A review of the applied behavioral neuroscience research used to develop the QCore™ tinnitus therapy platform

Tinnitus is a heterogeneous disorder of hearing with a complex biopsychosocial basis. This paper reviews the research used in the development of the QCore™ Tinnitus Therapy Platform. A narrative review based on a non-systematic literature search. The review describes the research underpinning the development of 3 QCore™ therapy modes (Relief, Relax, and Retrain) and compares them with major tinnitus guidelines. Based on an ecological model of tinnitus and adaptation-level theory, the therapy's goal is to reduce the perceived magnitude of tinnitus by desensitizing a core tinnitus network. Evidence used in developing the hypothesis is reported from multiple behavioral and physiological studies. The research supports the notion that therapy modes have different behavioral and physiological effects, consistent with changes in tinnitus audibility, annoyance, and attention. Much of the evidence is indirect, and further mechanistic studies are required to confirm the therapy's mode-specific contributions. Convergent behavioral and neuroscientific evidence has led to the development of the QCore™ tinnitus therapy. There is a need for a rigorous independent evaluation of the platform.

There is currently no curative medical treatment for tinnitus; however, existing therapies can provide relief from tinnitus for some people, some of the time (Kleinjung et al., 2024). Tinnitus is difficult to treat because it is not the result of a single punctate lesion but rather distributed neuroplastic changes (Searchfield, 2014). Tinnitus characteristics, emotional impact, neurophysiological mechanisms, and responses to sound vary from individual to individual (Cederroth et al., 2019). The general consensus is that tinnitus disorder results from complex interactions between sensory and affective neurophysiology (De Ridder et al., 2021). The mechanisms may include gain control (Parameshwarappa and Norena, 2024), attention (Vasudevan et al., 2021; Searchfield et al., 2025b), noise cancellation (Rauschecker et al., 2010), and prediction errors (Hullfish et al., 2019; Durai et al., 2018b). Hierarchically organized levels of auditory processing are likely to feed forward processing errors, resulting in sensitization and altered connectivity across multiple neural hubs (De Ridder et al., 2014). Feed-forward and feedback mechanisms between the auditory thalamus and cortex are hypothesized to facilitate the processing of ecologically significant aspects of sound, influenced by experience, context and arousal (Searchfield, 2014). Once the tinnitus signal is processed and detected, the absence of real-world context, such as an auditory object producing the sound, may require increased attention resources and cognitive load to extract further details and clarify and understand the perception (Searchfield, 2014). From a physiological perspective, these perceptual demands are believed to result in sensitization of a core tinnitus brain network (Ventromedial prefrontal cortex, Inferior-parietal cortex, Parahippocampal cortex, and Auditory cortex) (De Ridder et al., 2014). In this model, sensory sensitivity propagates to non-sensory affective networks, leading to tinnitus disorder (De Ridder et al., 2021).

Although no cure for tinnitus exists, many current therapies are effective in reducing the functional impact (Schlee et al., 2021). However, there is very limited objective evidence demonstrating mechanisms of tinnitus therapy (Burton-Harris et al., 2023). While tinnitus research is dominated by patient-reported questionnaires (behavioral data), incorporating objective neurophysiological evidence (e.g., fMRI or EEG) is critical for moving toward a definitive cure. An Implementation Science review (Burton-Harris et al., 2023) emphasized the importance of a “treatment–system fit”. There should be a shift of focus from symptoms to how treatments change the underlying physiology (Figure 1). Although tinnitus is a complex multifactorial problem, its underpinning mechanisms should be modifiable. The field of neurorehabilitation outlines rules and processes that, if followed appropriately, should enable reductions in tinnitus magnitude (Table 1; Kleim and Jones, 2008). Research on sound enrichment, attentional training, relaxation, and contextual learning provides a foundational, evidence-based approach that can be applied to tinnitus.

This narrative review aims to outline the behavioral neurophysiology that informed the development of a new digital tinnitus therapy platform (QCore™, by TrueSilence Therapeutics Inc.). The QCore™ is an audiologist-prescribed adaptive therapy designed to reduce the magnitude of tinnitus (the product of tinnitus loudness, annoyance and awareness Searchfield and Vajsakovic, 2025). It was developed based on the authors' 25 years of tinnitus research and was developed in an iterative process informed by user-centered design (Narejo et al., 2026), implementation science (Burton-Harris et al., 2023), and principles of experience-dependent plasticity (Kleim and Jones, 2008). The QCore™ is a full-stack software-based system designed to reduce the severity of tinnitus through multiple solutions tailored to individual psychoacoustic and goal-specific needs. The therapy includes tailored sound therapy and perceptual training with goal-oriented, motivational counseling. The therapy is delivered via smartphone software (iPhone or Android compatible) and streams to high-performance open-ear earphones. A cloud-based dashboard is used for clinician-guided customization, client engagement, and monitoring.

Understanding the mechanisms of therapy action supports the ongoing development, personalisation, clinical translation, and scientific credibility of therapies. The review will outline the behavioral and neural rationale used to develop the QCore™ Therapy platform, it will position it within current scientific understanding and how its components interact with known tinnitus pathways. As a substantial portion of the related literature is authored by the development team, this review necessarily draws on self-authored work (Searchfield et al., 2025a). Independent sources are included to contextualize and critique the theoretical and clinical framework. This review hypothesizes that current behavioral neuroscience evidence supports the multimodal approach to tinnitus therapy embodied in the QCore™ system.

This is a narrative review. Studies were included in the review if they informed the design of the TrueSilence Therapeutics Inc. QCore™ system or its evaluation. A non-systematic literature search was conducted in databases including PubMed and Google Scholar using the following keywords: [Neurorehabilitation]; [Neuroplasticity] and [training]; [tinnitus therapy], [personalization/personalization], and [assessment, relief, relaxation, retraining, or polytherapy]. Snowballing was used to identify additional relevant studies by exploring the reference lists of key papers and identifying newer papers that had cited them. Peer-reviewed publications were supplemented with research theses. The therapy components were compared to major recent tinnitus practice guidelines. No formal quality assessment was conducted due to the narrative review methodology. The review should be interpreted primarily as a theoretical synthesis and hypothesis-generating framework rather than an independent assessment of platform efficacy.

