Contribution of Tinnitus and Hearing Loss to Depression: NHANES Population Study.

OBJECTIVES: Hearing loss affects the emotional well-being of adults and is sometimes associated with clinical depression. Chronic tinnitus is highly comorbid with hearing loss and separately linked with depression. In this article, the authors investigated the combined effects of hearing loss and tinnitus on depression in the presence of other moderating influences such as demographic, lifestyle, and health factors. DESIGN: The authors used the National Health and Nutrition Examination Survey data (2011-2012 and 2015-2016) to determine the effects of hearing loss and tinnitus on depression in a population of US adults (20 to 69 years). The dataset included the Patient Health Questionnaire-9 for depression screening, hearing testing using pure-tone audiometry, and information related to multiple demographic, lifestyle, and health factors (n = 5845). RESULTS: The statistical analysis showed moderate to high associations between depression and hearing loss, tinnitus, and demographic, lifestyle, and health factors, separately. Results of logistic regression analysis revealed that depression was significantly influenced by hearing loss (adjusted odds ratios [OR] = 3.0), the functional impact of tinnitus (adjusted OR = 2.4), and their interaction, both in the absence or presence of the moderating influences. The effect of bothersome tinnitus on depression was amplified in the presence of hearing loss (adjusted OR = 2.4 in the absence of hearing loss to adjusted OR = 14.9 in the presence of hearing loss). Conversely, the effect of hearing loss on depression decreased when bothersome tinnitus was present (adjusted OR = 3.0 when no tinnitus problem was present to adjusted OR = 0.7 in the presence of bothersome tinnitus). CONCLUSIONS: Together, hearing loss and bothersome tinnitus had a significant effect on self-reported depression symptoms, but their relative effect when comorbid differed. Tinnitus remained more salient than hearing loss and the latter's contribution to depression was reduced in the presence of tinnitus, but the presence of hearing loss significantly increased the effects of tinnitus on depression, even when the effects of the relevant demographic, lifestyle, or health factors were controlled. Treatment strategies that target depression should screen for hearing loss and bothersome tinnitus and provide management options for the conditions.

Misophonia and Hearing Comorbidities in a Collegiate Population.

OBJECTIVES: Misophonia is a little-understood disorder in which certain sounds cause a strong emotional response in those who experience it. People who are affected by misophonia may find that noises like loud chewing, pen clicking, and/or sniffing trigger intense frustration, anger, or discomfort. The relationship of misophonia with other auditory disorders including loudness hyperacusis, tinnitus, and hearing loss is largely underexplored. This project aimed to investigate the prevalence and hearing-health comorbidities of misophonia in a college-aged population by using an online survey. DESIGN: A total of 12,131 undergraduate and graduate students between the ages of 18 and 25 were given the opportunity to answer an in-depth online survey. These students were sampled in a roughly 50 of 50 sex distribution. The survey was created using Qualtrics and included the following components: electronic consent, demographics questionnaire, Misophonia Questionnaire (MQ), Khalfa's Hyperacusis Questionnaire (HQ), Tinnitus and Hearing Survey, and Tinnitus Functional Index (TFI). To be eligible for compensation, answers for each of the above components were required, with the exception of the TFI, which was only presented to students who indicated that they experienced tinnitus. Respondents were determined to have high or possible likelihood of having misophonia if they gave specific answers to the MQ's Emotion and Behavior Scale or the MQ Severity Scale. RESULTS: After excluding duplicate responses and age-related outliers, 1,084 responses were included in the analysis. Just over 20% (n = 217) of the sample was determined to have a high or probable likelihood of having misophonia. The sample was primarily White, female, and of mid-to-high socioeconomic status. There was a strong positive correlation between MQ total scores and HQ total scores. High likelihood misophonia status showed a significant relationship with self-reported hearing loss and tinnitus. No statistically significant relationship was found between misophonia and age, ethnicity, or socioeconomic status. MQ total scores differed significantly when separating respondents by sex, self-reported tinnitus, and loudness hyperacusis. White respondents had significantly higher MQ total scores than Asian/Asian American respondents. CONCLUSIONS: The estimated prevalence of misophonia was about 8% to 20% of the sample, which agrees with most of the currently published research examining misophonia symptoms in collegiate populations. Results of data analysis suggest that misophonia severity may be related to loudness hyperacusis, sex, and possibly tinnitus. Future studies are needed to further examine the characteristics of these relationships, possibly in populations more optimized to reflect the general population or those with hearing-health disorders.

