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43 result(s) for "Rah, Yoon Chan"
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Prediction of hearing recovery in unilateral sudden sensorineural hearing loss using artificial intelligence
Despite the significance of predicting the prognosis of idiopathic sudden sensorineural hearing loss (ISSNHL), no predictive models have been established. This study used artificial intelligence to develop prognosis models to predict recovery from ISSNHL. We retrospectively reviewed the medical data of 453 patients with ISSNHL (men, 220; women, 233; mean age, 50.3 years) who underwent treatment at a tertiary hospital between January 2021 and December 2019 and were followed up after 1 month. According to Siegel’s criteria, 203 patients recovered in 1 month. Demographic characteristics, clinical and laboratory data, and pure-tone audiometry were analyzed. Logistic regression (baseline), a support vector machine, extreme gradient boosting, a light gradient boosting machine, and multilayer perceptron were used. The outcomes were the area under the receiver operating characteristic curve (AUROC) primarily, area under the precision-recall curve, Brier score, balanced accuracy, and F1 score. The light gradient boosting machine model had the best AUROC and balanced accuracy. Together with multilayer perceptron, it was also significantly superior to logistic regression in terms of AUROC. Using the SHapley Additive exPlanation method, we found that the initial audiogram shape is the most important prognostic factor. Machine/deep learning methods were successfully established to predict the prognosis of ISSNHL.
Pupil responses associated with the perception of gravitational vertical under directional optic flows
This study assessed the pupil responses in the sensory integration of various directional optic flows during the perception of gravitational vertical. A total of 30 healthy participants were enrolled with normal responses to conventional subjective visual vertical (SVV) which was determined by measuring the difference (error angles) between the luminous line adjusted by the participants and the true vertical. SVV was performed under various types of rotational (5°/s, 10°/s, and 50°/s) and straight (5°/s and 10°/s) optic flows presented via a head-mounted display. Error angles (°) of the SVV and changes in pupil diameters (mm) were measured to evaluate the changes in the visually assessed subjective verticality and related cognitive demands. Significantly larger error angles were measured under rotational optic flows than under straight flows ( p  < 0.001). The error angles also significantly increased as the velocity of the rotational optic flow increased. The pupil diameter increased after starting the test, demonstrating the largest diameter during the final fine-tuning around the vertical. Significantly larger pupil changes were identified under rotational flows than in straight flows. Pupil changes were significantly correlated with error angles and the visual analog scale representing subjective difficulties during each test. These results suggest increased pupil changes for integrating more challenging visual sensory inputs in the process of gravity perception.
Contralateral Hearing Loss in Temporal Bone Fractures: A Potential Association with Combined Intracranial Injury
BACKGROUND: Temporal bone (TB) fractures are frequently accompanied by intracranial injury. This study aimed to analyze combined intracranial injuries in relation to functional changes in the inner ear, including those of the contralateral ear, in patients with TB fractures. METHODS: Ninety-four patients (mean age: 35.6 [+ or -] 18.7 years, M : F = 67 : 27) diagnosed with unilateral TB fracture were included. Bone conduction (BC) threshold, word recognition score (WRS), and changes in vestibular function were compared based on intracranial injuries, focusing on the contralateral side. RESULTS: Various types of intracranial injuries were observed (67.9%). Among these, a significant association between traumatic brain injury (TBI) and otic capsule-violating fractures was noted. The BC threshold on the fractured side significantly deteriorated in patients with TBI. Additionally, a significantly worse BC threshold was confirmed on the contralateral side in patients with TBI, intracranial hemorrhage (ICH), and contrecoup injury. The follow-up BC threshold did not improve or differ, regardless of high-dose steroid administration. The initial WRS and canal paresis in the bithermal caloric test were not significantly different in the presence of each intracranial injury. Concurrent fluctuations in the pressure of the cerebrospinal fluid space and perilymphatic space were speculated to be the potential underlying mechanisms. CONCLUSION: A significantly worse BC threshold was confirmed on the contralateral side of patients with TBI, contrecoup injury, ICH, and on fracture sides of patients with TBI. KEYWORDS: Temporal bone fracture, contrecoup labyrinthine concussion, traumatic brain injury, hearing loss
