Auditory Processing in the Aging Brain

Author(s):  
Gregg Recanzone

Age-related hearing loss affects over half of the elderly population, yet it remains poorly understood. Natural aging can cause the input to the brain from the cochlea to be progressively compromised in most individuals, but in many cases the cochlea has relatively normal sensitivity and yet people have an increasingly difficult time processing complex auditory stimuli. The two main deficits are in sound localization and temporal processing, which lead to poor speech perception. Animal models have shown that there are multiple changes in the brainstem, midbrain, and thalamic auditory areas as a function of age, giving rise to an alteration in the excitatory/inhibitory balance of these neurons. This alteration is manifest in the cerebral cortex as higher spontaneous and driven firing rates, as well as broader spatial and temporal tuning. These alterations in cortical responses could underlie the hearing and speech processing deficits that are common in the aged population.

2018 ◽  
Vol 29 (01) ◽  
pp. 005-014 ◽  
Author(s):  
Cristina F. B. Murphy ◽  
Camila M. Rabelo ◽  
Marcela L. Silagi ◽  
Leticia L. Mansur ◽  
Doris E. Bamiou ◽  
...  

AbstractDespite the well-established relationship between aging and auditory processing decline, identifying the extent to which age effect is the main factor on auditory processing performance remains a great challenge due to the co-occurrence of age-related hearing loss and age-related cognitive decline as potential confounding factors.To investigate the effects of age-related hearing loss and working memory on the clinical evaluation of auditory processing of middle-aged and elderly.Cross-sectional study.A total of 77 adults between 50 and 70 yr of age were invited to participate in the study.The participants were recruited from a larger study that focused on the assessment and management of sensory and cognitive skills in elderly participants. Only participants with normal hearing or mild-to-moderate age-related hearing loss, with no evidence of cognitive, psychological, or neurological conditions were included. Speech-in-noise, dichotic digit, and frequency pattern tests were conducted as well as a working memory test. The hearing loss effect was investigated using an audibility index, calculated from the audiometric threshold. The performance on the digit span test was used to investigate working memory effects. Both hearing loss and working memory effects were investigated via correlation and regression analyses, partialling out age effects. The significance level was set at p < 0.05.The results demonstrated that, while hearing loss was associated to the speech-in-noise performance, working memory was associated to the frequency pattern and dichotic digit performances. Regression analyses confirmed the relative contribution of hearing loss to the variance in speech-in-noise and working memory test to the variance in frequency pattern and dichotic digit test performance.The performance decline of the elderly in auditory processing tests may be partially attributable to the working memory performance and, consequently, to the cognitive decline exhibited by this population. Mild-to-moderate hearing loss seems to affect performance on specific auditory processing tasks, such as speech in noise, reinforcing the idea that auditory processing disorder in the elderly might also be associated to auditory peripheral deficits.


2017 ◽  
Author(s):  
Muriel TN Panouillères ◽  
Riikka Möttönen

AbstractOlder adults often experience difficulties in understanding speech, partly because of age-related hearing loss. In young adults, activity of the left articulatory motor cortex is enhanced and it interacts with the auditory cortex via the left-hemispheric dorsal stream during speech processing. Little is known about the effect of ageing and age-related hearing loss on this auditory-motor interaction and speech processing in the articulatory motor cortex. It has been proposed that up-regulation of the motor system during speech processing could compensate for hearing loss and auditory processing deficits in older adults. Alternatively, age-related auditory deficits could reduce and distort the input from the auditory cortex to the articulatory motor cortex, suppressing recruitment of the motor system during listening to speech. The aim of the present study was to investigate the effects of ageing and age-related hearing loss on the excitability of the tongue motor cortex during listening to spoken sentences using transcranial magnetic stimulation and electromyography. Our results show that the excitability of the tongue motor cortex was facilitated during listening to speech in young and older adults with normal hearing. This facilitation was significantly reduced in older adults with hearing loss. These findings suggest a decline of auditory-motor processing of speech in adults with age-related hearing loss.


2017 ◽  
Vol 60 (9) ◽  
pp. 2394-2405 ◽  
Author(s):  
Lionel Fontan ◽  
Isabelle Ferrané ◽  
Jérôme Farinas ◽  
Julien Pinquier ◽  
Julien Tardieu ◽  
...  

