Search Results (93)

Developmental dyslexia (DD) often involves difficulties in phonological processing of speech. Objectives: While underlying neural changes have been identified in terms of stimulus- and task-related responses within specific brain regions and their neural connectivity, there is still limited understanding of how these changes affect the overall organization of brain networks. Methods: This study used EEG and functional network analysis, focusing on small-world propensity across various frequency bands (from δ to γ), to explore the global brain organization during the auditory discrimination of words and pseudowords in children with DD. Results: The main finding revealed a systemic inefficiency in the functional network of individuals with DD, which did not achieve the optimal small-world propensity. This inefficiency arises from a fundamental trade-off between localized specialization and global communication. During word listening, the δ-/γ1-networks (related to impaired syllabic and phonemic processing of words) and the θ-/β-networks (related to pseudoword listening) in the DD group showed lower local clustering and connectivity compared to the control group, resulting in reduced functional segregation. In particular, the θ-/β-networks for words in the DD group exhibited a less optimal balance between specialized local processing and effective global communication. Centralized midline hubs, such as the postcentral gyrus (PstCG) and inferior frontal gyrus (IFG), which are crucial for global coordination, attention, and executive control, were either absent or inconsistent in individuals with DD. Consequently, the DD network adopted a constrained, motor-compensatory, and left-lateralized strategy. This led to the redirection of information flow and processing effort toward the left PstCG/IFG loop, interpreted as a compensatory effort to counteract automatic processing failures. Additionally, the γ1-network, which is involved in phonetic feature binding, lacked engagement from posterior sensory hubs, forcing this critical process into a slow and effortful motor loop. The γ2-network exhibited unusual activation of right-hemisphere posterior areas during word processing, while it employed a simpler, less mature routing strategy for pseudoword listening, which further diminished global communication. Conclusions: This functionality highlights the core phonological and temporal processing deficits characteristic of dyslexia. Full article

The regulation of sensory processing by centralized neuromodulatory systems can alter behavioral responses to social cues. Neuromodulatory systems such as the serotonergic neurons in the dorsal raphé nucleus (DRN) show heterogenous responses to different types of sensory stimuli or to stimulus qualities such as reward, valence, or salience. Sensory neuromodulation could therefore be related to a broader quality of the behavioral context or to specific types of social cues. We assessed this issue by presenting male mice with either playback of female vocal signals associated with defensive aggression (squeaks) or silence, and the presence or absence of a female. Activity in regions of the DRN that project to the auditory midbrain was assessed through co-labeling with antibodies to the serotonin synthetic enzyme tryptophan hydroxylase (TPH) and the immediate early gene product c-Fos. Female presence or absence had the largest effect, decreasing the co-localization of TPH and c-Fos, while the playback of squeaks had effects that were condition-dependent, increasing co-label only when females were absent. Squeak playback further decreased the correlation in the numbers of co-labeled neurons between two dorsal subdivisions of the DRN, the DRD and DRL. These results are inconsistent with an auditory-exclusive feedback loop. Instead, cues associated with female presence heavily influence raphé activity, with squeaks playing a modifying and context-dependent role. Because the elevation of serotonin in the IC causes males to become more responsive to female squeaks, these findings suggest that a nuanced interaction of positive and negative cues during social interaction may fine-tune male responses to the vocalization of social partners, in part through the serotonergic system. Full article

This scoping review aims to synthesize peer-reviewed literature exploring quality of life (QoL) for individuals with age-related hearing loss (ARHL), age-related central auditory processing (ARCAP) deficits, and age-related cognitive decline. A growing body of research has identified ARHL as a risk factor for the development of dementia, highlighting the connection between the sensory and cognitive systems. As the aging population continues to grow, examining comorbid age-related hearing and cognitive decline is especially relevant. These conditions may have potential negative consequences on the daily functioning, social participation, mental health, and overall wellbeing of older adults. A systematic search of peer-reviewed literature was conducted across multiple databases, adhering to the PRISMA guidelines for scoping reviews. Studies that focused on the impact of ARHL, ARCAP deficits, and/or related cognitive deficits on QoL were included in the present review. Key data extracted included QoL measures categorized into the ICF framework, the effects of hearing loss intervention on QoL, and the impact of ARHL on QoL for aging individuals. This review summarizes the reported effects that ARHL, ARCAP, and/or cognitive decline have on older adults, and discusses the clinical and practical implications for managing clients with these conditions. In addition to preventative measures and deficit management, maintenance of life participation, social engagement, and overall wellbeing should be considered when caring for aging adults with hearing and/or cognitive impairment. Full article