Comparison of otoacoustic emissions in tinnitus and hyperacusis in adults with normal hearing sensitivity.

OBJECTIVE: To investigate the effect of tinnitus and/or hyperacusis on distortion product otoacoustic emission (DPOAE) measures in adults with normal hearing thresholds from 0.25 to 8 kHz, while accounting for extended high-frequency (EHF) thresholds. DESIGN: A behavioural study consisted of comprehensive audiological assessment, validated tinnitus and hyperacusis questionnaires, DPOAE amplitudes and input/output (I/O) functions. STUDY SAMPLE: Data of 56 participants with normal hearing were included for the analysis. Participants were categorised into four groups: (1) without tinnitus or hyperacusis, (2) with tinnitus only, (3) with hyperacusis only, and (4) with both tinnitus and hyperacusis. RESULTS: The groups with tinnitus showed elevated EHF thresholds compared with those without tinnitus. DPOAE amplitudes were not significantly affected by tinnitus and/or hyperacusis status; however, they were significantly affected by EHF thresholds. Further, no appreciable differences in DPOAE I/O functions were found across groups. CONCLUSIONS: The reported non-significant differences in DPOAEs in individuals with tinnitus and/or hyperacusis do not support a peripheral mechanism or an interaction between peripheral and central mechanisms underlying tinnitus or hyperacusis. Our findings, however, suggest the need to assess basal cochlear function (e.g. EHF thresholds) for a better understanding of differences in DPOAE measures in tinnitus and/or hyperacusis.

An online survey study of the association between tinnitus and hyperacusis using validated questionnaires.

OBJECTIVE: To investigate the association between the highly comorbid tinnitus and hyperacusis conditions using standard questionnaires. DESIGN: A cross-sectional internet-based survey consisted of general demographic questions, questions about hearing and emotional status, Tinnitus Primary Function Questionnaire (TPFQ), and Hyperacusis Questionnaire (HQ). STUDY SAMPLE: Six hundred sixteen completed surveys were obtained primarily from students and staff in a large university. RESULTS: About 6% of the respondents could be classified as having hyperacusis based on the criterion of HQ scores ≥ 28 and had significantly increased odds of reporting having tinnitus (OR 10.11; 95% CI 3.76-35.3). Tinnitus severity (TPFQ) and HQ scores were correlated regardless of the hearing loss status. When predicting TPFQ scores, after controlling for demographic factors and affective states, hyperacusis status became an insignificant predictor. In contrast, both affirmative answers to having anxiety and depression, together with hearing loss status and tinnitus were significant predictors of HQ scores. CONCLUSIONS: Having hyperacusis did not appear to contribute significantly to tinnitus severity, but having tinnitus contributed to the likelihood of having hyperacusis. Our findings provide a nuanced view of how tinnitus and hyperacusis conditions co-occur and influence each other, which may be valuable to clinicians and researchers.

Profiling intermittent tinnitus: a retrospective review.

Objective: We conducted a retrospective review of medical records of tinnitus patients at a tertiary ENT clinic in Groningen, Netherlands. Our goal was to identify factors that differentiated the intermittent subgroup from the larger continuous group with chronic tinnitus. Design: Tinnitus-related factors such as hearing loss, emotional aspects, and demographics were used to advance our understanding of the subgroups. We analysed the data using descriptive statistics and binomial logistic regression, supplemented by random forests classification. Study sample: Patients presenting with tinnitus visiting the tinnitus clinic. We examined 1575 medical intake records obtained at a tertiary ENT hospital. Results: Duration, total Tinnitus Handicap Inventory (THI), and THI Functional subscale scores differed significantly between the two groups. Increasing age and higher THI Emotional subscale scores were associated with an increased likelihood of intermittent tinnitus. Increases in duration, depressive scores and THI Functional and Catastrophic subscale scores, decreased the likelihood of intermittent tinnitus. Conclusions: Results from this study dissociate the factors affecting those with intermittent and those with continuous tinnitus and point to potentially different mechanisms underlying the two conditions.

