scholarly journals Olivocochlear Changes Associated With Aging Predominantly Affect the Medial Olivocochlear System

2021 ◽  
Vol 15 ◽  
Author(s):  
Sergio Vicencio-Jimenez ◽  
Madison M. Weinberg ◽  
Giuliana Bucci-Mansilla ◽  
Amanda M. Lauer
Keyword(s):  
Background Noise ◽  
Cholinergic Neurons ◽  
Public Health Problem ◽  
Auditory Brainstem ◽  
Olivocochlear System ◽  
Age Related ◽  
Inhibitory Proteins ◽  
Medial Olivocochlear System ◽  
Brainstem Response ◽  
Medial Olivocochlear

Age-related hearing loss (ARHL) is a public health problem that has been associated with negative health outcomes ranging from increased frailty to an elevated risk of developing dementia. Significant gaps remain in our knowledge of the underlying central neural mechanisms, especially those related to the efferent auditory pathways. Thus, the aim of this study was to quantify and compare age-related alterations in the cholinergic olivocochlear efferent auditory neurons. We assessed, in young-adult and aged CBA mice, the number of cholinergic olivocochlear neurons, auditory brainstem response (ABR) thresholds in silence and in presence of background noise, and the expression of excitatory and inhibitory proteins in the ventral nucleus of the trapezoid body (VNTB) and in the lateral superior olive (LSO). In association with aging, we found a significant decrease in the number of medial olivocochlear (MOC) cholinergic neurons together with changes in the ratio of excitatory and inhibitory proteins in the VNTB. Furthermore, in old mice we identified a correlation between the number of MOC neurons and ABR thresholds in the presence of background noise. In contrast, the alterations observed in the lateral olivocochlear (LOC) system were less significant. The decrease in the number of LOC cells associated with aging was 2.7-fold lower than in MOC and in the absence of changes in the expression of excitatory and inhibitory proteins in the LSO. These differences suggest that aging alters the medial and lateral olivocochlear efferent pathways in a differential manner and that the changes observed may account for some of the symptoms seen in ARHL.

scholarly journals Age-Related Changes in the Auditory Brainstem Response and Suprathreshold Processing of Temporal and Spectral Modulation

2019 ◽  
Vol 23 ◽  
pp. 233121651983961 ◽  
Author(s):  
John H. Grose ◽  
Emily Buss ◽  
Hollis Elmore
Keyword(s):  
Auditory Brainstem Response ◽  
Background Noise ◽  
Auditory Brainstem ◽  
Temporal Modulation ◽  
Amplitude Ratios ◽  
Spectral Modulation ◽  
Age Related ◽  
Brainstem Response ◽  
Modulation Detection ◽  
Hearing Difficulties

The purpose of this study was to determine whether cochlear synaptopathy can be shown to be a viable basis for age-related hearing difficulties in humans and whether it manifests as deficient suprathreshold processing of temporal and spectral modulation. Three experiments were undertaken evaluating the effects of age on (a) the auditory brainstem response as a function of level, (b) temporal modulation detection as a function of level and background noise, and (c) spectral modulation as a function of level. Across the three experiments, a total of 21 older listeners with near-normal audiograms and 29 young listeners with audiometrically normal hearing participated. The auditory brainstem response experiment demonstrated reduced Wave I amplitudes and concomitant reductions in the amplitude ratios of Wave I to Wave V in the older listener group. These findings were interpreted as consistent with an electrophysiological profile of cochlear synaptopathy. The temporal and spectral modulation detection experiments, however, provided no support for the hypothesis of compromised suprathreshold processing in these domains. This pattern of results suggests that even if cochlear synaptopathy can be shown to be a viable basis for age-related hearing difficulties, then temporal and spectral modulation detection paradigms are not sensitive to its presence.

scholarly journals Auditory Brainstem Responses to Successive Sounds: Effects of Gap Duration and Depth

2021 ◽  
Vol 11 (1) ◽  
pp. 38-46
Author(s):  
Fan-Yin Cheng ◽  
Craig A. Champlin
Keyword(s):  
Background Noise ◽  
Tone Burst ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Physical Parameters ◽  
Temporal Acuity ◽  
Harmonic Complex ◽  
Rapid Changes ◽  
Brainstem Response ◽  
Physiological Correlate

Temporal acuity is the ability to differentiate between sounds based on fluctuations in the waveform envelope. The proximity of successive sounds and background noise diminishes the ability to track rapid changes between consecutive sounds. We determined whether a physiological correlate of temporal acuity is also affected by these factors. We recorded the auditory brainstem response (ABR) from human listeners using a harmonic complex (S1) followed by a brief tone burst (S2) with the latter serving as the evoking signal. The duration and depth of the silent gap between S1 and S2 were manipulated, and the peak latency and amplitude of wave V were measured. The latency of the responses decreased significantly as the duration or depth of the gap increased. The amplitude of the responses was not affected by the duration or depth of the gap. These findings suggest that changing the physical parameters of the gap affects the auditory system’s ability to encode successive sounds.