Dicer is crucial for the generation of microRNAs (miRNAs), which are essential for regulating gene expression and keeping neuronal health. Dicer’s conditional deletion cuts all spiral ganglion neurons but spares a small fraction of vestibular ganglion neurons, innervating the utricle and part of the saccule. Hair cells develop in the utricle, saccule, posterior crista, and the cochlea in Pax2^Cre; Dicer^f/f. Cochlear hair cells develop at the base and expand the OHC and IHC in the middle, or split into a base/middle and the apex. In contrast, Foxg1^Cre; Dicer^f/f cuts all canal cristae and cochlea hair cells, leaving a reduced utricle and an exceedingly small saccule. Likewise, Foxg1^Cre; Gata3^f/f shows no cochlear hair cells and is absent in the horizontal and reduced in the posterior crista. In contrast, the utricle, saccule, and anterior crista are nearly normal, underscoring the intricate regulatory networks involved in hair cell and neuronal development. The central projections have been described as the topology of various null deletions. Still, without spiral ganglion neurons, fibers from Dicer null mice navigate to the cochlear nuclei and expand into the vestibular nuclei to innervate the caudal brainstem. Beyond a ramification around the CN, no fibers expand to reach the cerebellum, likely due to Pax2 and Foxg1 that cut these neurons. Genetic alterations, such as Dicer deletion, can lead to hearing loss and impairments in auditory signal processing, illustrating the critical role of microRNAs in the development and function of auditory and vestibular neurons. Further studies on this topic could help in understanding potential therapeutic targets for hearing loss associated with neuronal degradation of miRNA. Full article

Background/Objectives: Retrocochlear auditory dysfunctions (RADs), including auditory neuropathy (AN) and auditory processing disorders (APD), encompass disorders characterized by impaired auditory processing beyond the cochlea. This narrative review critically examines their distinguishing features, synthesizing recent advances in classification, pathophysiology, clinical presentation, and treatment. Methods: This narrative review involved a comprehensive literature search across major electronic databases (e.g., PubMed, Scopus) to identify and synthesize relevant studies on the classification, diagnosis, and management of AN and APD. The goal was to update the view on etiologies (genetic/non-genetic) and individualized rehabilitative strategies. Diagnosis relies on a comprehensive assessment, including behavioral, electrophysiological, and imaging tests. Rehabilitation is categorized into bottom-up and top-down approaches. Results: ANSD is defined by neural desynchronization with preserved outer hair cell function, resulting in abnormal auditory brainstem responses and poor speech discrimination. The etiologies (distal/proximal) influence the prognosis for interventions, particularly cochlear implants (CI). APD involves central processing deficits, often with normal peripheral hearing and heterogeneous symptoms affecting speech perception and localization. Rehabilitation is multidisciplinary, utilizing bottom-up strategies (e.g., auditory training, CI) and compensatory top-down approaches. Remote microphone systems are highly effective in improving the signal-to-noise ratio. Conclusions: Accurate diagnosis and personalized, multidisciplinary management are crucial for optimizing communication and quality of life. Evidence suggests that combined bottom-up and top-down interventions may yield superior outcomes. However, methodological heterogeneity limits the generalizability of protocols, highlighting the need for further targeted research. Full article

