Effect of Adult-Onset Deafness on the Human Central Auditory System

Degenerative change in the central auditory system was assessed in seven subjects with profound bilateral adult-onset deafness. The degree of transneuronal atrophy was determined by measuring cell size at three levels of the brain stem auditory pathway (anteroventral cochlear nucleus, medial superior olivary nucleus, and inferior colliculus). Within subjects, the relative degree of cell shrinkage was similar across all levels of the central pathway. Across subjects, the best neuronal preservation was seen in a case of viral labyrinthitis with 1 year of bilateral deafness and a near-normal population of cochlear ganglion cells. Reduction in cell size was greatest in cases of bacterial labyrinthitis or Scheibe degeneration with reduced populations of ganglion cells and longer periods of deafness. At the level of the cochlear nucleus, there was no consistent difference in cell size between the side stimulated by a functioning prosthetic device and the nonstimulated side.

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Dynamic Fidelity Control to the Central Auditory System: Synergistic Glycine/GABAergic Inhibition in the Cochlear Nucleus

Journal of Neuroscience ◽

10.1523/jneurosci.0719-14.2014 ◽

2014 ◽

Vol 34 (35) ◽

pp. 11604-11620 ◽

Cited By ~ 22

Author(s):

J. Nerlich ◽

T. Kuenzel ◽

C. Keine ◽

A. Korenic ◽

R. Rubsamen ◽

...

Keyword(s):

Auditory System ◽

Cochlear Nucleus ◽

Gabaergic Inhibition ◽

Central Auditory System

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Increased Gain in the Auditory Pathway, Alzheimer’s Disease Continuum, and Air Pollution: Peripheral and Central Auditory System Dysfunction Evolves Across Pediatric and Adult Urbanites

Journal of Alzheimer s Disease ◽

10.3233/jad-190405 ◽

2019 ◽

Vol 70 (4) ◽

pp. 1275-1286 ◽

Cited By ~ 3

Author(s):

Lilian Calderón-Garcidueñas ◽

Randy J. Kulesza ◽

Yusra Mansour ◽

Mario Aiello-Mora ◽

Partha S. Mukherjee ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Air Pollution ◽

Auditory System ◽

Auditory Pathway ◽

Central Auditory System

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Abnormal spontaneous neural activity of auditory cortex and auditory pathway in tinnitus: a resting-state fMRI study

10.1101/241216 ◽

2018 ◽

Author(s):

Wei-Wei Cai ◽

Jian-Gang Liang ◽

Zhi-Hui Li ◽

Yu-lin Huang ◽

Li Wang ◽

...

Keyword(s):

Auditory Cortex ◽

Hearing Impairment ◽

Auditory System ◽

Neural Activity ◽

Resting State ◽

Auditory Pathway ◽

Homeostatic Plasticity ◽

Central Auditory System ◽

Spontaneous Neural Activity ◽

Fmri Study

AbstractThis resting-state functional magnetic resonance imaging (rs-fMRI) study in tinnitus patients was conducted to observe the spontaneous neural activity of the central auditory system using a derived index, mean amplitude of low-frequency fluctuation (mALFF). Tinnitus subjects with right-ear hearing impairment (THL) and without hearing loss (TNH) and two age-, sex-, and education-matched control groups (NC1 and NC2) were recruited for rs-fMRI. mALFF maps of the tinnitus and matched NC groups were plotted in the central auditory system, including the primary auditory cortex (PAC), higher auditory cortex (HAC), and hubs of the central auditory pathway. mALFF values of the activity clusters in the central auditory system of THL and TNH patients were extracted and correlated with each clinical characteristic. Significantly increased mALFF clusters were found in bilateral PAC and HAC of THL-NC1 maps and in the left inferior colliculus and right HAC of TNH-NC2 maps. Thus, subgroups of tinnitus with and without hearing impairment might exhibit different homeostatic plasticity in the central auditory system. mALFF values of aberrant active clusters in the central auditory system are partly associated with specific clinical tinnitus characteristics.

