The medial olivocochlear (MOC) efferent system modifies cochlear output to aid signal detection in noise, but the precise role of efferents in speech-in-noise understanding remains unclear. The current study examined the contribution of the MOC reflex for speech recognition in noise in 30 normal-hearing young adults (27 females, mean age = 22.7 yr). The MOC reflex was assessed using contralateral inhibition of transient-evoked otoacoustic emissions. Speech-in-noise perception was evaluated using the coordinate response measure presented in ipsilateral speech-shaped noise at signal-to-noise ratios (SNRs) ranging from −12 to 0 dB. Performance was assessed without and with the presence of contralateral noise to activate the MOC reflex. Performance was significantly better with contralateral noise only at the lowest SNR. There was a trend of better performance with increasing contralateral inhibition at the lowest SNR. Threshold of the psychometric function was significantly correlated with contralateral inhibition. Response time on the speech task was not significantly correlated with contralateral inhibition. Results suggest that the MOC reflex contributes to listening in low SNRs and the relationship between the MOC reflex and perception is highly dependent upon the task characteristics.

variable with possible covariates in multiple regression modeling.Results The prevalence of moderate to severe depression in the PT population was 41.2%. Multiple regression to predict PHQ-9 diagnosed depression based on TFI total score, clinical variables, and demographics showed a significant odds ratio for TFI (OR: 1.084, CI: 1.065-1.096, p<0.001). The increase of sub-scores for quality of life interference and emotionality showed significant increases in odds for depression (OR: 1.031, CI: 1.016-1.046, p<0.001; OR: 1.042, CI: 1.027-1.058, p<0.001). Unemployed vs. employed and laterality were also associated with an increased odds of depression, and age with decreased odds while controlling for tinnitus score.Moderate to severe anxiety was present in 43.1%. Multiple regression analysis showed TFI was associated with increased of odds for anxiety (OR: 1.056, CI: 1.043-1.070, p<0.001). TFI sub-scores for emotionality (OR: 1.043, p<0.001), quality of life (OR: 1.019, p<0.005), and cognitive interferences (OR: 0.983, p = 0.015) were found to be significantly associated with anxiety scores. Conclusion The estimated prevalence of moderate to severe depression and anxiety in the US PT population is 41.2% and 43.1%, respectively, which is higher than a recent systematic review of depression in tinnitus suggesting a depression prevalence of 33%. TFI score was significantly associated with both depression and anxiety. Similarly, more granular sub-scores of the TFI elucidate how PT affects the psychological health of these patients. Disclosures E.

Purpose The medial olivocochlear (MOC) reflex enhances neural encoding of signals in noise, and measurement of its function may hold clinical utility. Previous research on how the reflex aids speech-in-noise perception has been equivocal. Motivated by animal work, we examined associations between MOC reflex activity and formant discrimination in noise in humans to better understand how the MOC reflex contributes to audition. We hypothesised that participants with stronger MOC reflex activity would have better formant discrimination in noise abilities. Method Twenty-six normal-hearing listeners met all inclusion and exclusion criteria (mean age = 21.5 years), with data from 25 participants included in the final analysis. Transient-evoked otoacoustic emissions (TEOAEs) were measured in right ears. MOC reflex activity was assessed using a contralateral inhibition paradigm in which the change in TEOAE amplitude without versus with a contralateral MOC reflex elicitor was computed. Formant discrimination thresholds for a synthetic vowel /[Latin Small Letter Open E]/ were obtained in right ears using a two-alternative forced-choice procedure that adaptively varied the second formant frequency. Discrimination thresholds were obtained at three signal-to-noise ratios (SNRs). Results TEOAE amplitudes were significantly reduced in the presence of the reflex elicitor (p < .05). Discrimination thresholds decreased significantly with increasing SNR (p < .05 in all cases). No significant correlations were found between contralateral inhibition measures and discrimination thresholds at any SNR (p > .05 in all cases). Conclusion Contrary to hypothesis, no significant associations were found between contralateral inhibition and formant discrimination in noise performance. It is possible that the MOC reflex contributes to formant discrimination but not in a monotonic fashion. Future work should consider investigating how the MOC reflex contributes to other perceptual properties to better characterise the functional relevance of the MOC reflex.

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Ischemic stroke is the primary reason for serious long‐term disability. Our recent studies demonstrated that the suppression of toll‐like receptors (TLRs) 2 and 4 alone or in combination attenuated the post‐ischemic inflammation and brain damage. The purpose of this study is to investigate the effect of the simultaneous knockdown of both TLR2 and TLR4 on post‐stroke neurological recovery in young adult male rats. Transient focal cerebral ischemia was induced to male Sprague‐Dawley rats by middle cerebral artery occlusion (MCAO) procedure. A silicone rubber‐coated monofilament suture was introduced into the internal carotid artery via the external and common carotid arteries and pushed until it reaches the origin of the middle cerebral artery followed by removal of the monofilament after 2 hours to initiate reperfusion. Appropriate cohorts of rats were treated with a nanoparticle formulations of TLR2shRNA (T2sh) and TLR4shRNA (T4sh) expressing plasmids (1mg/kg each of T2sh and T4sh) or scrambled sequence inserted vector (SVsh; vehicle) expressing plasmids (2 mg/kg) intravenously via tail vein immediately after reperfusion. The rats from both the cohorts were subjected to various standard neurological tests such as modified neurological severity scores (mNSS), modified adhesive removal (sticky‐tape), beam walking and accelerating rotarod performance before MCAO procedure and at days 1, 3, 5, 7, and 14 after reperfusion. The sensory and motor functions of vehicle treated stroke‐induced rats were markedly impaired when tested at 1d reperfusion followed by a gradual improvement over 14 days. Prevention of the post‐ischemic induction of TLR2 and TLR4 attenuated the degree of neurological impairment and facilitated the magnitude of functional recovery. Therefore, we conclude that the post‐stroke induction of TLR2 and TLR4 in rat ischemic brain contributes to neurological deficits.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.