Therapy model

Tinnitus has been organized and described using multiple taxonomies that reflect different traditions in psychology, hearing science, and neurophysiology. Each model has merits for expressing tinnitus within its respective discipline's knowledge. The QCore™ therapy model is based on an Ecological model of tinnitus (Searchfield, 2014) and Adaptation level Theory (ALT) (Searchfield et al., 2012; Helson, 1964) (Box 1). The Ecological Model is a biopsychosocial tinnitus model that attempts to explain why context matters in understanding tinnitus. The brain parses tinnitus as if it were an auditory object embedded in a real-world scene. Sounds perceived as near, such as tinnitus, are prioritized for attention (Brefczynski-Lewis and Lewis, 2017), but unlike ordinary sounds, tinnitus is internally generated and lacks confirmation of its existence from other senses. This incongruence with learned expectations makes the percept more likely to attract attention and to be appraised as potentially significant (Searchfield, 2014; Searchfield et al., 2025b). Quiet environments (Heller and Bergman, 1953), low task load (Knobel and Sanchez, 2008), stress (Patil et al., 2023) and fatigue (Icoz and Sendesen, 2026), or the personal meanings (Fagelson, 2022) attached to the sound bias competition between tinnitus and external auditory objects in favor of tinnitus. In predictive-coding terms, tinnitus behaves like a learned internal prediction (“prior”) that is given too much weight. When external sound is scarce or when attention shifts to tinnitus, its perceived salience increases, and attention locks onto it (Hullfish et al., 2019; Durai et al., 2018b).

Predictive coding The brain is constantly trying to predict what it expects to hear, see, and feel. In tinnitus, the brain may come to expect the tinnitus sound and continue to generate or pay attention to it, even when there is no external sound causing it.

Adaptation Level Theory Our perception of things is influenced by what we are used to experiencing. When tinnitus becomes the main focus of attention, it can seem louder or more significant. As attention shifts to other sounds and experiences, tinnitus often feels less noticeable because the brain recalibrates what it considers “normal.”

Sensory Gating Sensory gating is the brain's ability to filter out irrelevant information. Most everyday sounds, sensations, and background information are automatically screened out. With tinnitus, this filtering process may be less effective, allowing the tinnitus signal to remain in conscious awareness.

Auditory Object Formation The brain organizes sound into meaningful “objects” such as a person's voice, music, or the sound of rain. Tinnitus may draw attention as it does not have an real-world object making it.

Salience Salience refers to how important, relevant, or attention-grabbing something is. The more threatening, frustrating, or emotionally significant tinnitus feels, the more attention the brain gives it. Reducing the perceived importance of tinnitus lowers its salience and reduce its magnitude.

Tinnitus Magnitude Tinnitus magnitude refers to the overall impact or “size” of the tinnitus experience from the person's perspective. It is not just about how loud the sound seems. Tinnitus magnitude is influenced by several factors, including perceived loudness, how often it is noticed—the amount of attention it attracts, and emotional reactions to it. Two people with similar tinnitus sounds can experience very different tinnitus magnitudes depending on how their brains interpret and respond to the tinnitus signal.

ALT is the psychoacoustic “core” of the Ecological Model. ALT complements the ecological view by modeling how the brain judges tinnitus relative to a shifting baseline, the adaptation level (Searchfield et al., 2012; Helson, 1964). The adaptation level is shaped by external sound, internal state, and attentional set (Searchfield and Vajsakovic, 2025). Moment-to-moment changes in adaptation level determine tinnitus magnitude [defined as the product of loudness, annoyance and awareness (Searchfield and Vajsakovic, 2025)]. Monotonous or impoverished soundscapes, high arousal, and low cognitive load are believed to lower the adaptation level, allowing central gain to rise and increase tinnitus detectability and intrusiveness (Durai and Searchfield, 2017; Durai et al., 2017a, 2015). Conversely, enriching the environment with sound, lowering arousal, and engaging attention elsewhere are considered to raise the adaptation level, thereby reducing the relative salience of tinnitus. In short, based on ALT, when attention, emotion, and central gain favor tinnitus, the baseline shifts in a direction that makes tinnitus seem louder, more noticeable, and more intrusive; when external sound, engagement, and calmer physiology compete effectively, the baseline shifts back.

Sensitisation (Zenner et al., 2006) potentially provides the unifying physiological mechanism underlying the processes described by the Ecological Model of Tinnitus (Searchfield, 2014) and ALT (Searchfield et al., 2012). Tinnitus disorder can be considered a centrally mediated, context-dependent, and modifiable sensitization phenomenon. The QCore™ therapy model proposes that upon its onset, tinnitus-related neural activity becomes progressively amplified and prioritized so that the signal grows in salience, captures attention, and accrues emotional weight. This sensitization may be the result of central gain (Parameshwarappa and Norena, 2024), network coupling (De Ridder et al., 2014), cognitive factors such as prediction (Hullfish et al., 2019), emotional factors involving arousal and threat valuation, and contextual factors including the soundscape, task demands, time of day and social meaning (Searchfield, 2014). Sensitisation (Zenner et al., 2006) is used mechanistically to explain why tinnitus often “wins” the competition for perception and is intrusive: the system over-allocates attentional precision to the internal signal and under-weights external sensory evidence (Searchfield et al., 2012; Durai et al., 2019, 2018b). Within this view, QCore™ targets sensitization, which increases the perceived strength or prominence of the sensation (Searchfield and Vajsakovic, 2025).

Neurorehabilitation modes and evidence in behavioral neuroscience

The QCore™ therapy platform was developed to operationalize the therapy model targeting the three levers that determine tinnitus magnitude: loudness, annoyance, and attention (Searchfield and Vajsakovic, 2025). In the following sections, the research leading to the formulation of three therapy modes, “Relief, Relax, and Retrain” modes, are reviewed (Figure 2).