scholarly journals Chronic Oral Selegiline Treatment Mitigates Age-Related Hearing Loss in BALB/c Mice

2021 ◽  
Vol 22 (6) ◽  
pp. 2853
Author(s):  
Judit Szepesy ◽  
Viktória Humli ◽  
János Farkas ◽  
Ildikó Miklya ◽  
Júlia Tímár ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
Dose Range ◽  
Auditory Brainstem ◽  
High Frequency Hearing Loss ◽  
Age Related ◽  
Hearing Function ◽  
Brainstem Response ◽  
Aging Societies ◽  
Age Related Hearing Loss

Age-related hearing loss (ARHL), a sensorineural hearing loss of multifactorial origin, increases its prevalence in aging societies. Besides hearing aids and cochlear implants, there is no FDA approved efficient pharmacotherapy to either cure or prevent ARHL. We hypothesized that selegiline, an antiparkinsonian drug, could be a promising candidate for the treatment due to its complex neuroprotective, antioxidant, antiapoptotic, and dopaminergic neurotransmission enhancing effects. We monitored by repeated Auditory Brainstem Response (ABR) measurements the effect of chronic per os selegiline administration on the hearing function in BALB/c and DBA/2J mice, which strains exhibit moderate and rapid progressive high frequency hearing loss, respectively. The treatments were started at 1 month of age and lasted until almost a year and 5 months of age, respectively. In BALB/c mice, 4 mg/kg selegiline significantly mitigated the progression of ARHL at higher frequencies. Used in a wide dose range (0.15–45 mg/kg), selegiline had no effect in DBA/2J mice. Our results suggest that selegiline can partially preserve the hearing in certain forms of ARHL by alleviating its development. It might also be otoprotective in other mammals or humans.

scholarly journals The human auditory brainstem response to running speech reveals a subcortical mechanism for selective attention

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Antonio Elia Forte ◽  
Octave Etard ◽  
Tobias Reichenbach
Keyword(s):  
Mathematical Method ◽  
Selective Attention ◽  
Auditory Cortex ◽  
Auditory Brainstem Response ◽  
Background Noise ◽  
Ecological Validity ◽  
Acoustic Stimulus ◽  
Auditory Brainstem ◽  
Brainstem Response ◽  
Target Speaker

Humans excel at selectively listening to a target speaker in background noise such as competing voices. While the encoding of speech in the auditory cortex is modulated by selective attention, it remains debated whether such modulation occurs already in subcortical auditory structures. Investigating the contribution of the human brainstem to attention has, in particular, been hindered by the tiny amplitude of the brainstem response. Its measurement normally requires a large number of repetitions of the same short sound stimuli, which may lead to a loss of attention and to neural adaptation. Here we develop a mathematical method to measure the auditory brainstem response to running speech, an acoustic stimulus that does not repeat and that has a high ecological validity. We employ this method to assess the brainstem's activity when a subject listens to one of two competing speakers, and show that the brainstem response is consistently modulated by attention.

Differences in Responses from the Cochleae and Central Nervous Systems of Females with Low versus High Acceptable Noise Levels

2006 ◽  
Vol 17 (09) ◽  
pp. 667-676 ◽  
Author(s):  
Ashley W. Harkrider ◽  
Joanna W. Tampas
Keyword(s):  
Auditory System ◽  
Background Noise ◽  
Otoacoustic Emissions ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Intersubject Variability ◽  
Hearing Sensitivity ◽  
Central Regions ◽  
Central Nervous Systems ◽  
Medial Olivocochlear

Studies of acceptable noise level (ANL) consistently report large intersubject variability in acceptance of background noise while listening to speech. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, or efferent activity of the medial olivocochlear pathway. An exploratory study was conducted to determine if differences in aggregate responses from the peripheral and central auditory system can account for intersubject variability in ANL. Click-evoked otoacoustic emissions (CEOAEs), binaural auditory brainstem responses (ABRs), and middle latency responses (MLRs) were measured in females with normal hearing with low (n = 6) versus high (n = 7) ANLs. Results of this preliminary study indicate no differences between the groups for CEOAEs or waves I or III of the ABR. Differences between the two groups emerge for the amplitudes of wave V of the ABR and for the Na-Pa component of the MLR, suggesting that physiological variations arising from more central regions of the auditory system may mediate background noise acceptance.

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