Audiology Research最新文献

Background/Objectives: Speech produced by individuals with hearing loss differs notably from that of normal-hearing (NH) individuals. Although cochlear implants (CIs) provide sufficient auditory input to support speech acquisition and control, there remains considerable variability in speech intelligibility among CI users. As a result, speech produced by CI talkers often exhibits distinct acoustic characteristics compared to that of NH individuals. Methods: Speech data were obtained from eight cochlear-implant (CI) and eight normal-hearing (NH) talkers, while electroencephalogram (EEG) responses were recorded from 11 NH listeners exposed to the same speech stimuli. Support Vector Machine (SVM) classifiers employing 3-fold cross-validation were evaluated using classification accuracy as the performance metric. This study evaluated the efficacy of Support Vector Machine (SVM) algorithms using four kernel functions (Linear, Polynomial, Gaussian, and Radial Basis Function) to classify speech produced by NH and CI talkers. Six acoustic features-Log Energy, Zero-Crossing Rate (ZCR), Pitch, Linear Predictive Coefficients (LPC), Mel-Frequency Cepstral Coefficients (MFCCs), and Perceptual Linear Predictive Cepstral Coefficients (PLP-CC)-were extracted. These same features were also extracted from electroencephalogram (EEG) recordings of NH listeners who were exposed to the speech stimuli. The EEG analysis leveraged the assumption of quasi-stationarity over short time windows. Results: Classification of speech signals using SVMs yielded the highest accuracies of 100% and 94% for the Energy and MFCC features, respectively, using Gaussian and RBF kernels. EEG responses to speech achieved classification accuracies exceeding 70% for ZCR and Pitch features using the same kernels. Other features such as LPC and PLP-CC yielded moderate to low classification performance. Conclusions: The results indicate that both speech-derived and EEG-derived features can effectively differentiate between CI and NH talkers. Among the tested kernels, Gaussian and RBF provided superior performance, particularly when using Energy and MFCC features. These findings support the application of SVMs for multimodal classification in hearing research, with potential applications in improving CI speech processing and auditory rehabilitation.

Background/Objectives: Mobile health (mHealth) tools, such as smartphone apps, support person-centred care for persons with hearing loss engaging in the hearing aid management process. Hearing-aid-connected apps are increasingly common in audiological care, making it important to evaluate their availability and quality for clinicians, developers, and end-users. This scoping review aimed to identify, summarize, and synthesize information on clinically available hearing-aid-connected apps and evaluate their quality. Methods: A search of the Apple App Store (Canada) was conducted in August 2024 to identify current hearing-aid-connected apps that support hearing aid management. Metadata and features were extracted, and app quality was assessed using the Mobile Application Rating Scale (MARS). Quality was assessed across four objective domains (engagement, functionality, aesthetics, and information) and one subjective domain. Results: Apps had varying levels of metadata detail, including updates, compatibility, and target populations. All apps included common hearing aid controls (e.g., volume adjustment, microphone directionality), while more specialized features (tinnitus management, health tracking, remote clinician support) varied. High-performing apps scored significantly higher in engagement, functionality, aesthetics, and subjective quality, and all apps scored low in information quality, particularly for evidence and credibility. Conclusions: Findings highlight the need for transparent and informative metadata reporting and patient-centred design to improve clinical awareness, usability, and uptake of hearing-aid-connected apps.

Swallowing is mediated by the central nervous system, including cortical and subcortical structures, the cerebellum, and the brainstem. The brainstem contains the swallowing centre that is crucial for initiating and coordinating swallowing. Consequently, brainstem damage due to stroke often leads to severe and persistent dysphagia. The aim of the present narrative review is to provide an overview of dysphagia following brainstem stroke and its management. It summarizes the physiology and pathophysiology of dysphagia following brainstem stroke and the available therapeutic options, and evaluate their effectiveness for dysphagia following brainstem stroke, which would promote the development of therapeutic protocols. Neuromodulatory techniques, including pharyngeal electrical stimulation (PES), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS), modulate the excitability of corticobulbar circuits. These techniques promote neuroplasticity through peripheral or cortical electrical or electromagnetic inputs. Skill-based swallowing training emphasizes cortical involvement in enhancing swallowing skill, offering a targeted approach to behavioural rehabilitation. Finally, transient receptor potential (TRP) agonists increase sensory inputs to the swallowing system by stimulating the sensory receptors in the oropharynx, potentially activating the swallowing network. While these options have shown promise in dysphagia rehabilitation following stroke, most the available data comes from patients with mixed stroke lesions, with limited data focused specifically on brainstem lesions. Therefore, the evidence for their efficacy in patients with brainstem stroke remains underexplored. Therefore, treatment decisions should rely on the understanding of swallowing physiology, neuroplasticity, and clinical evidence from related stroke populations.