The Relief mode

The Relief Mode was designed to reduce the perceived loudness and detectability of tinnitus by providing continuous external sound that competes with the internally generated tinnitus signal. It uses personalized sound therapy and masking strategies (Figure 2). The goal is to give users practical tools to gain greater control over their tinnitus experience. Within the Ecological Model, Relief is believed to primarily intervene in the psychoacoustic ALT domain to diminish the perceptual dominance of tinnitus (Searchfield et al., 2012). Sustained external sound is proposed to raise the auditory adaptation level, thereby reducing neural contrast between tinnitus and background activity and lowering tinnitus salience (Searchfield et al., 2012; Durai and Searchfield, 2017). This may occur through diffuse desensitization processes (Zenner et al., 2006). Repeated periods of partial or complete masking may induce adaptation to the mean or variance of the masking sound-level distribution, shifting neural dynamic range away from tinnitus-driven activity (Willmore and King, 2023). By elevating the reference against which tinnitus is judged, the percept becomes harder to detect and easier to ignore. This may contribute to a degradation in the stability of tinnitus object formation and prevent quiet-driven central gain upregulation that would otherwise reinforce tinnitus salience (Durai et al., 2015, 2019; Parameshwarappa and Norena, 2024). The presence of structured external sound should draw attention outward, allowing periods of non-tinnitus listening to accrue and consolidate, which in turn weakens tinnitus dominance through experience-dependent plasticity (Knobel and Sanchez, 2008; Vasudevan et al., 2021; Searchfield et al., 2025b).

Principles of use-dependent plasticity are employed to weaken tinnitus-dominant activity and strengthen alternative circuits. The QCore™ Relief mode employs energetic and informational masking (Proudfoot, 2012; De Farias, 2017; Searchfield, 2020). Energetic masking occurs when the masking sound physically overlaps the target sound in time and frequency, reducing the audibility of the target at the level of the auditory periphery. Informational masking that occurs even when the target is audible, but the listener has difficulty segregating, attending to, or identifying it because of perceptual or cognitive interference from competing sounds (Kidd and Conroy, 2023). In therapy, users can apply energetic masking using Threshold Adjusted Noise (TAN), a sound tailored to hearing thresholds and masking levels that provides additional energy near the tinnitus pitch (Searchfield et al., 2002). This should reduce auditory contrast where expectations for tinnitus are strongest (Roberts et al., 2008). Informational masking options include using co-located external sound sources that align with the perceived tinnitus location. Spatial competition should reduce the coherence and stability of tinnitus object formation by impairing auditory grouping and segregation processes (Searchfield et al., 2015, 2016, 2025c; Durai et al., 2021). Such informational masking has been more efficient in reducing tinnitus than excitatory masking alone, as spatial disparity cues that would otherwise facilitate tinnitus segregation are minimized (Figure 3) (Searchfield et al., 2016; Singh, 2023). Spatial masking within the peri personal space may also reduce threat-based salience heuristics for nearby and looming auditory events (Kolarik et al., 2016). Spatially targeted masking is feasible, well tolerated, and often preferred by participants (Searchfield et al., 2016), Multi-week trials have demonstrated meaningful reductions in standard outcome measures for many users of spatial making. Objective neural measures converge with these behavioral effects. Responders to masking-based relief paradigms typically show altered EEG activity in insular, inferior parietal, thalamic, temporal, and cingulo-frontal regions, consistent with recalibration away from sustained, effortful frontal control toward more efficient posterior sensory integration (Burton-Harris et al., 2023). Spiking neural network models further demonstrate that baseline EEG features can distinguish masking responders from non-responders with high accuracy; responders are characterized by elevated occipitoparietal connectivity at baseline, which normalizes after therapy alongside more selective and task-appropriate frontal engagement, whereas non-responders retain their pre-therapy dynamics (Durai et al., 2021) (Figure 4). Complementing these findings, residual inhibition studies report band-limited power increases, most consistently in the alpha range and sometimes gamma, during tinnitus suppression, indicating a regulated cortical state rather than just distraction (King et al., 2021; Sanders et al., 2021).

Emerging evidence suggests that perceptual control through the methods employed in the Relief mode is an important first step before deeper retraining mechanisms become effective. Empirically, patient relief effects often emerge early and plateau, whereas subsequent therapy phases, tend to be seen as longer-term reductions in distress and annoyance rather than loudness (Barozzi et al., 2016). QCore's adaptive algorithm, therefore, emphasizes Relief early in the 90-day therapy trajectory and progressively down-weights its use as perceptual stability and control are believed to improve with time.

There are at least two caveats to the proposed benefit and mechanisms of the Relief mode. First, neural contrast control [gain increases for low-contrast signals (Rabinowitz et al., 2011)] may counteract benefits in a subset of users and could underlie declining masking effectiveness over time; monitoring responses and varying spectral–temporal contrast may help mitigate this risk. Second, sound class matters: broadband noise often produces larger short-term reductions in tinnitus loudness by providing a stable, spectrally dense anchor that rapidly shifts the adaptation level, whereas natural sounds may offer affective benefits that support relaxation and longer-horizon adaptation but deliver smaller immediate shifts in loudness (Barozzi et al., 2016; Durai and Searchfield, 2017).

The Relax mode

The Relax Mode was designed to reduce physiological and emotional arousal that can amplify tinnitus awareness. Through calming soundscapes, guided relaxation exercises, and predictable acoustic environments, its goal is to support relaxation, stress management, and improved sleep. The aim is to create conditions that allow the nervous system to settle, making tinnitus less intrusive and easier to manage. The Relax mode may reduce the annoyance component of tinnitus magnitude by down-regulating limbic–autonomic reactivity and weakening the emotion–attention loops that reinforce sensitization (Zenner et al., 2006; Searchfield, 2014). Using calming soundscapes, practicing guided visualization, mindfulness, and structured relaxation, it attempts to shift the nervous system from hypervigilance toward safety, thereby reducing the emotional gain applied to the tinnitus signal and diminishing its pull-on attention (Searchfield et al., 2025b). Within the Ecological Model, the Relax mode intent is to interrupt the cycle in which distress amplifies salience, salience captures attention, and attention further entrenches distress (Searchfield, 2014). In ALT terms, reducing arousal and improving affect raises the adaptation level relative to tinnitus, lowering comparative prominence (Searchfield et al., 2012). Although psychoacoustic variables inevitably interact (calming sounds can also reduce loudness and awareness), the primary target here is annoyance and its neural substrates (Aydin and Searchfield, 2019).