Assessing mindfulness-based cognitive therapy intervention for tinnitus using behavioural measures and structural MRI: a pilot study.

Objective: We used a minimally-modified version of Mindfulness-Based Cognitive Therapy (MBCT) to treat symptoms of distress associated with tinnitus.Design: Audiological screening (establishing a baseline) was conducted prior to treatment and at three time-points: pre-intervention, post-intervention and follow-up, 8 weeks after completion of training. MRI tests were also conducted at these three time-points.Study sample: Twenty-one participants were enrolled in the study, of whom 15 completed training and audiological testing and eight completed the MRI portion of the study.Results: Scores on tinnitus-related questionnaires showed a significant decline either from pre- to post-intervention or from pre-intervention to follow-up, despite no significant change during baseline. Voxel-based morphometric analysis of the structural MRI scans revealed clusters in bilateral superior frontal gyrus that exhibited significant increases in grey matter volume over the period of intervention and follow-up. Further, grey matter changes in occipital and cingulate regions correlated with declines in tinnitus handicap.Conclusions: This pilot study supports MBCT as an adequate approach for treating distressing tinnitus and suggests that neuroanatomical changes may reflect reductions in tinnitus-related severity. Although our small sample size precludes drawing strong conclusions, there is potential for assessing neuroanatomical changes due to mindfulness-based interventions in tinnitus.

Physical Activity, Tinnitus Severity, and Improved Quality of Life.

OBJECTIVES: The objective of this study was to examine the effects of tinnitus severity on quality of life (QOL) and the benefits physical activity may have on tinnitus severity and QOL. The authors hypothesized that (1) QOL would be negatively correlated with tinnitus severity, (2) physical activity would be negatively correlated with tinnitus severity, (3) tinnitus severity and physical activity would have significant independent effects on QOL, and (4) physical activity would have significant and independent effects on tinnitus severity. DESIGN: An online survey was used to collect data from adults with tinnitus; 1030 individuals initiated the survey. Approximately 40% of responses were not included in data analysis due to incomplete data. The following measures were included in the survey: the Tinnitus Functional Index, the Godin Leisure-Time Exercise Question, the Medical Outcomes Study 36-item short form (Physical Component Score [PCS]; Mental Component Score [MCS]), and the Satisfaction with Life Scale (SWLS). Descriptive statistics, Pearson correlations, and multiple linear regression analyses were conducted. RESULTS: Higher levels of physical activity were significantly associated with improved health-related and global QOL and lower levels of tinnitus severity. Both tinnitus severity (12.3% SWLS, 3.8% PCS, and 21.2% MCS) and physical activity (1.1% SWLS, 5.8% PCS, and 1.1% MCS) accounted for significant unique variations in the QOL measures. Physical activity accounted (0.8% Tinnitus Functional Index) for significant unique variation in tinnitus severity. CONCLUSIONS: Physical activity had a small but statistically significant correlation with QOL and tinnitus distress. Our results suggest that physical activity may be a management strategy for those with tinnitus, but further testing is necessary to assess the relationship between physical activity and tinnitus severity.

Neural Plasticity of Mild Tinnitus: An fMRI Investigation Comparing Those Recently Diagnosed with Tinnitus to Those That Had Tinnitus for a Long Period of Time.