Purpose The purpose of this article is to assess speech processing for listeners with simulated age-related hearing loss (ARHL) and to investigate whether the observed performance can be replicated using an automatic speech recognition (ASR) system. The long-term goal of this research is to develop a system that will assist audiologists/hearing-aid dispensers in the fine-tuning of hearing aids. Method Sixty young participants with normal hearing listened to speech materials mimicking the perceptual consequences of ARHL at different levels of severity. Two intelligibility tests (repetition of words and sentences) and 1 comprehension test (responding to oral commands by moving virtual objects) were administered. Several language models were developed and used by the ASR system in order to fit human performances. Results Strong significant positive correlations were observed between human and ASR scores, with coefficients up to .99. However, the spectral smearing used to simulate losses in frequency selectivity caused larger declines in ASR performance than in human performance. Conclusion Both intelligibility and comprehension scores for listeners with simulated ARHL are highly correlated with the performances of an ASR-based system. In the future, it needs to be determined if the ASR system is similarly successful in predicting speech processing in noise and by older people with ARHL.


2013 ◽  
Vol 22 (2) ◽  
pp. 299-302 ◽  
Author(s):  
Robert D. Frisina ◽  
D. Robert Frisina

Purpose The aim of this study was to highlight growing evidence of interactions between hormones and the structure and function of the auditory system. Method Recent studies implicating sex hormones and other natural hormones in the modulation of hearing status in age-related hearing loss were reviewed. Results Progesterone, a sex hormone, has been shown to have negative effects on the hearing of older women and aging mice, whereas, in contrast, estrogen was found in some cases to have a positive influence. Aldosterone, used in studies of animal models of autoimmune hearing loss, slowed the progression of hearing loss. Follow-up studies in humans revealed that auditory measures varied as serum aldosterone levels shifted within the normal range, in otherwise healthy older subjects. This was true for simple as well as complex auditory tasks (i.e., sound spatial processing), suggesting benefits of aldosterone to postperipheral auditory processing as well. In addition, evidence suggests that this functional hearing improvement occurred in association with anatomical improvements to the stria vascularis—an important site of anatomical change in presbycusis. Conclusions Audiology is now at the point where the search for biomedical interventions to modulate or prevent age-related hearing loss can move forward. Such interventions would require multidisciplinary collaborative initiatives by researchers in such areas as drug development, anatomy, auditory physiological and perceptual testing, and drug microdelivery systems.


2007 ◽  
Vol 18 (07) ◽  
pp. 539-547 ◽  
Author(s):  
Fergus I.M. Craik

The article presents a commentary on the accompanying six papers from the perspective of a cognitive psychologist. Treisman's (1964, 1969) levels of analysis model of selective attention is suggested as a framework within which the interactions between 'bottom-up' auditory factors and 'top-down' cognitive factors may be understood. The complementary roles of auditory and cognitive aspects of hearing are explored, and their mutually compensatory properties discussed. The findings and ideas reported in the six accompanying papers fit well into such a 'levels of processing' framework, which may therefore be proposed as a model for understanding the effects of aging on speech processing and comprehension. El artículo presenta un comentario sobre los seis trabajos acompañantes desde la perspectiva de un psicólogo de la cognición. Se sugiere el modelo de Treisman (1964, 1969) de niveles de análisis de la atención selectiva como el marco dentro del cuál las interacciones entre los factores de atención "de abajo hacia arriba" y los factores cognitivos de "de arriba hacia abajo" pueden ser comprendidos. Se exploran los papeles complementarios de los aspectos auditivos y cognitivos de la audición y se discuten sus mutuas propiedades compensatorias. Los hallazgos e ideas reportados en los seis trabajos acompañantes calzan bien en dicho marco de "niveles de procesamiento", los que puede, por tanto, ser propuestos como un modelo para comprender el efecto del envejecimiento para el procesamiento y la comprensión del lenguaje.


