Age-related hearing loss: ear and brain mechanisms.

Otolaryngology Department, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642-8629, USA.
Annals of the New York Academy of Sciences (Impact Factor: 4.31). 08/2009; 1170:708-17. DOI: 10.1111/j.1749-6632.2009.03931.x
Source: PubMed

ABSTRACT Loss of sensory function in the aged has serious consequences for economic productivity, quality of life, and healthcare costs in the billions each year. Understanding the neural and molecular bases will pave the way for biomedical interventions to prevent, slow, or reverse these conditions. This chapter summarizes new information regarding age changes in the auditory system involving both the ear (peripheral) and brain (central). A goal is to provide findings that have implications for understanding some common biological underpinnings that affect sensory systems, providing a basis for eventual interventions to improve overall sensory functioning, including the chemical senses.

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    ABSTRACT: Objective. Considering that both age-related hearing loss (presbycusis) and type 2 diabetes (DM2) are significant health issues, it is worthwhile to examine the relationship between the two. After evaluating the existing literature, it was evident that there have not been sufficient prospective studies about presbycusis and DM2 that include elderly participants. Therefore, the aim of this study was to focus on and evaluate the interaction between DM2 and presbycusis in an elderly population. Material and methods. The current study included 93 DM2 subjects, 65–89 years of age, as well as a control group of 90 non-diabetic subjects, aged 65–85 years of age, who were matched to the DM2 subjects by age and sex. Results. The current investigation produced five major findings: (1) the diabetics had higher thresholds for all frequencies, except 0.25 kHz, compared to the controls; (2) although there were significant differences at low frequencies, such as 0.5 and 1 kHz, the differences were most pronounced at 2, 4, and 8 kHz; (3) the thresholds for speech reception were significantly higher in the diabetics than in the controls; (4) there were no side differences between the right and left ears in the diabetics or the controls; and (5) the diabetics had lower speech discrimination scores than the controls, which is a finding for cochlear and/or retrocochlear pathology. Conclusion. This study convincingly demonstrates the contribution of DM2 to presbycusis as a factor in the acceleration of the aging process of auditory system. Keywords. age-related hearing loss; presbycusis; type 2 diabetes; geriatric; audiometric measurements
    Journal of International Advanced Otology 04/2014; 10(1):72-75. DOI:10.5152/iao.2014.016 · 0.13 Impact Factor
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    ABSTRACT: Aging is associated with deficits in the ability to ignore distractions, which has not yet been remediated by any neurotherapeutic approach. Here, in parallel auditory experiments with older rats and humans, we evaluated a targeted cognitive training approach that adaptively manipulated distractor challenge. Training resulted in enhanced discrimination abilities in the setting of irrelevant information in both species that was driven by selectively diminished distraction-related errors. Neural responses to distractors in auditory cortex were selectively reduced in both species, mimicking the behavioral effects. Sensory receptive fields in trained rats exhibited improved spectral and spatial selectivity. Frontal theta measures of top-down engagement with distractors were selectively restrained in trained humans. Finally, training gains generalized to group and individual level benefits in aspects of working memory and sustained attention. Thus, we demonstrate converging cross-species evidence for training-induced selective plasticity of distractor processing at multiple neural scales, benefitting distractor suppression and cognitive control. Copyright © 2014 Elsevier Inc. All rights reserved.
    Neuron 12/2014; 84(5):1091-103. DOI:10.1016/j.neuron.2014.10.034 · 15.98 Impact Factor
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    ABSTRACT: Objective This study was conducted to determine the concentration of EPCs in patients with ARHL. Methods Twenty patients with ARHL were evaluated. The number of EPCs was analyzed by flow cytometry analysis of peripheral blood CD34+/CD133+ cells. Results The concentration of circulating EPCs, both for CD34+/CD133+ cells, were significantly lower in ARHL patients compared to controls (p < 0.05). No statistically significant differences were found between these two groups in terms of the level of total cholesterol, LDL, HDL, triglycerides and GLU. Conclusions The possible role of circulating epithelial progenitor cells in the pathogenesis of age related hearing loss should be considered based on their significant reduction in patients with ARHL, although the association alone does not prove causality. Further studies were warranted to confirm the role of circulating EPCs in the pathogenesis of ARHL.
    American Journal of Otolaryngology 08/2014; 35(6). DOI:10.1016/j.amjoto.2014.08.005 · 1.08 Impact Factor


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Jul 16, 2014