Mechanistically, the Relax mode targets the limbic–autonomic reinforcement loops, fronto-striatal control, and associated gating processes. These processes may determine whether tinnitus becomes consciously prominent. Repeated exposure to positively valenced or affectively neutral soundscapes provides a counter-experience to tinnitus-driven distress, possibly engaging neuroplastic principles that stabilize a calmer baseline (Durai et al., 2015). As negative affect diminishes, sensory gating may improve and intrusive awareness is less likely to occur (Rauschecker et al., 2010). Counseling and supportive engagement are believed to complement this physiological shift by strengthening self-efficacy, reducing uncertainty, and addressing psychological “residuals” that maintain sensitization (catastrophic interpretations, stress reactivity, unhelpful coping) (Dauman et al., 2024; Searchfield et al., 2012; Fagelson and Smith, 2016).

The choice and construction of acoustic environments express specificity for affective regulation. The Relax mode uses slower tempo, predictable envelopes, and natural soundscapes to promote parasympathetic activity and perceived safety (Durai et al., 2018a; Searchfield, 2019b). It also leverages the attentional and emotional meanings carried by sound (Asutay and Västfjäll, 2015). Nature recordings, especially those with spatial auditory features, can draw attention away from tinnitus. Preferences for slow oscillations and damped envelopes (perceived as receding rather than approaching) underscore the role of predictability and subjective safety in lowering arousal (Searchfield, 2019b; Tajadura-Jiménez et al., 2010). In this way, the Relax mode targets affective sensitization probably by lowering sympathetic drive, weakening distress-driven attentional capture, and decreasing negative affective weighting (Forte et al., 2021; Aydin and Searchfield, 2019).

ALT provides a complementary explanation for why these state changes reduce the relative prominence of tinnitus. Experimental work shows that negative mood or unpleasant emotional sounds can increase perceived tinnitus loudness, whereas positive or neutral states reduce it, consistent with ALT's emphasis on the residual (emotional–autonomic) component in magnitude estimation (Durai et al., 2017a). Both broadband noise and self-selected nature sounds can improve subjective ratings, though their physiological signatures may differ over exposure time (Durai et al., 2017a; Durai and Searchfield, 2017).

Acute exposure to BBN and nature-based sounds can have distinct neural effects (Vajsaković, 2023). Auditory categorization training sounds that morphed a tinnitus avatar into a nature sound over 10 min increased activity in perceptual and parietal regions (primary visual cortex, secondary somatosensory cortex, supramarginal gyrus) while reducing activity in the dorsal-lateral prefrontal cortex and gamma-band activity in the auditory cortex, both changes associated with tinnitus distress and intensity, suggesting a potentially therapeutic mechanism targeting maladaptive prefrontal and auditory processes (Figure 5). In contrast, white noise produced more diffuse cortical activation, with recurrent involvement of the angular gyrus and parahippocampal cortex, possibly reflecting attentional diversion, adaptation, and modulation of auditory memory networks. Although both groups showed strong visual cortical connectivity, the therapies differentially engaged key neural targets: categorization of nature sounds primarily affected prefrontal control networks, whereas white noise predominantly modulated the angular gyrus (Vajsaković, 2023).

These findings suggest that two sound therapies can act through complementary but distinct neural mechanisms. Broadband noise tends to function as a neutral anchor that reliably lowers immediate arousal, while some nature sounds may transiently engage attention before producing a net calming effect, particularly at short durations (Vajsaković, 2023). Together, these data imply that state regulation, not rhythmic neuromodulation per se, is the proximal driver of benefit in the Relax mode. The differentiation between stimulus classes is consistent with selecting therapy sounds based on the patient's goals (to achieve rapid relief or extended immersion for relaxation) (Searchfield et al., 2017).

Sleep-related research further underscores the potential value of Relax mode content. In a randomized crossover design with adults experiencing tinnitus-related sleep disturbance, a 30-min pre-sleep positive visualization, with or without overnight natural-sound reinforcement, produced large reductions in sleep-onset latency, improved self-reported attentional control, and demonstrated high feasibility (Spittal et al., 2024). Mechanistically, the pre-sleep cognitive-affective intervention should have downshifted hyperarousal and reduced the precision assigned to tinnitus before sleep initiation, while continuous, low-salience natural sounds likely maintained a stable auditory context that limited nocturnal reorienting to tinnitus without adding cognitive load. This pattern of faster sleep onset, better attentional self-regulation, and comfort with gentle natural sound aligns closely with the mode's targets of regulation of affect, attentional quieting, and contextual anchoring (Searchfield, 2020; Spittal et al., 2024).

The principles of intensity and repetition in neuroplasticity are believed to be important. Immersive auditory environments may be needed to rebalance autonomic tone and shift limbic appraisal away from threat. Repeated exposures, hypothetically, teach the system to adopt a calmer default that can generalize beyond sessions, consistent with neurorehabilitation's time-and-practice principles (Kleim and Jones, 2008). Accordingly, as physiological tension falls and negative reactivity subsides, the brain receives implicit, repeated prediction-error feedback that tinnitus is not dangerous (Kleim and Jones, 2008; De Ridder et al., 2024). This should result in the emotional pathways sustaining annoyance weakening, and the annoyance-driven share of tinnitus magnitude declining. This perhaps explains the trend for nature sounds to show progressive benefit over time rather than an immediate effect, with a plateau seen for BBN (Barozzi et al., 2016).

The Retrain mode

The Retrain Mode was designed to help the brain gradually reduce the significance of tinnitus. Through structured listening activities, auditory training, and attention-based exercises, the aim is for users to learn to respond differently to tinnitus and strengthen their ability to focus on meaningful external sounds. The goal is to promote habituation and adaptation, allowing tinnitus to fade into the background of everyday life. The Retrain mode may reduce awareness of tinnitus by weakening habitual self-monitoring and reclassifying it as a low-priority, low-salience perception (Jastreboff and Hazell, 2008). It is designed to operate across the psychoacoustic and environmental domains, in which it is believed to act on social context, shaping learning and generalization, to reduce the precision assigned to the tinnitus signal while strengthening non-tinnitus listening pathways (Searchfield, 2014; Searchfield et al., 2025b). QCore™ attempts this through structured neuroplasticity training using repetition, intensity, and task specificity (Kleim and Jones, 2008); and through ecologically meaningful sounds and instruction, with the goal that attentional gains transfer outside the task itself. This approach aligns with feasibility and controlled trials showing that active, game-based perceptual-attention training reduces tinnitus impact and improves attention metrics compared with control gameplay (Vasudevan et al., 2021; Searchfield et al., 2025b, 2007).

