Circadian Sensitivity of Noise Trauma-Induced Hearing Loss and Tinnitus in Mongolian Gerbils.

Noise-induced hearing loss (HL) has a circadian component: In nocturnal mice, hearing thresholds (HT) have a significantly stronger effect to acoustic trauma when induced during the night compared to rather mild effects on hearing when induced during daytime. Here, we investigate whether such effects are also present in diurnal Mongolian gerbils and determined whether trauma-induced HL correlated with the development of a tinnitus percept in these animals. In particular, we investigated the effects of acoustic trauma (2 kHz, 115 dB SPL, 75 min) on HT and tinnitus development in 34 male gerbils exposed either at 9 AM, 1 PM, 5 PM, or 12 PM. HT was measured by acoustic brainstem response audiometry at defined times 1 day before and 1 week after the trauma. Possible tinnitus percepts were assessed behaviorally by the gap prepulse inhibition of the acoustic startle response at defined times 1 day before and 1 week after the trauma. We found daytime-dependent changes due to trauma in mean HT in a frequency-dependent manner comparable to the results in mice, but the results temporally shifted according to respective activity profiles. Additionally, we found linear correlations of these threshold changes with the strength of the tinnitus percept, with the most prominent correlations in the 5 PM trauma group. Taken together, circadian sensitivity of the HT to noise trauma can also be found in gerbils, and tinnitus strength correlates most strongly with HL only when the trauma is applied at the most sensitive times, which seem to be the evening.

A prospective comparative study to assess the risk of postoperative bleeding after dental surgery while on medication with direct oral anticoagulants, antiplatelet agents, or vitamin K antagonists.

BACKGROUND: The aim of this prospective study was to investigate the occurrence and severity of postoperative bleeding following dentoalveolar surgery in patients with uninterrupted anticoagulation therapy (AT). METHODS: Patients receiving AT (vitamin k antagonist (VK), direct oral anticoagulants (DOAC) or antiplatelet therapy (APT) and in need of surgical intervention classified as A, B or C (single or serial tooth extraction, osteotomy, or implant placement) were studied between 2019 and 2021. A healthy, non-anticoagulated cohort (CG) served as a control group. The main outcomes measured were the frequency of postoperative bleeding, the classification of the severity of postoperative bleeding (1a, 1b, 1c, 2, 3), and the correlation with the AT surgical intervention classification. RESULTS: In total, 195 patients were included in the study, with 95 patients in the AT group and 100 in the CG. Postoperative bleeding was significant in the AT group vs. the CG (p = 0.000), with a significant correlation with surgical intervention class C (p = 0.013) and the severity class of bleeding 1a (p = 0.044). There was no significant correlation with procedures of type A, B or C for the other postoperative bleeding gradations (1b, 1c, 2 and 3). There was a statistically significant difference in the occurrence of postoperative bleeding events between the DOAC/APT group and the VK group (p = 0.036), but there were no significant differences regarding the other AT agents. CONCLUSION: The continuation of anticoagulation therapy for surgical interventions also seems reasonable for high-risk interventions. Although significantly more postoperative bleeding occurs, the severity of bleeding is low. The perioperative management of anticoagulated patients requires well-coordinated interdisciplinary teamwork and detailed instruction of patients. Clinical trial registration The study is registered (29.03.2021) at the German clinical trial registry (DRKS00024889).

Open(G)PIAS: An Open-Source Solution for the Construction of a High-Precision Acoustic Startle Response Setup for Tinnitus Screening and Threshold Estimation in Rodents.

The modulation of the acoustic startle reflex (ASR) by a pre-stimulus called pre-pulse inhibition (PPI, for gap of silence pre-stimulus: GPIAS) is a versatile tool to, e.g., estimate hearing thresholds or identify subjective tinnitus percepts in rodents. A proper application of these paradigms depends on a reliable measurement of the ASR amplitudes and an exact stimulus presentation in terms of frequency and intensity. Here, we introduce a novel open-source solution for the construction of a low-cost ASR setup. The complete software for data acquisition and stimulus presentation is written in Python 3.6 and is provided as an Anaconda package. Furthermore, we provide a construction plan for the sensor system based on low-cost hardware components. Exemplary GPIAS data from two animal models (Mus musculus, Meriones unguiculatus) show that the ratio histograms (1-GPIAS) of the gap-pre-stimulus and no pre-stimulus ASR amplitudes can be well described by a log-normal distribution being in good accordance to previous studies with already established setups. Furthermore, it can be shown that the PPI as a function of pre-stimulus intensity (threshold paradigm) can be approximated with a hard-sigmoid function enabling a reproducible sensory threshold estimation. Thus, we show that the open-source solution could help to further establish the ASR method in many laboratories and, thus, facilitate and standardize research in animal models of tinnitus and/or hearing loss.