1988 ◽  
Vol 153 (S3) ◽  
pp. 105-108 ◽  
Author(s):  
John P. Feighner ◽  
William F. Boyer ◽  
Charles H. Meredith ◽  
Gordon Hendrickson

During the past 75 years, the proportion of elderly individuals in the USA has grown twice as fast as the general population. Depression in this age-group occurs four times more frequently than in the general population (Butler, 1975), and the suicide rate for people over 65 years of age is 15 times greater than that of the general population (Lehman, 1980).The elderly may be more susceptible to depression due to biological and/or psychosocial variables. Elderly people experience significant losses associated with increasing age, including death of spouse and friends, loss of work, social status, and physical and mental abilities (Lehman, 1980). The biogenic amine hypothesis suggests that the aging brain may experience a decrease in the functional availability of neurotransmitters (Lehman, 1980); this decrease may also play a role in the aetiology of depression.Due to age-related changes in the body, the elderly can be more sensitive to drug therapy. Older patients may require careful dosage adjustments and may also be more prone to experiencing drug-related adverse events. The elderly often receive medication for various indications, and drug interactions are a concern (Thompson et al, 1983). Therefore, efficacy and safety studies of new antidepressants in elderly patients are particularly important. We pooled data from both double-blind and open-label studies to evaluate the efficacy and safety of fluoxetine in geriatric outpatients with DSM-III major depression. Positive results of fluoxetine in the treatment of geriatric depression were reported in one of these studies (Feighner & Cohn, 1985). The favourable safety and side-effect profile of fluoxetine in the general population has been discussed elsewhere (Wernicke, 1985). Plasma concentrations of fluoxetine in elderly subjects are similar to those in younger individuals (I.emberger et al, 1985). These findings, combined with a lack of cardiovascular effects (Fisch, 1985), and low lethality with overdose, indicated promise for fluoxetine as a geriatric antidepressant.


2016 ◽  
Vol 126 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Leonid Livshitz ◽  
Reem Ghanayim ◽  
Carmi Kraus ◽  
Raymond Farah ◽  
Ella Even-Tov ◽  
...  

Objectives: The effects of age-related hearing loss are severe. Early detection is essential for maximum benefit. However, most hearing-impaired adults delay obtaining treatment. Diagnostic hearing testing at an appropriate facility is impractical, and new methods for screening audiometry aim to provide easy access for patients and reliable outcomes. The purpose of this study was to examine the accuracy of application-based hearing screening in an elderly population. Methods: The uHear application was downloaded to an iPad. Application-based hearing screening was performed in a non-soundproofed quiet room, and subsequently all participants underwent full diagnostic audiometry in a soundproof booth. Results: Sixty patients were recruited and completed both tests. Significant differences were observed between the hearing results obtained with the application and the standard audiogram at all frequencies and in both ears. Following subtraction of a constant factor of 25 dB from the application-based results in order to compensate for ambient noise, no significant differences in pure tone average were found between the 2 methods. Conclusions: The uHear application is inaccurate in assessing hearing thresholds for screening in the elderly. However, when site-specifically corrected, the uHear application may be used as a screening tool for hearing loss in an elderly population.


2021 ◽  
Vol 22 (11) ◽  
pp. 6158
Author(s):  
Parveen Bazard ◽  
Robert D. Frisina ◽  
Alejandro A. Acosta ◽  
Sneha Dasgupta ◽  
Mark A. Bauer ◽  
...  

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.


2013 ◽  
Vol 110 (12) ◽  
pp. 2873-2886 ◽  
Author(s):  
Michael Trujillo ◽  
Khaleel A. Razak

Presbycusis (age-related hearing loss) is a prevalent disability associated with aging that impairs spectrotemporal processing, but the mechanisms of such changes remain unclear. The goal of this study was to quantify cortical responses to frequency-modulated (FM) sweeps in a mouse model of presbycusis. Previous studies showed that cortical neurons in young mice are selective for the rate of frequency change in FM sweeps. Here single-unit data on cortical selectivity and response variability to FM sweeps of either direction and different rates (0.08–20 kHz/ms) were compared across young (1–3 mo), middle-aged (6–8 mo), and old (14–20 mo) groups. Three main findings are reported. First, there is a reduction in FM rate selectivity in the old group. Second, there is a slowing of the sweep rates at which neurons likely provide best detection and discrimination of sweep rates. Third, there is an increase in trial-to-trial variability in the magnitude and timing of spikes in response to sweeps. These changes were only observed in neurons that were selective for the fast or intermediate range of sweep rates and not in neurons that preferred slow sweeps or were nonselective. Increased variability of response magnitude, but not changes in temporal fidelity or selectivity, was seen even in the middle-aged group. The results show that spectrotemporal processing becomes slow and noisy with presbycusis in specific types of neurons, suggesting receptive field mechanisms that are altered. These data suggest neural correlates of presbycusis-related reduction in the ability of humans to process rapid spectrotemporal changes.


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