Objectives. The aim of the study was to compare differences in neural correlates of tinnitus in adults with recent onset and others who had the disorder for longer than a year. Design. A total of 25 individuals with tinnitus were divided into groups based on the amount of time for which they had experienced tinnitus: <1 year (RTIN) or >1 year (LTIN). Subjects underwent an fMRI scan while listening to affective sounds from the International Affective Digital Sounds database. Resting state functional connectivity data were also collected. Results. The RTIN group recruited the posterior cingulate and insula to a greater extent than the LTIN group when processing affective sounds. In addition, we found that the LTIN group engaged more frontal regions when listening to the stimuli compared to the RTIN group. Lastly, we found increased correlations between the default mode network and the precuneus in RTIN patients compared to LTIN at rest. Conclusion. Our results suggest that the posterior cingulate and insula may be associated with an early emotional reaction to tinnitus in both task and resting states. Over time, tinnitus patients may recruit more frontal regions to better control their emotional response and exhibit altered connectivity in the default mode network.

Comprehensive Characterization of Hearing Loss and Tinnitus in Military-Affiliated and Non-Military-Affiliated Individuals.

PURPOSE: Military-affiliated individuals (MIs) are at a higher risk of developing hearing loss and tinnitus. While these disorders are well-studied in MIs, their impact relative to non-military-affiliated individuals (non-MIs) remains understudied. Our study compared hearing, speech-in-noise (SIN) perception, and tinnitus characteristics between MIs and non-MIs. METHOD: MIs (n = 84) and non-MIs (n = 193) underwent hearing threshold assessment and Quick Speech-in-Noise Test. Participants with tinnitus completed psychoacoustic tinnitus matching, numeric rating scale (NRS) for loudness and annoyance, and Tinnitus Functional Index. Comorbid conditions such as anxiety, depression, and hyperacusis were assessed. We used a linear mixed-effects model to compare hearing thresholds and SIN scores between MIs and non-MIs. A multivariate analysis of variance compared tinnitus characteristics between MIs and non-MIs, and a stepwise regression was performed to identify predictors of tinnitus severity. RESULTS: MIs exhibited better hearing sensitivity than non-MIs; however, their SIN scores were similar. MIs matched their tinnitus loudness to a lower intensity than non-MIs, but their loudness ratings (NRS) were comparable. MIs reported greater tinnitus annoyance and severity on the relaxation subscale, indicating increased difficulty engaging in restful activities. Tinnitus severity was influenced by hyperacusis and depression in both MIs and non-MIs; however, hearing loss uniquely contributed to severity in MIs. CONCLUSIONS: Our findings suggest that while MIs may exhibit better or comparable listening abilities, they were significantly more affected by tinnitus than non-MIs. Furthermore, our study highlights the importance of assessing tinnitus-related distress across multiple dimensions, facilitating customization of management strategies for both MIs and non-MIs.

Review and Perspective on Brain Bases of Tinnitus.

In advancing our understanding of tinnitus, some of the more impactful contributions in the past two decades have come from human brain imaging studies, specifically the idea of both auditory and extra-auditory neural networks that mediate tinnitus. These networks subserve both the perception of tinnitus and the psychological reaction to chronic, continuous tinnitus. In this article, we review particular studies that report on the nodes and links of such neural networks and their inter-network connections. Innovative neuroimaging tools have contributed significantly to the increased understanding of anatomical and functional connections of attention, emotion-processing, and default mode networks in adults with tinnitus. We differentiate between the neural correlates of tinnitus and those of comorbid hearing loss; surprisingly, tinnitus and hearing loss when they co-occur are not necessarily additive in their impact and, in rare cases, additional tinnitus may act to mitigate the consequences of hearing loss alone on the brain. The scale of tinnitus severity also appears to have an impact on brain networks, with some of the alterations typically attributed to tinnitus reaching significance only in the case of bothersome tinnitus. As we learn more about comorbid conditions of tinnitus, such as depression, anxiety, hyperacusis, or even aging, their contributions to the network-level changes observed in tinnitus will need to be parsed out in a manner similar to what is currently being done for hearing loss or severity. Together, such studies advance our understanding of the heterogeneity of tinnitus and will lead to individualized treatment plans.

An Inverse Relationship Between Gray Matter Volume and Speech-in-Noise Performance in Tinnitus Patients with Normal Hearing Sensitivity.