Background/Objective: The Suppression Head Impulse Paradigm (SHIMP) is a specialized variant of the Head Impulse Test (HIT), designed to evaluate the suppression of the angular Vestibulo-Ocular Reflex (aVOR) by central mechanisms. These mechanisms are primarily mediated by brainstem structures, including the vestibular nuclei, their projections to ocular motor nuclei, and modulatory inputs from the cerebellum. Damage to these areas can impair the generation of anti-compensatory saccades (ACs), even when the peripheral vestibular apparatus remains intact. The present study explores this phenomenon in a cohort of patients with neurological disorders known to potentially involve the brainstem, including multiple sclerosis, severe traumatic brain injury, stroke, and Parkinson's disease. Methods: This cross-sectional study included 119 patients with multiple sclerosis (PwMS), severe traumatic brain injury (PwTBI), stroke (PwS), and Parkinson's disease (PwPD). The video Head Impulse Test was performed to assess the aVOR gain across all semicircular canals using both the HIMP and SHIMP. The presence, absence, or delay of ACs was systematically recorded. Results: Among the 119 patients evaluated (238 semicircular canals), 24 (20%) demonstrated normal aVOR gain but failed to generate ACs during SHIMP. The absence of ACs was observed in seven PwMS, five with PwTBI, six with PwS, and six with PwPD. Conclusions: The absence of ACs despite normal aVOR gain suggests a potential impairment in the central pathways controlling saccadic responses, independently of peripheral vestibular function. These findings underscore the clinical relevance of integrating the SHIMP into vestibular assessments to improve the identification of central vestibular dysfunction in neurological disorders.

Objectives: Facial paralysis is a devastating yet frequent complication of skull base surgery, significantly impacting quality of life through functional impairments and psychosocial consequences. Management is complex and requires an individualized approach based on duration of paralysis, etiology and extent of nerve injury, overall prognosis, and rehabilitative goals. This review provides a comprehensive overview of current strategies for managing post-skull base surgery facial paralysis.

Methods: A narrative review of the literature was performed, analyzing surgical reanimation techniques (nerve grafting, nerve transfers, regional and free muscle transfers), static procedures for facial symmetry and ocular protection, and non-surgical interventions such as physical therapy, botulinum toxin injections, and psychological support. Key criteria guiding treatment selection, including muscle viability and timing since injury, were examined.

Results: Dynamic surgical approaches remain central to restoring movement. Nerve grafting and transfers are effective when viable musculature is present, whereas regional or free muscle transfers are required in long-standing paralysis with irreversible atrophy. Static procedures provide adjunctive improvements in resting symmetry and eye protection. Non-surgical strategies, including rehabilitation therapy and botulinum toxin, enhance functional outcomes and reduce synkinesis. Psychological counseling addresses the profound emotional burden associated with facial disfigurement. Across modalities, individualized treatment planning is crucial.

Conclusions: Management of facial paralysis after skull base surgery demands a multidisciplinary, patient-centered approach. Combining surgical and non-surgical interventions optimizes functional and aesthetic outcomes, helping restore both facial movement and psychosocial well-being.

Background: Brainstem-related dysphagia represents a complex and severe form of neurogenic dysphagia (ND) arising from lesions that disrupt the central pattern generator (CPG) for swallowing located in the medulla oblongata.

Methods: This paper explores the physiological basis of swallowing and its disruption in various brainstem pathologies.

Results: The clinical presentation and electrophysiological evaluation of dysphagia are discussed, with a focus on volitional and spontaneous swallowing (SS) and the use of electromyography (EMG)-based assessment techniques.

Conclusions: Finally, therapeutic strategies are reviewed, including conventional rehabilitative methods, neuromuscular electrical stimulation, non-invasive brain stimulation, and invasive procedures such as neurobotulinum toxin-A (BoNT-A) injections, balloon dilation, and CP myotomy.

Background/Objectives: Swallowing and speech rely on shared brainstem circuits coordinating oropharyngeal motor functions. In neurodegenerative diseases affecting the brainstem-such as progressive supranuclear palsy (PSP), amyotrophic lateral sclerosis (ALS), and multiple system atrophy (MSA)-bulbar dysfunction often impairs tongue propulsion and motility, affecting both swallowing (dysphagia) and phonation (dysarthria). This study aimed to investigate whether vowel-based acoustic features are associated with swallowing severity in brainstem-related disorders and to explore their potential as surrogate markers of bulbar involvement. Methods: This was a cross-sectional observational study. Thirty-one patients (13 PSP, 12 ALS, 6 MSA) underwent clinical dysarthria assessment, acoustic analysis of the first (F1) and second (F2) formants during sustained phonation of /a/, /i/, /e/, and /u/, and swallowing evaluation using standardized clinical scales (DOSS, FOIS, ASHA-NOMS) and fiberoptic endoscopic evaluation (Pooling Score, Penetration-Aspiration Scale). The vowel space area (tVSA, qVSA) and Formant Centralization Ratio (FCR) were computed. Results: Significant correlations emerged between acoustic vowel metrics and dysphagia severity, especially for liquids. The FCR showed strong correlations with DOSS (ρ = -0.660, p < 0.0001), FOIS (ρ = -0.531, p = 0.002), ASHA-NOMS (ρ = -0.604, p < 0.0001), and instrumental scores for liquids: the Pooling Score (ρ = 0.538, p = 0.002) and PAS (ρ = 0.630, p < 0.0001). VSA measures were also associated significantly with liquid swallowing impairment. F2u correlated with dysarthria severity and all liquid-related dysphagia scores. Conclusions: Vowel-based acoustic parameters, particularly FCR and F2u, reflect the shared neuromotor substrate of articulation and swallowing. Acoustic analysis may support early detection and monitoring of bulbar dysfunction, especially where instrumental assessments are limited.

