Aging Processes in the Subcortical Auditory System

2018 ◽  
pp. 638-680 ◽  
Author(s):  
Donald M. Caspary ◽  
Daniel A. Llano
Keyword(s):  
Hearing Loss ◽  
Auditory System ◽  
De Novo ◽  
Auditory Brainstem ◽  
Superior Olivary Complex ◽  
Age Related ◽  
Medial Geniculate ◽  
Age Related Hearing Loss ◽  
The Impact ◽  
Age Related Changes

As arguably the third most common malady of industrialized populations, age-related hearing loss is associated with social isolation and depression in a subset of the population that will approach 25% by 2050. Development of behavioral or pharmacotherapeutic approaches to prevent or delay the onset of age-related hearing loss and mitigate the impact of hearing loss of speech understanding requires a better understanding of age-related changes that occur in the central auditory processor. This chapter critically reviews and discusses changes that occur in the auditory brainstem and thalamus with increased age. It briefly discusses age-related cellular changes that occur de novo within the central auditory system versus deafferentation plasticity and animal models of aging. Subsections discuss the cochlear nucleus, superior olivary complex, inferior colliculus, and the medial geniculate body with an emphasis on age-related changes in neurotransmission and how these changes could underpin the observed loss of precise temporal processing with increased age.

Presbyacusis and the Auditory Brainstem Response

2002 ◽  
Vol 45 (6) ◽  
pp. 1249-1261 ◽  
Author(s):  
Flint A. Boettcher
Keyword(s):  
Hearing Loss ◽  
Auditory System ◽  
Auditory Brainstem Response ◽  
Animal Studies ◽  
Auditory Brainstem ◽  
Clinical Tool ◽  
Age Related ◽  
Brainstem Response ◽  
Auditory Functions ◽  
Age Related Changes

Age-related hearing loss (ARHL or presbyacusis) is an increasingly common form of sensorineural hearing loss (SNHL) as a result of changing demographics, and the auditory brainstem response (ABR) is a common experimental and clinical tool in audiology and neurology. Some of the changes that occur in the aging auditory system may significantly influence the interpretation of the ABR in comparison to the ABRs of younger adults. The approach of this review will be to integrate physiological and histopathological data from human and animal studies to provide a better understanding of the array of age-related changes in the ABR and to determine how age-related changes in the auditory system may influence how the ABR should be interpreted in presbyacusis. Data will be described in terms of thresholds, latencies, and amplitudes, as well as more complex auditory functions such as masking and temporal processing. Included in the review of data will be an attempt to differentiate between age-related effects that may strictly be due to threshold elevation from those that may be due to the aging process.

scholarly journals Age-related changes of auditory brainstem responses in nonhuman primates

2015 ◽  
Vol 114 (1) ◽  
pp. 455-467 ◽  
Author(s):  
Chi-Wing Ng ◽  
Xochi Navarro ◽  
James R. Engle ◽  
Gregg H. Recanzone
Keyword(s):  
Hearing Loss ◽  
Nonhuman Primates ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
High Frequencies ◽  
Age Related ◽  
Wide Range ◽  
Brainstem Response ◽  
Age Related Hearing Loss ◽  
Age Related Changes

Nonhuman primates, compared with humans and rodents, have historically been far less used for studies of age-related hearing loss, primarily because of their long life span and high cost of maintenance. Strong similarities in genetics, anatomy, and neurophysiology of the auditory nervous system between humans and monkeys, however, could provide fruitful opportunities to enhance our understanding of hearing loss. The present study used a common, noninvasive technique for testing hearing sensitivity in humans, the auditory brainstem response (ABR), to assess the hearing of 48 rhesus macaques from 6 to 35 yr of age to clicks and tone stimuli between 0.5 and 16.0 kHz. Old monkeys, particularly those above 21.5 yr of age, had missing ABR waveforms at high frequencies. Regression analyses revealed that ABR threshold increased as a function of age at peaks II and IV simultaneously. In the suprathreshold hearing condition (70 dB peak sound pressure level), ABR-based audiograms similarly varied as a function of age such that old monkeys had smaller peak amplitudes and delayed latencies at low, middle, and high frequencies. Peripheral hearing differences remained a major influence associated with age-related changes in audiometric functions of old monkeys at a comparable sensation level across animals. The present findings suggest that hearing loss occurs in old monkeys across a wide range of frequencies and that these deficits increase in severity with age. Parallel to prior studies in monkeys, we found weak effects of sex on hearing, and future investigations are necessary to clarify its role in age-related hearing loss.

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 Auditory brainstem gap responses start to decline in mice in middle age: a novel physiological biomarker for age-related hearing loss

2014 ◽  
Vol 361 (1) ◽  
pp. 359-369 ◽  
Author(s):  
Tanika T. Williamson ◽  
Xiaoxia Zhu ◽  
Joseph P. Walton ◽  
Robert D. Frisina
Keyword(s):  
Hearing Loss ◽  
Middle Age ◽  
Auditory Brainstem ◽  
Age Related ◽  
Age Related Hearing Loss

The miR-34a/Bcl-2 Pathway Contributes to Auditory Cortex Neuron Apoptosis in Age-Related Hearing Loss

2017 ◽  
Vol 22 (2) ◽  
pp. 96-103 ◽  
Author(s):  
Qiuhong Huang ◽  
Yongkang Ou ◽  
Hao Xiong ◽  
Haidi Yang ◽  
Zhigang Zhang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Molecular Mechanisms ◽  
Primary Auditory Cortex ◽  
Auditory Brainstem ◽  
Hearing Ability ◽  
Age Related ◽  
Brainstem Response ◽  
The Central Nervous System ◽  
Age Related Hearing Loss