Speech-in-noise (SiN) recognition difficulties are often reported in patients with tinnitus. Although brain structural changes such as reduced gray matter (GM) volume in auditory and cognitive processing regions have been reported in the tinnitus population, it remains unclear how such changes influence speech understanding, such as SiN performance. In this study, pure-tone audiometry and Quick Speech-in-Noise test were conducted on individuals with tinnitus and normal hearing and hearing-matched controls. T1-weighted structural MRI images were obtained from all participants. After preprocessing, GM volumes were compared between tinnitus and control groups using whole-brain and region-of-interest analyses. Further, regression analyses were performed to examine the correlation between regional GM volume and SiN scores in each group. The results showed decreased GM volume in the right inferior frontal gyrus in the tinnitus group relative to the control group. In the tinnitus group, SiN performance showed a negative correlation with GM volume in the left cerebellum (Crus I/II) and the left superior temporal gyrus; no significant correlation between SiN performance and regional GM volume was found in the control group. Even with clinically defined normal hearing and comparable SiN performance relative to controls, tinnitus appears to change the association between SiN recognition and regional GM volume. This change may reflect compensatory mechanisms utilized by individuals with tinnitus who maintain behavioral performance.

Evaluating the Efficacy of a Smartphone App for Tinnitus Relief Using Behavioral and Brain Imaging Measures.

PURPOSE: In this exploratory, open-label study, we used behavioral and brain imaging measures to assess the effectiveness of a smartphone application (ReSound Relief app), which aims to help reduce tinnitus-related distress. METHOD: Fourteen participants with a wide range of tinnitus-related symptoms and who were not currently undergoing any external treatment participated. They completed the 6-month study and reported different levels of engagement with the app. RESULTS: Across a range of tinnitus questionnaires, most participants showed either no change or decrease in tinnitus handicap. Resting-state and task-based functional magnetic resonance imaging (fMRI) data were collected at baseline and the end of the study. Resting-state fMRI of 12 participants revealed alterations in interregional connectivity of default mode, salience, emotion, auditory, and visual processing networks at the end of the intervention period compared to baseline. Ratings of affective sounds (as pleasant, neutral, or unpleasant) were assessed using fMRI, and comparison after 6 months of app usage revealed reduced activity in the left superior temporal gyrus (secondary auditory cortex), right superior occipital gyrus, and left posterior cingulate cortex. Our findings were not significant at a false discovery rate level of p < .05. CONCLUSIONS: The reported changes were not significant, possibly due to the small sample size, heterogeneity of the tinnitus handicap among subjects at the start of the project, and the length of the intervention period. Nevertheless, this study underscores the ease of usage of the app and the potential use of brain imaging to assess changes due to a passive, self-administered intervention for individuals with varying levels of tinnitus severity.

Invariant structural and functional brain regions associated with tinnitus: A meta-analysis.

Tinnitus is a common, functionally disabling condition of often unknown etiology. Neuroimaging research to better understand tinnitus is emerging but remains limited in scope. Voxel-based physiology (VBP) studies detect tinnitus-associated pathophysiology by group-wise contrast (tinnitus vs controls) of resting-state indices of hemodynamics, metabolism, and neurovascular coupling. Voxel-based morphometry (VBM) detects tinnitus-associated neurodegeneration by group-wise contrast of structural MRI. Both VBP and VBM studies routinely report results as atlas-referenced coordinates, suitable for coordinate-based meta-analysis (CBMA). Here, 17 resting-state VBP and 8 VBM reports of tinnitus-associated regional alterations were meta-analyzed using activation likelihood estimation (ALE). Acknowledging the need for data-driven insights, ALEs were performed at two levels of statistical rigor: corrected for multiple comparisons and uncorrected. The corrected ALE applied cluster-level inference thresholding by intensity (z-score > 1.96; p < 0.05) followed by family-wise error correction for multiple comparisons (p < .05, 1000 permutations) and fail-safe correction for missing data. The corrected analysis identified one significant cluster comprising five foci in the posterior cingulate gyrus and precuneus, that is, not within the primary or secondary auditory cortices. The uncorrected ALE identified additional regions within auditory and cognitive processing networks. Taken together, tinnitus is likely a dysfunction of regions spanning multiple canonical networks that may serve to increase individuals' interoceptive awareness of the tinnitus sound, decrease capacity to switch cognitive sets, and prevent behavioral and cognitive attention to other stimuli. It is noteworthy that the most robust tinnitus-related abnormalities are not in the auditory system, contradicting collective findings of task-activation literature in tinnitus.

