Benzodiazepines alter cochleo-cochlear loop in humans

Abstract By using otoacoustic emission, we looked for change in outer hair cell (OHC) motile activity and medial olivocochlear (MOC) system inhibition due to benzodiazepine administration, a drug that is known to produce a pharmacological effect by interacting with GABAergic inhibitory neurotransmission. No effect was observed on OHC motile activity, in contrast benzodiazepines decreased MOC system effectiveness suggesting the existence of GABAergic fibers projecting onto the MOC system. z 1998 Elsevier Science B.V. All rights reserved

A European Perspective on Auditory Processing Disorder-Current Knowledge and Future Research Focus

Current notions of “hearing impairment,” as reflected in clinical audiological practice, do not acknowledge the needs of individuals who have normal hearing pure tone sensitivity but who experience auditory processing difficulties in everyday life that are indexed by reduced performance in other more sophisticated audiometric tests such as speech audiometry in noise or complex non-speech sound perception. This disorder, defined as “Auditory Processing Disorder” (APD) or “Central Auditory Processing Disorder” is classified in the current tenth version of the International Classification of diseases as H93.25 and in the forthcoming beta eleventh version. APDs may have detrimental effects on the affected individual, with low esteem, anxiety, and depression, and symptoms may remain into adulthood. These disorders may interfere with learning per se and with communication, social, emotional, and academic-work aspects of life. The objective of the present paper is to define a baseline European APD consensus formulated by experienced clinicians and researchers in this specific field of human auditory science. A secondary aim is to identify issues that future research needs to address in order to further clarify the nature of APD and thus assist in optimum diagnosis and evidence-based management. This European consensus presents the main symptoms, conditions, and specific medical history elements that should lead to auditory processing evaluation. Consensus on definition of the disorder, optimum diagnostic pathway, and appropriate management are highlighted alongside a perspective on future research focus

A randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of neramexane in patients with moderate to severe subjective tinnitus

<p>Abstract</p> <p>Background</p> <p>Neramexane is a new substance that exhibits antagonistic properties at α₉α₁₀cholinergic nicotinic receptors and <it>N</it>-methyl-D-aspartate receptors, suggesting potential efficacy in the treatment of tinnitus.</p> <p>Methods</p> <p>A total of 431 outpatients with moderate to severe subjective tinnitus (onset 3-18 months before screening) were assigned randomly to receive either placebo or neramexane mesylate (25 mg/day, 50 mg/day and 75 mg/day) for 16 weeks, with assessment at 4-week intervals. The primary (intention-to-treat) efficacy analysis was based on the change from baseline in Week 16 in the total score of the adapted German short version of the validated Tinnitus Handicap Inventory questionnaire (THI-12).</p> <p>Results</p> <p>Compared with placebo, the largest improvement was achieved in the 50 mg/d neramexane group, followed by the 75 mg/d neramexane group. This treatment difference did not reach statistical significance at the pre-defined endpoint in Week 16 (<it>p </it>= 0.098 for 50 mg/d; <it>p </it>= 0.289 for 75 mg/d neramexane), but consistent numerical superiority of both neramexane groups compared with placebo was observed. Four weeks after the end of treatment, THI-12 scores in the 50 mg/d group were significantly better than those of the controls. Secondary efficacy variables supported this trend, with <it>p </it>values of < 0.05 for the 50 mg/d neramexane group associated with the functional-communicational subscores of the THI-12 and the assessments of tinnitus annoyance and tinnitus impact on life as measured on an 11-point Likert-like scale. No relevant changes were observed for puretone threshold, for tinnitus pitch and loudness match, or for minimum masking levels. The 25 mg/d neramexane group did not differ from placebo. Neramexane was generally well tolerated and had no relevant influence on laboratory values, electrocardiography and vital signs. Dizziness was the most common adverse event and showed a clear dose-dependence.</p> <p>Conclusions</p> <p>This study demonstrated the safety and tolerability of neramexane treatment in patients with moderate to severe tinnitus. The primary efficacy variable showed a trend towards improvement of tinnitus suffering in the medium- and high-dose neramexane groups. This finding is in line with consistent beneficial effects observed in secondary assessment variables. These results allow appropriate dose selection for further studies.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00405886</p

STIMULATION AUDITIVE CONTROLATÉRALE ET OTO-EMISSIONS ACOUSTIQUES PROVOQUÉES : II - EFFET DE L'AGE ET DE LESIONS AUDIO-VESTIBULAIRES