The Retrain mode targets the way human audition parses scenes and forms auditory objects. Because tinnitus lacks visual confirmation and violates expectations for “real” sounds, it recruits attention and conflicts with memory-based predictions (Searchfield, 2014). Tinnitus is an over-dominant auditory object that captures attention when external evidence is weak. Short, home-based Auditory Object Identification and Localization (AOIL) tasks used in the QCore™ therapy have reduced tinnitus measures, with improvements in minimum masking level correlating with improved attention shifting (Searchfield et al., 2007). Building on this, a randomized controlled trial of a 20-day attention-training game (“Terrain”) produced clinically significant TFI reductions, with gains correlating to better mixed auditory–visual attention and shorter N1 latencies to non-tinnitus targets, evidence that training reallocates precision away from the internal signal and strengthens top-down control of auditory objects (Wise et al., 2016).

Multisensory attention-training has also shown significant, though more modest, TFI reductions and improvements in attentional ability, supporting the principle that targeted manipulation of attentional selection and multisensory integration can shift competitive gain away from tinnitus (Spiegel et al., 2015). Multisensory training was associated with small spatially coherent changes in percent BOLD signal coupling between distributed cortical regions (Searchfield et al., 2021). Enhanced bilateral coupling between the left and right posterior intraparietal sulcus suggested strengthening of dorsal attention mechanisms supporting spatial selection and multisensory integration. Increased connectivity between parietal regions and the frontal eye fields indicates closer alignment between multisensory representations and top-down visuospatial attention and oculomotor control. Strengthened coupling within the right-lateralised frontal eye field–temporoparietal junction–superior temporal sulcus network points to more efficient stimulus-driven reorienting and audiovisual integration. In parallel, increased coupling between primary visual cortices and the right middle frontal gyrus is consistent with enhanced top-down modulation of early visual processing. In contrast, a reduction in percent BOLD signal change between the right middle frontal gyrus and right primary auditory cortex suggests relative disengagement of executive control from early auditory processing. Overall, this pattern is consistent with a training-related reorganization of large-scale attention and multisensory networks, characterized by enhanced visuospatial and multisensory control and reduced reliance on direct prefrontal regulation of the auditory cortex (Searchfield et al., 2021).

QCore™ employs auditory spatial tracking and pattern–structure detection paradigms to target the mechanisms that sustain tinnitus salience; namely, attentional capture, auditory stream segregation, and schema-guided grouping (Wise et al., 2016). The use of ecologically valid, environmental sounds attempts to deprioritise the internally generated percept. As training progresses, attentional load is systematically increased, believed to recalibrate attention so that external sound streams are preferentially weighted over the tinnitus signal (Vasudevan et al., 2021; Searchfield et al., 2025b). Distributed practice with graduated difficulty is believed to engage control networks, while ecological validity supports generalization; over weeks, use-dependent plasticity and error-driven feedback should update internal models (Kleim and Jones, 2008). The intention is that tinnitus is encoded as low-value and low-relevance information. RCT and proof-of-concept data converge on this picture: 20 days of training improves TFI, attention performance, and early cortical processing of non-tinnitus targets (Wise et al., 2016); short-course AOIL reduces MML in tandem with attentional shifting; and multisensory attention-training yields measurable drops in tinnitus scales while enhancing attentional capacity (Searchfield et al., 2007). Together, these studies, along with scoping reviews of auditory attention (Searchfield et al., 2025b) and tinnitus perceptual training (de Barros et al., 2024; Kong and Jin, 2025), support a common conclusion: repeated listening that elevates external evidence and trains selection can re-weight salience and keep the tinnitus channel at the periphery of awareness in daily life. Neuroimaging syntheses show that tinnitus involves network-level alterations spanning the auditory, fronto-parietal control, salience, and limbic systems. Interventions that normalize connectivity within these systems are more likely to help patients maintain externally anchored listening (Burton-Harris et al., 2023).

Assessment and mode personalisation

Tinnitus is heterogeneous in its causes, experiences, and impacts on people (Cederroth et al., 2019). Person level variables meaningfully shape response to tinnitus (Durai et al., 2015, 2017b; Durai and Searchfield, 2016). In a case–control study, personality traits (higher stress reaction and alienation; lower social closeness and self-control) differentiated tinnitus from non-tinnitus (Durai et al., 2017b). Consequently, assessment in the QCore™ platform identifies the specific perceptual, emotional, attentional, and contextual factors driving an individual's symptoms and then maps them to tailored interventions (Searchfield, 2019a). A state-of-the-art review concluded that while many sound therapies claim “customization”, most adjust only a single feature (usually tinnitus pitch) (Searchfield et al., 2017). Multidimensional personalization (integrating hearing status, psychoacoustics, reaction to sound, and psychosocial factors) is recognized as being important in guidelines but underused in practice (Searchfield et al., 2017).

The development of the assessment portion of the QCore™ focused on two pillars: (1) goal-anchored planning, and (2) mechanism-informed profiling. For the first pillar, the Client Oriented Scale of Improvement in Tinnitus (COSIT; Searchfield, 2019a; Searchfield and Kwok, 2025) is used at baseline to elicit patient-defined priorities (e.g., sleep, control, hearing impact) and to track change in these measures. The COSIT shows convergent validity with TFI and is used to rank the treatment domains most often required in the clinic. For the second, the profile integrates hearing status and tinnitus psychoacoustics, including spatial characteristics (Searchfield et al., 2015) and masking profile to set TAN (Searchfield et al., 2002). The QCore™ assigns a recommended total therapy time of 60 min/day, allocating it adaptively across the three modes based on COSIT goals and interim outcomes. Early emphasis typically falls on Relief and Relax with the aim of establishing perceptual control and down-shift autonomic arousal in vulnerability windows (e.g., quiet periods, bedtime), before progressively increasing Retrain as awareness and intrusiveness abate, an approach consistent with ALT (raise the adaptation level and reduce contrast) and with attentional/salience mechanisms discussed previously.

