scholarly journals A large-scale diffusion imaging study of tinnitus and hearing loss

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rafay A. Khan ◽  
Bradley P. Sutton ◽  
Yihsin Tai ◽  
Sara A. Schmidt ◽  
Somayeh Shahsavarani ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Neural Plasticity ◽  
Large Scale ◽  
Diffusion Imaging ◽  
Structural Connectivity ◽  
Mean Diffusivity ◽  
Imaging Study ◽  
Normal Hearing ◽  
Imaging Data ◽  
Difficult Condition

AbstractSubjective, chronic tinnitus, the perception of sound in the absence of an external source, commonly occurs with many comorbidities, making it a difficult condition to study. Hearing loss, often believed to be the driver for tinnitus, is perhaps one of the most significant comorbidities. In the present study, white matter correlates of tinnitus and hearing loss were examined. Diffusion imaging data were collected from 96 participants—43 with tinnitus and hearing loss (TINHL), 17 with tinnitus and normal hearing thresholds (TINNH), 17 controls with hearing loss (CONHL) and 19 controls with normal hearing (CONNH). Fractional anisotropy (FA), mean diffusivity and probabilistic tractography analyses were conducted on the diffusion imaging data. Analyses revealed differences in FA and structural connectivity specific to tinnitus, hearing loss, and both conditions when comorbid, suggesting the existence of tinnitus-specific neural networks. These findings also suggest that age plays an important role in neural plasticity, and thus may account for some of the variability of results in the literature. However, this effect is not seen in tractography results, where a sensitivity analysis revealed that age did not impact measures of network integration or segregation. Based on these results and previously reported findings, we propose an updated model of tinnitus, wherein the internal capsule and corpus callosum play important roles in the evaluation of, and neural plasticity in response to tinnitus.

scholarly journals Group-Level Ranking-Based Hubness Analysis of Human Brain Connectome Reveals Significant Interhemispheric Asymmetry and Intraparcel Heterogeneities

2021 ◽  
Vol 15 ◽  
Author(s):  
Sahin Hanalioglu ◽  
Siyar Bahadir ◽  
Ilkay Isikay ◽  
Pinar Celtikci ◽  
Emrah Celtikci ◽  
...  
Keyword(s):  
Human Brain ◽  
Diffusion Imaging ◽  
Structural Connectivity ◽  
Population Level ◽  
Similar Distribution ◽  
Group Level ◽  
Imaging Data ◽  
Brain Connectome ◽  
Human Connectome Project ◽  
Intuitive Method

Objective: Graph theory applications are commonly used in connectomics research to better understand connectivity architecture and characterize its role in cognition, behavior and disease conditions. One of the numerous open questions in the field is how to represent inter-individual differences with graph theoretical methods to make inferences for the population. Here, we proposed and tested a simple intuitive method that is based on finding the correlation between the rank-ordering of nodes within each connectome with respect to a given metric to quantify the differences/similarities between different connectomes.Methods: We used the diffusion imaging data of the entire HCP-1065 dataset of the Human Connectome Project (HCP) (n = 1,065 subjects). A customized cortical subparcellation of HCP-MMP atlas (360 parcels) (yielding a total of 1,598 ROIs) was used to generate connectivity matrices. Six graph measures including degree, strength, coreness, betweenness, closeness, and an overall “hubness” measure combining all five were studied. Group-level ranking-based aggregation method (“measure-then-aggregate”) was used to investigate network properties on population level.Results: Measure-then-aggregate technique was shown to represent population better than commonly used aggregate-then-measure technique (overall rs: 0.7 vs 0.5). Hubness measure was shown to highly correlate with all five graph measures (rs: 0.88–0.99). Minimum sample size required for optimal representation of population was found to be 50 to 100 subjects. Network analysis revealed a widely distributed set of cortical hubs on both hemispheres. Although highly-connected hub clusters had similar distribution between two hemispheres, average ranking values of homologous parcels of two hemispheres were significantly different in 71% of all cortical parcels on group-level.Conclusion: In this study, we provided experimental evidence for the robustness, limits and applicability of a novel group-level ranking-based hubness analysis technique. Graph-based analysis of large HCP dataset using this new technique revealed striking hemispheric asymmetry and intraparcel heterogeneities in the structural connectivity of the human brain.