Background/Objectives: Music engages multiple brain networks simultaneously, yet most studies examine these networks in isolation. Methods: We investigated functional connectivity among the auditory, motor, and reward networks during music listening in different contexts using fMRI data from two samples (N = 39 each): focused music listening and background music during cognitive tasks. ROI-to-ROI, seed-based, and graph theory analyses examined connectivity patterns among 46 regions spanning the three networks. Results: Both contexts showed enhanced within-auditory network connectivity compared to rest, suggesting that this is fundamental to music processing. However, between-network patterns diverged markedly. Background music listening during cognitive tasks preserved reward-motor coupling while reducing auditory-motor and auditory-reward connectivity. Focused music listening produced widespread negative correlations between motor regions and both the auditory and reward networks, potentially reflecting motor suppression in the scanner environment. Graph theory measures revealed context-specific hub reorganization: reward regions (nucleus accumbens, caudate) showed increased centrality during background music listening, while the amygdala and frontal orbital cortex were selectively enhanced during focused listening. Conclusions: These findings demonstrate that music engagement involves context-dependent network reorganization beyond simple attention effects. The same musical stimulus engages different neural mechanisms depending on concurrent cognitive demands, motor requirements, and listening goals. Enhanced within-auditory connectivity appears consistent across contexts, but between-network interactions are shaped by the broader cognitive-behavioral context. These results highlight the importance of considering ecological context when studying music processing and designing music-based interventions, as network connectivity patterns during music listening reflect complex interactions between task demands, attentional resources, and musical engagement rather than music processing alone. Full article

Background/Objectives: Children with perinatal HIV (PHIV) are more at risk for hearing loss than HIV-unexposed (HU) children. Due to medical advances maternal HIV transmission to newborns is decreasing, but in children with perinatal HIV exposure, uninfected (PHEU) is increasing. The objectives were to evaluate (1) pure-tone audiometry and cochlear and auditory neural function in children with perinatally acquired HIV (PHIV), children with perinatal HIV exposure but uninfected (PHEU), and HIV-unexposed (HU) children and (2) differences in hearing measures for children with PHIV according to HIV disease severity. Methods: Three hundred and thirty-three children (105 PHIV [58 girls, 47 boys], 101 PHEU [51 girls, 50 boys], and 127 HU [65 girls, 62 boys]), aged 11–14 years, completed a hearing assessment that included a hearing-related questionnaire, otoscopy, tympanometry, pure-tone thresholds, distortion product otoacoustic emissions (DPOAEs) for cochlear function, and auditory brainstem responses (ABRs) for neural function. Results: Pure-tone thresholds, DPOAE, and ABR measures were similar in the three groups. Children with PHIV had a higher prevalence of hearing loss compared to children with PHEU and HU children. Children with PHIV and greater historical HIV disease severity had similar hearing, DPOAEs, and ABRs to those with lesser HIV disease severity. Conclusions: In utero HIV acquisition or HIV exposure might not affect the cochlear and neural function up to the level of the brainstem. Children with PHIV had a higher prevalence of hearing loss; it is possible there is a difference in central auditory processing across the three groups of children. Hearing loss identification is important since it may impact social and educational development. Full article

Background/Objectives: Environmental noise is a non-specific biological stressor that is becoming an escalating health concern for both industrialized and developing countries. A study by the World Health Organization identified ambient noise as the second most prevalent factor adversely affecting public health, causing high levels of stress. Extended or intense exposure to environmental noise (EN) has been linked to various alterations in auditory pathways and auditory-related central nervous system structures. We tested the hypothesis that acute exposure to intense noise could lead to such alterations. Therefore, the aim of this study is to evaluate neuronal activation in auditory-related brain regions resulting from acute noise exposure using immunohistochemistry processes. Methods: We examined a total of 12 Wistar rats (6 rats for noise exposure group; 6 rats for the control group). The noise exposure group was exposed to intense noise, while the control group experienced basal noise for thirty minutes. After scarification of the rats, tissues were collected and examined histologically using the immunohistochemical staining method. Results: Our research demonstrates that acute noise exposure markedly elevates neuronal activity in critical parts of the auditory system, such as the cochlear nuclei, inferior colliculi, trapezoid body, and primary auditory cortex. While we identified c-Fos immunoreactive neurons in the medial geniculate body of both the experiment and control groups, no statistically significant changes were found between these groups. Conclusions: These findings indicate that noise exposure-related stress could be caused primarily by the disruption of lower centers rather than the medial geniculate body. Full article