Evaluating the efficacy of hearing aids for tinnitus therapy - A Positron emission tomography study.

Brain imaging studies have revealed neural changes in chronic tinnitus patients that are not restricted to auditory brain areas; rather, the engagement of limbic system structures, attention and memory networks are has been noted. Hearing aids (HA) provide compensation for comorbid hearing loss and may decrease tinnitus-related perception and annoyance. Using resting state positron emission tomography our goal was to analyze metabolic and functional brain changes after six months of effective HA use by patients with chronic tinnitus and associated sensorineural hearing loss. 33 age and hearing loss matched participants with mild/moderate hearing loss were enrolled in this study: 19 with tinnitus, and 14 without tinnitus. Participants with tinnitus of more than 6 months with moderate/severe Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) scores composed the tinnitus group. A full factorial 2X2 ANOVA was conducted for imaging analysis, with group (tinnitus and controls) and time point (pre-intervention and post-intervention) as factors. Six months after HA fitting, tinnitus scores reduced statistically and clinically. Analysis revealed increased glycolytic metabolism in the left orbitofrontal cortex, right temporal lobe and right hippocampus, and reduced glycolytic metabolism in the left cerebellum and inferior parietal lobe within the tinnitus group. The hearing loss control group showed no significant metabolic changes in the analysis. Parsing out the contribution of tinnitus independent of hearing loss, allowed us to identify areas implicated in declines in tinnitus handicap as a result of the intervention. Brain regions implicated in the present study may be part of chronic tinnitus-specific network.

Treatment of Posttraumatic Stress Disorder Alleviates Tinnitus-Related Distress Among Veterans: A Pilot Study.

PURPOSE: Military service personnel are at increased risk for developing tinnitus due to heightened exposure to acoustic trauma. The auditory disorder is the leading service-connected disability among veterans and is highly comorbidly diagnosed with posttraumatic stress disorder (PTSD). The biopsychosocial model illustrates that chronic health conditions are exacerbated or maintained by psychiatric distress. Therefore, alleviation of such psychiatric distress can have beneficial impacts on health conditions, such as tinnitus. The aim of this study was to determine whether individuals with both disorders who receive evidence-based therapy for PTSD will experience decreases in both PTSD and tinnitus-related distress. METHOD: Veterans with comorbid bothersome tinnitus and PTSD received cognitive processing therapy and were assessed for PTSD, tinnitus-related distress, and depression at baseline and 1 month posttreatment follow-up. RESULTS: At posttreatment follow-up, participants demonstrated significant decreases in PTSD symptoms compared to their baseline scores. Participants also demonstrated decreased tinnitus-related distress and depression, with high effect sizes. CONCLUSIONS: This pilot study demonstrated that clinical management addressing psychiatric distress, as associated with PTSD, may simultaneously provide benefit for patients with bothersome tinnitus. Although not statistically significant due to the small sample size, large effect sizes indicate that tinnitus-related distress decreased as a function of receiving evidence-based therapy for PTSD. Future clinical trials should increase sample sizes and compare effects to control conditions.

Salience, emotion, and attention: The neural networks underlying tinnitus distress revealed using music and rest.