scholarly journals White-matter integrity and hearing acuity decline in healthy subjects: Magnetic resonance tractography

2020 ◽  
Vol 33 (3) ◽  
pp. 236-243
Author(s):  
Fahad H Alhazmi
Keyword(s):  
Hearing Loss ◽  
White Matter ◽  
Pure Tone ◽  
Structural Connectivity ◽  
Normal Hearing ◽  
Anxiety And Depression ◽  
Healthy Population ◽  
Hearing Acuity ◽  
The Right ◽  
Moderate Hearing Loss

Aim The association between hearing acuity and white-matter (WM) microstructure integrity was evaluated in a normal healthy population with a variety of hearing acuity using an automated tractography technique known as TRACULA (TRActs Constrained by UnderLying Anatomy) in order to investigate whether hearing acuity decline is correlated with brain structural connectivity. Methods Forty healthy controls were recruited to this study, which used a Siemens 3T Trio with a standard eight-channel head coil. Hearing acuity was assessed using pure-tone air conduction audiometry (Amplivox 2160, with Audiocups to eliminate noise and allow accurate pure-tone audiometry). Handedness and anxiety and depression were assessed for all participants in this study using the Edinburgh Handedness Inventory and the Hospital Anxiety and Depression Scale, respectively. Results This study showed a significant reduction in WM volume of the left cingulum angular bundle (CAB; t = 2.32, p = 0.02) in the mild to moderate hearing-loss group (238 ± 223 mm2) compared to the group with normal hearing (105  ± 121 mm2). The WM integrity of the left CAB was found to be significantly different ( t = 2.06, p = 0.04) in the mild to moderate hearing-loss group (0.18 ± 0.06 mm2/s) compared to the group with normal hearing (0.22 ± 0.05 mm2/s). The WM integrity of the left anterior thalamic radiation (ATR) was found to be significantly different ( t = 2.58, p = 0.014) in the mild to moderate hearing-loss group (0.33 ± 0.05 mm2/s) compared to the group with normal hearing (0.37 ± 0.03 mm2/s). A significant negative correlation was found between age and the WM integrity of the right ATR ( r = −0.33, p = 0.038), and between hearing acuity and the WM integrity of the right ATR ( r = −0.38, p = 0.013) and left CAB ( r = −0.36, p = 0.019). Discussion and conclusion: An important finding in this study is that brain structural connectivity changes in the left hemisphere seem to be associated with age-related hearing loss found mainly in the ATR and CAB tracts.

scholarly journals Development of brain structural connectivity between ages 12 and 30: A 4-Tesla diffusion imaging study in 439 adolescents and adults

NeuroImage ◽  
2013 ◽  
Vol 64 ◽  
pp. 671-684 ◽  
Author(s):  
Emily L. Dennis ◽  
Neda Jahanshad ◽  
Katie L. McMahon ◽  
Greig I. de Zubicaray ◽  
Nicholas G. Martin ◽  
...  
Keyword(s):  
Diffusion Imaging ◽  
Structural Connectivity ◽  
Imaging Study ◽  
Adolescents And Adults

scholarly journals Multifactorial Dynamics of White Matter Connectivity During Adolescence

2017 ◽  
Author(s):  
Birkan Tunç ◽  
Drew Parker ◽  
Russell T. Shinohara ◽  
Mark A. Elliott ◽  
Kosha Ruparel ◽  
...  
Keyword(s):  
White Matter ◽  
Expression Profiles ◽  
Community Sample ◽  
Diffusion Imaging ◽  
Structural Connectivity ◽  
Brain Network ◽  
Rapid Expansion ◽  
Imaging Data ◽  
Behavioral Repertoire ◽  
White Matter Connectivity