Background: Hearing loss results from diverse biological insults along the auditory pathway, including sensory hair cell death, neural degeneration, and central auditory processing deficits. Implantable auditory neuroprostheses, such as cochlear and brainstem implants, aim to restore hearing by directly stimulating neural structures. Advances in neurobiology and device technology underpin the development of more sophisticated implants tailored to the biological complexity of auditory dysfunction. Aim: This narrative review of reviews aims to map the integration of artificial intelligence (AI) in auditory neuroprosthetics, analyzing recent research trends, key thematic areas, and the opportunities and challenges of AI-enhanced devices. By synthesizing biological and computational perspectives, it seeks to guide future interdisciplinary efforts toward more adaptive and biologically informed hearing restoration solutions. Methods: This narrative review analyzed recent literature reviews from PubMed and Scopus (last 5 years), focusing on AI integration with auditory neuroprosthetics and related biological processes. Emphasis was placed on studies linking AI innovations to neural plasticity and device–nerve interactions, excluding purely computational works. The ANDJ (a standard narrative review checklist) checklist guided a transparent, rigorous narrative approach suited to this interdisciplinary, rapidly evolving field. Results and discussion: Eighteen recent review articles were analyzed, highlighting significant advancements in the integration of artificial intelligence with auditory neuroprosthetics, particularly cochlear implants. Established areas include predictive modeling, biologically inspired signal processing, and AI-assisted surgical planning, while emerging fields such as multisensory augmentation and remote care remain underexplored. Key limitations involve fragmented biological datasets, lack of standardized biomarkers, and regulatory challenges related to algorithm transparency and clinical application. This review emphasizes the urgent need for AI frameworks that deeply integrate biological and clinical insights, expanding focus beyond cochlear implants to other neuroprosthetic devices. To complement this overview, a targeted analysis of recent cutting-edge studies was also conducted, starting from the emerging gaps to capture the latest technological and biological innovations shaping the field. These findings guide future research toward more biologically meaningful, ethical, and clinically impactful solutions. Conclusions: This narrative review highlights progress in integrating AI with auditory neuroprosthetics, emphasizing the importance of biological foundations and interdisciplinary approaches. It also recognizes ongoing challenges such as data limitations and the need for clear ethical frameworks. Collaboration across fields is vital to foster innovation and improve patient care. Full article

Background: Children diagnosed with Speech Sound Disorders (SSDs) encounter difficulties in speech perception, especially when listening in the presence of background noise. Recommended protocols for auditory processing evaluation include behavioral linguistic and speech processing tests, as well as objective electrophysiological measures. The present study compared the auditory processing profiles of children with SSD and typically developing (TD) children using a battery of behavioral language and auditory tests combined with auditory evoked responses. Methods: Forty (40) parents of 7–10 years old Greek Cypriot children completed parent questionnaires related to their children’s listening; their children completed an assessment comprising language, phonology, auditory processing, and auditory evoked responses. The experimental group included 24 children with a history of SSDs; the control group consisted of 16 TD children. Results: Three factors significantly differentiated SSD from TD children: Factor 1 (auditory processing screening), Factor 5 (phonological awareness), and Factor 13 (Auditory Brainstem Response—ABR wave V latency). Among these, Factor 1 consistently predicted SSD classification both independently and in combined models, indicating strong ecological and diagnostic relevance. This predictive power suggests real-world listening behaviors are central to SSD differentiation. The significant correlation between Factor 5 and Factor 13 may suggest an interaction between auditory processing at the brainstem level and higher-order phonological manipulation. Conclusions: This research underscores the diagnostic significance of integrating behavioral and physiological metrics through dimensional and predictive methodologies. Factor 1, which focuses on authentic listening environments, was identified as the strongest predictor. These results advocate for the inclusion of ecologically valid listening items in the screening for APD. Poor discrimination of speech in noise imposes discrepancies between incoming auditory information and retained phonological representations, which disrupts the implicit processing mechanisms that align auditory input with phonological representations stored in memory. Speech and language pathologists can incorporate pertinent auditory processing assessment findings to identify potential language-processing challenges and formulate more effective therapeutic intervention strategies. Full article

