Increased contralateral suppression of otoacoustic emissions indicates a hyperresponsive medial olivocochlear system in humans with tinnitus and hyperacusis

Knudson, Inge M.; Shera, Christopher A.; Melcher, Jennifer R.

doi:10.1152/jn.00576.2014

Cited by 73 publications

(54 citation statements)

References 65 publications

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“…Moreover, the medial olivary cochlear system has anti-masking functions to adjust cochlear amplification in situations of listening to speech-in-noise (Bidelman and Bhagat, 2015). This might be involved in hyperacusis as shown by decreased distortion-product otoacoustic emissions, as elicited by noise presented to the contralateral ear in patients with tinnitus and low sound level tolerance (Knudson et al, 2014). …”

Section: Discussionmentioning

confidence: 99%

Speech Comprehension Difficulties in Chronic Tinnitus and Its Relation to Hyperacusis

Vielsmeier

Kreuzer

Haubner

et al. 2016

Front. Aging Neurosci.

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Objective: Many tinnitus patients complain about difficulties regarding speech comprehension. In spite of the high clinical relevance little is known about underlying mechanisms and predisposing factors. Here, we performed an exploratory investigation in a large sample of tinnitus patients to (1) estimate the prevalence of speech comprehension difficulties among tinnitus patients, to (2) compare subjective reports of speech comprehension difficulties with behavioral measurements in a standardized speech comprehension test and to (3) explore underlying mechanisms by analyzing the relationship between speech comprehension difficulties and peripheral hearing function (pure tone audiogram), as well as with co-morbid hyperacusis as a central auditory processing disorder.Subjects and Methods: Speech comprehension was assessed in 361 tinnitus patients presenting between 07/2012 and 08/2014 at the Interdisciplinary Tinnitus Clinic at the University of Regensburg. The assessment included standard audiological assessments (pure tone audiometry, tinnitus pitch, and loudness matching), the Goettingen sentence test (in quiet) for speech audiometric evaluation, two questions about hyperacusis, and two questions about speech comprehension in quiet and noisy environments (“How would you rate your ability to understand speech?”; “How would you rate your ability to follow a conversation when multiple people are speaking simultaneously?”).Results: Subjectively-reported speech comprehension deficits are frequent among tinnitus patients, especially in noisy environments (cocktail party situation). 74.2% of all investigated patients showed disturbed speech comprehension (indicated by values above 21.5 dB SPL in the Goettingen sentence test). Subjective speech comprehension complaints (both for general and in noisy environment) were correlated with hearing level and with audiologically-assessed speech comprehension ability. In contrast, co-morbid hyperacusis was only correlated with speech comprehension difficulties in noisy environments, but not with speech comprehension difficulties in general.Conclusion: Speech comprehension deficits are frequent among tinnitus patients. Whereas speech comprehension deficits in quiet environments are primarily due to peripheral hearing loss, speech comprehension deficits in noisy environments are related to both peripheral hearing loss and dysfunctional central auditory processing. Disturbed speech comprehension in noisy environments might be modulated by a central inhibitory deficit. In addition, attentional and cognitive aspects may play a role.

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Section: Discussionmentioning

confidence: 99%

Speech Comprehension Difficulties in Chronic Tinnitus and Its Relation to Hyperacusis

Vielsmeier

Kreuzer

Haubner

et al. 2016

Front. Aging Neurosci.

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“…The CAS was the same broadband noise as that used for measurements of MOC inhibition on CAPs and DPOAEs. A “suppressor” tone was used to suppress the stimulus frequency OAE (SFOAE) produced by the probe tone (Lilaonitkul & Guinan 2009a; Francis & Guinan 2010; Knudson et al 2014). Suppressing the SFOAE insures that any CAS-induced change in the ear-canal sound pressure level of the probe is due only to the MEMR and not to a MOC effect on the SFOAE.…”

