Efferent auditory pathways modulate outer hair cells of the cochlea, protect against noise, and improve the detection of sound sources in noisy environments. Genotoxicity is DNA damage. To study the association between auditory pathway efferent functions with genotoxic markers. The study also considered smoking and gender as two main variables. A prospective-clinical, quantitative, cross-sectional, contemporary study. The function of efferent auditory pathways and genotoxicity tests in 60 healthy young subjects were assessed. The mean age of subjects was 24.86 years +/- 3.68 years; there were 30 males and 30 females, 15 of each gender smokers and 15 non-smokers. Male smokers had a higher incidence of DPOEA suppression effect at 2000 and 6000 Hz in the left ear; female smokers had a higher prevalence of complaints of difficulty to hear in noisy environments; smokers and women had a higher mean DNA damage; subjects with complaints of hearing loss and tinnitus had higher genotoxicity. In young normal-hearing adults that complain about efferent auditory pathways functions, such as tinnitus and hearing impairment, there are possible associations with genotoxicity; interactions between gender and smoking are considered.
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http://dx.doi.org/10.1590/s1808-86942011000100018 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Neurobiology, Harvard Medical School, Boston, MA 02115.
The sense of hearing originates in the cochlea, which detects sounds across dynamic sensory environments. Like other peripheral organs, the cochlea is subjected to environmental insults, including loud, damage-inducing sounds. In response to internal and external stimuli, the central nervous system directly modulates cochlear function through olivocochlear neurons (OCNs), which are located in the brainstem and innervate the cochlear sensory epithelium.
View Article and Find Full Text PDFPLoS One
January 2025
Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil.
Background And Objective: One of the functions attributed to the auditory efferent system is related to the processing of acoustic stimuli in noise backgrounds. However, clinical implications and the neurophysiological mechanisms of this system are not yet understood, especially on higher regions of the central nervous system. Only a few researchers studied the effects of noise on cortical auditory evoked potentials (CAEP), but the lack of studies in this area and the contradictory results, especially in children, point to the need to investigate different protocols and parameters that could allow the study of top-down activity in humans.
View Article and Find Full Text PDFNoise Health
January 2025
Department of Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey.
Background: Patients with multiple sclerosis (MS) experience difficulties in understanding speech in noise despite having normal hearing.
Aim: This study aimed to determine the relationship between speech discrimination in noise (SDN) and medial olivocochlear reflex levels and to compare MS patients with a control group.
Material And Methods: Sixty participants with normal hearing, comprising 30 MS patients and 30 healthy controls, were included.
Front Cell Neurosci
November 2024
Department of Physiology, University of Kentucky, Lexington, KY, United States.
Introduction: Mammalian hearing depends on the dual mechanosensory and motor functions of cochlear hair cells. Both these functions may be regulated by Ca release from intracellular stores. However, it is still unclear how exactly intracellular Ca release may affect either hair cell mechano-electrical transduction (MET) or prestin-dependent electromotility in outer hair cells (OHCs).
View Article and Find Full Text PDFJCI Insight
December 2024
School of Biosciences, University of Sheffield, Sheffield, United Kingdom.
In the mammalian cochlea, sensory hair cells are crucial for the transduction of acoustic stimuli into electrical signals, which are then relayed to the central auditory pathway via spiral ganglion neuron (SGN) afferent dendrites. The SGN output is directly modulated by inhibitory cholinergic axodendritic synapses from the efferent fibers originating in the superior olivary complex. When the adult cochlea is subjected to noxious stimuli or aging, the efferent system undergoes major rewiring, such that it reestablishes direct axosomatic contacts with the inner hair cells (IHCs), which occur only transiently during prehearing stages of development.
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