Background/Objectives: Children with Autism Spectrum Disorder (ASD) often display heightened sensitivity to simple auditory stimuli, but have difficulty discriminating and integrating multiple phonological features (segmental: consonants and vowels; suprasegmental: lexical tones) at the syllable level, which negatively impacts their communication. This study aims to investigate the neural basis of segmental, suprasegmental and combinatorial speech processing challenges in Mandarin-speaking children with ASD compared with typically developing (TD) peers. Methods: Thirty children with ASD and thirty TD peers will complete a multi-feature oddball paradigm to elicit auditory ERP during passive listening. Stimuli include syllables with single (e.g., vowel only), dual (e.g., vowel + tone), and triple (consonant + vowel + tone) phonological deviations. Neural responses will be analyzed using temporal principal component analysis (t-PCA) to isolate overlapping ERP components (early/late MMN), and representational similarity analysis (RSA) to assess group differences in neural representational structure across feature conditions. Expected Outcomes: We adopt a dual-framework approach to hypothesis generation. First, from a theory-driven perspective, we integrate three complementary models, Enhanced Perceptual Functioning (EPF), Weak Central Coherence (WCC), and the Neural Complexity Hypothesis (NCH), to account for auditory processing in ASD. Specifically, we hypothesize that ASD children will show enhanced or intact neural discriminatory responses to isolated segmental deviations (e.g., vowel), but attenuated or delayed responses to suprasegmental (e.g., tone) and multi-feature deviants, with the most severe disruptions occurring in complex, multi-feature conditions. Second, from an empirically grounded, data-driven perspective, we derive our central hypothesis directly from the mismatch negativity (MMN) literature, which suggests reduced MMN amplitudes (with the exception of vowel deviants) and prolonged latencies accompanied by a diminished left-hemisphere advantage across all speech feature types in ASD, with the most pronounced effects in complex, multi-feature conditions. Significance: By testing alternative hypotheses and predictions, this exploratory study will clarify the extent to which speech processing differences in ASD reflect cognitive biases (local vs. global, per EPF/WCC/NCH) versus speech-specific neurophysiological disruptions. Findings will advance our understanding of the sensory and integrative mechanisms underlying communication difficulties in ASD, particularly in tonal language contexts, and may inform the development of linguistically tailored interventions. Full article

Background: Auditory Processing Disorder (APD) manifests as impaired auditory information processing despite normal peripheral hearing. Current clinical protocols lack standardization, hampering evidence-based intervention development. Objective: This review analyzes APD research developments from 2011 to 2025, examining diagnostic criteria, assessment protocols, and treatment effectiveness. Methods: Medline, Embase, Scopus, and Cochrane Library databases were analyzed (January 2011–January 2025), following PRISMA guidelines. Two reviewers independently screened 413 articles, with 156 meeting inclusion criteria. Analysis included chi-square tests for intervention distribution and t-tests for diagnostic comparisons (α = 0.05). Results: Among 156 studies analyzed, medical interventions were markedly underrepresented (n = 4) compared to rehabilitative approaches (n = 52; χ² = 50.28, p < 0.001). The Random Gap Detection Test and Dichotic Digits Difference Test were most frequently used (12.86% and 10.48% of studies, respectively). Cognitive skill enhancement dominated intervention strategies (52.8%), followed by computer-based rehabilitation (26.4%). Publication frequency showed consistent annual growth, peaking at 57 studies in 2024. Sample sizes were comparable between APD and CAPD studies (mean difference = 4.2 cases, t = 0.416, p = 0.679). Environmental modifications appeared in 15.1% of interventions, while speech therapy was reported in only 3.8% of studies. Conclusions: The substantial imbalance between medical and rehabilitative interventions necessitates standardized diagnostic protocols and enhanced multidisciplinary collaboration. Implementation of a hierarchical processing framework is recommended for assessment and treatment. Future research should prioritize large-scale controlled trials and unified diagnostic criteria development. Full article