AbstractStudying developmental changes in white matter connectivity is critical for understanding neurobiological substrates of cognition, learning, and neuropsychiatric disorders. This becomes especially important during adolescence when a rapid expansion of the behavioral repertoire occurs. Several factors such as brain geometry, genetic expression profiles, and higher level architectural specifications such as the presence of segregated modules have been associated with the observed organization of white matter connections. However, we lack understanding of the extent to which such factors jointly describe the brain network organization, nor have insights into how their contribution changes developmentally. We constructed a multifactorial model of white matter connectivity using Bayesian network analysis and tested it with diffusion imaging data from a large community sample. We investigated contributions of multiple factors in explaining observed connectivity, including architectural specifications, which promote a modular yet integrative organization, and brain’s geometric and genetic features. Our results demonstrated that the initially dominant geometric and genetic factors become less influential with age, whereas the effect of architectural specifications increases. The identified structural modules are associated with well-known functional systems, and the level of association increases with age. This integrative analysis provides a computational characterization of the normative evolution of structural connectivity during adolescence.

scholarly journals Identification of the Spectrotemporal Modulations That Support Speech Intelligibility in Hearing-Impaired and Normal-Hearing Listeners

2019 ◽  
Vol 62 (4) ◽  
pp. 1051-1067 ◽  
Author(s):  
Jonathan H. Venezia ◽  
Allison-Graham Martin ◽  
Gregory Hickok ◽  
Virginia M. Richards
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Speech Intelligibility ◽  
Large Scale ◽  
Recognition Performance ◽  
Recognition Task ◽  
Small Region ◽  
Normal Hearing ◽  
Hearing Impaired ◽  
Age Related

Purpose Age-related sensorineural hearing loss can dramatically affect speech recognition performance due to reduced audibility and suprathreshold distortion of spectrotemporal information. Normal aging produces changes within the central auditory system that impose further distortions. The goal of this study was to characterize the effects of aging and hearing loss on perceptual representations of speech. Method We asked whether speech intelligibility is supported by different patterns of spectrotemporal modulations (STMs) in older listeners compared to young normal-hearing listeners. We recruited 3 groups of participants: 20 older hearing-impaired (OHI) listeners, 19 age-matched normal-hearing listeners, and 10 young normal-hearing (YNH) listeners. Listeners performed a speech recognition task in which randomly selected regions of the speech STM spectrum were revealed from trial to trial. The overall amount of STM information was varied using an up–down staircase to hold performance at 50% correct. Ordinal regression was used to estimate weights showing which regions of the STM spectrum were associated with good performance (a “classification image” or CImg). Results The results indicated that (a) large-scale CImg patterns did not differ between the 3 groups; (b) weights in a small region of the CImg decreased systematically as hearing loss increased; (c) CImgs were also nonsystematically distorted in OHI listeners, and the magnitude of this distortion predicted speech recognition performance even after accounting for audibility; and (d) YNH listeners performed better overall than the older groups. Conclusion We conclude that OHI/older normal-hearing listeners rely on the same speech STMs as YNH listeners but encode this information less efficiently. Supplemental Material https://doi.org/10.23641/asha.7859981

When Hearing Does Not Mean Understanding: On the Neural Processing of Syntactically Complex Sentences by Listeners With Hearing Loss

2021 ◽  
pp. 1-13
Author(s):  
Margreet Vogelzang ◽  
Christiane M. Thiel ◽  
Stephanie Rosemann ◽  
Jochem W. Rieger ◽  
Esther Ruigendijk
Keyword(s):  
Hearing Loss ◽  
Sentence Processing ◽  
Secondary Task ◽  
Sentence Comprehension ◽  
Inferior Frontal Gyrus ◽  
Normal Hearing ◽  
Cognitive Demands ◽  
Sentence Complexity ◽  
Complex Sentences ◽  
And Task