In the present study, we used an innovative music-rest interleaved fMRI paradigm to investigate the neural correlates of tinnitus distress. Tinnitus is a poorly-understood hearing disorder where individuals perceive sounds, in the absence of an external source. Although the great majority of individuals habituate to chronic tinnitus and report few symptoms, a minority report debilitating distress and annoyance. Prior research suggests that a diverse set of brain regions, including the attention, the salience, and the limbic networks, play key roles in mediating both the perception of tinnitus and its impact on the individual; however, evidence of the degree and extent of their involvement has been inconsistent. Here, we minimally modified the conventional resting state fMRI by interleaving it with segments of jazz music. We found that the functional connectivity between a set of brain regions-including cerebellum, precuneus, superior/middle frontal gyrus, and primary visual cortex-and seeds in the dorsal attention network, the salience network, and the amygdala, were effective in fractionating the tinnitus patients into two subgroups, characterized by the severity of tinnitus-related distress. Further, our findings revealed cross-modal modulation of the attention and salience networks by the visual modality during the music segments. On average, the more bothersome the reported tinnitus, the stronger was the exhibited inter-network functional connectivity. This study substantiates the essential role of the attention, salience, and limbic networks in tinnitus habituation, and suggests modulation of the attention and salience networks across the auditory and visual modalities as a possible compensatory mechanism for bothersome tinnitus.

Cognitive Flexibility and Inhibition in Individuals with Age-Related Hearing Loss.

Growing evidence suggests alterations in cognitive control processes in individuals with varying degrees of age-related hearing loss (ARHL); however, alterations in those with unaided mild ARHL are understudied. The current study examined two cognitive control processes, cognitive flexibility, and inhibition, in 21 older adults with unaided mild ARHL and 18 age- and education-matched normal hearing (NH) controls. All participants underwent comprehensive audiological and cognitive evaluations including Trail Making Test-B, Verbal Fluency, Stroop, and two Go/NoGo tasks. Group differences in cognitive flexibility and inhibition as well as associations between peripheral and central hearing ability and measures of cognitive flexibility and inhibition were investigated. Findings revealed that the ARHL group took significantly longer to complete the Stroop task and had higher error rates on NoGo trials on both Go/NoGo tasks relative to the NH controls. Additionally, poorer peripheral and central hearing were associated with poorer cognitive flexibility and inhibitory control. Our findings suggest slower and more inefficient inhibitory control in the mild ARHL group relative to the NH group and add to decades of research on the association between hearing and cognition.

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

Subjective, 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.

Decreased resting perfusion in precuneus and posterior cingulate cortex predicts tinnitus severity.

Functional magnetic resonance imaging has been increasingly used to understand the mechanisms involved in subjective tinnitus; however, researchers have struggled to reach a consensus about a primary mechanistic model to explain tinnitus. While many studies have used functional connectivity of the BOLD signal to understand how patterns of activity change with tinnitus severity, there is much less research on whether there are differences in more fundamental physiology, including cerebral blood flow, which may help inform the BOLD measures. Here, arterial spin labeling was used to measure perfusion in four regions-of-interest, guided by current models of tinnitus, in a sample of 60 tinnitus patients and 31 control subjects. We found global reductions in cerebral perfusion in tinnitus compared with controls. Additionally, we observed a significant negative correlation between tinnitus severity and perfusion. These results demonstrate that examining perfusion from the whole brain may present a complementary tool for studying tinnitus. More research will help better understand the physiology underlying these differences in perfusion.

Imaging systems level consolidation of novel associate memories: a longitudinal neuroimaging study.

Previously, a standard theory of systems level memory consolidation was developed to describe how memory recall becomes independent of the medial temporal memory system. More recently, an extended consolidation theory was proposed that predicts seven changes in regional neural activity and inter-regional functional connectivity. Using longitudinal event-related functional magnetic resonance imaging of an associate memory task, we simultaneously tested all predictions and additionally tested for consolidation-related changes in recall of associate memories at a sub-trial temporal resolution, analyzing cue, delay and target periods of each trial separately. Results consistent with the theoretical predictions were observed though two inconsistent results were also obtained. In particular, while medial temporal recall related delay period activity decreased with consolidation as predicted, visual cue activity increased for consolidated memories. Though the extended theory of memory consolidation is largely supported by our study, these results suggest that the extended theory needs further refinement and the medial temporal memory system has multiple, temporally distinct roles in associate memory recall. Neuroimaging analysis at a sub-trial temporal resolution, as used here, may further clarify the role of the hippocampal complex in memory consolidation.