Association between the severity of hearing loss and the risk of dementia within the 2010–2017 national insurance service survey in South Korea
Hearing loss and dementia are highly prevalent neurologic conditions in older adults that can considerably impact the quality of life and create social and familial burdens. To investigate the impact of hearing loss on the risk of developing dementia in a nationwide long-term follow-up study using data obtained from the South Korean National Health Information Database. Retrospective medical data for patients of all ages were extracted from the database between January 2010 and December 2017. According to the national disability registry, the degree of severe-profound hearing loss is classified into six grades. We categorized hearing loss into three groups based on the disability registry severity: (1) severe hearing disability (HD), defined as 1st to 3rd grade disabling hearing loss; (2) non-severe HD, 4th and 5th grade disabling hearing loss; and (3) ipsilateral HD, 6th grade disabling hearing loss. After adjusting for potential confounding variables, the hazard ratio (HR) for all dementia types was 1.336 (95% CI 1.306–1.367) in the severe HD group, 1.312 (95% CI 1.286–1.338) in the non-severe HD group, and 1.257 (95% CI 1.217–1.299) in the ipsilateral HD group. On assessing by the age group, the risk of all dementia types in patients younger than 65 years was as follows: HR 1.933 (95% CI 1.779–2.101), 1.880 (95% CI 1.732–2.041), and 1.601 (95% CI 1.435–1.787) in the severe, non-severe, and ipsilateral HD groups, respectively. This study demonstrates that the impact of hearing loss on dementia incidence is severity-dependent, and the risk increases in patients younger than 65 years of age.
Electrophysiological Changes Associated with the Progression of Noise-Induced Hearing Loss
BACKGROUND: The aim of this study is to evaluate the clinical characteristics and electrophysiological changes in patients with different degrees of noise-induced hearing loss compared with those of normal controls to elucidate the progression of auditory neural damage attributed to noise exposure. METHODS: A retrospective cohort study was conducted through a review of the medical records for the patients who presented to a tertiary referral center. Sixty-nine participants were included in the study: 29 had noise-induced hearing loss, and 40 were healthy controls. All the participants underwent electrophysiological tests and pure-tone audiometry. RESULTS: Nine patients showed mild hearing loss (mild hearing loss group), while the others showed worse than moderate hearing loss on puretone audiometry (severe hearing loss group). Significantly reduced wave I and V amplitudes of auditory brainstem response were present in both mild and severe hearing loss groups compared to the control group (P <.001 and P = .002, respectively), without significant differences between the mild and severe hearing loss groups. In the multivariate analysis, auditory brainstem response wave V amplitude was negatively associated with auditory brainstem response wave I-V inter-peak latency delay (B = -0.48, P = .02). CONCLUSION: The results of the present study confirm the similarity in the electrophysiological characteristics between the mild and severe hearing loss groups. Thus, widespread disruption in the auditory neural conduction could have been established in the early period when the patient developed mild hearing loss following noise exposure. KEYWORDS: Noise-induced hearing loss, audiometry, auditory brainstem response, hearing loss, progressive hearing loss
Low expression of CD40L in tumor-free lymph node of oral cavity cancer related with poor prognosis
BackgroundRecently, the genetic alterations associated with tumor progression and impaired host immunity against transformed cells draw increased attention. Here, we characterized the differential gene expression patterns and protein expression in tumor-free lymph node from recurrent and non-recurrent tumors to identify independent prognostic markers for oral squamous cell carcinoma (OSCC).MethodsA cDNA microarray analysis was performed to identify the differentially expressed genes in regional tumor-free lymph nodes from OSCC patients with and without recurrence. Then, the protein expression of the selected genes was analyzed by immunohistochemistry in 60 OSCC patients to determine their association with survival.ResultsWidespread down-regulation of genes involved in antigen processing and recognition in lymph nodes was a distinctive feature. In univariate Kaplan–Meier analysis, lower expression of CD40L and CD80 in tumor-free lymph nodes was significantly correlated with poorer survival. In multivariate Cox regression analysis, CD40L was identified as an independent prognostic marker of disease-free survival.ConclusionOur data indicate that impaired host immunity (decreased CD40L expression) along with the TNM staging might be an important factor determining the prognosis of OSCC.