Purpose Adults with mild-to-moderate age-related hearing loss typically exhibit issues with speech understanding, but their processing of syntactically complex sentences is not well understood. We test the hypothesis that listeners with hearing loss' difficulties with comprehension and processing of syntactically complex sentences are due to the processing of degraded input interfering with the successful processing of complex sentences. Method We performed a neuroimaging study with a sentence comprehension task, varying sentence complexity (through subject–object order and verb–arguments order) and cognitive demands (presence or absence of a secondary task) within subjects. Groups of older subjects with hearing loss ( n = 20) and age-matched normal-hearing controls ( n = 20) were tested. Results The comprehension data show effects of syntactic complexity and hearing ability, with normal-hearing controls outperforming listeners with hearing loss, seemingly more so on syntactically complex sentences. The secondary task did not influence off-line comprehension. The imaging data show effects of group, sentence complexity, and task, with listeners with hearing loss showing decreased activation in typical speech processing areas, such as the inferior frontal gyrus and superior temporal gyrus. No interactions between group, sentence complexity, and task were found in the neuroimaging data. Conclusions The results suggest that listeners with hearing loss process speech differently from their normal-hearing peers, possibly due to the increased demands of processing degraded auditory input. Increased cognitive demands by means of a secondary visual shape processing task influence neural sentence processing, but no evidence was found that it does so in a different way for listeners with hearing loss and normal-hearing listeners.

An Evaluation of the Relationship between Retinal Nerve Fiber Thickness, Cochlear Nerve Thickness, the Level of Tinnitus, and Hearing Loss in Unilateral Tinnitus Patients

2021 ◽  
pp. 1-8
Author(s):  
Mustafa Avcu ◽  
Mehmet Metin ◽  
Raşit Kılıç ◽  
Muhammed Alpaslan
Keyword(s):  
Hearing Loss ◽  
Nerve Fiber ◽  
Normal Hearing ◽  
Cochlear Nerve ◽  
Significant Difference ◽  
The Relationship ◽  
Fiber Thickness ◽  
Moderate Hearing Loss ◽  
Group 1 ◽  
Retinal Nerve Fiber

Background: In this study, optic coherence tomography (OCT) examination was performed to check whether there was any interaction between ophthalmic axonal structures in unilateral tinnitus patients, and the relationship between optic nerve thickness and cochlear nerve thickness was evaluated. Objective: The aim of the study was to evaluate the relatioship between hearing loss, tinnitus, and nerve thicknesses. Study Design: Prospective study. Setting: Tertiary referral university hospital. Patients: The study included 88 patients with unilateral tinnitus, for which no organic cause could be found in physical examination, psychiatric evaluation, or with imaging methods. Study groups were formed of the tinnitus side and control groups were formed of the healthy side as follows: Group 1 (Non-tinnitus side normal hearing values – n = 30), Group 2 (non-tinnitus side minimal hearing loss – n = 27), Group 3 (non-tinnitus side moderate hearing loss – n = 31), Group 4 (tinnitus side normal hearing values – n = 25), Group 5 (tinnitus side minimal hearing loss – n = 25), and Group 6 (tinnitus side moderate hearing loss – n = 38). Intervention: Retinal nerve fiber layer (RNFL) thickness was evaluated with OCT, and the cochlear nerve cross-sectional area was evaluated with MRI. Main Outcome Measures: RNFL measurements were taken with OCT from the subfoveal area (RNFL-SF) and 1.5 mm temporal to the fovea (RNFL-T µm) and nasal (RNFL-N µm) sectors. On MRI, 3 measurements were taken along the nerve from the cerebellopontine angle as far as the internal auditory canal, and the mean value of these 3 measurements was calculated. Results: When the groups were evaluated in respect of cochlear nerve thickness, a significant difference was seen between Group 1 and both the groups with hearing loss and the tinnitus groups. In the subgroup analysis, a statistically significant difference was determined between Group 1 and Groups 3, 4, 5, and 6 (p = 0.013, p = 0.003, p < 0.001, and p < 0.001, respectively). When the groups were evaluated in respect of the RNFL-SF (µm), RNFL-T (µm), and RNFL-N (µm) values, the differences were determined to be statistically significant (p < 0.001 for all). In the correlation analysis, a negative correlation was determined between hearing loss and cochlear nerve diameter (r: −0.184, p = 0.014), and RNFL-N (r: −0.272, p < 0.001) and between tinnitus and cochlear nerve diameter (r: −0.536, p < 0.001), and RNFL-T (r: −0.222, p < 0.009). Conclusion: The study results clearly showed a relationship between cochlear nerve fiber thickness and hearing loss and the severity of tinnitus in cases with unilateral tinnitus and that there could be neurodegenerative factors in the disease etiology. A similar relationship seen with the RNFL supports the study hypothesis.

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