Functional changes in the human auditory cortex in ageing (original) (raw)
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Aging effects on functional auditory and visual processing using fMRI with variable sensory loading
Cortex, 2013
Visual sensory processing Auditory sensory processing fMRI a b s t r a c t Introduction: Traditionally, studies investigating the functional implications of age-related structural brain alterations have focused on higher cognitive processes; by increasing stimulus load, these studies assess behavioral and neurophysiological performance. In order to understand age-related changes in these higher cognitive processes, it is crucial to examine changes in visual and auditory processes that are the gateways to higher cognitive functions. This study provides evidence for age-related functional decline in visual and auditory processing, and regional alterations in functional brain processing, using non-invasive neuroimaging.
ABSTRACTObjectiveTo understand the effect of peripheral hearing loss on the representation of speech in noise in the aging midbrain and cortex.MethodsSubjects comprised 17 normal-hearing younger adults, 15 normal-hearing older adults and 14 hearing-impaired older adults. The midbrain response, measured with Frequency-Following Responses (FFRs), and the cortical response, measured with magnetoencephalography (MEG) responses, were recorded from subjects listening to speech in quiet and noise at varying signal to noise ratios (SNRs).ResultsBoth groups of older listeners showed both weaker midbrain response amplitudes and overrepresentation of cortical responses compared to younger listeners. However, significant differences between the older groups were found in both midbrain-cortex relationships and in cortical processing durations, suggesting that hearing loss may alter reciprocal connections between lower and higher levels of the auditory pathway.ConclusionsThe paucity of difference...
Impact of Aging on the Auditory System and Related Cognitive Functions: A Narrative Review
Frontiers in neuroscience, 2018
Age-related hearing loss (ARHL), presbycusis, is a chronic health condition that affects approximately one-third of the world's population. The peripheral and central hearing alterations associated with age-related hearing loss have a profound impact on perception of verbal and non-verbal auditory stimuli. The high prevalence of hearing loss in the older adults corresponds to the increased frequency of dementia in this population. Therefore, researchers have focused their attention on age-related central effects that occur independent of the peripheral hearing loss as well as central effects of peripheral hearing loss and its association with cognitive decline and dementia. Here we review the current evidence for the age-related changes of the peripheral and central auditory system and the relationship between hearing loss and pathological cognitive decline and dementia. Furthermore, there is a paucity of evidence on the relationship between ARHL and established biomarkers of Al...
Age-related changes in the central auditory system
Cell and Tissue Research, 2015
Aging is accompanied by the deterioration of hearing that complicates our understanding of speech, especially in noisy environments. This deficit is partially caused by the loss of hair cells as well as by the dysfunction of the stria vascularis. However, the central part of the auditory system is also affected by processes accompanying aging that may run independently of those affecting peripheral receptors. Here, we review major changes occurring in the central part of the auditory system during aging. Most of the information that is focused on age-related changes in the central auditory system of experimental animals arises from experiments using immunocytochemical targeting on changes in the glutamic-aciddecarboxylase, parvalbumin, calbindin and calretinin. These data are accompanied by information about age-related changes in the number of neurons as well as about changes in the behavior of experimental animals. Aging is in principle accompanied by atrophy of the gray as well as white matter, resulting in the enlargement of the cerebrospinal fluid space. The human auditory cortex suffers not only from atrophy but also from changes in the content of some metabolites in the aged brain, as shown by magnetic resonance spectroscopy. In addition to this, functional magnetic resonance imaging reveals differences between activation of the central auditory system in the young and old brain. Altogether, the information reviewed in this article speaks in favor of specific age-related changes in the central auditory system that occur mostly independently of the changes in the inner ear and that form the basis of the central presbycusis.
Aging and cortical mechanisms of speech perception in noise
Neuropsychologia, 2009
Spoken language processing in noisy environments, a hallmark of the human brain, is subject to agerelated decline, even when peripheral hearing might be intact. The present study examines the cortical cerebral hemodynamics (measured by fMRI) associated with such processing in the aging brain. Younger and older subjects identified single words in quiet and in two multi-talker babble noise conditions (SNR 20 and −5 dB). Behaviorally, older and younger subjects did not show significant differences in the first two conditions but older adults performed less accurately in the SNR -5 condition. The fMRI results showed reduced activation in the auditory cortex but an increase in working memory and attention-related cortical areas (prefrontal and precuneus regions) in older subjects, especially in the SNR -5 condition. Increased cortical activities in general cognitive regions were positively correlated with behavioral performance in older listeners, suggestive of a compensatory strategy. Furthermore, inter-regional correlation revealed that while younger subjects showed a more streamlined cortical network of auditory regions in response to spoken word processing in noise, older subjects showed a more diffused network involving frontal and ventral brain regions. These results are consistent with the decline-compensation hypothesis, suggestive of its applicability to the auditory domain.
einstein (São Paulo), 2022
Objective: To analyze age-related changes in the central auditory pathway in healthy elderly individuals. Methods: A prospective, quantitative cross-sectional study. The caseload comprised 18 adults (mean age, 22.78 years) and 18 elderly individuals (mean age, 66.72 years) of both sexes, who met inclusion criteria. Subjects were submitted to basic audiological evaluation and related electrophysiologic tests: brainstem auditory evoked potential with click stimulus and frequency-following response. Results: Elderly individuals had higher wave and interpeak latencies (waves I, III and V and interpeaks I-V and III-V) of brainstem auditory evoked potential. Latencies of frequency following response waves A, E, F and O were also higher in elderly individuals. Frequency following response amplitudes were better in A than in D, F and O waves in these subjects. Likewise, interpeak intervals (V-A and V-O) were larger in elderly relative to adult individuals. Lower slope values were observed in elderly individuals. Conclusion: Brainstem auditory evoked potential and frequency-following response allowed appropriate assessment of age-related changes in the auditory pathway. Slower neural response to auditory stimuli suggests reduced synchrony between neural structures.
Neuroanatomical Characteristics and Speech Perception in Noise in Older Adults
Ear and Hearing, 2010
Objectives-Previous research has attributed older adult's difficulty with perceiving speech in noise to peripheral hearing loss. Recent studies have suggested a more complex picture, however, and implicate the central nervous system in sensation and sensory deficits. This study examines the relationship between the neuroanatomical structure of cognitive regions and the ability to perceive speech in noise in older adults. In particular, the neuroanatomical characteristics of the left ventral and dorsal prefrontal cortex are considered relative to standard measures of hearing in noise.
Auditory temporal processing in healthy aging: a magnetoencephalographic study
BMC Neuroscience, 2009
Impaired speech perception is one of the major sequelae of aging. In addition to peripheral hearing loss, central deficits of auditory processing are supposed to contribute to the deterioration of speech perception in older individuals. To test the hypothesis that auditory temporal processing is compromised in aging, auditory evoked magnetic fields were recorded during stimulation with sequences of 4 rapidly recurring speech sounds in 28 healthy individuals aged 20-78 years.
Auditory function in presbycusis: peripheral vs. central changes
Experimental Gerontology, 2003
The hearing abilities of a group of 30 elderly (67–93yr of age) subjects were compared with those of a group of 30 young (19–27yr of age) normal hearing volunteers with the aim of characterizing the changes in the peripheral and central parts of the auditory system. In elderly subjects the pure-tone thresholds were typically represented by a gradually sloping curve