Une stimulation auditive par bruit blanc de 30 dB SL diminue l'intensité des oto-émissions acoustiques provoquées enregistrées dans l'oreille controlatérale. Cette diminution est moins importante chez les sujets âgés et dans les surdités liées au bruit.White noise auditory stimulation (30 dB SL) decreases intensity of evoked otoacoustic emissions recorded in contralateral ear. This decrease is weaker in alder subjects and in Noise Induced Hearing Loss

STIMULATIONS AUDITIVES CONTROLATÉRALES ET OTO-ÉMISSIONS ACOUSTIQUES PROVOQUÉES : I-CARACTÉRISATION DU STIMULUS

La modification, par des stimulations auditives controlatérales, des oto-émissions acoustiques provoquées par un clic (qualifié d'ipsilatéral) a été étudiée chez l'homme en faisant varier certaines caractéristiques des stimuli ipsi et controlatéraux. Les résultats principaux sont : (1) l'effet suppresseur controlatéral ne montre pas de saturation en fonction de l'intensité ipsilatérale. (2) La suppression controlatérale la plus forte est observée lorsque les stimulations ipsi et controlatérales sont de fréquence voisine. (3) Des stimulations auditives transitoires exercent également un effet suppresseur controlatéral lorsque l'intervalle entre chaque clic est inférieur à 32.9 ms. Toutes ces observations sont bien expliquées par les propriétés de décharge provoquées par des stimulations auditives sur la fibre efférente olivocochléaire.The suppression by contralateral stimulation of otoacoustic emissions evoked by ipsilateral click has been investigated in humans. The study has consisted to modify ipsi and contralateral stimulus caracteristics. The principal findings were : (1) The contralateral suppressive effect doesn't show a saturation as function of ipsilateral intensity. (2) Contralateral suppression is greatest when the contralateral frequency is near ipsilateral tone pip frequency. (3) Transient contralateral stimuli are effective suppressors when the interclick interval is less than 32.9 ms. All these observations are well explained by known sound-evoked discharge properties of single olivocochlear neurons

STIMULATIONS AUDITIVES CONTROLATÉRALES ET MÉCANISMES ACTIFS COCHLÉAIRES : VULNÉRABILITÉ PHYSIOLOGIQUE DE LA COCHLÉE

Les otoémissions acoustiques provoquées (OEAP) ont été enregistrées en présence de stimulations auditives controlatérales afin d'étudier l'effet suppresseur sur les différentes composantes spectrales de la réponse. Les résultats montrent qu'alors que l'amplitude de certaines bandes de fréquence diminue particulièrement bien et de façon fréquence spécifique, d'autres ne montrent que de faibles diminutions, non liées à la fréquence. Comme l'effet suppresseur semble inefficace sur les fréquences de l'OEAP aux alentours de 4 kHz, un rôle protecteur du système efférent médian est discuté.The evoked otoacoustic emissions (OEAP) were recorded in presence of contralateral acoustic stimulations in order to study the suppressive effect on the different frequency components of the response. The results show that the amplitude of some frequency bands decreases in a frequency selectivity manner, but for other bands, the decrease is small without frequency specificity or even absent. This absence of suppressive effect is more particularly observed on the frequency bands around 4 kHz. So, a protective role of the medial efferent system is discussed

Paradoxical and labile medial olivocochlear functioning as a potential marker of auditory processing disorder in a child with learning disabilities

International audienceIntroductionThe medial olivocochlear system (MOCS) is composed of fibres projecting directly onto outer hair cells and plays a role in improving the signal-to-noise ratio. The MOCS can be evaluated by measuring suppression of the otoacoustic emissions evoked by contralateral acoustic stimulation. Dyslexic children present an increased probability of auditory processing disorder (APD). These children may present paradoxical MOCS dysfunction.Case reportWe report the case of a dyslexic child with APD, who was severely disabled in a noisy environment. Audiometric tests were normal, and the central auditory assessment showed labile MOCS functioning that was not only ineffective, but also potentially deleterious, possibly accounting for this child's hearing impairment in a noisy environment.DiscussionThis case illustrates the importance of audiological assessment and objective investigation of MOCS function in children with a learning disability, especially with hearing difficulties in the presence of noise, in whom auditory training can be beneficial