Hypothesis: The miR-34a/Bcl-2 signaling pathway may play a role in the mechanisms related to age-related hearing loss (AHL) in the auditory cortex. Background: The auditory cortex plays a key role in the recognition and processing of complex sound. It is difficult to explain why patients with AHL have poor speech recognition, so increasing numbers of studies have focused on its central change. Although micro (mi)RNAs in the central nervous system have recently been increasingly reported to be associated with age-related diseases, the molecular mechanisms of AHL in the auditory cortex are not fully understood. Methods: The auditory brainstem response was used to assess the hearing ability of C57BL/6 mice, and q-PCR, immunohistochemistry, and Western blotting were used to detect the expression levels of miR-34a and Bcl-2 in the mouse auditory cortex. TUNEL and DNA fragmentation were adopted to detect the apoptosis of neurons in the auditory cortex. To verify the relationship of miR-34a and Bcl-2, we transfected an miR-34a mimic or miR-34a inhibitor into primary auditory cortex neurons. Results: In this study, miR-34a/Bcl-2 signaling was examined in auditory cortex neurons during aging. miR-34a and apoptosis increased in the auditory cortex neurons of C57BL/6 mice with aging, whereas an age-related decrease in Bcl-2 was determined. In the primary neurons of the auditory cortex, miR-34a overexpression inhibited Bcl-2, leading to an increase in apoptosis. Moreover, miR-34a knockdown increased Bcl-2 expression and diminished apoptosis. Conclusion: Our results support a link between age-related apoptosis in auditory cortex neurons and miR-34a/Bcl-2 signaling, which may serve as a potential mechanism of the expression of AHL in the auditory cortex.

scholarly journals Roles of Key Ion Channels and Transport Proteins in Age-Related Hearing Loss

2021 ◽  
Vol 22 (11) ◽  
pp. 6158
Author(s):  
Parveen Bazard ◽  
Robert D. Frisina ◽  
Alejandro A. Acosta ◽  
Sneha Dasgupta ◽  
Mark A. Bauer ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Ion Channels ◽  
Auditory System ◽  
Auditory Processing ◽  
Mechanical Energy ◽  
Transport Proteins ◽  
Oval Window ◽  
Cochlear Hair Cells ◽  
Age Related ◽  
Age Related Hearing Loss

The auditory system is a fascinating sensory organ that overall, converts sound signals to electrical signals of the nervous system. Initially, sound energy is converted to mechanical energy via amplification processes in the middle ear, followed by transduction of mechanical movements of the oval window into electrochemical signals in the cochlear hair cells, and finally, neural signals travel to the central auditory system, via the auditory division of the 8th cranial nerve. The majority of people above 60 years have some form of age-related hearing loss, also known as presbycusis. However, the biological mechanisms of presbycusis are complex and not yet fully delineated. In the present article, we highlight ion channels and transport proteins, which are integral for the proper functioning of the auditory system, facilitating the diffusion of various ions across auditory structures for signal transduction and processing. Like most other physiological systems, hearing abilities decline with age, hence, it is imperative to fully understand inner ear aging changes, so ion channel functions should be further investigated in the aging cochlea. In this review article, we discuss key various ion channels in the auditory system and how their functions change with age. Understanding the roles of ion channels in auditory processing could enhance the development of potential biotherapies for age-related hearing loss.

scholarly journals Evaluation of the Effects of Chronic Injection of D-Galactose on Auditory Brainstem Responses as a Model for Studying Age-Related Hearing Loss

2019 ◽  
Author(s):  
Elham Tavanai ◽  
Ghassem Mohammadkhani
Keyword(s):  
Hearing Loss ◽  
Wistar Rats ◽  
Natural Aging ◽  
Tone Burst ◽  
Auditory Brainstem ◽  
Young Group ◽  
Auditory Brainstem Responses ◽  
Age Related ◽  
Significant Difference ◽  
Age Related Hearing Loss

The D-galactose induced mimetic aging rat model has been widely used in studies of age-associated diseases recently. Evidence indicates that D-GAL could also play a key role in age-related hearing loss. However, there is conflicting data about the relationship between the D-GAL injection and tone-burst auditory brainstem responses (ABRs). The present study aimed to compare ABRs in D-GAL injected rats compared with young and naturally aged rats. Tone-burst ABR was recorded and analyzed at the frequencies of 4,6,8,12 and 16 kHz in male young (3-month-old, n=10), naturally aging (18-month-old, n=10) and D-GAL injected (3-month-old, 500 mg/kg D-GAL injection for 8 weeks, n=10) Wistar rats. When the ABRs thresholds obtained in the D-GAL group and the natural aging group were compared with the thresholds in the young group, we observed a significant increase in thresholds, which affected all of the frequencies (P<0.05). A statistically significant decrease in amplitude of wave PI at 4 and 8 kHz, PII at 4,8 kHz, PIV at 4,6,8,12 and 16 kHz was also observed in naturally aging group compared with young group. However, in D-GAL group, a significant difference was exclusively detected in amplitude of PIII at 4 kHz. Latency did not reveal any significant difference between the groups (P>0.05). The present study confirmed that experimental injection of 500 mg/kg/day D-GAL for 8 weeks to Wistar rats could lead to ABRs threshold shifts but not latency. Because there are several types of presbycusis, further studies are needed to determine what type of presbycusis is induced by D-GAL and where is the first region affected by it to provide the best treatment and prevention methods. © 2019 Tehran University of Medical Sciences. All rights reserved. Acta Med Iran 2019;57(5):281-288.

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