On the impairment of executive control of attention in chronic tinnitus: Evidence from the attention network test

Parallel EEG assessment of different sound predictability levels in tinnitus

Tinnitus denotes the perception of a non-environmental sound and might result from aberrant auditory prediction. Successful prediction of formal (e.g., type) and temporal sound characteristics facilitates the filtering of irrelevant information, also labelled as 'sensory gating' (SG). Here, we explored if and how parallel manipulations of formal prediction violations and temporal predictability affect SG in persons with and without tinnitus. Age-, education- and sex-matched persons with and without tinnitus (N = 52) participated and listened to paired-tone oddball sequences, varying in formal (standard vs. deviant pitch) and temporal predictability (isochronous vs. random timing). EEG was recorded from 128 channels and data were analyzed by means of temporal spatial principal component analysis (tsPCA). SG was assessed by amplitude suppression for the 2nd tone in a pair and was observed in P50-like activity in both timing conditions and groups. Correspondingly, deviants elicited overall larger amplitudes than standards. However, only persons without tinnitus displayed a larger N100-like deviance response in the isochronous compared to the random timing condition. This result might imply that persons with tinnitus do not benefit similarly as persons without tinnitus from temporal predictability in deviance processing. Thus, persons with tinnitus might display less temporal sensitivity in auditory processing than persons without tinnitus.

Deficient central mechanisms in tinnitus: Exploring the impact on speech comprehension and executive functions

Many individuals with chronic subjective tinnitus report significant problems in comprehending speech in adverse listening situations. A large body of studies has provided evidence to support the notion that deficits in speech-in-noise (SIN) are prevalent in the tinnitus population, while some studies have challenged these findings. Elemental auditory perception is usually only minimally or not impaired. In addition, deficits in cognitive functions, particularly executive functions, have also been observed in individuals with tinnitus. Given these previous findings, we theorize that deficient central mechanisms may be responsible for the reported speech comprehension problems in tinnitus. 25 participants suffering from chronic subjective tinnitus and 25 control participants, between 23 and 58 years of age, were examined in a cross-sectional design. The groups were case-matched for age, sex, education, and hearing loss. A large audiometric battery was used ranging from threshold and supra-threshold tasks to spoken sentence level speech tasks. Additionally, four cognitive tests were performed, primarily covering the area of executive functions. Tinnitometry and tinnitus-related questionnaires were applied to complement sample description and allow for secondary analyses. We hypothesized that tinnitus participants score lower in complex speech comprehension tasks and executive function tasks compared to healthy controls, while no group differences in elementary audiometric tasks were expected. As expected, individuals with chronic subjective tinnitus scored lower in the SIN and gated speech task, while there were no differences in the basic speech recognition threshold task and the other elementary auditory perception tasks. The cognitive tests revealed clear deficits in interference control in the Stroop task, but not in the Flanker task, in the tinnitus group. There were no differences in inhibition or working memory tasks. Our results clearly delineate differences between tinnitus individuals and control participants in two tests on speech intelligibility under adverse listening conditions. Further, the poorer performance in a task of interference control in individuals with tinnitus points towards an impaired central executive control in individuals with tinnitus. Taken together, our (partly) exploratory study provides novel evidence to the view that deficient central executive system in individuals with tinnitus probably account for impaired speech comprehension.

The Short and Long-Term Effect of Sound Therapy on Visual Attention in Chronic Tinnitus Patients

Sound therapy is one of the most common tinnitus treatments that can be used either to mask or to shift attention away from the tinnitus percept. However, the actual benefit of sound therapy and the mechanisms leading to the benefits remain limited. The objective of this study was to investigate the short-term (15 min) and long-term (2 months) effects of sound therapy on visual attention in chronic tinnitus patients. Visual attention was evaluated with the behavioral Attention Network Task, while the tinnitus-related distress was evaluated with the Tinnitus Handicap Inventory (THI) to quantify the effect of sound therapy. The study included 20 participants with chronic and bothersome tinnitus (>6 months, THI > 18) and 20 matched control participants. All participants took part in a first session consisting of a baseline condition, a short-term sound therapy condition and a silent control condition. The tinnitus participants also took part in a second session that evaluated the long-term effect of the therapy. A reduction in the tinnitus-related distress was found after the long-term use of sound therapy. Furthermore, a reduction in the differential index of the executive control (EC) attention network, indicating improved attention, was found after long-term use of sound therapy in the sound condition but not in the silent control condition. In contrast to earlier research, no differences were found between the tinnitus group and the control group for the baseline measurement of the EC attention network. Overall, the results suggest that there is no link between the visual attention networks and the sound therapy’s effect on tinnitus-related distress.

Hearing Aids Mitigate Tinnitus, But Does It Matter if the Patient Receives Amplification in Accordance With Their Hearing Impairment or Not? A Meta-Analysis

PURPOSE

The purpose of the present meta-analysis is to explore the potential effects of objective verification of hearing aid amplification on tinnitus-related outcomes.

METHOD

Twenty-seven studies reporting tinnitus outcomes pre and post hearing aid fitting were identified through a systematic literature search. From these studies, data from 1,400 participants were included in the present meta-analysis. Studies were divided into subgroups based on whether they had reported performing objective verification of the participants' hearing aid amplification or not. Outcome measures were tinnitus distress and tinnitus loudness.