Epilepsy is a multifaceted neurological disorder characterized by recurrent seizures and associated with molecular and immune alterations in key brain regions. The GASH/Sal (Genetic Audiogenic Seizure Hamster, Salamanca), a genetic model for audiogenic epilepsy, provides a powerful tool to study seizure mechanisms and resistance in predisposed individuals. This study investigates the proteomic and immune responses triggered by audiogenic kindling in the inferior colliculus, comparing non-responder animals exhibiting reduced seizure severity following repeated stimulation versus GASH/Sal naïve hamsters. To assess auditory pathway functionality, Auditory Brainstem Responses (ABRs) were recorded, revealing reduced neuronal activity in the auditory nerve of non-responders, while central auditory processing remained unaffected. Cytokine profiling demonstrated increased levels of proinflammatory markers, including IL-1 alpha (Interleukin-1 alpha), IL-10 (Interleukin-10), and TGF-beta (Transforming Growth Factor beta), alongside decreased IGF-1 (Insulin-like Growth Factor 1) levels, highlighting systemic inflammation and its interplay with neuroprotection. Building on these findings, a proteomic analysis identified 159 differentially expressed proteins (DEPs). Additionally, bioinformatic approaches, including Gene Set Enrichment Analysis (GSEA) and Weighted Gene Co-expression Network Analysis (WGCNA), revealed disrupted pathways related to metabolic and inflammatory epileptic processes and a module potentially linked to a rise in the threshold of seizures, respectively. Differentially expressed genes, identified through bioinformatic and statistical analyses, were validated by RT-qPCR. This confirmed the upregulation of six genes (Gpc1—Glypican-1; Sdc3—Syndecan-3; Vgf—Nerve Growth Factor Inducible; Cpne5—Copine 5; Agap2—Arf-GAP with GTPase domain, ANK repeat, and PH domain-containing protein 2; and Dpp8—Dipeptidyl Peptidase 8) and the downregulation of two (Ralb—RAS-like proto-oncogene B—and S100b—S100 calcium-binding protein B), aligning with reduced seizure severity. This study may uncover key proteomic and immune mechanisms underlying seizure susceptibility, providing possible novel therapeutic targets for refractory epilepsy. Full article

Statistical learning (SL), the ability to extract patterns from the environment, has been assumed to play a central role in whole cognition, particularly in language acquisition. Evidence has been gathered, however, from behavioral experiments relying on simplified artificial languages, raising doubts on the generalizability of these results to natural contexts. Here, we tested if SL is affected by the composition of the speech streams by expositing participants to auditory streams containing either four nonsense words presenting a transitional probability (TP) of 1 (unmixed high-TP condition), four nonsense words presenting TPs of 0.33 (unmixed low-TP condition) or two nonsense words presenting a TP of 1, and two of a TP of 0.33 (mixed condition); first under incidental (implicit), and, subsequently, under intentional (explicit) conditions to further ascertain how prior knowledge modulates the results. Electrophysiological and behavioral data were collected from the familiarization and test phases of each of the SL tasks. Behavior results revealed reliable signs of SL for all the streams, even though differences across stream conditions failed to reach significance. The neural results revealed, however, facilitative processing of the mixed over the unmixed low-TP and the unmixed high-TP conditions in the N400 and P200 components, suggesting that moderate levels of entropy boost SL. Full article

Background: The ionotropic glutamate receptor AMPA (AMPAR) mediates fast excitatory synaptic transmission and regulates synaptic strength in various parts of the CNS. Emotional challenges can affect these processes by influencing AMPAR levels and localization via stress hormones, resulting, e.g., in behavioral changes. AMPARs are essential for auditory processing, but their response to stress hormones in the central or peripheral auditory system remains poorly understood. Therefore, this scoping review examines the effects of corticosterone (CORT), a primary stress hormone in rodents, on AMPA receptor levels and localization in the rodent nervous system and considers potential implications for the auditory system. Methods: We systematically searched PubMed, Web of Science, and OVID EMBASE using MeSH terms related to AMPA receptors and corticosterone. Studies were screened based on predefined inclusion criteria, including original research published in English that focused on AMPA receptor subunits (e.g., GluR1-4, GluA1-4, Gria1-4). Of 288 articles screened, 17 met the criteria for final analysis. Results: No reports were found regarding CORT action in the auditory system. Three main experimental models used in the included research were identified: neuronal cultures, isolated tissue cultures, and animal models. Generally, short-term CORT exposure increases AMPAR surface localization and mobility in neuronal cultures, especially in the hippocampus and prefrontal cortex. However, results from animal models were inconsistent due to variations in experimental design and other factors. The isolated tissue study did not provide sufficient data for clear conclusions. Conclusions: Variability in experimental models limits our ability to draw definitive conclusions about the effects of CORT on AMPARs across different regions of the nervous system. The differences in live animal studies highlight the need for standardized methods and reporting. Since AMPARs play a crucial role in auditory processing, CORT-induced changes in neuronal cultures may occur in the auditory system. Further research is needed to explore the specific responses of AMPAR subunits and how stress hormones may influence auditory disorders, which could help identify potential treatment strategies. Full article