Goal-oriented motivational counseling for behavioral change

Counseling and behavioral strategies are widely recognized as being central to tinnitus care. Counseling provides a goal-oriented, foundational understanding of why therapy matters and how active engagement can contribute to change, thereby enhancing patient agency and self-efficacy. These principles are introduced during orientation to the QCore™ and reinforced throughout therapy via short, purposeful in-therapy messages. Counseling should complement sound-based training by explaining mechanisms of effect, prioritizing interesting and meaningful external sounds, and strengthening skills to down-weight the tinnitus percept (Searchfield, 2020). It also provides a corrective framework to counter feelings of helplessness, social invalidation, and negative messaging that often accompany chronic tinnitus (Searchfield et al., 2011). Through goal setting, users monitor their own behavioral change, learn to reinterpret tinnitus signals, and reduce the socially reinforced threat value of tinnitus (Searchfield et al., 2024).

A key counseling component is reframing the meaning of tinnitus. Negative beliefs are challenged with explanations grounded in contemporary neuroscience and the ecological model. Positive messaging, mindfulness-based coping principles (consistent with audiologist-led cognitive behavioral therapy, aCBT), and an emphasis on small, achievable steps attempt to build resilience and sustained engagement (Campbell et al., 2025; Narejo, 2023). Current messages are pre-programmed, theory-informed prompts developed from responses to a large-scale survey (Narejo, 2023), behavioral change principles, and are delivered automatically. They are not generated by AI and are not written individually by therapists.

Behavioral change is applied through structured scaffolding; users receive clear daily usage expectations, predictable routines, and immediate recognition of small achievements. The QCore™ dashboard should facilitate ongoing communication between clinician and client, supporting a strong therapeutic alliance. When usage declines or stops, automated reminders prompt reengagement, and clinicians are notified to intervene through in-person or remote follow-up.

The evidence used to develop the structured counseling includes a small a mixed-methods study that showed a single counseling session, whether delivered with brief homework or not, reduced Tinnitus Functional Index scores from an average of 45 to 29 within 3 weeks, with 50% of participants achieving clinically meaningful improvement (Searchfield et al., 2020a). Qualitative themes highlighted the benefits of counseling, clarity of content, practical application, and the value of active tasks. Targeted, high-impact counseling can produce clinically significant short-term reductions in distress (Searchfield et al., 2020a). In QCore™, this takes the form of short, integrated counseling moments embedded directly within the digital therapeutic. These moments potentially prepare the brain for sound-based retraining by (i) reframing tinnitus, (ii) reducing threat attribution, and (iii) enhancing self-efficacy, believe to be an essential precursor for successful engagement with the Retrain mode.

Combining effects

A controlled trial of the prototype QCore (labeled “UpSilent”) was undertaken to compare its effectiveness to an active control: a popular sound-therapy app (Searchfield and Sanders, 2022). Although the study was not designed to identify which specific components produced treatment effects, the pattern of results was consistent with hypothesized modes of effect. Participants using the QCore prototype showed clinically meaningful reductions in TFI scores at both 6 and 12 weeks, whereas those using the control app did not. The QCore prototype produced statistically significant early improvements in annoyance, unpleasantness, and the ability to ignore tinnitus (Figure 6). This is consistent with the first actions being on affective and attentional pathways. This likely reduces limbic amplification and eases the attentional capture that typically maintains tinnitus salience. These subjective shifts are consistent with early downregulation of sympathetic arousal and reduced precision of threat-related predictions, mechanisms that would decrease the emotional gain associated with tinnitus and weaken the tendency for tinnitus to dominate awareness. By comparison, the app produced a reduction in unpleasantness after 12 weeks, suggesting that low-information sound therapy can modulate affective circuits but may require more time than the prototype QCore therapy. As treatment progressed, the QCore prototype showed additional changes not only in annoyance and ability to ignore but also in tinnitus strength by week 12. This pattern implies that deeper sensory-gain recalibration occurred more slowly than affective and attentional changes. The gradual reduction in tinnitus magnitude aligns with the timescale of neuroplastic processes involved in central gain and adaptation-level shifts. In contrast, the group using the app did not show significant changes in the rating scale beyond unpleasantness. The limited effect of the control app suggests that the perceptual system may require richer stimulation or more salient sound features to disrupt object formation, raise the adaptation level, or promote recalibration of the contrast between tinnitus and background neural activity. The more extensive rating scale changes observed in the QCore prototype group likely reflect stronger or more multifaceted engagement of the neural systems underlying affect, attention, and sensory gain. These findings collectively suggest that the QCore prototype exerted its effects through a sequence of neurophysiological mechanisms consistent with hypothesized early limbic and salience network modulation, reducing distress and vigilance, concurrent attentional reweighting that reduces the priority assigned to tinnitus, and slower auditory system recalibration, reducing sensory contrast and loudness. Direct physiological measurements of the whole therapy system are underway to confirm these mechanisms.

QCore™ therapy compared to international guidelines

The QCore™ therapy system aligns well with international guidelines (Table 2) (VA, 2025; NICE, 2020). It is consistent with recommendations, while adding a uniquely structured framework that is not explicitly provided in any of the major guidelines but fits naturally within their scope. Across all three guidelines reviewed, assessment tools and outcome tracking emphasize the importance of validated patient-reported measures to understand tinnitus severity and monitor progress over time. The QCore™ platform recommends the use of the TFI and includes EMA based on the COSIT tool (Searchfield, 2019a; Searchfield and Kwok, 2025). Audiology and amplification approaches show broad agreement across guidelines. The QCore™ is designed to work alongside these established audiological interventions, the therapy audio can be streamed to hearing aids and, in the future, cochlear implants to support combined therapy. Perceptual-training recommendations vary more widely in the guidelines. The VA/DoD guideline highlights insufficient evidence for auditory cognitive training, including auditory-attention tasks (VA, 2025). NICE does not provide explicit recommendations in this area (NICE, 2020). The German S3 guideline recommends hearing therapy, including auditory training (Mazurek et al., 2022). QCore™ offers a structured and practical approach in this domain, providing perceptual training modules that target attention, sensory reweighting, and desensitization, potentially filling a gap that guidelines identify but have not yet fully resolved with evidence-based tools. Sound therapy and sound-enrichment recommendations differ across guidelines. The VA/DoD guideline “suggests” the therapeutic use of sound as part of self-care (VA, 2025). NICE includes sound options within its multimodal approach but does not endorse “sound therapy” in general due to heterogeneous evidence (NICE, 2020). The German S3 guideline is more conservative, concluding that many sound therapies lack sufficient evidence for routine use (Mazurek et al., 2022). The QCore™ tries to bridge these positions by offering customized, adaptive sound environments designed to support desensitization and attention modulation, aligning with general guidelines on sound use while providing a structured implementation. Psychological therapies show the strongest cross-guideline consensus. QCore™ integrates audiology-informed counseling and coaching approaches, targeting distress, sleep, attentional bias, and coping behaviors, areas in which all guidelines agree.