RESULTS

Meta-analyses of all included studies indicated verified amplification to result in significantly enhanced reduction of tinnitus loudness (p < .00001), while the enhanced reduction of tinnitus distress only approached statistical significance (p = .07). However, when excluding an outlier from the subgroup of studies using unverified amplification, individuals receiving verified amplification showed significantly greater reduction of tinnitus distress (p = .02). In addition, analyses of longitudinal effects revealed that the reductions of tinnitus distress decreased over time among individuals receiving unverified amplification but increased over time among individuals receiving verified amplification.

CONCLUSIONS

The present meta-analysis indicates verified hearing aid amplification to be superior to unverified amplification in terms of reduction of tinnitus loudness and distress. The longitudinal increase of mitigation of tinnitus distress with verified amplification only may reflect improved neural reorganization and/or better adherence to hearing aid use, with verified compared to unverified amplification. Due to the low cost of hearing aid verification compared to the high societal cost of tinnitus, objective verification of hearing aid amplification for tinnitus patients is recommended.

Tinnitus Affects Endogenous But Not Exogenous Auditory Attention Orienting

Purpose:

Previous studies have demonstrated that people with tinnitus show attention dysfunctions. In this study, we investigated the influence of tinnitus on attention orienting, especially whether the ability of attention orienting could be modulated by the degree of tinnitus.

Method:

Fifty-nine and 54 unilateral tinnitus participants were included in Experiment 1 and Experiment 2, respectively. All participants reported subjective tinnitus for at least 3 months and were divided into a mild tinnitus group (Tinnitus Handicap Inventory [THI] < 37) or a moderate to severe tinnitus group (THI ≥ 37) according to the THI score. An auditory exogenous attention task and an auditory endogenous attention task were adopted. In the exogenous task, a target sound following a cue sound was presented on either the left or right side. Participants were required to discriminate whether the target was pure tone or white noise. In the endogenous task, participants were required to pay attention to the stimuli on one side and judge the pitch of a target sound. Mixed-design analyses of variance were conducted for the mean reaction times and accuracy across the experimental conditions.

Results:

Our results showed that in the endogenous attention task, compared with the mild tinnitus group, moderate to severe tinnitus participants had better performance for stimuli presented on the tinnitus side but not on the nontinnitus side. In contrast, in the exogenous attention task, no differences were found between mild and moderate to severe tinnitus groups.

Conclusion:

The results suggest that the degree of tinnitus influences the performance of auditory endogenous attention but not auditory exogenous attention orienting.

Extended High Frequency Hearing, but Not Tinnitus, Is Associated With Every-Day Cognitive Performance

Research into the potential associations between tinnitus and cognition has investigated specific cognitive domains in laboratory settings despite adults with tinnitus reporting broad cognitive difficulties in every-day life. To address this limitation, the present study compared performance and perceived exertion on a visual office-like task in 38 adults with tinnitus (19 with normal hearing and 19 with hearing loss) and 38 adults without tinnitus (19 with normal hearing and 19 with hearing loss) matched for age, sex and educational background. All participants were also assessed for hearing, anxiety and depression, and participants with tinnitus were also assessed for tinnitus handicap. No associations were found between presence of tinnitus and cognitive performance (mean total rate correct score on the visual office-like task being 2.9 for the tinnitus group, 2.8 for the control group, p = 0.612) and perceived exertion (mean ratings of perceived exertion on the Borg CR10-scale being 5.8 for the tinnitus group, 6.5 for the control group, p = 0.063) on the visual office-like task when corrected for standard (0.125 to 8 kHz) and extended high frequency (10 to 16 kHz) hearing thresholds, anxiety, and depression. The correction for extended high frequency average (10, 12.5, 14, and 16 kHz) hearing threshold was significant for performance (p = 0.009) but not perceived exertion on the visual office-like task. Overall, the results showed extended high frequency hearing, but not tinnitus, was associated with every-day cognitive performance. This indicates clinical testing of hearing thresholds above 8 kHz could support clinicians’ identification and management of cognitive difficulties. One management method suggested by the current findings would include provision of auditory stimulation at frequencies exceeding the frequency response of many current hearing aids.

Relationships Among Temporal Fine Structure Sensitivity, Transient Storage Capacity, and Ultra-High Frequency Hearing Thresholds in Tinnitus Patients and Normal Adults of Different Ages

Background

Elderlies and tinnitus patients often find it challenging to process acoustic signals in noisy environments. The sensitivity to temporal fine structure (TFS), the transient storage capacity for TFS, and the ultra-high frequency (UHF) thresholds are all associated with aging-related damage, evidenced by speech-in-noise perception deficits. In the present study, we aimed to investigate the relationships among TFS sensitivity, transient storage capacity, and UHF thresholds in tinnitus patients and normal adults of different ages.

Methods

In the present study, 38 tinnitus patients (age ranging from 21 to 65) and 23 non-tinnitus adults (age ranging from 22 to 56) were enrolled, and some of their auditory indicators were examined, including the TFS-adaptive frequency (TFS-AF), break in interaural correlation (BIAC) delay threshold, and UHF thresholds.

Results

We found no significant difference in TFS-AF thresholds and BIAC delay thresholds between the tinnitus group and normal group, while their relationships with age were more evident in the tinnitus group. Moreover, these two tests were only significantly correlated in the tinnitus group. UHF thresholds were significantly correlated with TFS-AF thresholds only in the tinnitus group, suggesting that the UHF hearing was positively associated with the TFS sensitivity.

Conclusion

These findings indicated that the influencing factors, such as tinnitus and UHF thresholds, should be fully considered when examining age-related hearing decline, because the combination of tinnitus and poor UHF hearing might play a role in affecting hearing ability, such as TFS sensitivity.