A dramatic shift in societal demographics will lead to rapid growth in the number of older people with hearing deficits. Poorer performance in suprathreshold speech understanding and temporal processing with age has been previously linked with progressing inner hair cell (IHC) synaptopathy that precedes age-dependent elevation of auditory thresholds. We compared central sound responsiveness after acoustic trauma in young, middle-aged, and older rats. We demonstrate that IHC synaptopathy progresses from middle age onward and hearing threshold becomes elevated from old age onward. Interestingly, middle-aged animals could centrally compensate for the loss of auditory fiber activity through an increase in late auditory brainstem responses (late auditory brainstem response wave) linked to shortening of central response latencies. In contrast, old animals failed to restore central responsiveness, which correlated with reduced temporal resolution in responding to amplitude changes. These findings may suggest that cochlear IHC synaptopathy with age does not necessarily induce temporal auditory coding deficits, as long as the capacity to generate neuronal gain maintains normal sound-induced central amplitudes.
Objective: Sudden sensorineural hearing loss (SSHL) is a multifactorial disorder with high heterogeneity, thus the outcomes vary widely. This study aimed to develop predictive models based on four machine learning methods for SSHL, identifying the best performer for clinical application.Design: Single‐centre retrospective study.Setting: Chinese People's liberation army (PLA) hospital, Beijing, China.Participants: A total of 1220 in‐patient SSHL patients were enrolled between June 2008 and December 2015.Main outcome measures: An advanced deep learning technique, deep belief network (DBN), together with the conventional logistic regression (LR), support vector machine (SVM) and multilayer perceptron (MLP) were developed to predict the dichotomised hearing outcome of SSHL by inputting six feature collections derived from 149 potential predictors. Accuracy, precision, recall, F‐score and the area under the receiver operator characteristic curves (ROC‐AUC) were exploited to compare the prediction performance of different models.Results: Overall the best predictive ability was provided by the DBN model when tested in the raw data set with 149 variables, achieving an accuracy of 77.58% and AUC of 0.84. Nevertheless, DBN yielded inferior performance after feature pruning. In contrast, the LR, SVM and MLP models demonstrated opposite trend as the greatest individual prediction powers were obtained when included merely three variables, with the ROC‐AUC ranging from 0.79 to 0.81, and then decreased with the increasing size of input features combinations.Conclusions: With the input of enough features, DBN can be a robust prediction tool for SSHL. But LR is more practical for early prediction in routine clinical application using three readily available variables, that is time elapse between symptom onset and study entry, initial hearing level and audiogram.
Background: Accumulating evidence suggests that tinnitus may occur despite normal auditory sensitivity, probably linked to partial degeneration of the cochlear nerve and damage of the inner hair cell (IHC) synapse. Damage to the IHC synapses and deafferentation may occur even after moderate noise exposure. For both salicylate- and noise-induced tinnitus, aberrant N-methyl-d-aspartate (NMDA) receptor activation and related auditory nerve excitation have been suggested as origin of cochlear tinnitus. Accordingly, NMDA receptor inhibition has been proposed as a pharmacologic approach for treatment of synaptopathic tinnitus. Methods: Round-window application of the NMDA receptor antagonist AM-101 (Esketamine hydrochloride gel; Auris Medical AG, Basel, Switzerland) was tested in an animal model of tinnitus induced by acute traumatic noise. The study included the quantification of IHC ribbon synapses as a correlate for deafferentation as well as the measurement of the auditory brainstem response (ABR) to close-threshold sensation level stimuli as an indication of sound-induced auditory nerve activity. Results: We have shown that AM-101 reduced the trauma-induced loss of IHC ribbons and counteracted the decline of ABR wave I amplitude generated in the cochlea/auditory nerve. Conclusion: Local round-window application of AM-101 may be a promising therapeutic intervention for the treatment of synaptopathic tinnitus.
This retrospective cohort study aimed to investigate the association of sleep characteristics measured by the Pittsburgh Sleep Quality Index (PSQI) with the vertigo outcome in vertiginous patients ...
Background:Bilateral sudden sensorineural hearing loss (BSSHL) is rare and assumed to be a different clinical entity compared to unilateral SSHL (USSHL). This study examined the differences between the idiopathic BSSHL and USSHL.Methods:Forty-six sequential BSSHL patients (Se-BSSHL) and 68 simultane