Background/Objectives: Cochlear implants (CIs) are a common treatment of severe-to-profound hearing loss and provide reasonable speech understanding, at least in quiet situations. However, their limited spectro-temporal resolution restricts sound quality, which is especially crucial for music appraisal. Many CI recipients wear a hearing aid (HA) on the non-implanted ear (bimodal users), which may enhance music perception by adding acoustic fine structure cues. Since it is unclear how the HA should be fitted in conjunction with the CI to achieve optimal benefit, this study aimed to systematically vary HA fitting parameters and assess their impact on music sound quality in bimodal users. Methods: Thirteen bimodal CI recipients participated in a listening experiment using a master hearing aid that allowed controlled manipulation of HA settings. Participants evaluated three music excerpts (pop with vocals, pop without vocals, classical) using the multiple-stimulus with hidden reference and anchor (MUSHRA) test. To assess the reliability of individual judgments, each participant repeated the test, and responses were analyzed with the eGauge method. Results: Most participants provided reliable and consistent sound quality ratings. Compared to a standard DSL v5.0 prescriptive fitting, modifications in compression settings and low-frequency gain significantly influenced perceived music quality. The effect of low-frequency gain adjustments was especially pronounced for pop music with vocals, indicating stimulus-dependent benefits. Conclusions: The study demonstrates that HA fitting for bimodal CI users can be optimized beyond standard prescriptive rules to enhance music sound quality by increasing low-frequency gain, particularly for vocal-rich pieces. Additionally, the testing method shows promise for clinical application, enabling individualized HA adjustments based on patient-specific listening preferences, hence fostering personalized audiology care.

Background: Serotonin (5-HT) is a neurotransmitter and a hormone that regulates various functions. Serotonin receptors have been studied in animal experiments in the vestibular system, beginning from the inner ear and vestibular nuclei. However, the role of serotonin in the vestibular system and disorders remains to be clarified.

Methods: A review of the literature was performed on different databases according to the PRISMA guidelines. Only publications published on humans and in English have been included. A total of 41 articles were included in this review.

Results: There are many publications regarding the use of SSRI/SNRI in vestibular disorders. Regarding persistent postural perceptual dizziness (PPPD) and chronic subjective dizziness (CSD) the available evidence supports multimodality treatment incorporating vestibular rehabilitation, serotonergic medications, and cognitive behavior therapy, although most studies have not included a placebo control group. As for vestibular migraine (VM), SNRI and SSRIs were proposed as preventive therapy and demonstrated a reduction in vertigo attacks in patients with Menière's Disease (MD), especially when symptoms of anxiety disorder were present.

Conclusions: Although SSRIs/SNRIs are considered an off-label therapy for vertigo, several studies have assessed their efficacy in vestibular disorders, as indicated in the data published on PPPD, MD, and VM above all. As some studies report that serotonin receptors are also present in the inner ear and vestibular nuclei, it can be postulated that in cases where the natural levels of serotonin are altered, such as in depression and anxiety, the change in serotonin levels may affect vestibular function and play a role in vestibular disorders.

The brainstem plays a pivotal role in the generation and control of eye movements-including saccades, smooth pursuit, the vestibulo-ocular reflex (VOR), vergence, and gaze holding. Beyond its vital physiological functions, it is also essential for the coordination of balance and movement. Consequently, eye movement disorders of brainstem origin are often accompanied by vertigo, imbalance, unsteady gait, and diplopia, particularly during changes in head or body position. A sound understanding of the neural structures involved in oculomotor and vestibular control is therefore crucial for accurately identifying and localizing a wide variety of brainstem syndromes. However, oculomotor abnormalities resulting from brainstem disease represent a major diagnostic challenge for the neurotologist, owing to the wide spectrum of possible etiologies (vascular, traumatic, degenerative, neoplastic), their variable severity and clinical course (acute, fluctuating, or progressive), and the frequent concomitant involvement of other central structures, particularly the cerebellum. This mini review summarizes the pathophysiological mechanisms and clinical features of oculomotor disorders and nystagmus associated with brainstem disease.