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Age-related changes in sound onset and offset intensity coding in auditory cortical fields A1 and CL of rhesus macaques

Journal of Neurophysiology ◽

10.1152/jn.00373.2019 ◽

2020 ◽

Vol 123 (3) ◽

pp. 1015-1025 ◽

Cited By ~ 1

Author(s):

Deepa L. Ramamurthy ◽

Gregg H. Recanzone

Keyword(s):

Auditory Cortex ◽

Auditory System ◽

Rhesus Macaques ◽

Auditory Pathway ◽

Neuronal Firing ◽

Elderly Subjects ◽

Central Auditory System ◽

Rate Level ◽

Intensity Coding ◽

Age Related

Inhibition plays a key role in shaping sensory processing in the central auditory system and has been implicated in sculpting receptive field properties such as sound intensity coding and also in shaping temporal patterns of neuronal firing such as onset- or offset-evoked responses. There is substantial evidence supporting a decrease in inhibition throughout the ascending auditory pathway in geriatric animals. We therefore examined intensity coding of onset (ON) and offset (OFF) responses in auditory cortex of aged and young monkeys. A large proportion of cells in the primary auditory cortex (A1) and the caudolateral field (CL) displayed nonmonotonic rate-level functions for OFF responses in addition to nonmonotonic coding of ON responses. Aging differentially affected ON and OFF responses; the magnitude of effects was generally greater for ON responses. In addition to higher firing rates, neurons in old monkeys exhibited a significant increase in the proportion of monotonic rate-level functions and had higher best intensities than those in young monkeys. OFF responses in young monkeys displayed a range of intensity coding relationships with ON responses of the same cells, ranging from highly similar to highly dissimilar. Dissimilarity in ON/OFF coding was greater in CL and was reduced with aging, which was largely explained by a preferential decrease in the percentage of cells with nonmonotonic coding of ON and OFF responses. The changes we observed are consistent with previously demonstrated alterations in inhibition in the ascending auditory pathway of primates and could be involved in age-related deficits in the temporal processing of sounds. NEW & NOTEWORTHY Aging has a major impact on intensity coding of neurons in auditory cortex of rhesus macaques. Neural responses to sound onset and offset were affected to different extents, and their rate-level functions became more mutually similar, which could be accounted for by the loss of nonmonotonic intensity coding in geriatric monkeys. These findings were consistent with weakened inhibition in the central auditory system and could contribute to auditory processing deficits in elderly subjects.

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Evaluation of Efferent Auditory System and Hearing Quality in Parkinson's Disease: Is the Difficulty in Speech Understanding in Complex Listening Conditions Related to Neural Degeneration or Aging?

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-20-00337 ◽

2020 ◽

pp. 1-9

Author(s):

Nuriye Yıldırım Gökay ◽

Bülent Gündüz ◽

Fatih Söke ◽

Recep Karamert

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Auditory System ◽

Otoacoustic Emissions ◽

Pure Tone ◽

Pure Tone Audiometry ◽

Auditory Pathway ◽

Normal Hearing ◽

System Function ◽

Distortion Product

Purpose The effects of neurological diseases on the auditory system have been a notable issue for investigators because the auditory pathway is closely associated with neural systems. The purposes of this study are to evaluate the efferent auditory system function and hearing quality in Parkinson's disease (PD) and to compare the findings with age-matched individuals without PD to present a perspective on aging. Method The study included 35 individuals with PD (mean age of 48.50 ± 8.00 years) and 35 normal-hearing peers (mean age of 49 ± 10 years). The following tests were administered for all participants: the first section of the Speech, Spatial and Qualities of Hearing Scale; pure-tone audiometry, speech audiometry, tympanometry, and acoustic reflexes; and distortion product otoacoustic emissions (DPOAEs) and contralateral suppression of DPOAEs. SPSS Version 25 was used for statistical analyses, and values of p < .05 were considered statistically significant. Results There were no statistically significant differences in the pure-tone audiometry thresholds and DPOAE responses between the individuals with PD and their normal-hearing peers ( p = .732). However, statistically significant differences were found between the groups in suppression levels of DPOAEs and hearing quality ( p < .05). In addition, a statistically significant and positive correlation was found between the amount of suppression at some frequencies and the Speech, Spatial and Qualities of Hearing Scale scores. Conclusions This study indicates that medial olivocochlear efferent system function and the hearing quality of individuals with PD were affected adversely due to the results of PD pathophysiology on the hearing system. For optimal intervention and follow-up, tasks related to hearing quality in daily life can also be added to therapies for PD.

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