Protective Effects of (-)-Butaclamol Against Gentamicin-Induced Ototoxicity: In Vivo and In Vitro Approaches
Gentamicin-induced ototoxicity leads to irreversible sensorineural hearing loss due to structural and functional damage to inner ear hair cells. In this study, we identified (-)-butaclamol as a potent protective agent against gentamicin-induced cytotoxicity through high-content screening (HCS) of a natural compound library. (-)-Butaclamol significantly enhanced cell viability in both HEI-OC1 cells and zebrafish neuromasts, demonstrating robust protection against gentamicin toxicity. Mechanistically, (-)-butaclamol inhibited intrinsic apoptosis, as evidenced by reduced TUNEL-positive cell counts and the downregulation of BAX and caspase-3, alongside the upregulation of BCL-2. Moreover, (-)-butaclamol activated key survival signaling pathways, including AKT/mTOR and ERK, while suppressing the inflammatory regulator NF-κB. Additional analyses revealed that (-)-butaclamol effectively mitigated oxidative stress and restored autophagic activity, as confirmed by CellROX and LysoTracker assays. Notably, TMRE staining showed that (-)-butaclamol preserved mitochondrial membrane potential in zebrafish hair cells, indicating mitochondrial protection. Collectively, these findings suggest that (-)-butaclamol exerts comprehensive cytoprotective effects against gentamicin-induced ototoxicity by modulating apoptosis, enhancing survival signaling, and restoring mitochondrial and cellular homeostasis. These results highlight the therapeutic potential of (-)-butaclamol and provide a foundation for future studies aimed at its clinical application.
Protective Effects of Fasudil Against Cisplatin-Induced Ototoxicity in Zebrafish: An In Vivo Study
While cisplatin is an effective anti-tumor treatment, it induces ototoxicity through mechanisms involving DNA damage, oxidative stress, and programmed cell death. Rho-associated coiled-coil-containing protein kinase (ROCK) is essential for numerous cellular processes, including apoptosis regulation. Studies have suggested that ROCK inhibitors could prevent apoptosis and promote regeneration. We aimed to investigate the protective effects of the ROCK inhibitor fasudil against cisplatin-induced ototoxicity in a zebrafish model. The zebrafish larvae were exposed to 1 mM cisplatin alone or 1 mM cisplatin co-administered with varying concentrations of fasudil for 4 h. The surviving hair cell counts, apoptosis, reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), caspase 3 activity, and autophagy activation were assessed. Rheotaxis behavior was also examined. Cisplatin reduced hair cell counts; increased apoptosis, ROS production, and ΔΨm loss; and activated caspase 3 and autophagy. Fasudil (100 and 500 µM) mitigated cisplatin-induced hair cell loss, reduced apoptosis, and inhibited caspase 3 and autophagy activation. Rheotaxis in zebrafish was preserved by the co-administration of fasudil with cisplatin. Cisplatin induces hair cell apoptosis in zebrafish, whereas fasudil is a promising protective agent against cisplatin-induced ototoxicity.
Multi-modal virtual reality system for tinnitus treatment methods and validation
Virtual reality (VR) has been utilized in clinical treatment because it can efficiently simulate situations that are difficult to control in the real world. In this study, we evaluated the efficacy of VR in patients with chronic subjective tinnitus. We assessed the clinical effectiveness based on electroencephalogram (EEG) analysis and questionnaire responses after patients participated in a 6–8-week VR-based tinnitus relief program. The intervention involved removing tinnitus avatars in the VR, through which we expected the patients to experience subjective tinnitus control. Standardized low-resolution brain electromagnetic tomography was used to analyze changes in source activity in prefrontal regions associated with tinnitus. The study included patients aged 27–68 years with chronic non-pulsatile tinnitus lasting ≥3 months. Patients completed VR sessions, neurological EEGs, and questionnaires. Statistically significant differences were observed in the tinnitus handicap questionnaire total scores immediately after treatment (p = 0.002) and 1-month post-treatment (p = 0.001) compared to those before treatment. Significant changes were also found in the visual numeric scale and profile of mood states scores 1-month post-treatment. Additionally, significant changes were observed in sensor-level and source-level power spectrum criteria immediately following the VR experiment, suggesting that similar to some forms of cognitive behavioral therapy, VR-based programs may help alleviate tinnitus-related distress in patients with chronic subjective tinnitus.