A long-standing barrier to treatment has been the heterogeneity of tinnitus and the scarcity of therapies with a mechanistic rationale (Burton-Harris et al., 2023). QCore's proposed therapeutic effects are theorized as five interlocking processes. First, therapy reduces sensitization to tinnitus signals by diminishing the brain's readiness to amplify or track internal auditory activity. Second, it reduces the perceived loudness of tinnitus by reducing contrast with other auditory activity, making the percept less intrusive and easier to ignore. Third, it interferes with the perceptual and cognitive operations that extract tinnitus from ongoing neural activity, thereby lowering the likelihood that tinnitus emerges as a distinct auditory object. Fourth, it reduces the attentional priority afforded to the tinnitus signal, weakening the automatic capture of cognitive resources. Finally, fifth, it supports a positive psychological response to decreased intrusiveness, breaking cycles of distress and reinforcing self-efficacy. Hypothetically, when perceived magnitude is reduced, users may learn to shift their internal signal detection criteria, altering how auditory events are judged and allowing periods of unawareness. Current behavioral and neuroscientific evidence is consistent with these hypotheses, but further research is required to prove this.

Mechanistic integration of relief, relax, and retrain modes

The three functional modes of the therapy: Relief, Relax, and Retrain are intended to operate on complementary mechanisms within tinnitus-related networks (Figure 7) (Burton-Harris et al., 2023; De Ridder et al., 2014; Schlee et al., 2011). Relief primarily targets sensory gain and perceptual intrusiveness. By reducing auditory contrast, disrupting object formation, and raising the adaptation level, Relief is assumed to weaken the sensory precision and stability of tinnitus-related activity (Searchfield et al., 2012; Durai and Searchfield, 2017). The Relax mode is posited to influence magnitude indirectly through limbic–autonomic pathways; by reducing arousal, vigilance, and negative affect, it lowers the emotional gain applied to tinnitus signals and diminishes their salience (Durai et al., 2015; Aydin and Searchfield, 2019). Retrain likely modifies magnitude via predictive and attentional mechanisms: strengthening non-tinnitus listening pathways, destabilizing tinnitus-related predictions, and potentially reclassifying tinnitus as a low-value auditory object (Searchfield et al., 2025b). Although conceptually distinct, the modes inevitably overlap. Masking can lower anxiety, emotional down-regulation can alter detectability, and attentional training can reduce loudness perception. Such interactions are therapeutically beneficial but complicate the attribution of clinical change to any single mechanism, highlighting the need for future research designs capable of isolating or quantifying mode-specific contributions, such as factorial or crossover studies with washout periods, or mediation analyses incorporating mechanistic biomarkers.

Alignment with contemporary guidance and neurorehabilitation principles

QCore™ aligns with current international guidelines emphasizing personalisation, education and counseling, sound-based therapy, and multimodal care (Searchfield et al., 2025b). It operationalizes core neurorehabilitation principles, specificity, repetition and spacing, graded challenge, salience, and feedback/error-based learning (Kleim and Jones, 2008), with the intent to reshape distributed networks associated with tinnitus perception and distress. The modes are intended to raise the internal adaptation level relative to tinnitus, alter contrast, and shift attentional and emotional priorities so that meaningful external sounds dominate experience. QCore™ should therefore be viewed not as a collection of isolated tools but as a coordinated therapeutic platform driven by ecological and psychoacoustical principles (Searchfield et al., 2012; Searchfield, 2014).

Clinical implementation and pragmatic value

Personalisation of therapy draws on audiometric and self-report data to generate tinnitus profiles; adaptive algorithms refine sound prescriptions; smartphone delivery supports flexible, high-frequency use; and remote analytics enable continuous optimisation. It is believed that these features will reduce barriers to use, such as accessibility, clinician time, and adherence; all key drivers of outcomes in tinnitus care (Tyler et al., 2008). The staged workflow, with early Relief and Relax for stabilization, followed by progressive transition into Retrain to consolidate perceptual recategorization at lower sound levels, aligns with user preferences. Patients want practical tools that reduce loudness, annoyance, and awareness, and clear indicators of progress, and emphasize active engagement (Narejo et al., 2026). QCore™ embeds these expectations within a supportive counseling layer that fosters self-efficacy (Fagelson and Smith, 2016) and shared decision-making (Searchfield et al., 2024).

Additionally, for audiologists, QCore™ offers a structured counseling and sound-therapy framework for clinicians who may feel under-prepared for the psychological aspects of tinnitus care, or are constrained by limited training (Searchfield et al., 2020b). Simultaneously, some patients are skeptical of talk-based interventions (Narejo et al., 2026). QCore's design attempts to mitigate these barriers by providing concise, high-impact counseling moments that integrate directly with the therapy, enabling the client and reducing the resource burden of in-person psychological services while preserving therapeutic alliance and quality outcomes.

Limitations

Numerous mechanisms for tinnitus have been proposed; they include thalamocortical dysrhythmia (De Ridder et al., 2015), altered gain control (Parameshwarappa and Norena, 2024), network-level dysfunction (De Ridder et al., 2014), sensory prediction errors (Hullfish et al., 2019; Durai et al., 2018b) and noise cancellation (Rauschecker et al., 2010). The psychoacoustical model emphasized in this review (Searchfield, 2014; Searchfield et al., 2012) describes: auditory scene analysis, attention, predictive processing, adaptation, and salience as modifiers of tinnitus. The behavioral vs. neuroscience models are not mutually exclusive; rather, they are “mirrors” of each other. Physiology explains the processes underpinning psychosocial effects. Although the therapy framework should be viewed as one plausible interpretation, its value lies in avoiding reliance on a single, exclusive physiological mechanism of tinnitus.

