locus of control were associated with tinnitus distress. Anxiety and depression were more prevalent among the tinnitus clinical population and at elevated levels.Conclusions: Personality traits have a consistent association with the distress experienced by adult tinnitus help-seekers, and help-seekers are also more likely to experience affective symptoms and/or disorders. [ABSTRACT FROM AUTHOR]

Background: Despite evidence that hearing aids can improve the social and psychological functioning of older hearing-impaired adults, hearing aid uptake is low. High cost of hearing aids and poor access to audiology services in rural areas are potential barriers to hearing aid acquisition. Methods of hearing aid delivery deviating from the traditional clinician-based model have been available to consumers for many years. One such method is Internet hearing aid sales. However, research exploring Internet-based hearing aid delivery, as a method to improve hearing aid uptake in this population, is limited. Purpose: The purpose of this study was to explore the perceptions of older hearing aid users (aged >65 yr) toward Internet-based hearing aid delivery. Research Design: A qualitative approach was adopted to investigate older adults' perceptions of buying hearing aids online. Study Sample: The sample consisted of 18 participants aged between 64 and 81 yr. Fourteen men and four women participated in this study. Participants were all experienced hearing aid users. Data Collection and Analysis: Face-to-face semistructured interviews were conducted. An interview schedule guided the interview. Interviews were recorded with a voice recorder and transcribed verbatim. Thematic analysis of the data was carried out. Results: Seven main themes emerged from the data. A general lack of awareness, but willingness to learn more about Internet hearing aid sales, was found. Two perceived benefits of Internet-based hearing aid delivery were identified: lower cost of hearing aids and greater convenience or physical accessibility. Numerous concerns and limitations were communicated. Concerns regarding the availability of clinical procedures, such as hearing tests, obtaining the correct-sized earmolds, and fine-tuning of hearing aids, were expressed. Participants conveyed distrust in online retailers. However, trust in and a preference for audiologists' expertise, which was not perceived to be available online, was found. Participants further conveyed a preference for face-to-face contact. Finally, in this sample, a general lack of familiarity and confidence in using the Internet was communicated. Conclusions: Internet sales of hearing aids is a controversial topic in audiology. Although Internet-based delivery of hearing aids was perceived by older adults to be potentially beneficial, several shortcomings and concerns were conveyed. Irrespective of opinion of the role of Internet sales, audiologists should consider the opinions of the elderly as to how different service models may improve hearing aid uptake. [ABSTRACT FROM AUTHOR]

Masking is widely used in the management of tinnitus, however, masking at the perceived spatial location of tinnitus has not been investigated. This article examines the development of a method for the spatial masking of tinnitus. This report consists of three studies: Study I is a proof of concept study comparing customized spatial masking to conventional bilateral masking; Study II is a prototype evaluation in which the spatial masking paradigm was compared to a bilaterally equal masker using iPods connected to hearing aids in a 4-week cross-over trial; and Study III is a 4-month crossover pilot study-using prototype hearing aid-based maskers, and in which three-dimensional (3D) masking (2 months) was compared to a Tinnitus Retraining Therapy (2 months). There was a preference for the 3D masking stimulus across all three studies. Individual changes in the Tinnitus Handicap Inventory (THI) after 2 weeks of trial (Study II) and Tinnitus Functional Index (TFI) after 2 months of trial (Study III) were observed without large group differences. The spatial masking concept was piloted successfully. The qualitative and quantitative results obtained indicate directions for future clinical trials and therapy development. This study indicates that spatial masking of tinnitus is feasible, of benefit to many participants, and warrants further trials. [ABSTRACT FROM AUTHOR]

Tinnitus is an interaction of the environment, cognition, and plasticity. The connection between the individual with tinnitus and their world seldom receives attention in neurophysiological research. As well as changes in cell excitability, an individual's culture and beliefs, and work and social environs may all influence how tinnitus is perceived. In this review, an ecological framework for current neurophysiological evidence is considered. The model defines tinnitus as the perception of an auditory object in the absence of an acoustic event. It is hypothesized that following deafferentation: adaptive feature extraction, schema, and semantic object formation processes lead to tinnitus in a manner predicted by Adaptation Level Theory (1, 2). Evidence from physiological studies is compared to the tenants of the proposed ecological model. The consideration of diverse events within an ecological context may unite seemingly disparate neurophysiological models. [ABSTRACT FROM AUTHOR]

The main aim of this study was to investigate the shape variation in the human ear canal and the effects of venting on the spatial design of hearing aids. The second aim was to determine the design feasibility of a multiple venting hearing aid and assess the flexibility of design provided. A statistical shape model based on principal component analysis was created from a dataset of 60 left and 49 right ears. The modal variations of these models were then examined to determine the narrowest portion of the ear canal likely to limit effective venting. Finally, 3D models of two hearing aid shells, one with multiple 0.4-mm vents and the other with a single large 3-mm vent were created. Results showed that more than 50% of the shape variation in the human ear canal can be described by the first three modes of the statistical shape model developed. The narrowest predicted variation of this model had a minimum area of 36.4mm2, and the mean ear shape was found to have a minimum area of approximately 48mm2. It is estimated that even with a conservative vent packing of 0.4, multiple venting equivalent to at least a single 2-mm vent is achievable. The predicted variation in the human ear canal provides adequate physical space for a feasible multiple vented hearing aid shell. Furthermore, as multiple small vents are able to fit in around other components in the hearing aid design, certain design flexibility is provided by this venting approach. [ABSTRACT FROM AUTHOR]