Section: Methodsmentioning

confidence: 99%

Medial olivocochlear efferent reflex inhibition of human cochlear nerve responses

et al. 2016

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Inhibition of cochlear amplifier gain by the medial olivocochlear (MOC) efferent system has several putative roles: aiding listening in noise, protection against damage from acoustic overexposure, and slowing age-induced hearing loss. The human MOC reflex has been studied almost exclusively by measuring changes in otoacoustic emissions. However, to help understand how the MOC system influences what we hear, it is important to have measurements of the MOC effect on the total output of the organ of Corti, i.e., on cochlear nerve responses that couple sounds to the brain. In this work we measured the inhibition produced by the MOC reflex on the amplitude of cochlear nerve compound action potentials (CAPs) in response to moderate level (52–60 dB peSPL) clicks from five, young, normal hearing, awake, alert, human adults. MOC activity was elicited by 65 dB SPL, contralateral broadband noise (CAS). Using tympanic membrane electrodes, approximately 10 hours of data collection were needed from each subject to yield reliable measurements of the MOC reflex inhibition on CAP amplitudes from one click level. The CAS produced a 16% reduction of CAP amplitude, equivalent to a 1.98 dB effective attenuation (averaged over five subjects). Based on previous reports of efferent effects as functions of level and frequency, it is possible that much larger effective attenuations would be observed at lower sound levels or with clicks of higher frequency content. For a preliminary comparison, we also measured MOC reflex inhibition of DPOAEs evoked from the same ears with f2’s near 4 kHz. The resulting effective attenuations on DPOAEs were, on average, less than half the effective attenuations on CAPs.

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“…This is possible experimentally by decoupling the input to the two ears: When playing broadband noise to one ear, the sensitivity of the other ear is reduced. This is called contralateral suppression and presumably mediated by the olivo-cochlear system (Knudson et al, 2014). The exact proportion of ipsi-vs. contralateral olivo-cochlear innervation is variable and depends on the species and tonotopic position on the cochlea.…”

Section: Anatomy and Physiology Of The Olivo-cochlear Systemmentioning

confidence: 99%

Cholinergic top-down influences on the auditory brainstem

Künzel

Wagner

2017

E-Neuroforum

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Abstract:Descending connections are present in many sensory systems and support adaptive information processing. This allows the sensory brain to code a wider range of inputs. A well characterized descending system is the olivo-cochlear cholinergic innervation of the inner ear, which mediates a reduction of the sensitivity of the inner ear upon perception of intense sounds. Because this inhibits the response to background noise, the olivo-cochlear system supports detection of transient sound events. Olivo-cochlear neurons also innervate the cochlear nucleus through axon collaterals. Here, acetylcholine increases the excitability of central neurons without reducing their temporal precision. Thus their target neurons in the superior olivary complex can more effectively process binaural temporal cues. We argue that the central effect of the olivo-cochlear system augments the peripheral effect. In addition, olivo-cochlear cholinergic neurons are under top-down control of cortical inputs, providing further adaptability of information processing on the level of the auditory brainstem.Keywords: auditory brainstem; sound localization; cochlear nucleus; modulation; acetylcholine Imagine you return to a cocktail party after a quiet walk outside. Suddenly you are in a room filled with loud music and many talking people and are engulfed in intense noisiness coming from many directions. The sound level is much higher now and relevant information can be overpowered ("masked") by the various noise sources in the room. Identification and localization of individual speakers is still possible, although more difficult than in a quiet room. What are the mechanisms in the brain that allow you to do this? Sensory pathways are often mistakenly seen as purely ascending streams of information, where a given neuron feeds information only "upwards" to stations of increasing complexity in a higher hierarchical level. In a wellknown example, time-coding neurons in the cochlear nucleus are contacted by giant synaptic terminals of the auditory nerve (Felmy and Künzel, 2014) and pass information about the timing of the perceived sound up along the auditory pathway into binaural nuclei with more complex functions. These neurons are clearly dominated by information flow from hierarchically lower to higher stations, as the ascending synaptic connection from the auditory nerve onto the time-coding neuron is very powerful. Although it is well established that the auditory periphery and the first stages of the auditory pathway indeed show activity dependent dynamics, these adaptive phenomena can only rely on the limited information that is available at the given neuron. In this scheme, however, the background noise from the cocktail party could easily drown the important information, since one can expect it to activate the ascending stream of auditory information as intense as the relevant auditory event. However, recurrent connections within hierarchical levels and descending connections towards neurons in lower hierarchical orders that provide dyn...

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Increased contralateral suppression of otoacoustic emissions indicates a hyperresponsive medial olivocochlear system in humans with tinnitus and hyperacusis

Cited by 73 publications

References 65 publications

Speech Comprehension Difficulties in Chronic Tinnitus and Its Relation to Hyperacusis

Speech Comprehension Difficulties in Chronic Tinnitus and Its Relation to Hyperacusis

Medial olivocochlear efferent reflex inhibition of human cochlear nerve responses

Cholinergic top-down influences on the auditory brainstem

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