Not all individuals with tinnitus are likely to benefit equally from interventions. Therapy studies consistently demonstrate substantial variability in treatment outcomes, with some patients reporting meaningful reductions in tinnitus distress while others experience minimal or no benefit (Niemann et al., 2024). Publication bias, the tendency for studies with favorable results to be published more frequently than studies with null, negative, or inconclusive findings (Sterling et al., 1995), may mean that the research used in the development of the QCore™ is prejudiced. Placebo and expectancy effects represent another important consideration in tinnitus research (Walters et al., 2024). Improvements in tinnitus perception and distress may result from therapeutic engagement, clinician interaction, increased self-monitoring, or participation in a structured treatment programme, rather than from the specific features of an intervention itself. Given the inherently subjective nature of tinnitus, treatment efficacy is commonly assessed using patient-reported outcome measures. Placebo and expectancy effects can therefore contribute to reported improvements, while equivalent changes may not be detectable in objective physiological or audiological measures. Basing therapy development on physiology rather than behavioral results alone should limit the placebo effect. Control of concomitant factors remains a priority and a potential weakness of the studies reviewed.

The generalizability of the therapy awaits prospective, pragmatic investigations. Tinnitus is a heterogeneous condition rather than a single disorder. Consequently, treatment models that are effective for one subgroup may not generalize to others. The therapy model should not be viewed as universally applicable to all tinnitus presentations. Factors contributing to non-response may include tinnitus duration, psychological comorbidities, and functional impact (Luo et al., 2025). Large multifactorial designs or deliberately focused trials that attempt to tease apart different factors will help elucidate the physiology. For example, an EEG study that partitioned responders from non-responders based on the TFI found that responders were characterized by elevated occipitoparietal connectivity at baseline, which normalized after therapy, whereas non-responders retained their pre-therapy patterns (Durai et al., 2021). Some supporting evidence remains indirect or inferential, and key mechanistic domains require formal quantification. Longitudinal studies with appropriate control conditions are required to distinguish treatment-related changes from spontaneous fluctuations (Luo et al., 2025). Dose–response relationships for Relief, such as intensity, spacing, and total usage, are not yet precisely defined. The causal pathways linking relaxation-induced autonomic changes to sustained reductions in distress and salience need to be validated. The specificity of Retrain's targets and their neural signatures requires systematic evaluation. The heterogeneity of tinnitus etiologies, including hearing-loss profiles, hyperacusis or misophonia, migraine-like presentations, and somatosensory contributors, highlights the need for phenotype-tailored adaptation of protocols to maximize benefit and minimize non-response (Cederroth et al., 2019). Early outcomes with the prototype system are encouraging, but larger, independent, comparative trials are essential to establish efficacy, durability, and scalability. As the review draws on research conducted over approximately 25 years by the developer and collaborators, the potential for investigator bias must also be acknowledged. Independent findings have been integrated into the review where possible. Many conclusions are testable hypotheses rather than definitive claims. Current intervention evidence consists largely of pilot, feasibility, proof-of-concept and early controlled studies.

Future needs

Articulating mechanisms enables the development of clear, empirically testable predictions. Future research should determine which tinnitus phenotypes derive the greatest benefit from different therapy modes and how autonomic indices, such as heart-rate variability and skin conductance, reflect Relax engagement or predict clinical outcomes. It will also be important to establish whether changes in attentional metrics mediate Retrain's clinical effects, and to define mode-specific dose–response functions and optimal spacing schedules. These questions are ideally addressed through adequately powered randomized controlled trials incorporating active control conditions, longitudinal follow-up, and repeated measures of target engagement. Phenotype-stratified designs and mediation analyses may be particularly valuable for testing proposed mechanisms and identifying treatment responders. Trials incorporating target-engagement biomarkers, or ecological momentary assessment of context-dependent variations, will strengthen mechanistic insight. Longer-term follow-up studies are also required to determine the durability of treatment effects and the extent to which improvements generalize to everyday listening environments. Implementation research examining digital equity, adherence trajectories, interoperability with hearing aids, and cost-effectiveness relative to standard care will be essential for widespread use. This research should strengthen the feedback loop between mechanistic understanding and clinical improvement, enabling QCore™ to evolve as both a scientific tool and a scalable therapeutic solution.

As with many therapeutic innovations, the early evidence base for the QCore™ Tinnitus Therapy Platform has largely come from those directly involved in its conception and development. This is both expected and necessary, as innovators are often best positioned to undertake the initial research required to translate novel concepts into clinical practice. Nevertheless, scientific confidence is strengthened when findings are replicated and extended by independent investigators. Future independent evaluations will be important in confirming the robustness, reproducibility, and broader applicability of the outcomes reported to date.

The aim of this review was to articulate the theoretical and mechanistic foundations that informed the design of QCore™. Establishing a clear conceptual basis is essential for integrating the approach with prevailing models of tinnitus and for deriving testable predictions. Tinnitus is a heterogeneous, multisystem condition sustained by maladaptive plasticity, attentional biases, persistent prediction errors, limbic reinforcement, and context-dependent gain changes. QCore™ was designed around these contemporary insights, combining perceptual disruption (Relief), emotional/autonomic modulation (Relax), and attentional–predictive recategorization (Retrain) within a personalized therapy framework.

The convergent behavioral and neuroscientific evidence reviewed here supports the plausibility and clinical relevance of therapy mechanisms, while underscoring the need for rigorous, independent evaluation. It would be neither realistic nor responsible to suggest that the current QCore™ can resolve tinnitus for every individual; however, the conceptual and methodological foundations for pursuing that long-term ambition are now clearly articulated. In its present form, QCore™ delivers a structured, evidence-aligned framework that improves therapeutic clarity, treatment consistency, and patient engagement. Its development was based on applying established behavioral neuroscience with practical clinical tools to enhance outcomes.

QCore™ was also deliberately engineered as a scalable platform that other researchers can to contribute to. By providing a unified mechanistic account alongside a pragmatic clinical pathway, QCore™ offers a coherent basis for integrative tinnitus therapy and a platform for translational research that links theory, biomarkers, and outcomes.